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Project Dual
- Thread starter Blackfoot Tucker
- Start date
Day Six: (The home air compressor is once again working properly. The replacement magnetic starter was different, and Scott told me how to connect all the wires properly.)
Due to the significant space limitations on the left side of the engine, the manifold required a number of modifications to achieve an acceptable result. We still aren’t done, but we’re pretty far along in the process. We needed to move the outlet flange forward quite a bit, and getting the rear cylinder’s exhaust gasses to flow in the desired direction required a bunch of work.
We had planned to move some things before working on the manifold, but decided to postpone the relocating and make some more headway on the manifold. (I'm not looking forward to the relocating phase.)
Earlier, we had added a wedge piece to align the rear cylinder’s runner with the rest of the manifold. Well, moving the outlet flange so far forward was going to have the rear cylinder’s gasses flowing in the wrong direction to join with the exhaust flow from the other three cylinders. To avoid that situation, we decided to cut off a big chunk of the rear cylinder’s runner and splice in a section from another manifold. But of course the respective parts did not align very well. So, Scott would clamp the various parts to the shop’s welding table, heat the part needing some persuasion red hot, and then put a large adjustable wrench on the part needing some encouragement. Generally the parts cooperated, though sometimes they needed a second heating and bending. By doing this he was able to get the individual pieces in reasonably good alignment before welding them. Here are a couple pics.
This is the outlet flange piece and the red section needed to be bent outward to make it wider. This is on the side of the manifold that faces the engine. (It had cooled a bit before I got my camera out and took the photo.)
Here, Scott is making more adjustments to the outlet flange after tack welding it to the manifold. He’s about to bend the red hot section down for better alignment with the manifold.
In true Gorilla fashion the parts fit together pretty well and the not-complete-but-pretty-far-along manifold is looking remarkably good.
After welding everything in the jig we let it cool and then bolted the manifold to the engine to check our progress. The current plan is to cut the outlet flange itself off, then shorten the runner where it attaches, and re-weld it in the shortened location. But we’ll also change the angle the flange is welded to the manifold to more optimally aim the exhaust outlet toward where it needs to go.
After it was initially welded, I wanted him to add some additional weld in places so I could make the parts blend more smoothly as part of my planned cosmetic enhancement. You should have heard the howls from the self-proclaimed “precision surgeon”. “It’s fine” as it is", “You can’t see it anyway”, you get the idea…. Now he is calling it his "Frankenstein manifold".
Here are some pics. You can see the runner to the outlet flange can be shortened substantially, and the angle of the flange itself can be repositioned as well. Yes, we need to add another threaded boss to attach the heat shield.
Due to the significant space limitations on the left side of the engine, the manifold required a number of modifications to achieve an acceptable result. We still aren’t done, but we’re pretty far along in the process. We needed to move the outlet flange forward quite a bit, and getting the rear cylinder’s exhaust gasses to flow in the desired direction required a bunch of work.
We had planned to move some things before working on the manifold, but decided to postpone the relocating and make some more headway on the manifold. (I'm not looking forward to the relocating phase.)
Earlier, we had added a wedge piece to align the rear cylinder’s runner with the rest of the manifold. Well, moving the outlet flange so far forward was going to have the rear cylinder’s gasses flowing in the wrong direction to join with the exhaust flow from the other three cylinders. To avoid that situation, we decided to cut off a big chunk of the rear cylinder’s runner and splice in a section from another manifold. But of course the respective parts did not align very well. So, Scott would clamp the various parts to the shop’s welding table, heat the part needing some persuasion red hot, and then put a large adjustable wrench on the part needing some encouragement. Generally the parts cooperated, though sometimes they needed a second heating and bending. By doing this he was able to get the individual pieces in reasonably good alignment before welding them. Here are a couple pics.
This is the outlet flange piece and the red section needed to be bent outward to make it wider. This is on the side of the manifold that faces the engine. (It had cooled a bit before I got my camera out and took the photo.)
Here, Scott is making more adjustments to the outlet flange after tack welding it to the manifold. He’s about to bend the red hot section down for better alignment with the manifold.
In true Gorilla fashion the parts fit together pretty well and the not-complete-but-pretty-far-along manifold is looking remarkably good.
After welding everything in the jig we let it cool and then bolted the manifold to the engine to check our progress. The current plan is to cut the outlet flange itself off, then shorten the runner where it attaches, and re-weld it in the shortened location. But we’ll also change the angle the flange is welded to the manifold to more optimally aim the exhaust outlet toward where it needs to go.
After it was initially welded, I wanted him to add some additional weld in places so I could make the parts blend more smoothly as part of my planned cosmetic enhancement. You should have heard the howls from the self-proclaimed “precision surgeon”. “It’s fine” as it is", “You can’t see it anyway”, you get the idea…. Now he is calling it his "Frankenstein manifold".
Here are some pics. You can see the runner to the outlet flange can be shortened substantially, and the angle of the flange itself can be repositioned as well. Yes, we need to add another threaded boss to attach the heat shield.
BFT i am kinda with scott on this it is starting to look pretty good to me , take it out and run it Steve said just put some black header paint on it and run it , at 7 MPH and the hood closed on one will see your remarkable job any way , I am sure it will be as good as it can be before you take it out
Travler,
My posts almost always lag where we actually are in terms of progress on a project. Typically, I’ll write the post in draft form and share it with Scott before posting. If he takes major exception to something, I’ll usually revise it (I pretty much expect some objection - it’s just his style). But that means there’s a delay between action and the forum post.
