Help. SHOP SAYS SPUN BEARING AFTER H/C
02-29-2008, 04:07 PM
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Help. SHOP SAYS SPUN BEARING AFTER H/C I am in alabama, and i paid a shop in DFW area (parents live their to put install H/C package while they were replacing the rear end w/ 9". Car went on the dyno last night and made 435 rwhp on the first pull w/o any tunning. Shop said A/F was 10.5:1 which is rich. Oil pressure is good. Next pull it started making a clatering noise in the upper RPMs, and they shut it down.
I am not there mind you, but i had one of my buddies there to pick the car up after the dyno. They said it sounded like valve train noise. Decided to put the stock rockers back on there, and give it another try. Didn't fix the problem. They cut open the oil filter, and apparently there were metal shavings. They think it is a spun bearing but are currently pulling the oil pan off to double check. I asked how this was possible, and they replied "The bottom end must not have liked the additional power." I mean WTF? The car has a N2O kit on it, but it was just installed and has NEVER been sprayed. I haven't even driven/seen the car yet? Am I responsible for the short block, or is this their problem?
I am not there mind you, but i had one of my buddies there to pick the car up after the dyno. They said it sounded like valve train noise. Decided to put the stock rockers back on there, and give it another try. Didn't fix the problem. They cut open the oil filter, and apparently there were metal shavings. They think it is a spun bearing but are currently pulling the oil pan off to double check. I asked how this was possible, and they replied "The bottom end must not have liked the additional power." I mean WTF? The car has a N2O kit on it, but it was just installed and has NEVER been sprayed. I haven't even driven/seen the car yet? Am I responsible for the short block, or is this their problem?
02-29-2008, 04:10 PM
#2
It certainly isn't unheard of...most people with H/C spin their motors higher than stock, and if everything isn't in perfect order, you are gonna find the shortcomings real quick, including spun bearings. This wouldn't be their problem...this one is on you.
02-29-2008, 04:17 PM
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Yea, Kinda my thoughts. It just sucks to poor money into a car and then be told that your bottom end went. I guess I am shopping for a forged 408. Hopefully the shop will work with me on the labor end of it.
02-29-2008, 04:19 PM
#6
Well I am glad I decided that I will be replacing the bearings in the bottom end now. I'm putting H/C in my 125k engine, its lived a fairly tame life, but I will still sleep better at night knowing it has fresh bearings now. Its the one to many threads like this that I have seen that made me decide to spend the little extra now while its all apart so I don't have to worry.
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02-29-2008, 04:24 PM
#8
I spun number #8 and #7 after only 100 miles after my head/cam swap. Seems that the additional power and more importantly RPM put a lot of strain on the bearings. My motor had 120k on it and ran 11.71 cam only, so it was strong till the end.
May she rest in peace....
May she rest in peace....
02-29-2008, 10:09 PM
#11
A tune will only help with the A/F mixture at WOT and idle. Since it was running rich and not lean, it was on the safe side of WOT runs. Lean would have wrecked a piston.
The bottom end is completely on your shoulders. No one can predict what will happen on the bottom end unless you specifically asked them to tear it down completely and inspect it. No 2 high mileage motors lead the same life, one could have been babied with the best protecting oil against wear. Another could have been beat on all its life and had bearings just holding up by a thread. Then you ask the unknown from such a bottom end to hit higher rpm with more torque?
The bottom end is completely on your shoulders. No one can predict what will happen on the bottom end unless you specifically asked them to tear it down completely and inspect it. No 2 high mileage motors lead the same life, one could have been babied with the best protecting oil against wear. Another could have been beat on all its life and had bearings just holding up by a thread. Then you ask the unknown from such a bottom end to hit higher rpm with more torque?
03-01-2008, 04:38 AM
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I'd just get a new bottom end and put the worries aside in the future...now if something else breaks after that myseteriously, then look at the shop. I had all new internals put into my motor when I H/C'd it because a friend bombed his lucky number 7 miles after he got it tuned, but he didn't replace anything he didn't have to because he was trying to save money, only thing was by saving a little money there, cost him a lot of money later
Good luck with whatever you do and keep us updated.
Good luck with whatever you do and keep us updated. 
03-01-2008, 07:41 AM
#15
A tune will only help with the A/F mixture at WOT and idle. Since it was running rich and not lean, it was on the safe side of WOT runs. Lean would have wrecked a piston.
The bottom end is completely on your shoulders. No one can predict what will happen on the bottom end unless you specifically asked them to tear it down completely and inspect it. No 2 high mileage motors lead the same life, one could have been babied with the best protecting oil against wear. Another could have been beat on all its life and had bearings just holding up by a thread. Then you ask the unknown from such a bottom end to hit higher rpm with more torque?
The bottom end is completely on your shoulders. No one can predict what will happen on the bottom end unless you specifically asked them to tear it down completely and inspect it. No 2 high mileage motors lead the same life, one could have been babied with the best protecting oil against wear. Another could have been beat on all its life and had bearings just holding up by a thread. Then you ask the unknown from such a bottom end to hit higher rpm with more torque?
UNLESS you can prove they ran it oil starved, how do they, or even you know your bearing were not already hurt.
I have killed bearing due to a too rich A/F and the washing down of the cyl lead to watery oil and eventually lead to killing of the beaings.
Just pull it and re build it, hopefully the cam bearing journals didnt take too bad of a hit.
03-01-2008, 08:19 AM
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10.5:1 is rich enough to contaminate the oil enough to the point where it breaks down. The question is how many pulls did they do with that rich of A/F and did you drive it in that condition? I know this sounds ****, but every time you suspect fuel in the oil it should be changed immediately as a precautionary move. If you really want to know the condition of the oil, pull a sample and send it to a lab that does oil analysis.
03-01-2008, 09:27 AM
#17
I can't imagine it washing down a cylinder in 2 pulls. At part throttle and idle, it would have been correcting itself from the lean, not running ideal yet, but since they had A/F running on it, they probably had a good indicator if it was being drenched or not.
I think it's simply tough to prove if there was a problem or not. Mentioned that 2 pulls were done and oil pressure was good. If the o-ring or pump was an issue, it would have been fluctuating from startup.
I think it's simply tough to prove if there was a problem or not. Mentioned that 2 pulls were done and oil pressure was good. If the o-ring or pump was an issue, it would have been fluctuating from startup.
