engine swap

[mocheese]

I picked up a 85' m1028 about a month ago and have had a friend of mine working on getting it running. After replacing the entire break lines, calipers, rotors and figured out what was wrong with the injection pump we discovered a new problem. Looks like the 6.2 is dead and now i have to figure out if should attempt to fix it or put in a 350. Does anyone know if the stock trans will mate up to a 350? If not, are there any adapters that will help? I know that the 24v system and the exhaust will have to be addressed. Can anyone thinking of any other concerns/problems and possible solotions. Please keep in mind that i dont want to throw a ton of money at the truck. Thanks

 

[biggestc69]

We did the Rosscommon 12v conversion on the boss's truck. If your going with a small block the motor mounts and exhaust should work. Did on ours anyway. New starter, torque converter, brackets and your gonna have to neck down your radiator hoses if you plan to keep the stock radiator. Use the pink wire going to the injector pump for your key on hot ignition and your pretty much good to go.

 

[wayne pick]

We need more info in order to help you. Any history on the truck? Did you get it from GL or a private sale in not running condition? Dead meaning what? Engine won't turn-seized, turns but won't fire-fuel, turns fires, with sounds of broken internals? You replaced all those brake parts before getting the engine running? A 350 is an easy swap but with 4.56 gears it will turn 3251 RPMs @60 MPH and it WILL CHUG FUEL. If your engine is no good, put a good running 6.5 turbo motor in it. You will be limited to 55 MPH, but get at the least 18=20 MPG.

 

[Warthog]

The transmission will bolt up, but the torque converter and govenor will need to be changed to a gasser version.

 

[mocheese]

i got the truck from GL and picked it up from Aberdeen Maryland. I have no clue about the trucks history. The engine starts without a problem and continues to run. These are just my observations...... there is a loud noise coming from the bottom of the engine as its running and speeds up as the rpm's go up. the crank pulley is not turning straight and looks like there is a lot of play in it. that is oil leaking from the crank area and there are metal shavings in it. the guy that's working on it is guessing, without getting into the motor, that its a spun main bearing.

 

[wayne pick]

Well, that does not sound good. The cheapest way to go would be to get another 6.2, upgrade to a 6.5 turbo, or as you said go with a 350. There are a few build threads here on swaping to gas motors. I don't think there is much hope in rebuilding your motor on the cheap from what you discribe. You would have to tear into it to see exactly whats broken, and it may not be worth all that work machining the block and money in parts All Chevy small and big block engines will bolt up to the TH400, as Warthog stated above, the govenor and converter will have to be changed. Good luck.

 

[tamecrow]

the crank pulley is not turning straight and looks like there is a lot of play in it.

I'd guess that's where your noise is coming from as well. A worn crank pulley or vibration damper will make it sound like a crank knock. And by your description, either one, or more likely both of those items are shot.

 

[twomorestrokes]

X2 ^ ^ ^ Check those items before making a costly mistake. Hard to imagine main bearings being worn enough to make the pulley wobble.

 

[biggestc69]

My boss's did the same thing. When we picked it up form GSA auctions it had "GET A FORK ITS DONE" written in chalk on the air cleaner. Not what we were wanting to see. The glow plugs weren't firing so we tracked that down the glow plugs cycled and it fired right up. And it was LOUD. I have been around hundreds if not thousands of this motors in the service and this was by far the loudest. The harmonic dampner was all over the place. We replaced that and it quieted it down some. He then drove it as a work truck for two years. One morning I came to work and it was sitting halfway down the drive. He told me it got REALLY loud and then lost alot of power but would still run. Turns out it snapped the crank. My guess is was it always going out the entire time he had it, yes. But it held for what its worth. I dont know what your plans are for the truck but there still might be some life left in it. If not like I said earlier small block swap and 12v conversion aren't a hard thing to do.

 

[mocheese]

thanks for all the advise. I think i will be doing 350 swap. a couple of people have mention the poor gas mileage. can anyone advise on how to better the mpg. I know this truck will never sip gas but i'd like to keep from ending up in the poor house trying to fuel it. also, with the mpg in mind, what else can i do to help the truck keep up with traffic on the highway. I plan on upgrading to 37' (h1) tires later. thanks again.

 

[MidnightDuramax]

To improve fuel mpg keep it diesel.

 

[twomorestrokes]

Obviously tall tires or gear ratio changes are the best thing you can do for better mileage and drivability. As others have said, when converting to gas make sure to change the torque converter and other transmission controls to components more compatible to the gas motor.

 

[Skinny]

Why not just replace it with another 6.2? It will be cheaper than doing a 350 conversion, all the systems remain stock, and your MPG's will be better. The 6.2 isn't exactly a gem but neither is a plain jane 350. I could understand it if you were doing some fancy stroker with fuel injection or upgrading to a vortec 5.3 or 6.0, but I don't see the gain by ripping out the 6.2 for a 350. I think most people do it because they don't take the time to learn the diesel systems. After I have spent countless hours researching how things work, troubleshooting, and repairing, I wouldn't swap my diesel for a gas motor any day of the week.

 

[troll]

Search the SS classifieds for a used engine (several have been listed around $500). Swap in a 700r trans if you want to run interstate speeds. I did this swap on my 08 last year and run 65-70 everywhere with the stock 235 tires. KEEP the DIESEL, someday you will be glad you did.

 

[wayne pick]

 

[trukhead]

Why not try a chevy inline 6 cylinder. You can rev it and still be using less gas. I think they had 230, 250 and 292 CID versions. With the stock gearing of the CUCV, you should get 3,000 rpms around 60-65 mph.

I got a '79 firebird for free and it had the 230 version in it and I may give it a try for giggles.opcorn:

 

[Tanner]

Stay with a 6.2 - it'll be a smoother swap with less hacking to be done for a swap. You can find a civvy 6.2 J-code motor in running condition to do the swap. I bought a running/driving '89 GMC 3500 pickup in Virginia off of a farm through Ebay auction for $900; added 2 new batteries & fixed a leaking heater hose - drove truck back to NC. Yanked motor & sell-able bits, then sold rest for scrap. After all was said/done, I had ~$200 bucks investment in a good motor for swap.

'Tanner'