Broken Crankshaft Count?
- Thread starter EDP
- Start date
The block i used the for the build is the original block. Holland automotive machine did the machine work. The block was magged, Decked to 90 deg, bored 40 over deck plate honed. the original mains were not scored and measured within spec after the first cracked crank. Socal billet mains were installed and torqued to 225 align bored and honed to .0035 The entire rotating assembly was exteranally balanced on a CWB balancing machine. That being said, I dont think I will go to holland automotive machine again for machine work. They did some things that made me second guess their attenion to detail.
The block and all the components were taken to my friend Brian Robbins shop. He builds top notch blown alcohol motors. He personally re measured everything before I assembled it.
The truck itself is very quiet with the 2 turbos 4" exhaust with 2 mufflers. Its easy to hear the motor over the exhaust. The sound distinction between the original motor and the built motor was subtle. I worried about it at first but with 30,000 miles and every oil changed being lab tested and coming back clean there was no evidence that something was wrong inside before the crank broke the second time. I'm not saying i'm an amazing engine builder but if I did something wrong, It seemed like there would have been some evidence before just snapping a crank.
The original stock bottom end never dynoed over 580 rwp and 1012 ft lbs.
The built motor was never on the dyno with the 100 over injectors but judging by the stock/s475 turbo setup it probably only made low 700s on the rollers. Rob Coddens has always tuned my truck and i have always been pleased with his ability to tune.
I'm going to tear it apart Saturday and see if the block is trashed. even if it looks good i agree Ill have second guesses about reusing it. Its just hard to toss a block with billet mains and all the machine work invested into it.
The block and all the components were taken to my friend Brian Robbins shop. He builds top notch blown alcohol motors. He personally re measured everything before I assembled it.
The truck itself is very quiet with the 2 turbos 4" exhaust with 2 mufflers. Its easy to hear the motor over the exhaust. The sound distinction between the original motor and the built motor was subtle. I worried about it at first but with 30,000 miles and every oil changed being lab tested and coming back clean there was no evidence that something was wrong inside before the crank broke the second time. I'm not saying i'm an amazing engine builder but if I did something wrong, It seemed like there would have been some evidence before just snapping a crank.
The original stock bottom end never dynoed over 580 rwp and 1012 ft lbs.
The built motor was never on the dyno with the 100 over injectors but judging by the stock/s475 turbo setup it probably only made low 700s on the rollers. Rob Coddens has always tuned my truck and i have always been pleased with his ability to tune.
I'm going to tear it apart Saturday and see if the block is trashed. even if it looks good i agree Ill have second guesses about reusing it. Its just hard to toss a block with billet mains and all the machine work invested into it.
I do understand the feeling of wasted money. I just felt the had to be something that wasn't accounted for even though it all checked out. What main clearances did you run? I hear there are more broken cranks with tighter clearances than with looser ones. I usually run .0035 to .004 mains now. I believe the one that broke was about .001 tighter than those.
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looks like hes saying main clearance came out to .0035 after the align hone with the billet mains.
Sounds like that maybe the case. The only way hone to a clearance is setting up and checking again and re honing. Maybe that's ultimately what he meant.
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I can vouch for the noise change as well. Changed to fingers oval bowls and a 6480af cam with this last build. The noise difference was pretty moderate. Has messed with me a lot as I'm overly paranoid about the sounds this truck makes haha.
I can agree, the wagler stage 1 street AF cams have a distinctive sound to them. I'm paranoid of different engine sounds from my AF cam lly I drive on the weekends while I drive a stock lb7 and stock lly during the week
I noticed the same changes as well, my truck now has a really distinct tone to it after the motor build. Fingers ovals, 6480af cam, ported stock heads, HSP billet manifolds
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Won't let me vote again, but chalk up another LMM.
Buddy just purchased an 08 with 180k an a random misfire. He drove it home 30 miles, said ran like crap and ask me to take a look. Crank sensor and cyl misfire codes. Quick glance at the damper, wobble wobble...
