4.3L gas to 6.2 or 6.5 diesel swap

[superdave796]

I have a 1987 Chevy 1/2 ton 4X4 pickup with a 4.3L V6 and a 4 spd manual. I would like to swap to a 6.2 or 6.5 diesel. I was wondering what all is involved with the swap: motor mounts, radiator, and will it bolt up to the 4 spd? How difficult to switch to automatic? Also which would you reccomend, the 6.2 or 6.5? Thanks.

[NH2112]

My signature tells about my truck that's very similar to yours. I didn't do the work, but the guy who did is a friend and there's really not much to it. You'll need the diesel flywheel if you're going to keep the manual, first of all. That's probably going to be the most expensive part besides the engine. You'll also need the diesel radiator, a hydroboost unit and matching P/S pump (if you don't get all this stuff with the engine) and a fuel filter. That's really pretty much it for the needed parts. Use an ignition-hot pushbutton switch to power a heavy-duty relay for the glow plugs. The + coil wire goes to the fuel shutoff solenoid, and the electric choke wire is good for powering the fuel heater if the filter you get has one. Make sure to either use diesel gauges or else put gasser senders on the engine.

As far as which engine to use, any of the 3 - 6.2l NA, 6.5l NA, or 6.5l turbo with mechanical pump - will pretty much install in the same way. The turbo may have fitment problems if you have AC, and you'll probably need to notch the frame for downpipe clearance. It all depends on what you want for power. Durability-wise, the late 6.2l and early 6.5l will be best because of heavier castings, plus they have 1-piece rear main seals. I've had 2 6.2ls that have went past 250K miles, though, and my current one is at 265K or so and still running strong.

[trbankii]

Since you converted from gas to diesel, can you give me some idea of the differences between the two? You mention the A/C and frame interference. Is the engine basically the same size but accessories are in different places? Also, did you have to modify the suspension at all for the additional weight?

[NH2112]

Well, I didn't do the work but I know wha twas involved. The 6.2l is about twice the weight of the 4.3l, and slightly bigger in size than a 350. It would probably be a good idea to put heavier front springs in, but as far as I know mine are the stock 4.3l springs and they do pretty well. I can't zoom through cloverleafs at 40-45 like I did with my K10, though! The alternator is on the passenger side, the p/s pump and AC compressor are on the driver side. Clearance with the AC won't be an issue unless you use a GM factory turbo, I believe both the Banks and ATS setups for the 82-87 g.2l trucks had enough clearance. The same goes for the GM turbo's downpipe. I wish I had a better mental image of how the 4" exhaust a friend (the one who put this diesel in my truck) exits his 80s model SRW K30, I want to say he cut the inner fender and ran it out the fenderwell and under the cab floor then back to the frame.