I’ll spill the beans and admit at this point the manifolds are essentially ready to be installed. The previous manifolds were installed with ARP 12-point stainless steel flange bolts. Those manifolds didn’t have heat shields, these do. GM used a stud and one nut to secure the exhaust manifold to the cylinder head, then the heat shield, and a second nut. I’ve ordered ARP stainless steel studs and 12-point nuts to attach the heat shields, and some short ARP 12-point stainless steel flange bolts to attach the heat shields to the manifolds. I‘ve found Allen's Fasteners in Needles, CA has an excellent selection, and while I hate to use the term “reasonable prices” on anything that comes from ARP, it's fair to say their prices are better than most.
We still need to re-route/re-plumb the transmission cooler lines, the engine oil cooler lines, the brake line and the hydraulic lines from the orbitrol to the steering cylinder. Thundercat is a 1980 model, and your 1544 is a 1986. During the interim period Tucker made a number of changes to the machines, one of them was relocating the orbitrol inside the cab. That would provide a lot more room for an exhaust system, but alas, we have the older setup with a steering column that goes through the floor to the orbitrol below. We’ve started the re-routing/re-plumbing process, and it’s slow and tedious. The brake line is just about finished and in theory the engine oil cooler flex lines have been done. I say “in theory”, because I’m not proud of how they look, and I think there’s some room for improvement. We’ve started on the orbitrol, but barely.
We’ll wait until the re-routing/re-plumbing phase is complete before installing the manifolds. Then it will be off to the exhaust shop….
Thanks Travler.
I looked at their website and they have a great selection. I like AN washers, and Scott hates them with a passion, or at least he pretends to. Specialty carries AN washer kits with an assortment of different sizes. That gives me an idea for a Christmas gift for The Gorilla!
As The Infamous WBJ1 would say, “MUAHAHAHA”.
Day Seven involved modifying the outlet flange and runner to get them into a more optimal configuration.
We had a section of 3” exhaust tubing with some bends in it laying around, and one bend was close to what we were going to need. We cut that from the rest of the tubing so we could use it for mock-up purposes. Then we bolted the manifold to the cylinder head and used the bent tube to visualize what changes we needed to make to the manifold.
Back to the shop and Scott cut the manifold runner, removing about 1 1/4” in front and 1" in back. This would both shorten the runner and change the angle of the outlet flange. Then he tack welded it in position and we took the modified manifold back to check our progress. We had removed the expanded metal side shields for better access, but in our fitting and mock-up attempts we wanted to ensure there was adequate clearance between the side shields and the exhaust tubing when the exhaust system is installed.
Here’s a pic of the runner section Scott removed.
We thought shortening the runner further would be beneficial, and it would also help to adjust the angle of the outlet flange some more. In addition, we wanted to slightly rotate the outlet flange to reposition the studs more optimally for the exhaust tubing to fit, as well as where the studs were in relation to the orbitrol.
Back to the shop for more refinement. Scott then fully welded the outlet flange in it’s new position on the shortened runner.
We also modified the heat shield which required a lot of cutting, and some bending, to account for all the changes we had made to the manifold itself. Finally, Scott welded on a threaded boss salvaged from a scrap piece of manifold for heat shield attachment purposes.
I took the manifolds home for their cosmetic enhancement to try and make all these modifications look better… so we can cover most of them up when we install the heat shields. Here are some pics of the manifolds. Right side.
Left side.
A "before" photo of both manifolds.
And an after.
In my last post I mentioned Scott had started referring to the manifold as his Frankenstein manifold (it’s comprised of six pieces from four different manifolds). My recollection is Frankenstein was not the monster, but rather the name of the doctor who created the monster. That would make Scott “Dr. Frankenstein”. However, in deference to the Mel Brooks movie "Young Frankenstein", I’ll change the spelling to the phonetically correct pronunciation “Fronkensteen”. Scott was of course quick to point out that would make me Igor (pronounced Eye-Gore in the movie).
Honestly, these manifolds exceeded my expectations as far as the way they fit and should allow a true dual exhaust system to be fitted to Thundercat. Of course they’re not perfect, but they’re a more than acceptable work product from a couple of knuckleheads.
But now the less fun aspects of rerouting the various lines begins….
We had a section of 3” exhaust tubing with some bends in it laying around, and one bend was close to what we were going to need. We cut that from the rest of the tubing so we could use it for mock-up purposes. Then we bolted the manifold to the cylinder head and used the bent tube to visualize what changes we needed to make to the manifold.
Back to the shop and Scott cut the manifold runner, removing about 1 1/4” in front and 1" in back. This would both shorten the runner and change the angle of the outlet flange. Then he tack welded it in position and we took the modified manifold back to check our progress. We had removed the expanded metal side shields for better access, but in our fitting and mock-up attempts we wanted to ensure there was adequate clearance between the side shields and the exhaust tubing when the exhaust system is installed.
Here’s a pic of the runner section Scott removed.
We thought shortening the runner further would be beneficial, and it would also help to adjust the angle of the outlet flange some more. In addition, we wanted to slightly rotate the outlet flange to reposition the studs more optimally for the exhaust tubing to fit, as well as where the studs were in relation to the orbitrol.
Back to the shop for more refinement. Scott then fully welded the outlet flange in it’s new position on the shortened runner.
We also modified the heat shield which required a lot of cutting, and some bending, to account for all the changes we had made to the manifold itself. Finally, Scott welded on a threaded boss salvaged from a scrap piece of manifold for heat shield attachment purposes.
