Catastrophic LS2 engine failure, see pictures inside, help needed
06-17-2010, 11:11 AM
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Catastrophic LS2 engine failure, see pictures inside, help needed
I have a 2005 Corvette LS2 MN6 with some bolt-ons (Z06 exhaust with SLP catback, ported TB, intake, UD pulley and a tune) with 12.000 miles, the engine has never been touched. Ever. Last week I was accelerating in 3rd on the motorway, and at about 4500 rpm's the engine suddenly died. I pulled over, the DIC showed reduced engine power, and service traction control. I took my device to pull the codes and besides some MAF and throttle position codes I saw the P00340 and P00341. As a regular reader on the forum, I already knew: timing chain. So this week we disassembled the engine and to our suprise, the chain was intact. The three bolts holding the cam sprocket however sheared completely off, and we found the little pin ( sorry I'm not good in mechanics, nor is my english up to your expectations) from the cam undamaged in the oil pan.
See it here:
Other pictures:
http://s790.photobucket.com/albums/y...ta1988/Engine/
We also found that one cylinder has not been functioning properly, the spark plug is black and also the head and the piston looks different. But I think it had nothing to do with the failure itself. You can see, the valves have touched the pistons as well, 5 of the valves seem to be bent, some pushrods are also bent (one of them heavily). So here are my questions:
1., Did anybody experience the same without prior cam removal (I know there has been cases like this but always after a cam change)?
2., What do you think I shall do with the pistons?
3., As I already have the L76 intake on the self, should I go with L92 heads or repair these ones?
4., If I use the L92 heads, is it always necceassary to flycut the pistons, or is it depending on the cam?
5., The cam is obviously shot as well, shall I use the stock one or go bigger?
I'm in the middle of Europe, so if the decision is made, and I order the wrong parts, I will be sitting here for weeks with unreturnable parts and car without engine. So please vendors, is there somebody who can offer me a package with a good set of cylinder heads and a small cam with nearly stock idle? As always: money matters as well, I don't want to do it cheap, I want to do it right, but take into consideration, that with delivery, taxes and VAT I pay the double of what you see on the price tags.
Many thanks to you all, this forum has always been a very kind to us, foreign Corvette-enthusiasts, I'm sure, this time my problem will be solved as well
Sebaj
See it here:
Other pictures:
http://s790.photobucket.com/albums/y...ta1988/Engine/
We also found that one cylinder has not been functioning properly, the spark plug is black and also the head and the piston looks different. But I think it had nothing to do with the failure itself. You can see, the valves have touched the pistons as well, 5 of the valves seem to be bent, some pushrods are also bent (one of them heavily). So here are my questions:
1., Did anybody experience the same without prior cam removal (I know there has been cases like this but always after a cam change)?
2., What do you think I shall do with the pistons?
3., As I already have the L76 intake on the self, should I go with L92 heads or repair these ones?
4., If I use the L92 heads, is it always necceassary to flycut the pistons, or is it depending on the cam?
5., The cam is obviously shot as well, shall I use the stock one or go bigger?
I'm in the middle of Europe, so if the decision is made, and I order the wrong parts, I will be sitting here for weeks with unreturnable parts and car without engine. So please vendors, is there somebody who can offer me a package with a good set of cylinder heads and a small cam with nearly stock idle? As always: money matters as well, I don't want to do it cheap, I want to do it right, but take into consideration, that with delivery, taxes and VAT I pay the double of what you see on the price tags.
Many thanks to you all, this forum has always been a very kind to us, foreign Corvette-enthusiasts, I'm sure, this time my problem will be solved as well
Sebaj
06-17-2010, 01:58 PM
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Sebaj
Holy Smokes! Your English is better than some of the Americans that post here..
What are you performance Goals???? Be realistic and figure out how much power you want and what drivability standards do you need to adhere to? \
I do not know your country’s emissions standards so; we will need to know that also.
HEADS: Unless the head castings are damaged, the valves can easily be replaced. Unless you desire better higher compression & better flowing heads, repairing yours can save you some money.
CAM: The cam doesn’t look like it’s damaged. Those bolts can easily be removed and you can reinstall the pin. If you desire a new cam,, the choices are unlimited. Again, knowing what your engine performance goals are will help.
