Help! Stock Engine: Valve to Piston Contact :(
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Teching In
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From: Toronto
Help! Stock Engine: Valve to Piston Contact :( I have a stock engine and did the dreaded 2-3-2 mis-shift. Some valves are bent bad and a few pistons are scored, pushrods are FUBAR. Now, I have an extended warranty with an aftermarket company. The car is at the dealers with the heads off and they are waiting for an adjuster to inspect the damage. The timing chain turned out to be okay (no slack or stretching).
Here is the question: What other than a mis-shift (over rev) or timing chain stretch can cause a condition whereby the valves hit the pistons? I want to attribute the damage to something mechanical rather than my stupidity and driver error
Here is the question: What other than a mis-shift (over rev) or timing chain stretch can cause a condition whereby the valves hit the pistons? I want to attribute the damage to something mechanical rather than my stupidity and driver error
Last edited by LensLS1; Mar 31, 2004 at 11:38 AM.
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From: Kansas City, MO
Originally Posted by LensLS1
I have a stock engine and did the dread 2-3-2 mis-shift. Some valves are bent bad and a few pistons are scored, pushrods are FUBAR. Now, I have an extended warranty with an aftermarket company. The car is at the dealers with the heads off and they are waiting for an adjuster to inspect the damage. The timing chain turned out to be okay (no slack or stretching).
Here is the question: What other than a mis-shift (over rev) or timing chain stretch can cause a condition whereby the valves hit the pistons? I want to attribute the damage to something mechanical rather than my stupidity and driver error
Here is the question: What other than a mis-shift (over rev) or timing chain stretch can cause a condition whereby the valves hit the pistons? I want to attribute the damage to something mechanical rather than my stupidity and driver error
My brother did the same on his '00 SS. We replaced the heads and pushrods with new complete heads from Valvegod. We filed down the eyelash/witness marks on the pistons. Ran like a champ.
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From: Toronto
Originally Posted by DenzSS
You must have had a hell of a miss-shift to do that much damage. You either took out the valve stems or broke/stretched a few rod bolts. Essentially, its pretty damn dead.
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Teching In
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From: Toronto
Thanks to the generosity of a fellow f-body club member, I already have a replacement engine lined up 
However, I want the warranty company to pay the bill to diagnose the problem which is now totaling more than $1300. I paid good money for this warranty and now that I have a serious engine problem, I want them to at least pay for some of the damage.
How much slack is allowed in the timing chain exactly? What about the possibility of out of spec lifters, pushrods? Etc? There has to be other possible causes…
However, I want the warranty company to pay the bill to diagnose the problem which is now totaling more than $1300. I paid good money for this warranty and now that I have a serious engine problem, I want them to at least pay for some of the damage.How much slack is allowed in the timing chain exactly? What about the possibility of out of spec lifters, pushrods? Etc? There has to be other possible causes…
Do you think the insurance adjuster is going to be someone who just fell off a turnip truck? You already know what caused the problem. If you ran your car into a curb, would you expect the warranty co to pay for the repairs?
I have a stock engine and did the dreaded 2-3-2 mis-shift. I want to attribute the damage to something mechanical rather than my stupidity and driver error.
Only two things could cause that damage...mechanical over-rev resulting in valve float or an improperly degreed camshaft resulting in valve-piston contact. The latter of which was obviously not the case.
The bottom line is the damage was done when you missed a shift causing the mechanical over-rev. The stock valve springs can't control the valves past 6200 rpms...this resulted in pistons hitting the valves, etc.
$1300 is a hell of a lot of cash for a diagnosis...that's about 18 hours worth of work...it doesn't take that long to pull a set of heads and see the damage. Maybe 2-3 hours for an experienced mechanic. I think they are ripping you off.
No offense, but since you did the damage yourself, you should be paying to repair it.
The bottom line is the damage was done when you missed a shift causing the mechanical over-rev. The stock valve springs can't control the valves past 6200 rpms...this resulted in pistons hitting the valves, etc.
$1300 is a hell of a lot of cash for a diagnosis...that's about 18 hours worth of work...it doesn't take that long to pull a set of heads and see the damage. Maybe 2-3 hours for an experienced mechanic. I think they are ripping you off.
No offense, but since you did the damage yourself, you should be paying to repair it.
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From: Kansas City, MO
Depending on where you shifted, you could have taken the engine to 7500rpm or higher.
You should see what a missed shift does on a blown 4.6L sohc motor. Ford pulls fuel when you hit the rev limiter.
You should see what a missed shift does on a blown 4.6L sohc motor. Ford pulls fuel when you hit the rev limiter.
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From: Kansas City, MO
mechanical over rev + pulling fuel under peak boost with a centrifugal supercharger. I was just stating that it can be a lot worse. Yours might be able to be saved. There was very little left of the 4.6.
Originally Posted by DenzSS
mechanical over rev + pulling fuel under peak boost with a centrifugal supercharger. I was just stating that it can be a lot worse. Yours might be able to be saved. There was very little left of the 4.6.
LIL piston meltage?
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From: MI
Originally Posted by 2xLS1
Do you think the insurance adjuster is going to be someone who just fell off a turnip truck? You already know what caused the problem. If you ran your car into a curb, would you expect the warranty co to pay for the repairs?
On The Tree
Joined: Aug 2003
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From: Bradenton, Florida Perico Island
Sorry to hear about your problem. I wish you good luck in getting help with the warranty company. If they do pay anything I say...Good for you!
I have to go to work now....Gotta go warm up the truck....Gotta load of large turnips to deliver! Tell that dude in the back to hang on!
I have to go to work now....Gotta go warm up the truck....Gotta load of large turnips to deliver! Tell that dude in the back to hang on!