I took the manifolds home for their cosmetic enhancement to try and make all these modifications look better… so we can cover most of them up when we install the heat shields. Here are some pics of the manifolds. Right side.
Left side.
A "before" photo of both manifolds.
And an after.
In my last post I mentioned Scott had started referring to the manifold as his Frankenstein manifold (it’s comprised of six pieces from four different manifolds). My recollection is Frankenstein was not the monster, but rather the name of the doctor who created the monster. That would make Scott “Dr. Frankenstein”. However, in deference to the Mel Brooks movie "Young Frankenstein", I’ll change the spelling to the phonetically correct pronunciation “Fronkensteen”. Scott was of course quick to point out that would make me Igor (pronounced Eye-Gore in the movie).
Honestly, these manifolds exceeded my expectations as far as the way they fit and should allow a true dual exhaust system to be fitted to Thundercat. Of course they’re not perfect, but they’re a more than acceptable work product from a couple of knuckleheads.
But now the less fun aspects of rerouting the various lines begins….
The Gorilla and hammers. Hmmm, that’s a bad combination. If a little force doesn’t work - hit it harder. If that doesn't work - get a bigger hammer. You get the idea….
And it’s easy to damage the surface, so you use a wood block... or something. The concept of using soft face or dead blow hammers rarely occurs to The Gorilla. I think it was in 2022, Trusty-Cook, a US dead blow hammer manufacturer, had a sale at Christmas and their blems were ridiculously reasonable and shipping was a bargain, too. I bought The Gorilla their biggest dead blow sledge hammer. Twelve pounds worth. I was hoping that would have a positive impact on his methods of persuasion.
Almost 18 months later... I’m not sure it’s been used.
These days my preferred SLC bolt supplier is Fastener Engineering. I get great customer service from James and their selection and pricing are pretty darn good. “The guy behind the counter” is crucially important, and many companies don’t seem to grasp that concept. To management, it’s "all about the cheap”, yet customers build relationships with the guy they work with, and that relationship breeds loyalty. Maybe they don’t understand my loyalty is to James, not the company.
Stainless steel fastener selection tends to be more limited, and that where Allen’s Fasteners comes in. I don’t know of any company in SLC that stocks stainless steel AN washers. Allen’s Fasteners has them in both various sizes, and thicknesses, and they’re inexpensive. That's a win all the way around.
Finally… an update:
Well, things came to a grinding halt for a bit. Scott went to Lake Powell on a fishing trip (and picked up the name “Catfish Slayer”). We’ve also tackled some automotive repair and maintenance projects.
The orbitrol in Thundercat has been making non-normal noises, such as chattering and/or groaning. We were pretty much clueless as to the problem so I reached out to Midwest Steering for their thoughts. They were somewhat stumped as well, but suggested I send it to them and they would put it on their test bench. With the hydraulic system completely drained of fluid, there is no better time, so I boxed it up and shipped it via USPS “Priority Mail”. If you’re thinking “Uh Oh, bad call BFT”, you’d be right.
Mailed on 5//29, it was supposed to be delivered on 6/2. Well, it didn’t even leave SLC until 6/5, and then no updates other than “It’s in transit and will arrive late”. It eventually got there on 6/12; ten days late. But... at least they didn’t lose it.
We completed the re-plumbing of the engine and transmission cooler lines. Here’s a pic of the engine cooler lines. (The vertical braided stainless steel lines are fuel supply and return lines. You can see the orbitrol has been removed from the steering column mount.)
We also decided on a minor electrical system upgrade. When we originally assembled Thundercat we used a 150 AMP fuse. That's great, but if it blows and you don’t have/can’t find a spare, you’re stuck. On both CHUGSzilla and the 1544 projects, we used 150 AMP re-settable circuit breakers, and decided to replace the fuse setup with one of those.
Then things started downhill… and picked up steam.
The thickness of the exhaust manifold flange on the stock 8.1 exhaust manifolds was thinner than the flange thickness on the manifolds we had been using, so those expensive ARP bolts were too long. My machinist friend in Vermont swears by ARP fasteners, and though I was not very impressed with them the first time around, I ordered another set of shorter ARP 12-point stainless steel bolts. Planning for future removal, I bought a lifetime supply of high temperature never seize, specifically made for stainless steel. We liberally applied this to the new bolts and started to install the manifolds. Then… "Oh… fudge” (that wasn’t the real word). Scott had installed, I think six bolts on the left side not fully torqued, but more than finger tight. When he went back to finish tightening the bolts, four of them got stuck. In a stainless steel on stainless steel situation, galling is a problem and using some lubricant helps prevent that. Well, this was stainless steel on cast iron, AND we had applied the never seize, so we were dumbfounded why. But, we had a problem because they would move a little, but that was it. More “Oh, “fudge”.
Using some WD-40 and working the bolt back and forth multiple times, Scott got one bolt out. But the other three? Ah, no. “Oh, fudge” went from bad to worse. Broken bolts are bad enough, broken stainless steel bolts magnifies the ass pain. We discussed removing the cylinder head and taking it to a machine shop, but that’s a lot of disassembly, and we didn’t want to do that, unless we had to. The other three bolts? We broke every one. Great. Just great.
I have previously mentioned buying tools Track Addict has recommended, and one of those was an Owatonna Tool Company jig for drilling out broken bolts. I had also bought some cobalt drill bits, which work better on stainless steel than standard High Speed Steel bits. We thought let’s give this a try before we remove the cylinder head. I had also told Scott, “If we have to remove the cylinder head, let’s change the cam”. Not wanting to go down that rabbit hole, he had extra incentive to make the broken bolt removal successful.