TUNING: If you make the engine breath better, you will need a Professional PCM tune. Do you have access to a reliable Tuner who can tune your car? If not, you will need to arrange a mail order tune from a US tuner.
UP-GRADED Parts: You will need a new timing chain, chain dampener, better springs, Hardened Valve Push Rods. New cam bolts, new sprockets.
CAUSE and EFFECT; If your cam bolts were working loose, the cam sprocket would have been working clock wise and counter clock wise. That gear motion would have caused the bolts to weaken and shear.
When the cam came out of timing and then stopped, the OPEN valves would have crashed into the pistons. If the pistons just have slight marks, i would think you would not have any piston issues. Some good pictures would help.
COST OF OVERSEAS PARTS. If you have the shipper inventory the parts as "USED AUTO PARTS", do they tax you less than if they were new parts.
BC
Holy Smokes! Your English is better than some of the Americans that post here..
What are you performance Goals???? Be realistic and figure out how much power you want and what drivability standards do you need to adhere to? \
I do not know your country’s emissions standards so; we will need to know that also.
HEADS: Unless the head castings are damaged, the valves can easily be replaced. Unless you desire better higher compression & better flowing heads, repairing yours can save you some money.
CAM: The cam doesn’t look like it’s damaged. Those bolts can easily be removed and you can reinstall the pin. If you desire a new cam,, the choices are unlimited. Again, knowing what your engine performance goals are will help.
TUNING: If you make the engine breath better, you will need a Professional PCM tune. Do you have access to a reliable Tuner who can tune your car? If not, you will need to arrange a mail order tune from a US tuner.
UP-GRADED Parts: You will need a new timing chain, chain dampener, better springs, Hardened Valve Push Rods. New cam bolts, new sprockets.
CAUSE and EFFECT; If your cam bolts were working loose, the cam sprocket would have been working clock wise and counter clock wise. That gear motion would have caused the bolts to weaken and shear.
When the cam came out of timing and then stopped, the OPEN valves would have crashed into the pistons. If the pistons just have slight marks, i would think you would not have any piston issues. Some good pictures would help.
COST OF OVERSEAS PARTS. If you have the shipper inventory the parts as "USED AUTO PARTS", do they tax you less than if they were new parts.
BC
06-17-2010, 03:26 PM
#6
Drifting
you say one cylinder looked different? it it possible that it was taking in a small amount of coolant or oil, then it gradually got bad enough to hydrolock the engine.
06-17-2010, 03:55 PM
#7
Advanced
All of us are very sorry for your bad luck. But I'm very happy you already started to plan the rebuild. Good luck!
And please don't give up and keep being a member of our small Corvette community here in Hungary!
Experts here, your help for this great guy will be greatly appreciated. Thanks in advance!
And please don't give up and keep being a member of our small Corvette community here in Hungary!
Experts here, your help for this great guy will be greatly appreciated. Thanks in advance!
06-18-2010, 03:48 AM
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06-18-2010, 03:55 AM
#9
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Sebaj
Holy Smokes! Your English is better than some of the Americans that post here..
What are you performance Goals???? Be realistic and figure out how much power you want and what drivability standards do you need to adhere to? \
I do not know your country’s emissions standards so; we will need to know that also.
HEADS: Unless the head castings are damaged, the valves can easily be replaced. Unless you desire better higher compression & better flowing heads, repairing yours can save you some money.
CAM: The cam doesn’t look like it’s damaged. Those bolts can easily be removed and you can reinstall the pin. If you desire a new cam,, the choices are unlimited. Again, knowing what your engine performance goals are will help.
TUNING: If you make the engine breath better, you will need a Professional PCM tune. Do you have access to a reliable Tuner who can tune your car? If not, you will need to arrange a mail order tune from a US tuner.
UP-GRADED Parts: You will need a new timing chain, chain dampener, better springs, Hardened Valve Push Rods. New cam bolts, new sprockets.
CAUSE and EFFECT; If your cam bolts were working loose, the cam sprocket would have been working clock wise and counter clock wise. That gear motion would have caused the bolts to weaken and shear.
When the cam came out of timing and then stopped, the OPEN valves would have crashed into the pistons. If the pistons just have slight marks, i would think you would not have any piston issues. Some good pictures would help.
