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LMC 3700c parts and tracks ?

A

Any and ALL Builders

New member
I just bought my first cat. LMC 3700c groomer. With 12 person cab. Going through the cat right now 12 way blade is off drag is removed and de tracked today. The cats in overall decent shape. Motor runs great installing new electronics cleaning up wiring full service on the 3208 install 4 new rubber filled tires and packed all 10 wheel bearings. The track rubber is shot and has mis matched sprockets. Degreased whole cat and didn't find many leaks. Hydraulic fluid look good. Tracks have 78 gr was wanting to cut down on the tracks from 3 8in drive belts and 2 4in powder belts and just get ride of one of the power belts to get the cat to around 12 foot 2" wide instead of 13' 10" any thoughts. The cat will be used for back county skiing and tours and also vehicle recovery and some remote access construction. Please let me know if there's anything I have left out and any things that i should look out for on this cat as weak spot's so I can fix now. Thanks again Chad I use the cat in the Serria Nevada's in California elevation is 7k-10k
 
Any and ALL Builders said:
I just bought my first cat. LMC 3700c groomer. With 12 person cab. Going through the cat right now 12 way blade is off drag is removed and de tracked today. The cats in overall decent shape. Motor runs great installing new electronics cleaning up wiring full service on the 3208 install 4 new rubber filled tires and packed all 10 wheel bearings. The track rubber is shot and has mis matched sprockets. Degreased whole cat and didn't find many leaks. Hydraulic fluid look good. Tracks have 78 gr was wanting to cut down on the tracks from 3 8in drive belts and 2 4in powder belts and just get ride of one of the power belts to get the cat to around 12 foot 2" wide instead of 13' 10" any thoughts. The cat will be used for back county skiing and tours and also vehicle recovery and some remote access construction. Please let me know if there's anything I have left out and any things that i should look out for on this cat as weak spot's so I can fix now. Thanks again Chad I use the cat in the Serria Nevada's in California elevation is 7k-10k
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you want to narrow the tracks from 13'10" to 12'2". The net effect is the cat will depress the track further in the snow, thus it will work harder to move over the snow, it will not float on top it will be down in the snow.

Why do you want to do this ?
 
factory ground pressure is .72psi cat is 11,400 pounds. removing one power band will get me into .79-.81 psi. The cat will be towed on the hwy a lot at almost 14 feet requires 2 pilot cars at 12 feet requires 1 that's a big cost in savings and time and fuel.
 
One thought might be that if you take off one powder band you had better take off the one on the other side of the track. If you do not, your bogies are no longer in the center of the load, and the track will tilt as you drive in powder snow, not a good thing I am thinking. But I don't own one either, just think there is a reason for the balance of equal amounts of track on each side of the drive line, resulting in the driveline being centered in the grousers.....:whistling:

Regards, Kirk
 
tracks are 66 in wide each factory it comes not centered 2- 8 in bands then sprocket then 8 in band then 5 in band then another 5 in band if you removed one 5 in band the tracks would be now equal on either side of sprocket
 
Any and ALL Builders said:
factory ground pressure is .72psi cat is 11,400 pounds. removing one power band will get me into .79-.81 psi. The cat will be towed on the hwy a lot at almost 14 feet requires 2 pilot cars at 12 feet requires 1 that's a big cost in savings and time and fuel.
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Ok, and taking tracks off is not an option, it will work fine just sit lower. If I remember correctly when the cat came new from the factory it was 149" wide is your wider ?


http://www.safetyoneinc.com/specsheets/pdf/THKL3700.PDF
 
Cutting your outside belt is not an issue as it is done all the time. They will tend to sag toward the inside as they are not perfectly balanced but they tend to sag to the outside as they are right now. Just keep good track tension.

As long as you have the tracks off look closely for cracks in the frame and repair. Also make sure your fluid levels in all the gearboxes are where they are suppose to be. Myself, I would change the filters and fluid in your transmission if it has not recently been done. The 3700 is a great snowcat, sounds like a fun adventure.
 
Thanks for the input going to flush the whole hydro system just because but the fluid does look decent. I here you on the sagging and yes sags on the out side now. My cat has 17 tooth sprockets and 76 gr a lot of them ran 14 tooth sprockets and 66 gr does anybody know the best gearing for these cats I know 17 tooth will run in high to about 12-13 mph
 
I have the same cat 78 grousers 17 tooth sprocket. Mine is cut down I may be interested in your long grousers if you wanted my short ones? Just the outside ones? Let me know?
 
