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Thread: 6.5 engine swap

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    Default 6.5 engine swap

    I am new to the hummer and am considering swapping the 6.2 to the 6.5. I have read the posts about the swap and I think I can handle it. I am wondering about the fuel delivery. Do they both use an electric pump? I heard the 6.2 uses a mechanical and the 6.5 an electric. Any advice out there?

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    4 Star General Retiredwarhorses's Avatar
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    Assuming your going with the detuned 6.5, you will notice no real improvement in anything.
    if it were me, I would go with a full A2 6.5 drivetrain and install TCM to make the 4 speed trans operable.
    more work and money for sure, but a detuned 6.5 will do nothing for you.
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    4 Star General Wire Fox's Avatar
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    Default

    Quote Originally Posted by exoilfld View Post
    I am new to the hummer and am considering swapping the 6.2 to the 6.5. I have read the posts about the swap and I think I can handle it. I am wondering about the fuel delivery. Do they both use an electric pump? I heard the 6.2 uses a mechanical and the 6.5 an electric. Any advice out there?
    You heard wrong, at least for the HMMWV. All HMMWVs use a mechanical fuel lift pump and mechanical injection pump. The difference in fuel delivery between the engines is how the injection pump is tuned, and the injectors used. In regular civilian vehicles using this engine, they DID switch to electronic injection pumps around the time the engine size switched to 6.5L.

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    what is a tcm?

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    never mind; I figured it out.

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    3 Star General TOBASH's Avatar
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    I have a 6.2 and it works just fine. There are ways to slightly increase the HP, by slightly increasing fuel delivery and increasing timing BUT if done improperly you will fry your pistons.

    If you want more HP, I think you're talking about a 6.5 Turbo.

    The 6.5 normally aspirated (n/a) would yield little benefit IMHO.

    Hope this answers your questions.

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    I have heard that parts (at least readily available from non-military sources) for the 6.2 are hard to come by.
    My local repair shop (staffed by former Chevy dealer refugees) said in terms of parts availability, to go with the 6.5 non turbo.
    True?
    --------------------------------------------------
    They also like the idea of a Duramax swap, saying it's a good engine.
    There is a large wrecking years here that gets lots of GM stuff, including factory salvage.
    Is there a kit or instructions for a swap?

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    4 Star General NormB's Avatar
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    Quote Originally Posted by JEB View Post
    I have heard that parts (at least readily available from non-military sources) for the 6.2 are hard to come by.
    My local repair shop (staffed by former Chevy dealer refugees) said in terms of parts availability, to go with the 6.5 non turbo.
    True?
    --------------------------------------------------
    They also like the idea of a Duramax swap, saying it's a good engine.
    There is a large wrecking years here that gets lots of GM stuff, including factory salvage.
    Is there a kit or instructions for a swap?
    For an idea of how many after market and OEM parts ARE available for 6.2L diesel motors, surf on over to the forbidden auction side (fleabay) and do a search for "6.2L diesel motor/engine/parts/rebuild/etc".

    There's only been several million Detwah (Detroit) diesels manufactured in the past four decades, 6.2s are generally easily found and most shops know how to rebuild/service them.

    From what I've learned through this forum, talking to guys like "Scrounger" (Andrew), reading RWH's and many, many other posts here, unless you're going with the turbo upgrade, there's little HP/performance increase with the 6.5s and they seem to grenade about as often as any (even the turbos detonate from time to time).

    I'm writing this partially as a self-serving note as I have a 6.2NA in mine with a 3-speed, absolutely HATE highway traffic so 40-50mph is fine with me (still considering taking the truck down to TN in a few years, sticking with backroads, take a few days to cover the 800 miles), there's less electronics and such to deal with than a 4-speed and the TH400 3 speed is SO smooth I can't even tell it's shifting (look into how many of these transmissions have been used in dragsters)... I AM still looking for a good/used salvage 6.2 with/without transmission/TC for a "spare" (little bit of "scrounger" in all of us) as I have boocoo storage space at my farm in TN.

    Keep us posted with your decision process, triumphs and travails, costs, details.

    Norm
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    I have the 6.5 with the three speed trans in my HMMWV. I just bought two 6.2 diesels from my local Chevy dealer. They have been on the shelf for years. When the 6.5 dies I’ll be swapping in one of the 6.2s. For my money I’ll stick with a 6.2 all day any day.
    Shannon Deese

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