When drilling stainless steel the preferred technique is to use lower RPMs, cutting oil and lots of pressure. If you use higher RPMs and not much pressure you’ll work harden the surface, and now you have an even bigger problem. I started the drilling process using a 1/8” diameter drill bit in the drill jig’s alignment collar, and both Scott and I were really impressed how well that worked. It wasn’t like cutting butter, but it worked. Neither of us like the completely miss-named EZ Outs. In our opinion, they're a recipe for disaster.) So we upsized the drill bit three times and Scott used a special punch he has to carefully pick away at the bolt remnants. The process also requires using a tap, and a lot of patience is required, too. It took about 90 minutes per bolt, but we got them out.
Pics. Here’s Scott drilling out the first bolt. I have an old school Milwaukee 3/8” right angle drill, also called a Duck Bill drill. That was very helpful because of limited space for a typical drill.
A close up showing the jig. If you look to the right, you can see the other two broken bolts.
I’m not sure what we’ll use for fasteners at this point. The cheapest option would be to buy more ARP to replace the broken ones. But their track record on this project is less-then-optimal. GM used carbon steel studs, but way back when, researching the Internet showed those were somewhat problematic, and the conventional wisdom was to use ARP. I thought removing the factory studs and going with ARP was the smart thing to do, and would avoid problems down the road. Ha! But now, after doing more research on the OEM GM studs, they are grade 10.9, which is slighter better than grade 8 on US bolts. How much time and money did I waste on ARP? Too much.
The Infamous WBJ1 and I exchange texts from time to time, and we sometimes chat via phone. He asked me to “Say Hi to the Sweet Gorilla”. Yes, a totally absurd name. So, later that day I shared the text string with Scott, and he announced he is more properly called (I’m not making this up) “The Sweet, Knowledgeable and Kind Gorilla”. OMG. Unbelievable….
Well, things came to a grinding halt for a bit. Scott went to Lake Powell on a fishing trip (and picked up the name “Catfish Slayer”). We’ve also tackled some automotive repair and maintenance projects.
The orbitrol in Thundercat has been making non-normal noises, such as chattering and/or groaning. We were pretty much clueless as to the problem so I reached out to Midwest Steering for their thoughts. They were somewhat stumped as well, but suggested I send it to them and they would put it on their test bench. With the hydraulic system completely drained of fluid, there is no better time, so I boxed it up and shipped it via USPS “Priority Mail”. If you’re thinking “Uh Oh, bad call BFT”, you’d be right.
Mailed on 5//29, it was supposed to be delivered on 6/2. Well, it didn’t even leave SLC until 6/5, and then no updates other than “It’s in transit and will arrive late”. It eventually got there on 6/12; ten days late. But... at least they didn’t lose it.
We completed the re-plumbing of the engine and transmission cooler lines. Here’s a pic of the engine cooler lines. (The vertical braided stainless steel lines are fuel supply and return lines. You can see the orbitrol has been removed from the steering column mount.)
We also decided on a minor electrical system upgrade. When we originally assembled Thundercat we used a 150 AMP fuse. That's great, but if it blows and you don’t have/can’t find a spare, you’re stuck. On both CHUGSzilla and the 1544 projects, we used 150 AMP re-settable circuit breakers, and decided to replace the fuse setup with one of those.
Then things started downhill… and picked up steam.
The thickness of the exhaust manifold flange on the stock 8.1 exhaust manifolds was thinner than the flange thickness on the manifolds we had been using, so those expensive ARP bolts were too long. My machinist friend in Vermont swears by ARP fasteners, and though I was not very impressed with them the first time around, I ordered another set of shorter ARP 12-point stainless steel bolts. Planning for future removal, I bought a lifetime supply of high temperature never seize, specifically made for stainless steel. We liberally applied this to the new bolts and started to install the manifolds. Then… "Oh… fudge” (that wasn’t the real word). Scott had installed, I think six bolts on the left side not fully torqued, but more than finger tight. When he went back to finish tightening the bolts, four of them got stuck. In a stainless steel on stainless steel situation, galling is a problem and using some lubricant helps prevent that. Well, this was stainless steel on cast iron, AND we had applied the never seize, so we were dumbfounded why. But, we had a problem because they would move a little, but that was it. More “Oh, “fudge”.
Using some WD-40 and working the bolt back and forth multiple times, Scott got one bolt out. But the other three? Ah, no. “Oh, fudge” went from bad to worse. Broken bolts are bad enough, broken stainless steel bolts magnifies the ass pain. We discussed removing the cylinder head and taking it to a machine shop, but that’s a lot of disassembly, and we didn’t want to do that, unless we had to. The other three bolts? We broke every one. Great. Just great.
I have previously mentioned buying tools Track Addict has recommended, and one of those was an Owatonna Tool Company jig for drilling out broken bolts. I had also bought some cobalt drill bits, which work better on stainless steel than standard High Speed Steel bits. We thought let’s give this a try before we remove the cylinder head. I had also told Scott, “If we have to remove the cylinder head, let’s change the cam”. Not wanting to go down that rabbit hole, he had extra incentive to make the broken bolt removal successful.
When drilling stainless steel the preferred technique is to use lower RPMs, cutting oil and lots of pressure. If you use higher RPMs and not much pressure you’ll work harden the surface, and now you have an even bigger problem. I started the drilling process using a 1/8” diameter drill bit in the drill jig’s alignment collar, and both Scott and I were really impressed how well that worked. It wasn’t like cutting butter, but it worked. Neither of us like the completely miss-named EZ Outs. In our opinion, they're a recipe for disaster.) So we upsized the drill bit three times and Scott used a special punch he has to carefully pick away at the bolt remnants. The process also requires using a tap, and a lot of patience is required, too. It took about 90 minutes per bolt, but we got them out.