COST OF OVERSEAS PARTS. If you have the shipper inventory the parts as "USED AUTO PARTS", do they tax you less than if they were new parts.
BC
Holy Smokes! Your English is better than some of the Americans that post here..
What are you performance Goals???? Be realistic and figure out how much power you want and what drivability standards do you need to adhere to? \
I do not know your country’s emissions standards so; we will need to know that also.
HEADS: Unless the head castings are damaged, the valves can easily be replaced. Unless you desire better higher compression & better flowing heads, repairing yours can save you some money.
CAM: The cam doesn’t look like it’s damaged. Those bolts can easily be removed and you can reinstall the pin. If you desire a new cam,, the choices are unlimited. Again, knowing what your engine performance goals are will help.
TUNING: If you make the engine breath better, you will need a Professional PCM tune. Do you have access to a reliable Tuner who can tune your car? If not, you will need to arrange a mail order tune from a US tuner.
UP-GRADED Parts: You will need a new timing chain, chain dampener, better springs, Hardened Valve Push Rods. New cam bolts, new sprockets.
CAUSE and EFFECT; If your cam bolts were working loose, the cam sprocket would have been working clock wise and counter clock wise. That gear motion would have caused the bolts to weaken and shear.
When the cam came out of timing and then stopped, the OPEN valves would have crashed into the pistons. If the pistons just have slight marks, i would think you would not have any piston issues. Some good pictures would help.
COST OF OVERSEAS PARTS. If you have the shipper inventory the parts as "USED AUTO PARTS", do they tax you less than if they were new parts.
BC
thank you for your kind words! My goal is about 500 fwhp or 430-440 rwhp. The car must have good street manners, smooth idle, and no driveability issues. I drive it a lot to the local Corvette and American car events, and sometimes I drag race it.
I just re-read my post, and of course it was the pin we found undamaged in the oil pan, not the cam.
Thanks all for the support!
Cheers/Sebaj
Yeah, and some more pictures:
Pistons:
Cylinder where we suspect, that it did not function properly (on the right):
Last edited by sebaj; 06-18-2010 at 03:59 AM. Reason: Forgot the pictures
06-18-2010, 01:59 PM
#11
Instructor
Very unfortunate that happend with an engine that has never been moded. I have seen that happen with guys who have forgotton to loctite the cam retainter bolts, but never a stock engine.
Good luck on the rebuild! I assume you have no powertrain warranty left.
Good luck on the rebuild! I assume you have no powertrain warranty left.
06-19-2010, 12:47 AM
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Having that information,,,here are some FACTS that may help you in your future MOD plans:
To obtain that HP, your going to need Long Tube Headers, new intake (FAST 90) 90mm Throttle body, high 230's duration/.600 lift/114 duration cam, and some better heads. That will easily get you there.
Once you obtain that HP/TQ level,,,,you may start to have clutch issues like I did. My stock 50,000 mile 02 ZO6 clutch would stick to the floor under full throttle puls and i would have to pull the clutch peddel up with my toe between shifts.
I am upgrading my clutch to a SPEC duel disk to solve that issue. With a good tune my high 240ish duration CAM may bost a few more HP.
BC
To obtain that HP, your going to need Long Tube Headers, new intake (FAST 90) 90mm Throttle body, high 230's duration/.600 lift/114 duration cam, and some better heads. That will easily get you there.
Once you obtain that HP/TQ level,,,,you may start to have clutch issues like I did. My stock 50,000 mile 02 ZO6 clutch would stick to the floor under full throttle puls and i would have to pull the clutch peddel up with my toe between shifts.
I am upgrading my clutch to a SPEC duel disk to solve that issue. With a good tune my high 240ish duration CAM may bost a few more HP.
BC
06-21-2010, 06:35 AM
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Having that information,,,here are some FACTS that may help you in your future MOD plans:
To obtain that HP, your going to need Long Tube Headers, new intake (FAST 90) 90mm Throttle body, high 230's duration/.600 lift/114 duration cam, and some better heads. That will easily get you there.
Once you obtain that HP/TQ level,,,,you may start to have clutch issues like I did. My stock 50,000 mile 02 ZO6 clutch would stick to the floor under full throttle puls and i would have to pull the clutch peddel up with my toe between shifts.
