Allis Chalmers diesl engine siezes on LMC 3700 . . what next?

[kgracey]

Hey guys,

I know that pictures help keep the discussion going, so here's the first one. More will follow on Friday after I see the problem up close.

Today my friend was driving his 1983 LMC 3700 snowcat shown in the attached photo. He was moving some snow around in his parking area when the engine started to produce a click-click-click-clunk-clunk-clunk that got louder and louder.

Okay, so he turned the machine off. A local snowcat mechanic came by and said "let's move it to the garage". So they started it up and drove it about 10 feet before the engine siezed.

We don't know what's wrong, but it appears pretty serious. He and I have been getting by with pretty used machines and they've served us well.

Which brings me to the line of questions.

Does anybody know much about these engines, to take an educated guess about what went wrong?

If it's fatal, do you know where we could find a replacement Chalmers 200hp diesel used in this machine?

Thanks much!

Ken

 

[BigAl]

Was the Engine heat gauge climbing at that time .Where was the oil pressure at ? Could be the oil pump broke and it stopped the flow of oil causing it to seize . Does not sound good . Last time my engine did that on a paving machine I owned it was BYE BYE in just minutes !!!!! Hope you have better luck !

 

[kgracey]

Hey BigAl,

I wasn't there, but it sounds like nothing crazy was happening with the vitals. I'm starting to wonder if this is how lawn ornaments are created. . .

 

[Snowcat Operations]

YUP!

 

[fogtender]

Normally when you hear that steady tap tap tap that is a rod bearing starting to go out for whatever reason. Sometimes the bearing flip (rotate) and cover the oil hole and that stops the oil to the rod bearing and then it starts to hammer because of no oil. Then it melts and finely locks up. But if he stopped it, and let it cool for a few min's, it may have melted and then cooled welding the bearing to the crank...

If he is lucky, the crank can be turned and polished and reused, sometimes it can be welded back up and cut to spec's and used again.

Otherwise if a valve dropped, that is pretty much a quick death to the engine and it would have died/smoking by blowing blue smoke fairly quickly.

Unless the rod broke free of the crank and punched a hole in the block, I think that a good machine shop will be able to get it back together.... that and some bucks...

When he pulls the oil pan off, he will be able to see the problem... The bad rod bearing will have no oil on it and the metal will be a pretty bluish color while the rest of the rods are all oily and a mess... and if I am right, there will be a nasty stench to the oil....

Just a good guess and having dealt with that issue a bunch of times....

 

[Av8r3400]

I don't know these motors intimately, BUT, most "tractor" diesels are wet-sleeved engines and can be overhauled even after catastrophic failures.

The seizing is a worry in not knowing the circumstances of the seizure. Did the motor lose power, slow and stop; or did it suddenly go from operating rpm to zero. The latter (of course) is much worse.

The proof will be in the tear down. Don't call it a lawn ornament yet. There may still be hope.

 

[Thiokol2track]

Hey guys,

I know that pictures help keep the discussion going, so here's the first one. More will follow on Friday after I see the problem up close.

Today my friend was driving his 1983 LMC 3700 snowcat shown in the attached photo. He was moving some snow around in his parking area when the engine started to produce a click-click-click-clunk-clunk-clunk that got louder and louder.

Okay, so he turned the machine off. A local snowcat mechanic came by and said "let's move it to the garage". So they started it up and drove it about 10 feet before the engine siezed.

We don't know what's wrong, but it appears pretty serious. He and I have been getting by with pretty used machines and they've served us well.

Which brings me to the line of questions.

Does anybody know much about these engines, to take an educated guess about what went wrong?

If it's fatal, do you know where we could find a replacement Chalmers 200hp diesel used in this machine?

Thanks much!

Ken

I have a used allis -chalmers in a dmc 3700 , I just sent you a pm.

 

[BigAl]

I have a used allis -chalmers in a dmc 3700 , I just sent you a pm.

Man ! I just love this place !!! Talk about getting Quick help when you got a problem ! Way to go Guys !!! This is exactly what makes this Snow Cat forum work so well ! The Members !

 

[kgracey]

Providing an update to you.

Well, today we got the tracks off the machine and we took a good look at the engine. Sure enough, fogtender is correct and it threw a rod right through the engine block. Amazing how the engine did it - just punched a hole! The first sign was the foul oil, like he mentioned.

We were able to drag the machine into his shop and start removing the engine, piece by piece.

Thiokol2Track: I'll be in contact with you shortly.

Thanks for all the help!

 

[fogtender]

Providing an update to you.

Well, today we got the tracks off the machine and we took a good look at the engine. Sure enough, fogtender is correct and it threw a rod right through the engine block. Amazing how the engine did it - just punched a hole! The first sign was the foul oil, like he mentioned.

We were able to drag the machine into his shop and start removing the engine, piece by piece.

Thiokol2Track: I'll be in contact with you shortly.

Thanks for all the help!

Sorry I was right, don't like to be on things like that, but your discription was pretty classic of that outcome. Good luck with the engine replacement... Sounds like Thiokol2track may have you covered!

