1982 GMC diesel resurrection

[WIDTIO]

So I have an opportunity to have a pickup very similar to the one in the picture from my uncle for FREE!!!! Basically its been sitting on his property forever and hes tired of looking at it. The only thing is, is that it hasnt ran in over 2 years.

I had just a couple questions on what i should do to revive this thing and at least get in the the proper condition to start 'er up. I know that i probably should drain the fuel tank and start with fresh diesel. im going to charge the battery then take it in to get it tested. Although I'm not quite sure how old the battery is and maybe i should just replace it? Im thinking about replacing the glow plugs... I really can't think of what else i should exactly do to get this thing in the proper condition this is the first time ive done something like this so any help/suggestions would be very much appreciated!

thanks!

[lumpy4000]

change the oil, replace battery, check the electrical....

but i was actually just having a conversation with a diesel mechanic yesterday about gm and how they killed north american interest in diesels as a whole. turns out gm used a gas engine and just converted it to a diesel... not the best idea, because diesels require higher tolerances then gas to operate properly. you might find this thing more problematic then its worth... nice find though, i would still take it and just have it to f' around with...

[Will]

No, the diesel in that truck is not a gas conversion. The gas conversion engine was an Oldsmobile 403 that was reworked into a diesel 350--that was used from '78-'85 in cars and it was available in shortbed 2wd pickups for '80-'81. There was also a 4.3 V8 with that same block and a small bore, and then a V6 4.3 with the same block chopped off.

The 6.2 diesel isn't part of that program. It was designed from ground up by Detroit Diesel to be a diesel for the truck market--showing up in everything from 1/2 tons to 14,000#GVWR step vans and motorhomes. There's nothing wrong with these engines except people treated them like gas engines. You can't let a diesel set for long periods of time or neglect the oil changes. They didn't turbocharge them because it would have added a couple thousand to an already very expensive option. They are pretty weak naturally aspirated--about 130hp/240ft# in LD trim, and 155hp/285ft# in HD trim. The light-duty trim motors are emissions certified for under 8,500# and they use an EGR valve in the center of the intake manifold and pick up exhaust gas from a valve in the left exhaust manifold. That valve can (and will) jam shut and cut your power even more.

The one thing you should know about these motors is that they use the same fuel system that is on the 6.9/7.3 Ford--the Stanadyne DB2 injection pump. This pump is capable of moving enough fuel for 250hp and 450ft#. Problem is, you need a turbo to get past the 155hp/ 285ft# the HD nastily-asspirated motors produce. Once you turbocharge them, they are fine provided you keep the turbine-inlet temps below 1,100F. Their extremely high compression conpared with an engine meant specifically for turbocharging means their combustion temps can get out of hand quickly. Mine puts out 12psi of boost and has no trouble at all pulling a 10,000# trailer.

Incidently, these motors are still produced by AM General's General Engine Products division, who took them over in 1999 from GM. They have been made for 27 years. So the idea that they are bad is only held in the minds a a few. They are sold as military, marine and idustrial engines, and you can buy one too through GM as a serivce part. They are not cheap. I believe Penninsular Diesel still make a 400hp version with twin turbos.

The best thing about them is they are all over Ebay as the military pulls them out when they overhaul Hummers. They are cheap compared to Cummins so it's easy to have a diesel truck. The older 6.2/6.5s can't be pumped up to 400hp, but they can get the job done and get great fuel economy doing it--which is why I have a diesel. Maybe someday I'll feel like I need 800ft# of torque and swap in a Cummins.

[WIDTIO]

Thanks for the info fellas!

Will- Hey i appreciate the history of the motor, i was pretty curious because ive never really dealt with anything especially GM from the 80's. (Ford rules!)

So about starting this thing... I should???????
1) get fresh fuel
2) replace batteries or just charge 'em and see what they got left?
3) Glow plugs, yes... no..?
4) oil
5) might have to check/flush the coolant aswell

I mean i really wanna get this thing goin and sell it but dont want to drop a small fortune on it if its just not going to run at all.

Thanks again!

[BDAB]

check out DTR..... www.dieseltowingresource.com they have a 6.2/6.5 section and its a TRS quality site.

[Will]

Your best chance of starting it is to have strong batteries and plug in the block heater for an hour or so, even if it's warm out. It's all about heat--fast cranking and warming the precombustion chambers with the surrounding coolant.

Changing the fuel out might sound like a good idea, and in a way it is. But in a way it isn't. When you do it you are going to introduce air into the fuel system and it's going to be a lot more cranking to get it started. So I would just go ahead and try to start it. The worst thing would be water in the fuel. But there is a seperator for that. You can tell if at least some glow plugs are working when you turn the key--they suck enough power to dim the dash lights. They are on an electronic controller and it will give them about an 8 second burn, and then cycle them on and off, even after it's initially running. On mine, I left the controller in place and added a parrallel starter relay controlled by a momentary switch so I could give them a second full burn if needed. What I would check before starting is that the wires are still attached to each individual plug. They are right amongst the exhaust manifolds and it's common for the ends to corrode off. If you want to test them in place, pull off the wire, ground a prog of the multi8meter and touch the other to the connector on the plug. It should read around 1 ohm.

[WIDTIO]

BDAB- Hey ill have to check that out, thanks!

Will- Thanks again, I'll be tryin it out this thursday so i'll be letting you guys know asap how it went. Ill have to load up some pics and the "official" cold start vid!!

-dave