My GMC, a little update

The civilian version with 7.2 compression ration is 260 ft. lbs at 1400. The military ratio is around 6 to one.

Wow! I was guestimating the 302 put out atleast 320 ft lbs. That is surprising, you would be correct in your assumption of increased performance with the 6.2. That makes me wonder if the 455 that used to be in the truck was a little too much muscle for the rest of the driveline. Over at the Mil-Veh board there is a lot of discussion about GMC engine swaps. A lot of them feel big block V8's create too much power for the GMC, most advise sticking to small block torque specs. Now I definitely feel the 455 would have eventually caused a failure point somewhere, or at least vastly accelerated wear of the Tcase.

The fan shroud idea is great. Thanks for passing it along.

Gunfreak25 said:

Wow! I was guestimating the 302 put out atleast 320 ft lbs. That is surprising, you would be correct in your assumption of increased performance with the 6.2. That makes me wonder if the 455 that used to be in the truck was a little too much muscle for the rest of the driveline. Over at the Mil-Veh board there is a lot of discussion about GMC engine swaps. A lot of them feel big block V8's create too much power for the GMC, most advise sticking to small block torque specs. Now I definitely feel the 455 would have eventually caused a failure point somewhere, or at least vastly accelerated wear of the Tcase.

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The 455 would have its maximum torque at a higher RPM so it might very well give the same feel at lower RPM's that you get from a 302 or 6.2. The 455 would wrap tighter, but that higher RPM and torque/horsepower would start straining things that would be turning faster than normal. It would/does run, but the driver would have to be sensitive to the added strains.

Oh my god! Henderson, you HAVE to give me more details on your crew cab M135!!!!! It will be the best thing since sliced bread! You have me giddy as a schoolgirl wanting more info. I'll bet it will be very well done, too! I've only seen 1 M211 crew cab and it was done horrrrrribly...

Gunfreak25 said:

Oh my god! Henderson, you HAVE to give me more details on your crew cab M135!!!!! It will be the best thing since sliced bread! You have me giddy as a schoolgirl wanting more info. I'll bet it will be very well done, too! I've only seen 1 M211 crew cab and it was done horrrrrribly...

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Huh? Did I miss something in this thread?

How about a pic of the trans/engine adaptor? Never seen one.

I don't have the adapter yet, but here is what i'll be using.

JEGS Engine to Trans Adapter Plates - JEGS

it Sounds like a good idea

I made my motor plates today, they mount onto the sides of the block using the 3 original motor mount bolt holes on the 6.2's. I think 3/16 plate will be good. It cuts easy and welds nicely. 1/4 I think would be overkill.

For those who say the 6.2 will be a dog in a deuce......

M35A2
-13,000lbs
-6.72 gears (9.00x20s)
-Most owners say they cruise comfortably at 48-50 at 2200rpm.
-The LDT465 makes 130hp and 330lbs of torque.
-The Ldt465 weighs 1800lbs and displaces 478 cubic inches. It uses 22quarts of oil.
-A complete filter service and oil change runs over $300.

M211
-13170lbs factory (w/original drivetrain)
-6.17 gears (9.00x20s)
-Will cruise at 59mph at 2900rpm
-Army 6.2 makes 150hp and 260lbs of torque
-Army 6.2 weighs 750lbs and displaces 379 cubic inches. It uses 8 quarts of oil.
-A complete filter service and oil change is under $75. And K&N's are reusable.

I joined Steel Soldiers in Sep 2009 after seeing an M35A2 for the first time. After learning that they could be obtained for under $2000 (at the time) I became obsessed with owning one. I was 18 at the time. Then I stumbled onto the GMC that was sitting 250 miles away. It's important for us to live within our means. In every way imaginable. The M35's were not within my means at the time, nor would they be today. It took me awhile to admit that. The GMC was in the cards at the time and when it's finished I will have the means to own, operate and maintain it. As much as I wanted to get a "Multifuel" and I would still love to have one today, I feel fortunate to have the GMC. In fact, I am very dang lucky to have the GMC at 20 years old while living with two of the best grandparents a person could have. They are proud to see I have come so far with it, and I look forward to taking them camping for the 1st time in 30+ years in Northern Arizona in it.


EDIT: The 6.2 making 330ftlbs is BOGUS. This was taken from a Wikipedia page and after much discussion on this at another board, the consensus is it's simply not true. The Army 6.2 makes 150hp at 3600rpm and 260ft lbs at 2000rpm. That's it. Those numbers are straight from the M998A1 manual too.

I really want to see some pics of the engine in there. I know there are quite a few people looking hard at this thread and some cheap 6.2/211s running about. I am definitely one of them.

Yeah, I am working as fast as I can. Only have so much cash to work with at any given moment too. In the meantime i'm picking up some home depot 5 gal buckets and lids so I can start stocking up on WMO. I will be using the "sock filter on a hook" method for now. Filtering down to 5 microns should be fine, and the oil flows like water here when it's 110. No joke. Like water. I'll be using blue jeans to filter the big stuff out first. Even just blue jeans lighten the color of the oil considerably. When it's all said and done I should be able to cruise around all day and not spend more than $10 on fuel. Probably drop to a heavier diesel ratio when it starts getting cold.

I would filter it quite a bit better then that for a 6.2. There are lots and lots of good water separator/filters for cheap that will do at least 10 micron. I don't think the 6.2 handles the nasty stuff as well as the multifuel.

5 microns is just right for the 6.2 from what i'm reading. It shouldn't be forgotten that there's also the firewall filter I have yet to purchase. It will filter down to 3 microns and it has a water separator built in.

The 6.2 does not really like to run on WMO. It wan'ts good clean diesel fuel and the cleaner the better. I would make sure that you filter it very well and IMHO I would cut it with some regular diesel fuel to help it flow better.

At least when the 6.2 goes from using the WMO you will already have all the fab work done to drop another 6.2 in.

In all honesty, I am not worried about the injection pump. I opted for the 6.2 because parts are cheaper than almost any other diesel. Fact is that the majority of the 6.2's out there are in need of a IP rebuild sooner than later. Most are 25 years old and have more than 50-80k on them. And the Military JP8 doesn't lube as well as No.2 diesel. I am going to run WMO as planned, filtered down to 5 microns and using a 3 micron firewall filter. That should be plenty enough for the old 6.2 IP, and if it does decide to quit I am looking forward to getting my hands dirty and learning how to rebuild them myself. If somebody in a shop can do it, so can I with the right amount of patience.

You make a valid point SETOYOTA. Surplus 6.2's are so cheap right now I will be stocking up on 2, 3 or more. It would take me less than a day to swap an engine in this truck and be back on the road.

Gunfreak25 said:

It would take me less than a day to swap an engine in this truck and be back on the road.

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Not when it takes you a day to drag it around the house in the dirt...

nattieleather said:

Not when it takes you a day to drag it around the house in the dirt...

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That is funny!!