LMC 1200 problems info needed SAR cat

mbsieg · Jan 2, 2016

Ok Here is the scoop. Our local sar has a lmc 1200 10 man cab. I am looking for info from others. We are brainstorming.
It is a 300 6cyl cat has 110 hrs on the meter Runs and shifts well.

1st problem Speed
This cat has a high speed rear end in it. tops out 24ish mph at redline in high gear. We do not have the HP to pull the cat above 1st 2nd gear up a hill at 8-10k feet. Steep snow covered hills are not possible because 1st gear is to tall it just bogs. This is not a running issue this is a gearing issue. Cat runs out great. What are everyones thoughts on a reasonable way to gear the cat down to make the 300 perform at elevation. All the guys have ideas we are looking for the most reasonable bulletproof way to get it down to 12-15 mph.

2nd problem cooling.
This cat came with a 5 blade rigid blade fan. We took this off and put a 2 speed electric fan on for noise, and power. We like the fact the cat is quiet inside now. Butt now we are fighting a cooling issue. it is a 1800cfm 18in fan about the largest we can fit in the engine tunnel. It has a shroud to cover entire radiator. and it is set up as a puller currently. This on the cat today at about 40* was not enough to cool. Ideas to get more airflow to cool the beast. Thanks For Any and all ideas. Mike

Dr. Zaugg · Jan 2, 2016

The speed issue is simple. The Spryte has TALL drop box gears. You can switch to gears from a 2100. They are much slower. There are guys who will trade with you, like Don in NOME! That will also help with the cooling. I really think you should pull the Radiator next summer and have a shop install a core with an extra row of tubes. That will end your cooling issues.

MNoutdoors RIP · Jan 2, 2016

I would check your timing also, it will effect heating. But if it were my cat I would convert to fuel injection your hp will increase dramatically. A gear change
Can't hurt either

tomelroy · Jan 2, 2016

tbi and an under drive. I would keep the high speed gears! Once those 2 items are complete you may not have a cooling issue.

mbsieg · Jan 2, 2016

Dr. Zaugg said:
The speed issue is simple. The Spryte has TALL drop box gears. You can switch to gears from a 2100. They are much slower. There are guys who will trade with you, like Don in NOME! That will also help with the cooling. I really think you should pull the Radiator next summer and have a shop install a core with an extra row of tubes. That will end your cooling issues.

I forgot to mention this is a new radiator from the orig manufacture of the radiators for the 1200. Yes they are still available and not priced to bad for every ones fyi. It is a full 4 core radiator no more room for more cores. Thanks

tomelroy · Jan 2, 2016

but i will swap gears if that is the route you want to go..

MNoutdoors RIP · Jan 2, 2016

These guys make a good unit

http://www.affordable-fuel-injection.com

300 H and H · Jan 2, 2016

If you can find one, a mid 90's F150 with the 4.9 liter tuned port injection might be considered. They have a split e+haust manifold set up, and this beautiful super long runner tuned port intake manifold. Ford spent some big bucks developing this manifold that has the Plenum on the opposite side from the intake ports. These mods gave 170 hp to those engines, with stump pulling low end torque. I have on in a truck here with 310,000 miles on it..

IMHO this engine, or yours with the Factory stuff on it is worth considering, especially since you can use the factory computer and programming..

Regards, Kirk

mbsieg · Jan 3, 2016

searching for a diagram of the dropboxes. Anyone have it ?

MNoutdoors RIP · Jan 3, 2016

Another thought, if you could locate a divorced transfer case and modify the driveline would also work for you

Snowtrac Nome · Jan 3, 2016

Mike I wouldn't count on your electric fan working had one on my jeep it worked great if I was pushing with it but it wouldn't pull worth a crap. as paul said I would swap drop box gears I have plenty of power with my turbo diesel to push it I also have a divorced t- case that I would love to find the time to install backwards for you could use the same concept for an under drive also gear venders make under drive units.

mbsieg · Jan 3, 2016

How hard is it to find the dropbox gears? Anyone have a set of the lower speed gears laying around?

Snowtrac Nome · Jan 3, 2016

pat at sprite improvement has a lot of the low ratio gears those tall ones you have are quite hard to come by.

Snowcat Pat · Jan 3, 2016

Here is some pics of the Klune-V under drive that was in our LMC1500. The machine has hi-speed drop box gears too and the under drive would help out greatly, instead of lugging uphill powder in first gear, it would be in third. The Klune uses NP241 transfer case gears that are 2.72 ratio.

I removed it because it needs rebuilt. I'm not sure of this driveshaft arrangement either.

Klunes aren't made anymore but there are a few other 'extreme underdrive' rock crawler units out there.

Low speed drop box gears do give more steering leverage. We have some ratios are 1.83 hi speed vs 2.44 low speed.

We have the AFI fuel injection too on the AMC 258, its very nice but idles too fast. No overheating problem though. But I've never had good results from electric fans just my experience.

Re-reading your OP, that top speed is beyond any gearing combo I know of. There was supposedly a 4.08 R&P with 1.83 drop boxes but its just a photo with specs that I have.

Does your cat even have Drop Boxes? Some of B's came with straight axles.

-Pat

mbsieg · Jan 3, 2016

Yes pat it has drop boxes. Do you have any of the lower speed sets we are thinking 4-5 mph may do what we need.

Snowcat Pat · Jan 3, 2016

We have them, If my math is correct it would give you a 25% speed reduction, doesn't sound like enough, but we'll trade for yours if you want.

-Pat

mbsieg · Jan 3, 2016

I need to post pics of this cat. This cat orig came from the salt flats in western Utah. It was a US Army cat. It was equipped with all kinds of coolers Had A large roof mount Diff cooler, And AC. The cat only had 100 hrs on it when we got it. we stripped everything off of it that was extra. We got it from a Bombing range in Florida!!! Saved this gem gave it another life.

mbsieg · Jan 3, 2016

Semi pic is in Florida, truck pic is when we picked it up in south Dakota. We also got 3 bv206 from florida

mkntrakes · Jan 3, 2016

1800 cfm isn't enough fan to move the air as the motor gets no push air need to put one of these on SPAL Automotive USA IX-30102113 - Spal Electric Fans I have also put a large heather core in tunnel just to releave heat from the back of the motor

mbsieg · Jan 3, 2016

Ok we pulled 1 dropbox apart. you guys were right that was easy. It is the 1.83 ratio so we are looking for a 2.44 ratio to purchase. We will probably sell the other set down the road but do not want to put us out of commission totally until we are sure we like the new ratio.

sno-drifter · Jan 3, 2016

You may want to have both the mechanical fan and the electric pushing. Are the fans shrouded?

I wood not do any thing with the cooling until you get the gear ratio down to what you need for deep snow and/or hills. The engine is working too hard, thus over heating.

PJL · Jan 5, 2016

How was that acquired? Through GSA surplus? Mine came through the 1033 program to government agencies. It has the 6 man cab, 3 heaters, no AC. I'm taking out on Thursday for the first time since we got it in October. It's an 89 LMC1200 that the Navy used to access a mountain top radio site.

mbsieg · Jan 5, 2016

This one was also through the 1033 program.

PJL · Jan 5, 2016

Ahh, very good deal for you. Except for the shipping. :sad:

Ours was one county north. 4 hour drive there and back with a flat bed roll back and it was mine. Sorta, belongs to my agency. What year is yours?

LMC 1200 problems info needed SAR cat

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