 

[Alaska Snow Cat]

Ken, I bought a Thiokol 3700AC with a thrown rod many years ago and learned quite a bit about those engines. First thing to know is they were very popular and were used in all sorts of applications including generators and tractors. Last time I bought parts was 4 years ago - a water pump- and parts were no problem. I suggest you look around on the internet for one or the local tractor dealer. I found a replacement at a local diesel shop in Chugiak, Alaska near where I live and he had two cores in his yard. Also turned out he used to work at the Allis-Chamers factory for many years and knew everything about the engine. If you need manuals I think I have a copy kicking around the house somewhere. I've since sold the machine but retained some of the knowlage. Randy

 

[Snowcat Pat]

As a '78 3700 AC owner that has not yet thrown a rod in my machine I wish to ask; How Can This Be Prevented?
I must preserve the old machine, its my best plow.
-Pat

 

[snowbird]

I don't know of a low-cost way. Perhaps there would be somewhat a drop in oil pressure over time. When I farmed I had a large (140 HP) Allis tractor that had a bad rod bearing, but we only discovered it on a major engine overhaul.

 

[naturerules1]

So sad Ken...
I worked at an automotive and industrial engine rebuilding shop for 12 years and we did alot of fixes on engine blocks. I did the valve jobs (also line boring some boring and honing, balancing) but when we got to welding and brazing I got the job. We did some patch work on deisel blocks but it took so much with line-boring crank and cam bores. Also welding cranks for stroking or bringing to spec.
I reccomend an "engine replace" and would not waste my time with a repair. The cost will be comparable and I figure you lose alot in the engines strength. Just incase you are contemplating it...
A small repair may be ok? If time is not a factor.
Too bad you tried to drive it in the shop.Those loud knocking sounds are a "shut down" and I have been there where just alittle more would get me there. ONE never knows. Luck is not a good thing to count on when hearing anything louder than a slap. I guess we all have learned the HARD WAY....SORRY!
Hope I do not sound gruff. I got atleast 3 blown engines under my belt sooo.
Well I HOPE everything goes smooth!!!
Robert

 

[kgracey]

Hey everybody,

Update on our end. We nearly purchased an Allis Chalmers engine from Thiokol2Track, but we were able to find one in California from a second hand tractor dealer.

Removing the engine took us about 20 hours, but it's now out and sitting on a stand. You should see the holes that were blown in both sides. Something went way wrong and spare parts of the rod and cam were shoved right through the lower block. There must have been a lot of force behind this explosion of metal parts - both sides were blown out. What a mess! Dirty oil was everywhere, mixed in with tree sap, tree needles and gunk from the last 20 years of operation.

Tomorrow we pick up the new engine and we hope to install it on Sunday/Monday. . . etc.

Thanks for all the encouragement and tips.

 

[fogtender]

As a '78 3700 AC owner that has not yet thrown a rod in my machine I wish to ask; How Can This Be Prevented?
I must preserve the old machine, its my best plow.
-Pat

Well, watch your oil pressure and make sure it doesn't drop. If the engine starts to "Click", you can put a screwdriver on the block and your ear to it and go around and see where the noise is coming from.

In the event that the "Click" has been upgraded to the sound of a "Singer Sewing Machine", you might be getting to the short end of a long stick...

By the time the noise is really audible, the rod bearings have reached the point to where they are starting to hammer out of shape and may be doing the same to the crank. In which case you need to pull the crank out and have it turned and install new bearings.

But if you keep the oil changed and the pressure is up, more often than not you will just wear the engine out normally, instead of the quick version as discribed at the start of this thread.... You can also take a sample of the oil and send it in to see what kind of metal is in it, even though you can't see any it is always there. That will tell what is going down the tube quicker than it should and give you a heads up on what to expect. Most major Diesel Engine Companies in your area will be able to tell you where to send the used oil sample or they may even do it their on site.

Good Luck

 

[teledawg]

... You can also take a sample of the oil and send it in to see what kind of metal is in it, even though you can't see any it is always there. That will tell what is going down the tube quicker than it should and give you a heads up on what to expect. Most major Diesel Engine Companies in your area will be able to tell you where to send the used oil sample or they may even do it their on site...

This is where I send all of my UOA (Used Oil Analysis) work to:

http://www.blackstone-labs.com/

They are very accurate and thorough. Price is not too bad at $17 per sample. Cheap insurance for me.

 

[Snowcat Pat]

Thanks for the tips. What is the correct RPM to run this engine? I heard over revving was very bad, but I might be lugging the motor out of fear. Reading kgracey's story isn't helping my uneasyness
-Pat

 

[Alaska Snow Cat]

Pat, my 3700 had a redline of 2000rpms and I ran it at 1700 as recommended by the book.That was the max torque and anything over was wasting fuel and only gained a little top speed. I know the newer DMC I looked at once, ran at a higher RPM but the old Thiokol Guru at LMC that I used to get parts and info from told me ,when I asked why, "that was because they were built to run at those RPMs you dummy". Words of wisdom.
Also the company I bought mine from had it out on lease when a knock was heard in the engine. The operator shut it down right away and shipped it back to town. Then the owner, against his mechanics advice, started romping on the accelerator to "figure out what was wrong"! duh
IF YOU HEAR A KNOCK IN ANY ENGINE SHUT IT DOWN AND INVESTIGATE!!!

By the way in my opinion the 3700 was one of the best work horses ever made in the big snowcat industry. I would love to own one again.

 

[kgracey]

We were running at 1700 per the manual and some old-timer mechanics from the local ski area. Of about five mechanics, they have one who knows the older LMCs, Thiokols and Bombardiers inside out. All the younger guys only know the Prinoth machines.

This engine had about 10K hours on it, by the way.