LBZ bottom end with LMM Top end

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03-10-2020, 18:24
dmaxjeep

LBZ bottom end with LMM Top end

Hello All,

If I posted this in the wrong place on the forum please advise. I'm Potentially looking at buying an LMM with bottom end issues. The previous owner has had the machine work on the heads done and ordered gasket kits for the Top end but I have a couple good LBZ motors. One of them is low miles but had a small head gasket leak. My question is can I just swap the top end parts from the LMM (Heads and up) onto the LBZ and reinstall it? Since the blocks are almost identical besides the casting design I figured it wouldn't be a big dealt just use the lbz bolt on the top end and stud it and reinstall it. Has anyone done this or have any idea if I'd run into any known issues doing this? I went to a local shop who said he didn't think it would be an issue and he quoted me 40 man hours ~ $4k with fluids and filters. I'm not opposed to paying someone to do it, but since this would require little engine assembly in terms in only doing the top end of the lbz converted to the LMM top end, I figure I could know it out in a weekend since the engine is already pulled. Any advice to or fluids I should change (trans etc.) I should so while I'm at it would be appreciated as well. TIA!, Paul
03-11-2020, 16:08
More Power

I don't know about sensor compatibility. I'd try setting a head onto a block to double-check bolt alignment, and anything else, like cooling/oil passages.

Jim
03-12-2020, 12:47
ToddMeister

These guys might know the answer

Contact dirtyhookerdiesel.com, ask for Tony Burkhard. Their phone number is at the top of the webpage.

They build up Duramax engines for sled-pulling and drag racing trucks.

They may know if the LBZ/LMM combo would work.
03-13-2020, 08:31
Kennedy

Quote:

Originally Posted by dmaxjeep

Hello All,

If I posted this in the wrong place on the forum please advise. I'm Potentially looking at buying an LMM with bottom end issues. The previous owner has had the machine work on the heads done and ordered gasket kits for the Top end but I have a couple good LBZ motors. One of them is low miles but had a small head gasket leak. My question is can I just swap the top end parts from the LMM (Heads and up) onto the LBZ and reinstall it? Since the blocks are almost identical besides the casting design I figured it wouldn't be a big dealt just use the lbz bolt on the top end and stud it and reinstall it. Has anyone done this or have any idea if I'd run into any known issues doing this? I went to a local shop who said he didn't think it would be an issue and he quoted me 40 man hours ~ $4k with fluids and filters. I'm not opposed to paying someone to do it, but since this would require little engine assembly in terms in only doing the top end of the lbz converted to the LMM top end, I figure I could know it out in a weekend since the engine is already pulled. Any advice to or fluids I should change (trans etc.) I should so while I'm at it would be appreciated as well. TIA!, Paul

Pull the heads on the low miles LBZ skim cut them and reinstall with studs. No need to buy a bunch of other stuff.

The LBZ and LMM heads should interchange, but there is really no need to machine anything but the surface.