Rollie, Diesel 6.2

Hey Rollie
How's that diesel working for you? get enough power to spin thoses wheels in the deep stuff or would you go with the 6.5?
Rick

Rick,

The 6.2 I've got is in pretty good shape. With new injectors, injector pump, timing gears and a turbo, I would say it is comparable to a gas 350. Seems like suffient power to me. Not as torquey as a bigblock, but it gets the job done. Actually I prefer the 6.2 over the 6.5. I believe it has a shorter stroke and it holds up to extreme high rpm better then the 6.5.
Just my opinion.

Rollie

Thanks for the real life imput, I have a buddy that gets all types of engines in per week, I've been thinking about a 454 but he is trying to talk me into a 6.2 or 6.5 diesel, I just pick up a rebuilt SM465 with cast iron bell and get this it has mounts off the bellhousing, very heavy duty.

Rick

Rick,
Measure the center hole in that bellhousing. That housing was used in Chevy trucks with the divorced t-case. Some had SM240 or small holes and some had the larger hole for the SM465. I have seen both. My '66K20 Chevy has that kind of bell housing and it works great for the engine with basically four mounts. My problem has been that my tranny will flex around some since it doesn't have a mount at all. I eat up pilot bearing rather fast. When or rather if I ever get to redoing it again, I will fab up a tranny cross member. Good luck with your project.

If you use the truck now and then and live where it gets cold for the winter you may want to go with a very mellow 454 build. Try and get at least 38" gummies for highway speed. I've been in motors a long time and am still waiting to really be impressed with the 6.5 diesel. It just seems like they become a little problematic when they get some miles...seems like more than others. Granted, it no 5.7 Olds grenade, but it's not a simple 6.2 either. I've got several manual flywheels for the external balance 454 if you need one too.

Rollie, what kind of Revs you talking with the 6.2 ?
Got a shot at a couple and was curious what the can put up with.

I don't have a tach so I've been estimating the rpms. With stock gears I typically drive 65mph with 40" tires or 70mph with 44" tires. I think that calculates out to around 3200rpm cruising. My son drives the truck often and he really raps out the engine before he shifts gears. With a turbo, 3" exhaust and no muffler, he really likes the sound. Also when driving offroad, we quite often hold the accelerator to the floor when going through mudholes and allow the engine to run as fast as it can. I guess what I'm saying is that we don't baby it at all, but thrash it hard without any concern for high rpm damage. The engine has over 350k miles on it with out any bottom end work.

On the other hand I've heard horror stories about 6.2's cracking their crankshaft or having bearing problems at less then 100k miles. Then after they fix it, it fails again. My opinion is that sometimes you get a good one and sometimes you get a bad one. Some people reccommend you never regrind the crankshaft as it will change the radiused bearing surface edges to sharp corners and create a weak area that will be prone to cracking. I also have a 6.2 in my second M715 and it has about 250k miles and is still goinfg strong.

Rollie

Cool, Glad to here you are having good luck with it!
I hear the horror stories about the 6.2 also, but have known only a couple to base my opinion on, They were less than 200k, but still going strong.

I am also under the impression that diesels suffer more from increased cylinder temperature associated with higher RPMs than the issues with the bottom end. I'm sure that different engines and compression ratios are why you see the difference in recommended redlines with the different designs. Please straighten me out if this is not correct, I'm diesel dumb for the most part.

Thanks again for the real world input.

I've got a temperature sensor on my exhaust manifold and monitor it ,especially when pulling a heavy load on the road. The temperature climbs fast when pulling hard up a long hill. I think the point of concern for the 6.2 is around 1100-1200 degrees. Mine rarely gets above 1000 degrees. The turbo actually helps it breathe better and run cooler. Overtemp usually occurs when the injector pump is turned up and delivering more fuel which burns and heats up the cylinders. Offroading usually consists of much shorter bursts of high rpm and never result in high cylinder head temperatures.

Rollie