I am upgrading my clutch to a SPEC duel disk to solve that issue. With a good tune my high 240ish duration CAM may bost a few more HP.
BC
To obtain that HP, your going to need Long Tube Headers, new intake (FAST 90) 90mm Throttle body, high 230's duration/.600 lift/114 duration cam, and some better heads. That will easily get you there.
Once you obtain that HP/TQ level,,,,you may start to have clutch issues like I did. My stock 50,000 mile 02 ZO6 clutch would stick to the floor under full throttle puls and i would have to pull the clutch peddel up with my toe between shifts.
I am upgrading my clutch to a SPEC duel disk to solve that issue. With a good tune my high 240ish duration CAM may bost a few more HP.
BC
as I already have the L76 intake, I was thinking about a fully assembled L92 head with titanium retainers, double springs, and a smaller cam, like this one, to avoid flycutting.
http://www.texas-speed.com/shop/item...d=166&catid=44
As far as I know, they are vendors here, if not, administrators please delete!
I don't know what happened to the pistons, but I will change them as well. What about the internals and other stuff?
Do I have to use different connecting rods at that HP level?
Can I reuse my lifters and rockers?
regards/Sebaj
06-21-2010, 08:45 AM
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Thanks Bill,
as I already have the L76 intake, I was thinking about a fully assembled L92 head with titanium retainers, double springs, and a smaller cam, like this one, to avoid flycutting.
http://www.texas-speed.com/shop/item...d=166&catid=44
As far as I know, they are vendors here, if not, administrators please delete!
I don't know what happened to the pistons, but I will change them as well. What about the internals and other stuff?
Do I have to use different connecting rods at that HP level?
Can I reuse my lifters and rockers?
regards/Sebaj
as I already have the L76 intake, I was thinking about a fully assembled L92 head with titanium retainers, double springs, and a smaller cam, like this one, to avoid flycutting.
http://www.texas-speed.com/shop/item...d=166&catid=44
As far as I know, they are vendors here, if not, administrators please delete!
I don't know what happened to the pistons, but I will change them as well. What about the internals and other stuff?
Do I have to use different connecting rods at that HP level?
Can I reuse my lifters and rockers?
regards/Sebaj
Since you had a major event, closely inspect all internal parts, roller bearings for debris and damage.
06-22-2010, 11:17 AM
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So, checked the pistons, 3 were shot, so ordered 8 new ones, I went with an L92 head assembled with double prings, and tend to use a different cam, the G6XE, which requires no flycutting. I know, it's not a strong combo, but I want to stay on the safe side, I will put more than $6000 in parts (VAT and taxes, and delivery included) and the labour won't be cheap either. One more disaster, and this year's events are shot for me....
06-23-2010, 02:08 PM
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In my poor Hungarian...
Sajnalom hogy gondja van a motorral.
If there is any way that I can help let me know. I make about 2 trips a year to Budapest to visit on average. I have 3 trips scheduled between now and July of next year.
I have seen the bolts shear before on 100% stock cars. Rare, but definitely a problem.
Max
Sajnalom hogy gondja van a motorral.
If there is any way that I can help let me know. I make about 2 trips a year to Budapest to visit on average. I have 3 trips scheduled between now and July of next year.
I have seen the bolts shear before on 100% stock cars. Rare, but definitely a problem.
Max
06-23-2010, 04:52 PM
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In my poor Hungarian...
Sajnalom hogy gondja van a motorral.
If there is any way that I can help let me know. I make about 2 trips a year to Budapest to visit on average. I have 3 trips scheduled between now and July of next year.
I have seen the bolts shear before on 100% stock cars. Rare, but definitely a problem.
Max
Sajnalom hogy gondja van a motorral.
If there is any way that I can help let me know. I make about 2 trips a year to Budapest to visit on average. I have 3 trips scheduled between now and July of next year.
I have seen the bolts shear before on 100% stock cars. Rare, but definitely a problem.
Max
06-24-2010, 04:57 AM
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06-24-2010, 09:16 AM
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Very sorry to read about this, but with two respected tuners responding, you should be good. And your English is absolutely ok. Good luck with the rebuild.