Pics. Here’s Scott drilling out the first bolt. I have an old school Milwaukee 3/8” right angle drill, also called a Duck Bill drill. That was very helpful because of limited space for a typical drill.
A close up showing the jig. If you look to the right, you can see the other two broken bolts.
I’m not sure what we’ll use for fasteners at this point. The cheapest option would be to buy more ARP to replace the broken ones. But their track record on this project is less-then-optimal. GM used carbon steel studs, but way back when, researching the Internet showed those were somewhat problematic, and the conventional wisdom was to use ARP. I thought removing the factory studs and going with ARP was the smart thing to do, and would avoid problems down the road. Ha! But now, after doing more research on the OEM GM studs, they are grade 10.9, which is slighter better than grade 8 on US bolts. How much time and money did I waste on ARP? Too much.
The Infamous WBJ1 and I exchange texts from time to time, and we sometimes chat via phone. He asked me to “Say Hi to the Sweet Gorilla”. Yes, a totally absurd name. So, later that day I shared the text string with Scott, and he announced he is more properly called (I’m not making this up) “The Sweet, Knowledgeable and Kind Gorilla”. OMG. Unbelievable….
)))))sledhead Ed
Member
something to do a search on. I use a lot of stainless steel over the years and even good quality stainless seems to gall up with neversieze for no reason and it usually taken it back out even if it's been together for a short time.
So i watch a show on building fishing lodges in Alaska with like 100ft pontoons hand made in shop in Alaska. there was multiple fishing lodges there on pontoons and the builders of the pontoons and lodges said to use pipe dope with teflon in for the stainless bolts because neversieze didn't work and this worked better. they said they would gall up brand new bolts putting them in with neversieze. something to check out. just started trying it out my docks this year
So i watch a show on building fishing lodges in Alaska with like 100ft pontoons hand made in shop in Alaska. there was multiple fishing lodges there on pontoons and the builders of the pontoons and lodges said to use pipe dope with teflon in for the stainless bolts because neversieze didn't work and this worked better. they said they would gall up brand new bolts putting them in with neversieze. something to check out. just started trying it out my docks this year
We could have a whole thread on stainless tapped holes.. One thing I found screws things up is mixing different classes of fit. If a hole is tapped for a 3B fit (tight tolerance) and you run in a 2A (not as tight tolerance) screw it is easy to get enough interference to cause it to seize no matter how much of what. Add to that the "H" limits and you can get torqued off just thinking about it.
Sledhead Ed,
Thank you for the suggestion. I don't think it would ever have occurred to me to use pipe dope with Teflon. I will definitely get some and try it.
At this point we're going back with the OEM fasteners that came on the engine. We know they work.
After months and months of working on non-snowcat projects, it’s time to get the exhaust finished on Project Dual.
The original plan had been to take it to the same shop that did the exhaust system on CHUGSzilla. They did a nice job, no question about it. That was done with aluminized pipe, which is what the vast majority of custom exhausts are constructed from. Scott and I have put so much time and effort into this machine that I didn’t want to spend a bunch of money on an exhaust system that would rust. I discussed this with the fellow who built the system for CHUGSzilla and he said the stainless steel tubing they can get rusts also.
Huh? (I thought the whole idea of stainless steel is that it doesn’t rust.) He explained that the stainless steel used in exhaust systems is 409 stainless, which can be bent with the bending system they have. Stainless steel alloys that don’t rust, don’t have good bending characteristics. Well… that sucks.
He then suggested getting the system ceramic coated, but I had that done on Thundercat’s previous system, and it was extremely disappointing. It looked great… until it was used.
This is after about 30 hours of run time. If you like taking a few hundred dollar bills and feeding them into a paper shredder, you’ll love ceramic coating.
Exhaust shops typically use a hydraulically powered bender with external dies. A die presses on the tube on the inside of the bend, and there are dies that support the outside of the tube as the bending takes place. Depending on the type of tubing, the wall thickness, the bend radius, and the degree of bend, the finished bend can show distortion such as ripples or flattening. (Sometimes this is referred to as "crush bending".) A mandrel bender on the other hand supports the tube internally during the bending process, and the tube’s internal diameter is maintained. The tool that supports the internal part of the tube being bent is called a mandrel.
If you're logically thinking "Why don't exhaust shops use mandrel benders?" The answer is cost, space, and time. Mandrel benders are very expensive, and they're large. There are computerized mandrel benders that can make multiple bends in different places on a length of tubing, and in different radial planes. But to build a one-off custom exhaust would require it be designed on a computer and undoubtedly it would still take multiple attempts. It's just not economically feasible.
So, after discussing options with The Gorilla we decided to build our own… from a kit. I ordered one from Summit Racing that is made from 304 stainless steel and it’s polished stainless at that! The kit includes lengths of straight pipe as well as mandrel bent pieces with different degrees of bend. Like the manifolds, it will be a cut, piece and and weld operation.
Our secret weapon is non other than The Gorilla himself. Remember my line earlier in this thread “Never underestimate The Gorilla”? Well, you’ll see that demonstrated again. You’ll also see why I call him a “crafty bastard” (a compliment).
