I am in the process of installing a 6.2L diesel back into my 83 chevy truck as I had it converted years ago :mad: and now I want it back. I was wondering if I need to change out the torque converter on the 400 turbo or will the one that powers the current 454 motor work?

The original 6.2 convertor was a six lug unit (six bolts holding it to the flex plate) and had a slightly lower stall speed than the gas engine convertor. The three lug gas convertor doesn't have the heavy duty welds on the lugs that the later style three lug diesel convertor has. Other than that, it will function. Just won't be exactly like the original setup.

Well I guess with that said I had better get the heavy duty one as I don't want the lugs coming of a torque converter, especially since it will be chareper now than later.

I put my 6.2L in my 1970 Chev. C20 with a 350 auto trans. and I never had a problem. I think it had only three attachments on the torque convertor. I did have to change the bell housing for the starter to clear the housing. I think it was a 400 bell housing that I used.

I would run it with the converter that you have as long as the welds on the lugs appear sound. I just had a lug weld fail on a 6 lug 700r4 converter fail, and I have never had a 3 lug converter fail a lug on a 6.2. Go figure.:eek:

Dave, Me too! I had a 6-lug weld fail once. The newer H.D. 3-lug convertor I purchased had the lugs beefed up and welded solidly on both ends, not just tacked like the early ones. These are stronger than the 6-lug convertor if the welding is done right. The other issue is flex-plate cracking around the crank flange area. I havn't seen a real heavy-duty replacement flex plate yet. Let me know if you see one!

Ok, I guess I'll try the current torque converter and save the cash for later. Now do I need to replace the vacumn modulator or is it also the same and can be used with the diesel? Also got a question on the cooling/radiator for this 6.2L. Will the factory 4-core radiator be sufficient if I later decide to upgrade to a turbo as I only want to buy this expensive item once but I want to ensure I have adequate cooling for this diesel. I will install any and all cooling upgrades I can now as its much easier with the motor on an engine stand than in the vehilce.

The modulator will work ok. You will need the vacuum regulator valve on the I.P. to vary the vacuum signal to the modulator.

The radiator will work fine for the 6.2 engine. I have never seen overheating problems from 6.2 turbo combos unless the boost is real high. Most aftermarket turbos for the old 6.2 (Banks, BAE, etc.) only put out about 8 - 10 lbs. of boost. The pump is turned up for more fuel and the EGT's are held down to a liveable leve. The cooling system is adequate for that. If you get carried away with power boosting, cooling could become an issue.

Fred482,

Appreciate the help on this as very different than hot rodding a gasser, which I am very familiar with.

When working with the vacuum system, be aware that the 6.2 Vacuum Regulator Valve (VRV) is a "controlled vacuum leak". It takes the vacuum pump signal of approximately 28" hg and varies it down to about 12"-14" hg @ idle and about 7"-9" hg @ WOT. Sometimes, an adjustable modulator is needed to get the shift points down to normal speed. It depends on how the transmission responds to the vacuum signal. Some transmissions shift at higher than normal speeds when converted from gas to diesel. A shift improver kit will make it even more pronounced.

I use an adjustable modulator (available, over the counter, at NAPA) to help overcome the loss of vacuum through the use of the VRV. Most VRV's just don't put out enough vacuum to the modulator to get the shift points down to what the gas engine did. At light throttle, the gas engine had a higher vacuum signal than the VRV can put to the modulator. The lower the vacuum signal, the higher the shift points will be. The adjustable modulator allows you the back the slotted screw in the end of the vacuum fitting out to "tailor" the shift points. The screw controls the spring pressure of the modulator. The spring pressure acts against the vacuum signal, which is trying to move the valve. The higher the pressure, the higher the shift points. By lowering the spring pressure, you will lower the shift points.I usually start out by backing the screw out two full turns and adjust as needed.

Another tip to consider: Use a factory steel vacuum line between the VRV and the modulator, it has a restrictor on the end that goes into the modulator. The restrictor prevents the modulator from reacting too quickly to changes in vacuum. It keeps the trans from downshifting every time you step down on the throttle. Your gas engine probably has one on it that would work. Look for the restricted (swedged) end.

Good luck,
Fred