Engine Killed the Mains, Engine builder says crank flex, I call BS... ***PICS***
10-20-2013, 07:39 PM
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Engine Killed the Mains, Engine builder says crank flex, I call BS... ***PICS*** I've got a forged piston/rod stock crank LQ4. (Eagle H-Beams, ARP 2000 rod bolts, SRP forged pistons, stock block/crank/main caps and bolts.
Its got an under-drive pulley that doesn't have a harmonic balancer built in to it... Ill get to that later...
Anyway, its making around 16lb's of boost on huge 24gph meth nozzles, on a 76mm turbo... Around 700whp. 16 degrees of timing. 10:1 CR (stock 317 heads with custom pistons to bring compression up)....11.7:1 A/F across the board under boost. smooth transition, everything looks perfect!
After 200 miles of break in, we finally got to tuning the car... after a full day of tuning, we were on our way back to the shop when we made 1 last pull...
We made a pull and went through 2nd, 3rd, 4th gears... after slowing down oil pressure went from 50 hot idle to 20 hot idle.
I knew something wasn't right.
Took apart the oil filter, HUGE metal shavings everywhere...
We looked at datalogs and shows NO signs of detonation.
Took the motor to my machinist, he said the crank is flexing under boost..
He sent the crank out to get wet mag'd and he said everything checks out ok... He said the crank just isn't strong enough for what I am doing, and flex
d under boost and ate the mains.
The 3 center mains were destroyed. the outer 2 were fine.
All the rod bearings were scuffed up pretty much all the way around, but I think it was because the mains started getting eaten up... Idk...
. the pistons, heads, plugs look PERFECT! no pitting or anything that hints to detonation...
The engine builder stated that he will do all the labor for free, and stated that if we turn the crank and put it back together its going to do the same thing... and that we need to put a 4340 Eagle crank in it.
I PERSONALLY think he just messed up... as in to tight clearances possibly, but im NO machinist to come up with a good conclusion.. Maybe the stupid under-drive pulley had something to do with this???? (no harmonic dampener)
He appears that he definitely knows his ****. All he does is small blocks/big blocks and has been in business for 20+ years and hes a 1 man operation...
What do you think happened????
here are the pics:
Its got an under-drive pulley that doesn't have a harmonic balancer built in to it... Ill get to that later...
Anyway, its making around 16lb's of boost on huge 24gph meth nozzles, on a 76mm turbo... Around 700whp. 16 degrees of timing. 10:1 CR (stock 317 heads with custom pistons to bring compression up)....11.7:1 A/F across the board under boost. smooth transition, everything looks perfect!
After 200 miles of break in, we finally got to tuning the car... after a full day of tuning, we were on our way back to the shop when we made 1 last pull...
We made a pull and went through 2nd, 3rd, 4th gears... after slowing down oil pressure went from 50 hot idle to 20 hot idle.
I knew something wasn't right.
Took apart the oil filter, HUGE metal shavings everywhere...
We looked at datalogs and shows NO signs of detonation.
Took the motor to my machinist, he said the crank is flexing under boost..
He sent the crank out to get wet mag'd and he said everything checks out ok... He said the crank just isn't strong enough for what I am doing, and flex
d under boost and ate the mains.
The 3 center mains were destroyed. the outer 2 were fine.
All the rod bearings were scuffed up pretty much all the way around, but I think it was because the mains started getting eaten up... Idk...
. the pistons, heads, plugs look PERFECT! no pitting or anything that hints to detonation...
The engine builder stated that he will do all the labor for free, and stated that if we turn the crank and put it back together its going to do the same thing... and that we need to put a 4340 Eagle crank in it.
I PERSONALLY think he just messed up... as in to tight clearances possibly, but im NO machinist to come up with a good conclusion.. Maybe the stupid under-drive pulley had something to do with this???? (no harmonic dampener)
He appears that he definitely knows his ****. All he does is small blocks/big blocks and has been in business for 20+ years and hes a 1 man operation...
What do you think happened????
here are the pics:
Last edited by 1SIKZ31; 10-20-2013 at 09:15 PM.
10-20-2013, 08:05 PM
#2
It will take awhile to find out what happend...
Sorry to see this, you should check your spec sheet and start listing all the clearances, tolerances etc..
Hopefully an experienced engine guy can figure it out!
How many ls style engines has your guy built?
Sorry to see this, you should check your spec sheet and start listing all the clearances, tolerances etc..
