LB7 crank
- Thread starter tracygto
- Start date
damn so wouldn't it be better just to use a lmm crank???? I have a engine at the machine shop with a LMM block bad LMM crank good LB7 crank that was given to me by junk yard that sold me motor so i need to positively know if the LB7 crank will work???
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LMM/LBZ crank is heavier/thicker/stronger than LB7/LLY crank. LB7/LLY crank will work if balanced correctly. AS in internally balance crank by machining the crank self which can be pretty pricey or I think you could just use LB7/LLY balancer and flywheel again lil pricey. IMHO not worth trouble or money just get a good LBZ/LMM crank.
I think your getting that mixed up with LB7/LLY pistons. stock LB7/LLY pistons were made by mahle and less prone to cracking in higher hp setups like 700hp plus than LBZ/LMM pistons
I never heard that. also here guys wanting to start with LBZ/LMM block and crank to build because LBZ/LMM block and crank were strengthen and thickened in certain areas.
Easiest to just find an LMM crank. Not that expensive. Then get it checked for straightness and fluxed. Key it and install.
Never heard this before.... It must not matter because they break just as much as the others. Pretty sure last I checked the broken crank thread, all models were neck and neck.
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No I'm not getting it mixed up lol. Pretty sure Kyle harbin for example just put a new lb7 crank in his lmm.
No I'm not getting it mixed up lol. Pretty sure Kyle harbin for example just put a new lb7 crank in his lmm.
dont know kyle harbin but The part where the cranks break at the journals as in where the rods ride on are the same size lb7/lly to lbz/lmm. So thats prolly why the cranks breaking is pretty even. I guess maybe they go with LB7 crank since its lighter so to make more power with less rotating mass.
I wasnt saying one more prone to break just that their different mass so need balanced differently just to answer the OP question. Just think be easier and cheaper for him just get lbz/lmm crank. depends tho on how much hes building the motor like if getting internally balance already then go with lb7 crank he has already.
I wasnt saying one more prone to break just that their different mass so need balanced differently just to answer the OP question. Just think be easier and cheaper for him just get lbz/lmm crank. depends tho on how much hes building the motor like if getting internally balance already then go with lb7 crank he has already.
sorry i didnt mean to mislead that one crank is less prone to break than other by saying stronger. I just answering the OP questions and explaining the physical difference.
Don't hear it often but if you do the LB7 crank seems to be preferred for whatever reason, along with the LBZ block and LB7/LLY pistons with LBZ rods. If you are looking to mix and match stock parts.
My LMM truck had an LLY block with a new LB7 crank with carrilos and SoCal pistons. Had the appropriate balancer and flywheel for lb7. We are putting an LBZ crank back on it this time.
The lb7 only lasted 4,000 and a handful of times over 900hp. Could have been a fluke but said the hell with it and got a used crank from a buddy.