The original plan had been to take it to the same shop that did the exhaust system on CHUGSzilla. They did a nice job, no question about it. That was done with aluminized pipe, which is what the vast majority of custom exhausts are constructed from. Scott and I have put so much time and effort into this machine that I didn’t want to spend a bunch of money on an exhaust system that would rust. I discussed this with the fellow who built the system for CHUGSzilla and he said the stainless steel tubing they can get rusts also.
Huh? (I thought the whole idea of stainless steel is that it doesn’t rust.) He explained that the stainless steel used in exhaust systems is 409 stainless, which can be bent with the bending system they have. Stainless steel alloys that don’t rust, don’t have good bending characteristics. Well… that sucks.
He then suggested getting the system ceramic coated, but I had that done on Thundercat’s previous system, and it was extremely disappointing. It looked great… until it was used.
This is after about 30 hours of run time. If you like taking a few hundred dollar bills and feeding them into a paper shredder, you’ll love ceramic coating.
Exhaust shops typically use a hydraulically powered bender with external dies. A die presses on the tube on the inside of the bend, and there are dies that support the outside of the tube as the bending takes place. Depending on the type of tubing, the wall thickness, the bend radius, and the degree of bend, the finished bend can show distortion such as ripples or flattening. (Sometimes this is referred to as "crush bending".) A mandrel bender on the other hand supports the tube internally during the bending process, and the tube’s internal diameter is maintained. The tool that supports the internal part of the tube being bent is called a mandrel.
If you're logically thinking "Why don't exhaust shops use mandrel benders?" The answer is cost, space, and time. Mandrel benders are very expensive, and they're large. There are computerized mandrel benders that can make multiple bends in different places on a length of tubing, and in different radial planes. But to build a one-off custom exhaust would require it be designed on a computer and undoubtedly it would still take multiple attempts. It's just not economically feasible.
So, after discussing options with The Gorilla we decided to build our own… from a kit. I ordered one from Summit Racing that is made from 304 stainless steel and it’s polished stainless at that! The kit includes lengths of straight pipe as well as mandrel bent pieces with different degrees of bend. Like the manifolds, it will be a cut, piece and and weld operation.
Our secret weapon is non other than The Gorilla himself. Remember my line earlier in this thread “Never underestimate The Gorilla”? Well, you’ll see that demonstrated again. You’ll also see why I call him a “crafty bastard” (a compliment).
I see a book/movie story, that needs to be told, "Gorilla in the Snow"
Track Addict
Bronze Member
Jinn Goodall?
Thankfully our system is much easier than the one in the photo DAVENET posted. That was some serious work!
The kit arrived from Summit Racing and the box was damaged. Uh oh… but most fortunately - the individual components were okay.
Next began the process of determining the general layout. We had wanted the exhaust tubing to end under the bed with the tube angled out, however the Mile Marker hydraulic winch requires access to two levers on the side of the winch. The exhaust routing would have made that both difficult and hazardous, so… plan B. Plan B is to terminate the exhaust at the front of the bed, just behind the cab, but also with the tubing angled out.
In addition to the kit, I ordered stainless steel mufflers, some extra lengths of straight tubing, and some stainless steel hangars. The fellow who built the system on CHUGSzilla welded flanges to the front of the mufflers and to the exhaust tubing that connects to the mufflers. We thought that was a good idea as it gave you the option of unbolting and removing the exhaust system without cutting it. So, I ordered some stainless steel flanges and gaskets, as well.
We started by positioning the mufflers in very close proximity to their installed position to determine the angle of the bend for the short length of tail pipe. The answer was 62º. I ended up taking some bends home and doing the figuring and cutting to get two virtually identical bends. At home, I can take my time, and get them as good as my limited skills allow, whereas Scott is more production oriented, and is less focused on striving for perfection. He often quotes his late grandfather “It’s not a piano”.
With the 62º elbows cut, Scott TIG welded the new elbows to the rear of the mufflers, and the flanges to the front of the mufflers as well as flanges to the ends of two sections of straight exhaust tubing.
Here's an elbow welded to a muffler. (We will add a short length of straight tubing to the end of the muffler to direct the flow of exhaust gasses further away from the machine.)
We also looked at how we’re going to make the connections to the exhaust manifolds as well as the routing of the tubing. Both sides have their issues and it's guaranteed to be challenging. Right off the bat on the right side... there’s an issue. The exhaust manifold flange is too close to the starter. (We installed a new starter which has a heat shield, and the exhaust pipe flange did not have clearance between the flange and the heat shield.)
Having previously cut and welded the manifold to reconfigure the manifold’s shape, doing that again wouldn’t be too difficult. So with our plan made, Scott put marks on the manifold and we removed it from the engine. Then the cut, modify, and tack weld process started. After doing that once, we needed to rotate the flange to move the flange studs to a different position. So, cut the tacks and recheck. Nope, we need more clearance, so cut the tacks, make the changes and re-tack. Check again. Okay, that’ll work and Scott welded the flange in its new position. Of course I had to take the manifold home to clean it up a bit. We also had to slightly modify the manifold’s heat shield.
Here's a pic of the right side exhaust manifold before the latest modifications.
And after revision.
But now we’re at the point where we’ve done the easy part and it's time to figure out the optimal configuration of bends, and a lot more cutting, tacking, checking, modifying and eventually welding. This is truly the hard part, and it can take a lot of time to get it just so. This part really “is a piano”.
The kit arrived from Summit Racing and the box was damaged. Uh oh… but most fortunately - the individual components were okay.
