# low compression after valve job



## c_mac (Mar 13, 2008)

had a valve job done and car came back throwin misfire codes on the driver side bank of cylinders. Took to 2d mechanic, who tested engine and found low compression and bad leakdown on the driver side bank of cylinders. He said there was probably cylinder scoring. Took car back and 1st mechanic re-ringed it. Came back again with misfire codes. 2d mechanic tested and found low compression and poor leakdown again. Took to dealer, who noted that timing was off due to improper reinstallation of camshaft. Said proper installation would fix problems. In over my head here - any thoughts?


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## blackcoupe (Oct 5, 2003)

*Re: low compression after valve job (c_mac)*

Good possibility that the cams are off. Ive seen when the timing chains start to get miles on them that they will stretch out. And when you would remove the cams for lets say a head job it can be difficult to get the cams to time up right because of the stretch in the chain. You say they are doing a leak down test to your car. That should be able to tell you were the problem is coming from. So you had a leak down test done after it got reringed. So where was it leaking from?


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## c_mac (Mar 13, 2008)

*Re: low compression after valve job (blackcoupe)*

Timing belt is new. Mechanic 2 says it is a ring/piston problem, probably due to cylinder wall scoring. Dealer says cam timing adjuster is off on the left bank. The thing that seems odd to me is that the entire bank has low compression in the same degree, which seems to comport with a timing adjuster issue on that cam. But then, I don't know what I am talking about.
A little more background. After valve job, the low compression was all in one bank, and all 3 cylinders were low almost equally. Timing belt was replaced each time Mechanic 1 worked on car, so it was brand new. After initial repair, Mechanic 2 thought that that the cyclinder walls were probably scored, but has never provided much info other than to say "leakdown is bad" and "indicates issue with pistons / rings." When car went back to Mechanic 1, he said there was cylinder wall glazing, but not scoring. He then reringed the car. When he returned it, there was still low compression in the one bank. He claimed leakdown was "perfect." I opened a complaint and put payment in dispute, making the relationship with Mechanic 1 tendentious at best.
Then had Mechanic 2 check it out again. He said, "compression on left bank still low, leakdown is bad" and "indicates issue with pistons / rings" - again. So I took it to the dealer.
Dealer said "Bank 2 cam adjuster installed incorrectly." Asked about performing leakdown - to which he said "I can see that the thing is installed incorrectly - that is your problem. A leakdown will be an extra $300 that you do not need to spend."
I am hoping the dealer assessment is correct, because I am tired of fighting with Mechanic 1 and would prefer not to end up in court. 


_Modified by c_mac at 12:42 PM 3/20/2008_


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## blackcoupe (Oct 5, 2003)

*Re: low compression after valve job (c_mac)*

Why did you have the valve job done in the first place? What was the problem before any of else?


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## aarononymous (Aug 2, 2006)

*Re: low compression after valve job (blackcoupe)*

as a dealer tech I like when other shops screw something up. Not that I'm perfect but it doesn't always save money to go somewhere cheaper. The leakdown test should indicate where the leak is, but if the cams are installed wrong whoever you paid to install should fix it for free. You need th have basic timing set.
edit:AND YES I'M AN IDIOT FOR REOPENING THIS READ


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## Quasy (May 19, 2008)

*Re: low compression after valve job (aarononymous)*

http://****************.com/smile/emthup.gif I totally agree with this guy. Check Volksguru.com and read the special report I will assure you this will not happen to you again after you read the special report.


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