I have like 200 short grousers I only have 78 long ones what do you have yours cut down too and what type of snow and does it work well Thanks Chad. I might be interested in getting ride of the long ones tho.
 
1 Band cutoff it is 12'2" wide I would have to count But 78 should be right for half the track. LOL I bought it this way was a trail grooming cat I want to use it in the really steep deep and as a tow truck.
 
heres a pic from when I bought it the old owner went out of buisness Im installing 2 more windows in the sides for snow tours
1294505984.jpg
 
This i thought was pretty well thought out. the cab wraps around the fuel and hydro tank but you still fill it from the outside that good. The small little window is to inspec hydro level and theres a latch cover to fill from the inside. Also has hatch in floor to get to the hydro check points
1294505989.jpg
 
I was thinking about your enterprise, I say "go for it".
However there is one thing that has happened far too many times......
Find out for sure, FOR SURE, when the flex plate was changed last. It is the cushion drive plate attached to the flywheel. On those cats, every 4000 hours or so it MUST be changed. It breaks suddenly and always at the worst place. It is no fun to change in the shop let alone outside. You have to pull the pumps out or at least pull them back with the splitter box.
To help this problem, set the low idle up to 950 RPM. I got aquainted with the engineer who designed this engine back in the "seventies". He said that the engine does not rotate smoothly until 935RPM. It is warm up idling and low speed operations that kill the flex plate.
You can get one from a "Brake and Clutch" rebuilder.
Those are good cats but you have to know them or they will bite you.
Paul
 
Thanks for the info I hadn't heard that one before. Both the pumps have less than 200hrs on them since rebuild but the cat has 9550 on the hr meter but the motor looks really clean and so does the hose's and the drives. I was going to replace the bearings on the pumps and in the hubs and the O-rings in the brakes. Put new batteries new alt. 140 amp and belts and some hose's. Also putting 4 new tires and brand new track rubber. Last but not least were doing a vinyl wrap on the cab and hood. Digital Snow Camo :-)
 
Normally the 3208 engine will run to about 8000 hours before it is tired, though i did note one that made it to 19,000. Most likely the flex plate was changed with the engine. Look at the very top front of the engine just in front of the inj. pump, I bet there is a cat reman tag on it. Whatever you do, set the low idle up to 950. you will like it as much as the engine will.
Paul
 
Sweet I'll check for that. I total believe you on that 950 idle when i first start it up almost seams to surge so I bump up the idle on the manual throttle to 950-1000 and sounds like a champ. thanks for your help.
 
I was just looking at your project, Since you are going to depend on this cat way out back, I would STRONGLY suggest that you take the awfull time and trouble now and change out the drive plate on the back of the engine between it and the splitter box. I have seen so many of them fail, just when it could not be a worse time or place. this is the one critical spot in these cats that always gets missed. It is NOT a fun job but when it fails, and it does, NOTHING works but the engine. You are dead in the water where it stands. It is not expensive, but it WILL be out in the bush! excessive idling at under 900RPM is what takes them out. I have personally hauled at least ten of them out to a shop and have changed at least 30 of them. Just do it! you will be glad you did.
Paul
 
The symmetrical tracks that came with my 3700 b are 57 inches wide. They have grousers that are 43 inches long on the inside and outside. They use four 8 inch belts. I also use a 3700 c with asymmetrical tracks, which works well in the deep powder. I am going to make a tracked trailer out of a 2100 or 3700 I have scrapped out. I don't know how well the cut down tracks will work for you in the powder snow in the Sierras, but taking the tracks on and off is definitely a bummer. Where will you be doing most of your work?
 
Dr ZZaugg,
How does one inspect the drive plate to see if it's day is done? I'm about to exchange the 3208 with another, so will have the plate out...I do not have the history of the cat I'm working on.
 
SWIXB
It is really easy. There are coil springs around the perimeter of the center that act as a cushion/damper for the drive. The "slots" that the springs set in should not show any wear. the springs should be tight in their containment. If it is getting bad, the springs will have lots of room to slop around in and you will be able to see dramatic wear patterns on the plates of the drive where it is rotating back and forth. It is REALLY obvious when you see it. It is 90% chance it is bad. Be aware, when you pull the splitter box away from the engine that the shaft will want to stay in the flex plate because it is a very tight fit between that shaft and the bearing on the inside of the crankshaft. to keep the flex plate in good shape going forward adjust the low idle speed up to 950 RPM. That is a proven fix. I did that to all of Vail's fleet back in the day and they went from changing six or eight flex plates per year for the fleet to none ever. (40 cats)
Be sure to put new water hoses on the engine oil cooler too before you put it in the cat.
Paul
 
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