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PostPosted: Wed Mar 21, 2007 5:22 am 
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Joined: Fri Nov 29, 2002 7:34 am
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Location: DALTON, GA
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Ok here is the problem I think. The motor is pushing oil back through the pcv valve on to the valve cover. Car sounds ok so I decided to check the compression in each cylinder. Numbers 1,2,3 had 210 lbs #4 only had 190 and #5 had 210 but #6 had 200. Are these numbers any indication that I may have a broken ring. Any help will be appreciated. Racing season is here and I dont want to miss out. HELP Norm


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PostPosted: Wed Mar 21, 2007 2:00 pm 
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Supercharged
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Location: Gilbert, Arizona
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Those are some pretty healthy compression readings and pretty even to boot. Unless someone sees something I don't I would say that those numbers do not indcate a ring problem.

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PostPosted: Wed Mar 21, 2007 8:00 pm 
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EFI Slant 6
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Location: San Diego
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sounds like you crankcase is not vented. the pcv should be hooked to manifold vacuum and there should be a breather or a hose leading to the aircleaner to get clean air to let into the engine. also, check your oil level to make sure you don't have too much oil in the engine.

is this a freshly built engine? it must be to have 200+ lbs of compression. was the block thoroughly cleaned? it could also be that there is a restriction in the drains and the oil is not draining properly. how much oil pressure do you have? sorry for all the questions. keep us posted.

zedpapa

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PostPosted: Thu Mar 22, 2007 6:36 am 
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SSRN National Champion

Joined: Fri Nov 29, 2002 7:34 am
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Location: DALTON, GA
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This is a 3 year old race engine. The crankcase is vented into the headers and it is run on alcohol so no vac. The engine has about 70lbs of pressure.

Here is new numbers just pulled with the plugs out and the throttle at wide open. #1-230 #2-220 #3-240 #4-200 #5-220 #6-205

Replaced the pcv valve.

Just put on roller rockers and adjusted the valves. Could this have anything to do with such a widespred in these numbers.


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PostPosted: Thu Mar 22, 2007 6:51 am 
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Joined: Mon Oct 21, 2002 11:08 am
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Location: Blacksburg, VA
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Yes, if the valve adjustments are off, especially with a race cam, then you could see variations like that. Still, #4 is consistently lower than the rest. Probably not a big problem since the numbers are quite high overall.

Did you put some oil into each cyl and test again? If the psi improves then it's likely rings, if not, it's likely valve sealing. A leakdown test would be the only sure fire way to know if you're OK, but I would lean towards just running the car.

Lou

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PostPosted: Thu Mar 22, 2007 7:08 am 
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SSRN National Champion

Joined: Fri Nov 29, 2002 7:34 am
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Location: DALTON, GA
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Thanks Lou and I will get with Dale for some help on resetting the valve lash. How hard is it to do a leak down test. Do you need special equipment to do this? Hate to be so stupid but I just drive this car and not much good when it comes to mechanics. thanks


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PostPosted: Thu Mar 22, 2007 3:58 pm 
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Joined: Thu Oct 31, 2002 3:56 pm
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Location: Dalton, GA
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Hey Storming Norman do you think Dale could do a better job setting the vavle lash than me and you. OK doint answer that. One thing i have thought about you remember the shim deal maybe we were looking at that and did not get one locked down. I am pretty sure we checked all that but pull the vavle cover and check them again. Thanks Ron Parker :D
PS Storming Norman did not tell you last Saturday his car went the fastest it has ever run 7.30





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