6.5 vs. 6.6 Duramax?

[N900WM]

Need some help on the diesel front...

 

Looking at a 98 3500 dump that is advertised with a D-Max. I looked at the truck today and the sticker under the hood says it's a 6.5L.

 

I know the D-Max is a more powerful engine. What's the differences and any advise/info on the 6.5? Is it a good engine? What year did GM come out with the D-Max?

 

This is our first diesel, in a truck, since the famed 1980 350 converted to a diesel GM fiasco.

[RonJ]

The Duramax came out in 2001. I've had two 6.5 TD's and a 6.2(1984) I have a 3500HD now that is ok...now... but its been a PIA.

[R Dogg 56]

I'm sure I'm not the only one who will share their info and/or advise on this matter, but here I go anyway.

 

The GM 6.5L was an evolution of the 6.2L. With a slightly increased bore and stroke, it was larger by a few cubic inches but had a stronger bottom end, better heads, and best of all, turbocharging. There were NA versions that were rated at 155hp available (at the time) for use in the Humvee, but not in the general use in LD pickups. The turbo-powered engines put out 190 hp/385 lb-ft. They use(d) a mechanical DB-2 pump, and the DS-4 injection system. This system had been the “weak link” in the engine. It is capable of producing outputs of nearly 300hp/550 lb-ft, but you will need to spend quite a bit in order to get those results (a special injection, intercooling, et cetera), but it is doable. The 6.5L is still in production, but reserved for the Humvee and the civilian Hummer H1. It is a 396 c.i. engine with a bore and stroke measurement of 4.05x3.82 inches. The compression ratio is 21.3:1. The injection system is a Stanadyne Rotary DS-4 indirect and mechanical pump with electronic controls. Aspiration is through a wastegated turbocharger. Reportedly, EGT’s are 950*F sustained (per industry sources) and 1250*F maximum.

 

In it's day, the 6.5L was a very reliable and strong engine. But like all things, times change, and the time of the 6.5L was 1993-present in the Humvees and Hummers and 1993-2000 in the LD and HD pickups. Now, the Duramax is the diesel of choice for GM owners and enthusiasts. Compared to the Duramax, the 6.5L seems old, almost ancient technology. It's not a bad engine at all. It's just that the internal design limited that power somewhat severly.

 

But, it really all depends on your choice. Good luck to you and let us know how it turns out.