To be or not to be.... Lb7 with lml piston+rods

justinakers37

justinakers37

New member
What kind of numbers can a lml rod and piston setup hold? I see a few people have lml short blocks pushing 650. But is it safe and could you go higher near 700? Just like to hear either horror stories or fairy tales either way I'd be happy with any input. Thank you
 
I thought lmm rods were the newest that would work in an lb7. Not sure though never tried it. I would like to know though.
 
Well I know fleece has an lml short block truck layed down around 650 but see no evidence of there breaking point. Haven't heard anything of lmm rods
 
kauser44 said:
I thought lmm rods were the newest that would work in an lb7. Not sure though never tried it. I would like to know though.
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If you use an LML piston, you can also use the LML rods. The LMM rods are pretty similiar to the LB7's as far as dimensions, but the LML rod is narrower at the top where it sits inside the piston. I know to run LML pistons you either have to machine the pistons, run LML rods, or machine the rods to fit. As far as how much it can hold, theres not that many out there that have pushed them and found the limit since you would have to swap the LML parts into an 10- truck to find out since the LML doesn't have enough fuel in stock form to find the limits.
 
Well are they any better then lbz rods? Because I feel like that build would be kind of pointless, on the other hand if I can squeeze a little over 650 out of the lml rod and piston setup I would be willing to try it
 
From what i have heard, The LML rod is supposed to be close to the LB7 rod as far as power handling capabilities. If you're looking for a budget build to make 650-700hp then use LBZ rods on delipped LB7 pistons. Run a large single charger and keep the torque out of the lower rpm range and bring the power in way up top.
 
I might consider trying it.. my brother ran a lly lml bottom end at what I believe was 700+ as it beat many built trucks.. dual pumps, head studs 100% overs modded 4094.. for a year of pulling and dd. so I would also like to know whats the bast way to make them work
 
Yes I have seen a set. You cannot base the strength of a connecting rod on what it looks like. IMO, there is not enough high hp trucks running LML internals to answer your question. If you wanna test it, by all means go ahead. I personally don't have enough money to waste on rebuilding an engine a couple times. Also, I think it's dumb to rebuild any duramax with any factory rods. Especially if you are doing a build because of a bottom end failure.
 
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DirtyMaxx03 said:
Yes I have seen a set. You cannot base the strength of a connecting rod on what it looks like. IMO, there is not enough high hp trucks running LML internals to answer your question. If you wanna test it, by all means go ahead. I personally don't have enough money to waste on rebuilding an engine a couple times. Also, I think it's dumb to rebuild any duramax with any factory rods. Especially if you are doing a build because of a bottom end failure.
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Well I just didn't know if they were noticeably beefier I can't find thickness dimensions. And yea I think this is about where I'm at with it. I don't want to sink a few thousand into a motor to only to make a few new windows in the block, because of not spending the extra thousand or two on good rods. Just wanted to check into it and see if it was worth while
 
It's going to take a long time before there is an answer to that question. Yes, there are 700+hp duramax's with LML rotating assemblies. But, there are also 700+hp duramax's with stock LB7, LLY, LBZ and LMM rotating assemblies. If you want to use more than 600hp on any sort of regular basis, go billet rods.
 
Lb7_Katie said:
Honestly could go 2 ways with it. Happy with that 6-700 range or all out DPC 14. I'm still so undecided.


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overbuilt is always better.... granted woosley been winning with a 600-700hp truck because its deadly stupid reliable .. i think DPC for the MPG test SHOULD have the skidsteer on the back of the truck!

makes me miss being deployed in combat theater floating in a box :lolly:
 
Agreed overbuilt is always better. Just gotta afford it haha but a daily with 700hp would be nice.


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Lb7_Katie said:
Agreed overbuilt is always better. Just gotta afford it haha but a daily with 700hp would be nice.


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depending what you can work out labor wise looking at less then ~10k parts
that's rods, piston, HS/MS, keyed crank/cam and waterpump, large single CP3 and either large turbo or twining the stock turbo with a 75-80mm turbo will get you really close to that. twining the stock would make for a very reliable DD

i have built a short block for ~7k. i just did a bore and balance using mahle race cast pistons for ~3500.00
 
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