Bent valve ? Or other problem
#1
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Bent valve ? Or other problem
Ok so I did a compression test and got 160 195 190 200. So I also did a leakdown and got 45% 5% 8% 4%. So i know cylinder 1 is off way off. I could hear the air commong out of the exhaust and nothing out of the intake on cyl 1. So I checked the valve clearences and they were ok except 3 which is why I was a little higher then the other and it fixed that one but cyl 1 was on so does that mean I have a bent valve or could it be something else like retainer? I had the head checked and milled and cleaned about 30k miles ago.
I know some of you are going to say my compression is low but it's a stroked motor with lower compression ratio.
I know some of you are going to say my compression is low but it's a stroked motor with lower compression ratio.
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Pistions have about 300 miles on them and I checked them with another test they are good I know it's the valves just don't know how to check without taking the head off again can u change retainers without taking the head off?
#4
Originally Posted by drhess06259,Jun 8 2010, 07:21 AM
Pistions have about 300 miles on them and I checked them with another test they are good I know it's the valves just don't know how to check without taking the head off again can u change retainers without taking the head off?
#5
Usually these are the steps that I take:
Compression test. If numbers are good then go do something else. Otherwise pour a very small amount of oil in that cylinder, if the numbers go up, then you have a ring problem.
Leakdown test. Once you determine that there is a cylinder that is leaking too much, try to hear for a hissing/air leaking noise:
- Intake off … if you hear it through here then you have an intake valve problem
- exhaust manifold off … here you would hear an exhaust valve leak
- oil pan off … you would hear piston rings leaking.
The last two are somewhat more difficult, but still easier than removing the cylinder head.
J
Compression test. If numbers are good then go do something else. Otherwise pour a very small amount of oil in that cylinder, if the numbers go up, then you have a ring problem.
Leakdown test. Once you determine that there is a cylinder that is leaking too much, try to hear for a hissing/air leaking noise:
- Intake off … if you hear it through here then you have an intake valve problem
- exhaust manifold off … here you would hear an exhaust valve leak
- oil pan off … you would hear piston rings leaking.
The last two are somewhat more difficult, but still easier than removing the cylinder head.
J
#6
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There's also a possibility that that exhaust valve and/or its seat is burned. 30k miles would certainly be enough for that to happen, especially if the valves were adjusted too tight.
You mentioned a low-compression stroker build; does this engine have boost?
You mentioned a low-compression stroker build; does this engine have boost?
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#10
Originally Posted by RedY2KS2k,Jun 8 2010, 08:09 PM
Valve seals affect oil consumption; they have nothing to do with compression or leakdown. I still vote burned exhaust valve.
J