Another GM 6.2 question

[Wilk]

I plan to do GM 6.2/700R4/NP208 into a wag. Found a 6.2 with a blown head gasket, still hooked to the 700R4 from an 86 model Suburban. I can get it all for near give-away prices. The question; do these engines repair well, or should I stay away and look for the military version 6.2. Also, does anyone know the differences between 6.2 civilian and 6.2 military. Are the military 6.2's different castings, better parts internally or what? Can 6.2 civilian engines be upgraded to military spec? Just looking for some good background info before spending money.

[FSJeeper]

The military and civilian 1 ton trucks use the J series blocks. These are heavier duty than the 1/2 and 3/4 ton civilian 6.2 versions. All parts interchange between the two engines. You should be fine with the 6.2 civy block. I would find a J series intake manifold as they are good for 10 hp.
(I have some if interested)

The 6.2 uses "torque to yeild" cylinder head bolts. When you repair the headgaskets you must throw the old bolts away and buy new GM head bolts. Many people try to use the old head bolts and blow head gaskets. This is due to the 22 to 1 compression ratio.

Also, you will need to upgrade the injection pump to late model specs.

These engines are not very powerful unless you upgrade to a turbo, that really wakes them up.

[Thomas DeBusk]

Isn't the military version 24-volt?

Thomas

[FSJeeper]

Originally posted by Thomas DeBusk:
Isn't the military version 24-volt?

ThomasOnly the starter is 24 volt and it has dual 12 volt altenators on CUCV's. Everything else on the CUCV's are 12 volts.

The military Hummer 6.2's have a 24 volt injection pump, starter, and glow plug system.

[Wilk]

As far as power, how will the 6.2(with J-series intake and upgraded fuel pump) compare to AMC 360? The vehicle will be used as a semi-daily driver, and might pull a small boat or trailer with a couple of motorcycles. It will be wheeled sometimes but nothing hardcore. With 31 or 33 inch tires and 3.31 gears I would be happy with the same power(and double? the fuel mileage) as a well tuned 360. Am I on the right track? Any opinions?

[FSJeeper]

If you upgrade the injection pump and bump up the flow to your engines limit (easy to do), J series intake, and good dual exhaust your HP will be a little less than the 360 but you will have more torque. You will get 20 MPG with the 6.2 in there.

In other words, it won't be a hot rod or anything but fine for a daily driver and tow mule.

You will have a problem with 3.31, 31" tires and the 700R4. At 60 you will be turning 1500 rpms, too low. The 6.2 makes max torque at 1900 rpms and that is where your cruise range should be. 4.10's or 4.56's would be better choices with the 700R4. You will also get better performance with the lower gears.

[Wilk]

OK I'm sold on this diesel thing. One final issue; will the vacuum pump on the diesel run the factory Jeep brake system, or do I need to go to hydroboost(I have access to hydroboost)?

[reddog]

You will need to go with the hydroboost. The vacuum pump will run the heater and xfer motors.

Kerry

[FSJeeper]

The vacuum pump can run the vacuum booster. I know 2 people who are using the stock FSJ brake system with 6.2's. No problems.

The hydroboost system is superior to the FSJ setup and very, very easy to adapt to the FSJ. If the donor vehicle has hydroboost, swap it, you will not believe how well your brakes will perform.

[Wilk]

All right, it's time to start buying parts. FSJeeper; at some point in the future I'll talk to you about an intake. Thank you all for your input.

[sandmanb]

i just saw this post and i have been wondering about the gm 6.2 for a while but i didn't know who to ask about it. how is the dependability of them? how hard and how much money would it take to change over to a turbo? whats a good price on a 6.2 engine? i have some leeds on a few from cucv's but wasn't sure what options i would have if i bought one. how hard is it to swap one into an fsj?

[ December 22, 2002, 09:19 PM: Message edited by: sandmanb ]