On a good note, last owner just paid someone to put 8 new injectors in it... :thumb:
Buddy just purchased an 08 with 180k an a random misfire. He drove it home 30 miles, said ran like crap and ask me to take a look. Crank sensor and cyl misfire codes. Quick glance at the damper, wobble wobble...
On a good note, last owner just paid someone to put 8 new injectors in it... :thumb:
Just confirmed another broken crank in a built motor:
2015 LML:
New stock LB7 crank
Carillo Rods
Mahle Performance Cast .040" over pistons
ATI Damper
LB7 flywheel with BD flexplate
Balanced Rotating assembly
All 5 main caps doweled to block
Main studs
Head Studs
SoCal 9100AF cam
200% over injectors running less than stock pulse (962uS) and 17* max timing
12mm S&S CP3 conversion
S363/68/.90T4 and S480/96/1.32 Forced Inductions ETR-HOs in HSP kit
PPE Manifolds and up-pipes
Mishimoto intercooler
Stock heads with Hamilton valve springs and Empire pushrods
Dynoed 840 rwhp on a dyno that couldn't give it near enough load to come close to full boost.
Ran 11.7s@117 his first time to the track on stock 20s.
Motor had about 12,000 miles on it.
We had a 369SXE and a Forced Inductions S488 on order for the truck, a set of heads is being ported with bigger valves and everything, and a new cam is on the way - so we were about to push it up over 1000 rwhp and I was starting to worry about doing that on those pistons and stock main caps with no girdle.
Sounds like he will be going back with a Callies Ultra billet, our new .202" longer X beam rods, forged pistons with steel inserts, internally balanced, half fill, billet main caps and girdle, CA625 head studs.
2015 LML:
New stock LB7 crank
Carillo Rods
Mahle Performance Cast .040" over pistons
ATI Damper
LB7 flywheel with BD flexplate
Balanced Rotating assembly
All 5 main caps doweled to block
Main studs
Head Studs
SoCal 9100AF cam
200% over injectors running less than stock pulse (962uS) and 17* max timing
12mm S&S CP3 conversion
S363/68/.90T4 and S480/96/1.32 Forced Inductions ETR-HOs in HSP kit
PPE Manifolds and up-pipes
Mishimoto intercooler
Stock heads with Hamilton valve springs and Empire pushrods
Dynoed 840 rwhp on a dyno that couldn't give it near enough load to come close to full boost.
Ran 11.7s@117 his first time to the track on stock 20s.
Motor had about 12,000 miles on it.
We had a 369SXE and a Forced Inductions S488 on order for the truck, a set of heads is being ported with bigger valves and everything, and a new cam is on the way - so we were about to push it up over 1000 rwhp and I was starting to worry about doing that on those pistons and stock main caps with no girdle.
Sounds like he will be going back with a Callies Ultra billet, our new .202" longer X beam rods, forged pistons with steel inserts, internally balanced, half fill, billet main caps and girdle, CA625 head studs.
Another alternate fire cam motor bites the dust.........
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I haven't been on here much lately, but the first I know of off hand that was a brand new crank that had only ever been run with an AF cam.
Now that the Callies Durastar/Compstars are out we have started using them in all cast piston builds. Our forged piston builds get Callies Ultra Billet cranks.
Are the Callie's durastar and compstar cranks any better then a Stock crank in design? Or is the improvement in those limited to material and manufacture process only?
Seems to lots of contradicting info out there.
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if the LML crank is no stronger then why do people choose it quite a bit for their new build?
As far as the af cam goes. I can see both ends of it not being 100% proven but honestly if you've got a new build or even just doing a swap I see absolutely no reason not to run it. Even if there is a .00000000000000001 chance of it helping what's the point of not going af
As far as the af cam goes. I can see both ends of it not being 100% proven but honestly if you've got a new build or even just doing a swap I see absolutely no reason not to run it. Even if there is a .00000000000000001 chance of it helping what's the point of not going af