Chevy Diesel - Replace or Convert?

[stickshift_or_walk]

Originally Posted by Cowboy Eddie

Stickshift or walk, I have an 84 toyota diesel p/u. Found it accidentally, and I'm intriqued by diesels. Now I have an opportunity to buy a 83 Chev diesel p/u, with no engine. Its always been my understanding that Chev diesels were not so good. What do you think of reinstalling a later model diesel in it, or just converting it to gas? Thanks Ed

Ed,

I've owned an '82 Jimmy and this '85 G20 with the 6.2 diesel. As you might expect, neither were hotrods, but IMO they are adequate, get decent mileage under most conditions, and are suited for pulling trailers. Maintenance on both was comparable in quantity to the 350's I've owned, but more expensive. I have heard from others who have had much worse experience, but I can only speak for my own.

If the 6.2 in my van died tomorrow, or required significant repairs, I would seriously consider a conversion. The factors that influence this decision are:

1) power - my G20 has trouble keeping up on 70mph highways
2) noise - even with the extra insulation from the factory, the noise is significant.
3) fuel cost - with 20 MPG max, the additional cost of diesel fuel here pretty much negates the advantage it would have over the 15 MPG I would expect from a 350.

I know where there are several G-series in salvage yards, and the 350 & tranny would likely cost less than rebuilding the diesel. I would also get the tranny, because based on advice from this board, I understand the diesel version of the 700R4 is weaker in addition to being programmed quite differently, and won't stand up to the higher-revving gas engines, even if you adjusted the shift points. FYI, my van hits overdrive at 25-30 mph if left to shift on its own.

I would keep the hydrovac brakes and big radiator. I suspect bringing the starting voltage down to 12V would be no big deal, and the dual batteries could come in handy.

As for a later engine, I've heard even worse reviews of the 6.5, and later engines would require computer swaps into your non-computer truck, which can be both tricky and expensive.

I'm sure others will be happy to give you their views as well, or correct me if I've missed something.

SSOW

[jimfulco]

No personal experience here, but I once sold a 305 to a guy who had had his fill of 6.2 problems and wanted to convert. I saw him a few months later and he said he was glad he did it.

[motopatzo]

The 6.2 and 6.5's aren't that bad. The earlier 5.7 oldmobile diesel engines were notoriously bad on the other hand and that's why I think GM's diesels got a bad rap.

If a diesel won't do 70mph, I would look for other causes. Perhaps gear ratio or maybe a mechanical fault in the engine. Yes diesels are noisy, can be expensive to repair and a lot of people don't know how to work on them....but they are very good when used in the right applications.