6.2l or 6.5l diesel

[Blazer Eagle]

How can i definitely tell if i have a 6.2l or 6.5 l in my suburban? Its a 1986 which should be a 6.2, the owner swears its a 6.2.....but the valve covers say gm performance 6.5


how can i tell for sure there wasnt just a valve cover swap?

[MadManAndrew]

Don't really know much about either engine, but find the casting number on the back of the block and then google it. That will tell you.

[OnDaTrail]

6.2 and 6.5 valve covers are the same, check the heads.

[odee]

check the numbers on the rear of the block

[andrewmp6]

Isn't all 6.5 turbo and the 6.2 isn't?

[Blazer Eagle]

from what ive read the 6.5 was usually turbo....but the suburban was originally a 6.2l nonturbo

ive also read that in the 90's they sold 6.5l as replacement motors for the 6.2ls since they were bolt in replacements and were being mass produced at the time


so it looks like ill have to check the block casting numbers - the only reason im really asking is i hve a friend who has a turbo for a 6.2l, which supposedly wont work on a 6.5l

[Edahall]

Originally Posted by Blazer Eagle

from what ive read the 6.5 was usually turbo....but the suburban was originally a 6.2l nonturbo

ive also read that in the 90's they sold 6.5l as replacement motors for the 6.2ls since they were bolt in replacements and were being mass produced at the time


so it looks like ill have to check the block casting numbers - the only reason im really asking is i hve a friend who has a turbo for a 6.2l, which supposedly wont work on a 6.5l

A turbo for a 6.2L will work just fine on a 6.5L. What brand of turbo is it? The reason I'm asking is many aftermarket turbo's provided too much turbo boost for these engines and would greatly compromise engine longevity. The bottom end just isn't strong enough. For a 6.2L, about 9 psi is about all you want to go and even that's pushing it.

[lindstromjd]

Look on the front right part of the engine right behind the water pump housing. If it's a 6.2, it'll be stamped GM 6.2L D.

Not all 6.5's were turbo'd. Just most of them. There's too many variables to reliably tell you just by looking at one piece of the puzzle.

If you want to beef up your engine and help it out on the bottom end, look into getting main girdle studs (similar to head studs). They really help a lot with being able to hold extra compression from a turbo, and bottom-end longevity in general.

[joe231]

The 6.5 TD injectors are angled and shorter to clear the turbo, where the 6.2 has longer injectors and are straight (perpendicular to the head). I'm in sure if tge 6.5 NA heads are the same as the TD though....
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[lindstromjd]

Originally Posted by joe231

The 6.5 TD injectors are angled and shorter to clear the turbo, where the 6.2 has longer injectors and are straight (perpendicular to the head). I'm in sure if tge 6.5 NA heads are the same as the TD though....
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Don't forget that sometimes it depends on what vehicle the 6.2 came out of, too. Vans had shorter injectors than a standard 6.2... just wanted to throw that out there.

[joe231]

Originally Posted by lindstromjd

Don't forget that sometimes it depends on what vehicle the 6.2 came out of, too. Vans had shorter injectors than a standard 6.2... just wanted to throw that out there.

Right, but as far as I know all 6.2's had perpendicular (straight) injectors, no?
But I don't know if all 6.5's have angled injectors.
And since the heads will interchange you would really have to check the block to make sure what it is. I don't know of a clear advantage between a 6.5 and a 6.2 if you take the turbo out of the equation.

Keep in mind that I'm still fairly new to these engines and trying to learn all I can,but I'm definitely a detroit diesel convert

Oh, and I also read that the 85-up 6.2 injectors will swap with the 6.5 injectors, I have no real world experience with it yet though

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[lindstromjd]

Originally Posted by joe231

Right, but as far as I know all 6.2's had perpendicular (straight) injectors, no?
But I don't know if all 6.5's have angled injectors.
And since the heads will interchange you would really have to check the block to make sure what it is. I don't know of a clear advantage between a 6.5 and a 6.2 if you take the turbo out of the equation.

Keep in mind that I'm still fairly new to these engines and trying to learn all I can,but I'm definitely a detroit diesel convert

Oh, and I also read that the 85-up 6.2 injectors will swap with the 6.5 injectors, I have no real world experience with it yet though

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I don't know about anything being angled... maybe it's in the heads. But any 6.2 and 6.5 injector is interchangeable as long as you have the fine thread injectors from later model 6.2's. Some of the early years have coarse threads. Late model 6.2's and all 6.5's have fine threads. I have marine 6.5 injectors in my 6.2, and they're just a little shorter than the standard 6.2 injectors.

[joe231]

Good to know!

Yeah the threaded holes in the 6.5 heads are angled
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