Next began the process of determining the general layout. We had wanted the exhaust tubing to end under the bed with the tube angled out, however the Mile Marker hydraulic winch requires access to two levers on the side of the winch. The exhaust routing would have made that both difficult and hazardous, so… plan B. Plan B is to terminate the exhaust at the front of the bed, just behind the cab, but also with the tubing angled out.
In addition to the kit, I ordered stainless steel mufflers, some extra lengths of straight tubing, and some stainless steel hangars. The fellow who built the system on CHUGSzilla welded flanges to the front of the mufflers and to the exhaust tubing that connects to the mufflers. We thought that was a good idea as it gave you the option of unbolting and removing the exhaust system without cutting it. So, I ordered some stainless steel flanges and gaskets, as well.
We started by positioning the mufflers in very close proximity to their installed position to determine the angle of the bend for the short length of tail pipe. The answer was 62º. I ended up taking some bends home and doing the figuring and cutting to get two virtually identical bends. At home, I can take my time, and get them as good as my limited skills allow, whereas Scott is more production oriented, and is less focused on striving for perfection. He often quotes his late grandfather “It’s not a piano”.
With the 62º elbows cut, Scott TIG welded the new elbows to the rear of the mufflers, and the flanges to the front of the mufflers as well as flanges to the ends of two sections of straight exhaust tubing.
Here's an elbow welded to a muffler. (We will add a short length of straight tubing to the end of the muffler to direct the flow of exhaust gasses further away from the machine.)
We also looked at how we’re going to make the connections to the exhaust manifolds as well as the routing of the tubing. Both sides have their issues and it's guaranteed to be challenging. Right off the bat on the right side... there’s an issue. The exhaust manifold flange is too close to the starter. (We installed a new starter which has a heat shield, and the exhaust pipe flange did not have clearance between the flange and the heat shield.)
Having previously cut and welded the manifold to reconfigure the manifold’s shape, doing that again wouldn’t be too difficult. So with our plan made, Scott put marks on the manifold and we removed it from the engine. Then the cut, modify, and tack weld process started. After doing that once, we needed to rotate the flange to move the flange studs to a different position. So, cut the tacks and recheck. Nope, we need more clearance, so cut the tacks, make the changes and re-tack. Check again. Okay, that’ll work and Scott welded the flange in its new position. Of course I had to take the manifold home to clean it up a bit. We also had to slightly modify the manifold’s heat shield.
Here's a pic of the right side exhaust manifold before the latest modifications.
And after revision.
But now we’re at the point where we’ve done the easy part and it's time to figure out the optimal configuration of bends, and a lot more cutting, tacking, checking, modifying and eventually welding. This is truly the hard part, and it can take a lot of time to get it just so. This part really “is a piano”.
changing the name from "Thunder Cat" to "thunder piano" I can hear the music
pretty sure we will hear a new tune from "Thunder Piano" at Wyoming wild
We haven't finished the system yet, but we are making progress. Lots to do and I hope we can test it before Wyoming Wild.
The routing of the exhaust to connect the tubing from the manifold to the muffler’s intake flange is just slow going. We started on the left side and then cheated a bit. Rather than attach the tube to the flange perpendicularly, we angled the tube to get a start on the tube’s path. Scott needed to weld a short piece of straight tube to a pre-bent length of tube to position that 45º bend in the optimal location to route the tube around the orbitrol. The pieces initially get small tack welds, then they get checked for position. If they pass the positioning test, the next piece in the sequence is worked on. Once all the pieces have been tacked, and confirmation of fit has been determined, they all get fully TIG welded.
The photo DAVENET provided shows what can be accomplished with pie cuts. Mandrel bends have a bend radius and in some cases one may not have enough room for that radius. In that case the fabricator can take angled slices of straight tube and combine them to create a smaller radius bend. Those angled slices can also be rotated to create compound bends, which is also illustrated in DAVENET's photo. When assembling pie cuts, the angles cut on two adjoining pieces should be the same.
In the case of our system, we needed some pretty slight angular changes to properly route the exhaust tubing. We could have cut small sections from a mandrel bend, but by slightly angling the cuts in both a mandrel bent tube and a straight tube we were able to connect everything with fewer welds. We talked about this, and we agreed having fewer welds is more visually appealing than a section with a bunch of short pieces and welds. I suppose, in theory anyway, one could carefully grind, sand and then polish the welds and surrounding tube to eliminate the look of the welds. That would be hugely labor intensive.
As the left side is coming together it’s very apparent how little the total amount of angular bend will be necessary. Bends equal restriction, and the lower the amount of angular change, the more free flowing the system will be. Free flowing improves engine performance and it reduces engine temperatures, two noteworthy gains.
We are hoping for a fairly quiet system, more so for the occupants of the cab, but we don’t have a clue how the system will sound once it’s complete, and that’s concerning. The muffler choice was limited by the availability of mufflers that were polished stainless steel. I chose the longest oval ones I could find, but they really aren’t all that long. Scott says “It will sound “healthy”.
Here's a pic of the straight tube, the connecting flanges and the muffler. There is a gasket that goes between the flanges and that will be installed during final assembly.
The photo DAVENET provided shows what can be accomplished with pie cuts. Mandrel bends have a bend radius and in some cases one may not have enough room for that radius. In that case the fabricator can take angled slices of straight tube and combine them to create a smaller radius bend. Those angled slices can also be rotated to create compound bends, which is also illustrated in DAVENET's photo. When assembling pie cuts, the angles cut on two adjoining pieces should be the same.
