My beloved 1994 Chevy truck spun a main bearing. Was over 300k mileage. My friend offered me a low mileage 6.2 non turbo diesel and he wonders if the lower unit could be combined with the 6.5 top to have a functional engine? Lots of labor, of course, but maybe a way to put the 94 back on the road. Great, rustfree 2 wheel drive truck but would be crazy to spend a fortune rebuilding the lower end. Anyone attempt this? Thanks, Harland
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Can a 1983 GM 6.2 L diesel block mate successfully with a 1994 6.5 Turbo diesel
- Thread starter hr47cars
- Start date
Yes
ak diesel driver
6.5 driver
Only issue might be one piece rear main seal vs two piece
dbrannon79
I'm getting there!
Heads, intake, and exhaust manifolds are all interchangeable. only issue you might run into is the long vs short injectors. non turbo applications in the 6.2's used a longer body injector.
1994ch
Well-Known Member
Oil pan is different. I don't think it would fit a 4x4 truck but might work in a 2x4. (can't swap the pan out due to the different rear main seal AK talked about.....)
ak diesel driver
6.5 driver
IIRC MGW did a write up on pans and there was a couple of years that would work
1994ch
Well-Known Member
I want to say that the year break on that was later 80's like maybe 88 or 89 .... they started having the same oil pan (think it goes with the body style change....) But AK is correct that there is a year where they are the same. I went through all of this when I did the 6.2 swap into my tahoe and I used MGW,s write up a bunch...
Paveltolz
Доверяй, но проверяй
I'm currently running a 6.2 N/A 660 block and just as dbrannon79 said, everything save the oil pan coming off 6.5s fits just fine.
Oil Pan: If the 6.2's oil pan's shape is the like your 94's, there will be no 4x4 fitment issues.
Injectors: Since you are keeping your 6.5 heads, there's no concern about short or long body injectors, just use the ones you have or, new 6.5's.
Turbo & OPS Oil Feed ports: You will need to pay attention to the turbo oil feed port on the front of the block because chances are your donor block won't have one. There may not be an OPS port cast in the valley either. On my block, is a port at the back of the motor, driver's side. I cobbled up brass fittings (1/4"NPT) to a 'T' block to accommodate both OPS and Turbo Oil Feeds. If you have to go this route, do it before you drop the motor in, Pretty tight working area back there along with back strain. Trust me.
Don't get fancy, use brass. I tried to 'upgrade' to ARP anodized blingy stuff and there's no path to ground for the OPS.
Oil Pan: If the 6.2's oil pan's shape is the like your 94's, there will be no 4x4 fitment issues.
Injectors: Since you are keeping your 6.5 heads, there's no concern about short or long body injectors, just use the ones you have or, new 6.5's.
Turbo & OPS Oil Feed ports: You will need to pay attention to the turbo oil feed port on the front of the block because chances are your donor block won't have one. There may not be an OPS port cast in the valley either. On my block, is a port at the back of the motor, driver's side. I cobbled up brass fittings (1/4"NPT) to a 'T' block to accommodate both OPS and Turbo Oil Feeds. If you have to go this route, do it before you drop the motor in, Pretty tight working area back there along with back strain. Trust me.
Don't get fancy, use brass. I tried to 'upgrade' to ARP anodized blingy stuff and there's no path to ground for the OPS.
Price a new truck : any engine. Your budget should now reflect that for repairs to this one. Hell even drop in a gas engine from a junk yard.
Check for cracks in the block and heads. (just pull the oil pan and check main webs) Low miles (on the 6.2) doesn't mean anything RE: if it's cracked to death or not. I doubt the 300K block is crack free. If it actually IS it may be worth rebuilding.
1983 primitive glow plugs and control system may have fed the engine a busted glow plug. They need to be replaced with the self limiting AC-Delco 60G's anyway. This is the only inspection I would do short of actually pulling the heads.
I would drop the complete 6.2 in without swapping heads. I wouldn't even swap the likely wore out short body injectors over. Header wrap the turbo side manifold and use two header gaskets if needed for long body injector clearance to the manifold. 6.5 heads have a different injector angle for better manifold clearance, but, So What?! Save some $$$ : labor, bolts, and gaskets. (I recall the long body injectors fit the 6.5 manifold tightly with the gaskets and header wrap to keep the heat off em, but, it's been over a decade since I did that.)
Rebuild your short body injectors with not china nozzles if you want to use them in the 6.2 heads.
Stock the 6.2 NA precups will cause more smoke and a slight power loss = about 2MPH off top speed flat out towing around ~63 MPH. The uncoated pistons will heat the engine oil up more. Unless you work the truck you won't notice.
IF you are going to pull the heads at the minimum deglaze the cylinders and drop in gapless rings. To prevent any additional main web cracking block stress I would do so without touching the main bearing bolts.
Because you are looking at it change the timing chain on the 6.2L. They stretch out by 30K miles. Best is a aftermarket gear drive if they make em at this time.