Hopefully an experienced engine guy can figure it out!
How many ls style engines has your guy built?
10-20-2013, 08:54 PM
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10-20-2013, 09:07 PM
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How many ls style engines has your guy built?
Honestly I have no idea... but he builds 1000+hp small/big blocks all the time...
What Oil?
Valvoline NON-syn VR1 20w50 (I told him I will be running this so he clearances the bearings properly)
What oil filter?
K&N
What oil pick up?
F-body pick up tube and F-body oil pan... Car does NOT lose oil pressure on acceleration, I have watched my oil pressure gauge before under boost..
What oil pump and pressure spring?
Mellings Standard Pump, and he shimmed it... it ended up being 70psi cold idle, 45-55psi hot idle...
What transmission?
Stock T56
How do the cam lobes and lifters look?
Literally perfect!!! What would this have to do with anything? Just curious!
What RPM's are you turning?
The max we saw was 6500rpms, rev limiter is set to 6800...
Clearances:
Mains at 30 thousandths
Rods at 20 thousandths...
He said he shoots for around 25 on both rods and mains...
Honestly I don't know if its the solid or drilled crank, but since its the same crank from the stock LQ4, I'm pretty sure its solid.
Oh and the stupid under-drive pulley is GONE!!!! I bought a factory brand new f-body balancer...
I think you answered all your questions.
really? lol hows that?!
Honestly I have no idea... but he builds 1000+hp small/big blocks all the time...
What Oil?
Valvoline NON-syn VR1 20w50 (I told him I will be running this so he clearances the bearings properly)
What oil filter?
K&N
What oil pick up?
F-body pick up tube and F-body oil pan... Car does NOT lose oil pressure on acceleration, I have watched my oil pressure gauge before under boost..
What oil pump and pressure spring?
Mellings Standard Pump, and he shimmed it... it ended up being 70psi cold idle, 45-55psi hot idle...
What transmission?
Stock T56
How do the cam lobes and lifters look?
Literally perfect!!! What would this have to do with anything? Just curious!
What RPM's are you turning?
The max we saw was 6500rpms, rev limiter is set to 6800...
Clearances:
Mains at 30 thousandths
Rods at 20 thousandths...
He said he shoots for around 25 on both rods and mains...
Honestly I don't know if its the solid or drilled crank, but since its the same crank from the stock LQ4, I'm pretty sure its solid.
Oh and the stupid under-drive pulley is GONE!!!! I bought a factory brand new f-body balancer...
I think you answered all your questions.
really? lol hows that?!
10-20-2013, 09:32 PM
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If dude is offering you free labor, give him the benefit of a doubt by buying the crank he recommends and have him put it back together. If it happens again, you'll both know who's at fault and also who's fixing it. It sucks having the car down, but understand that racing parts are always subject to extenuating circumstances.
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10-20-2013, 10:52 PM
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I would like to know how many LS motors he has built. They require a different touch than old school sbc stuff.
I think the guy means well based of him wanting to redo it for free but I really think he had the clearances wrong. That crank will hold 700 no problem.
I think the guy means well based of him wanting to redo it for free but I really think he had the clearances wrong. That crank will hold 700 no problem.
10-20-2013, 10:53 PM
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I ask those questions to rule out in things.
I doubt very serious that it was do to the stock crankshaft flexing as they are pretty tough units that have had more torque applied to them than your 347ci.
Curious as to why he shimmed the melling 10295 it already has a high pressure spring or use the melling 10296 HV pump.
I think you have an oilling issue or lack of.
Try stepping it down to 15w-40 Cheveron delo conventinal w/ Lucas ZDDP the next go round. I pretty sure your turbo will thank you.
I doubt very serious that it was do to the stock crankshaft flexing as they are pretty tough units that have had more torque applied to them than your 347ci.
Curious as to why he shimmed the melling 10295 it already has a high pressure spring or use the melling 10296 HV pump.
I think you have an oilling issue or lack of.
Try stepping it down to 15w-40 Cheveron delo conventinal w/ Lucas ZDDP the next go round. I pretty sure your turbo will thank you.
Why would it select only certain main bearings?
My turbo is actually oil less! Thank god.
He shimmed it because I asked him to... just for higher pressure... good point on the high volume pump though.
It's actually a 364 my signature is wrong. Not that it matters...