In the case of our system, we needed some pretty slight angular changes to properly route the exhaust tubing. We could have cut small sections from a mandrel bend, but by slightly angling the cuts in both a mandrel bent tube and a straight tube we were able to connect everything with fewer welds. We talked about this, and we agreed having fewer welds is more visually appealing than a section with a bunch of short pieces and welds. I suppose, in theory anyway, one could carefully grind, sand and then polish the welds and surrounding tube to eliminate the look of the welds. That would be hugely labor intensive.
As the left side is coming together it’s very apparent how little the total amount of angular bend will be necessary. Bends equal restriction, and the lower the amount of angular change, the more free flowing the system will be. Free flowing improves engine performance and it reduces engine temperatures, two noteworthy gains.
We are hoping for a fairly quiet system, more so for the occupants of the cab, but we don’t have a clue how the system will sound once it’s complete, and that’s concerning. The muffler choice was limited by the availability of mufflers that were polished stainless steel. I chose the longest oval ones I could find, but they really aren’t all that long. Scott says “It will sound “healthy”.
Here's a pic of the straight tube, the connecting flanges and the muffler. There is a gasket that goes between the flanges and that will be installed during final assembly.
In my previous post I wrote this "I suppose, in theory anyway, one could carefully grind, sand and then polish the welds and surrounding tube to eliminate the look of the welds. That would be hugely labor intensive.”
Being a certifiable knucklehead, I decided to see just how much work that polishing would actually entail. The answer is... too much! I think if you did this professionally, and had all the right equipment, it would be doable, but I don’t have that equipment and honestly, at the end of the day it is a snowcat. But Scott, being his ever-so-helpful self, encouraged me to polish the whole system. Yeah... not going to happen.
I decided to clean the welds up a bit, but it won’t look like a one piece, fully polished system.
Our plan had been to make the exhaust system removable by unbolting the flanges on the mufflers and then snaking out the exhaust tubing from the engine through the truss frame’s various braces. Well that was “the plan”, and to do that on the left side we had to remove two of the exhaust manifold's outlet flange studs in order to remove the tubing. There are more obstructions on the right side, so that plan was not completely workable. I wanted both sides to be as close to the same as possible, so I bought more flanges to be welded strategically to make removal of the system easier/possible.
By the time the flanges arrived we were almost finished with the right side. Scott welded a set of flanges where the manifold down pipe attaches to the straight run of tubing headed to the muffler. We also added two stainless steel hangers to support the system. Then I took all those components home and cleaned up the welds to make them look presentable. We have since installed the system on the right side, and we think it's turned out well.
We also added a set of flanges to the previously welded left side, and all of those pieces are now in the weld clean-up stage.
Here are some pics. This is where the right side tubing is welded to the flange that bolts to the exhaust manifold. (The hanging wire with the connector exposed is for the oxygen sensor that has not been installed.)
This is slightly aft of the previous shot. You can see how the tubing goes below the hydraulic lines. You can also see the bung welded to the tubing for the oxygen sensor I mentioned.
This is where the tube heads back uphill after getting past the hydraulic lines. And of course you can see the front flange that allows removal of the system.
Here's the back end of the system, showing the muffler and its flange, as well as the tail pipe and where it terminates. If you look closely you can see a hanger welded to the tubing behind the muffler. The hangar bolts to the cab frame.
I should get the weld clean-up completed and we'll install the left side tonight. We should be able to get the oxygen sensors installed and the side screens bolted back in place... and then the moment of truth: How does it sound?
Being a certifiable knucklehead, I decided to see just how much work that polishing would actually entail. The answer is... too much! I think if you did this professionally, and had all the right equipment, it would be doable, but I don’t have that equipment and honestly, at the end of the day it is a snowcat. But Scott, being his ever-so-helpful self, encouraged me to polish the whole system. Yeah... not going to happen.
I decided to clean the welds up a bit, but it won’t look like a one piece, fully polished system.
Our plan had been to make the exhaust system removable by unbolting the flanges on the mufflers and then snaking out the exhaust tubing from the engine through the truss frame’s various braces. Well that was “the plan”, and to do that on the left side we had to remove two of the exhaust manifold's outlet flange studs in order to remove the tubing. There are more obstructions on the right side, so that plan was not completely workable. I wanted both sides to be as close to the same as possible, so I bought more flanges to be welded strategically to make removal of the system easier/possible.
By the time the flanges arrived we were almost finished with the right side. Scott welded a set of flanges where the manifold down pipe attaches to the straight run of tubing headed to the muffler. We also added two stainless steel hangers to support the system. Then I took all those components home and cleaned up the welds to make them look presentable. We have since installed the system on the right side, and we think it's turned out well.
We also added a set of flanges to the previously welded left side, and all of those pieces are now in the weld clean-up stage.
Here are some pics. This is where the right side tubing is welded to the flange that bolts to the exhaust manifold. (The hanging wire with the connector exposed is for the oxygen sensor that has not been installed.)
This is slightly aft of the previous shot. You can see how the tubing goes below the hydraulic lines. You can also see the bung welded to the tubing for the oxygen sensor I mentioned.
This is where the tube heads back uphill after getting past the hydraulic lines. And of course you can see the front flange that allows removal of the system.
Here's the back end of the system, showing the muffler and its flange, as well as the tail pipe and where it terminates. If you look closely you can see a hanger welded to the tubing behind the muffler. The hangar bolts to the cab frame.
I should get the weld clean-up completed and we'll install the left side tonight. We should be able to get the oxygen sensors installed and the side screens bolted back in place... and then the moment of truth: How does it sound?
sounds like a well tuned piano, hitting all the high notes!