10-21-2013, 12:54 AM
#12
I think what OP meant is that he didn't have a dampener designed for high Hp/rpm and instead had a regular non dampening pulley?? He doesn't specify brand..
But I don't think that's his problem
10-21-2013, 01:17 AM
#13
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I had my engine built by a guy who owned a huge workshop, they built Rally cars, Targa cars from scratch, all engine work etc.
He told me he had 30yrs experience building engines.
I was his first LS1 engine, boy did he F--k it big time.
What he wasn't aware of was the Scat rods I was using were not installed any old how but as an offset pair.
My bearings,Mahle pistons, bores, cam, crank, were wrecked after 5k
Is this your issue! Could be since he's an old school engine builder.
Way to many people think that any good engine builder can build an LS engine, a lot proberly can.....BUT there is only a limited number world wide that can build them right first time.
He told me he had 30yrs experience building engines.
I was his first LS1 engine, boy did he F--k it big time.
What he wasn't aware of was the Scat rods I was using were not installed any old how but as an offset pair.
My bearings,Mahle pistons, bores, cam, crank, were wrecked after 5k
Is this your issue! Could be since he's an old school engine builder.
Way to many people think that any good engine builder can build an LS engine, a lot proberly can.....BUT there is only a limited number world wide that can build them right first time.
10-21-2013, 06:46 AM
#15
Any time you make a shitload of power a quality balancer should be used...
especially with a production crank.
Pics 4 & 5 tell the story IMO. First the 2 bearing shells.. The one from the cap
is down to the copper and the one from the block looks halfway decent save
for the shrapnel thet it had to deal with.
Secondly the 5th photo was taken to show the rod bearings however in the
background it is blatantly obvious to me that the teflon coating is being worn
off the valley thrust side of the pistons which means only one thing with as
few miles as you have on this combo.......DETONATION
The sparkplug fires by the exhaust thrust side and when it's early it tries to
back the northerly moving crank and ***** the piston in the bore..scuffing it
more on the valley side than the exhaust side.
especially with a production crank.
Pics 4 & 5 tell the story IMO. First the 2 bearing shells.. The one from the cap
is down to the copper and the one from the block looks halfway decent save
for the shrapnel thet it had to deal with.
Secondly the 5th photo was taken to show the rod bearings however in the
background it is blatantly obvious to me that the teflon coating is being worn
off the valley thrust side of the pistons which means only one thing with as
few miles as you have on this combo.......DETONATION
The sparkplug fires by the exhaust thrust side and when it's early it tries to
back the northerly moving crank and ***** the piston in the bore..scuffing it
more on the valley side than the exhaust side.
10-21-2013, 08:31 AM
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that's what the engine builder told me also that could be a possibility. Detonation.
The bearings are clevite 77 A-1
Why would detonation kill the bearings before it hurt the pistons or heads or especially the plugs?
That's truly a big reason why I'm confused.
The bearings are clevite 77 A-1
Why would detonation kill the bearings before it hurt the pistons or heads or especially the plugs?
That's truly a big reason why I'm confused.
10-21-2013, 11:40 AM
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Is this a typo?
Clearances:
Mains at 30 thousandths
Rods at 20 thousandths...
He said he shoots for around 25 on both rods and mains...
depending on the cranks main bearing diameter using vr1 oil we have set our mains at .003 ( 3 thousandths )
Clearances:
Mains at 30 thousandths
Rods at 20 thousandths...
He said he shoots for around 25 on both rods and mains...
depending on the cranks main bearing diameter using vr1 oil we have set our mains at .003 ( 3 thousandths )
10-21-2013, 12:07 PM
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I had an issue similar to this on a Gen 1 383 using a Eagle crank, I built the engine and it knocked the center bearings out. The block was line bored after this and the crank was magged and was good...did it again I went through everything and couldn't figure it out.. so the third time putting it together I checked every step of the way measuring the torque it took to turn the crank after each rod/piston install and when I got through 5 pistons there was a slight load change, I pulled the crank back out and sent it to an actual crank shop and found that it was slightly bent and spinning it by hand you couldn't tell. I never thought to check this because it was brand new and balanced but it happened...
On a second note I would be sure that you don't have to big of water/meth injection nozzles, you may be trying to compress water in some cylinders causing flex on the crank.......
On a second note I would be sure that you don't have to big of water/meth injection nozzles, you may be trying to compress water in some cylinders causing flex on the crank.......