Compression test

[Stanger00]

I ran a compression check on my motor today. I got it up to operating temp and pulled the plugs as fast as I could and tested each cylinder.

1. 148 5. 140
2. 150 6. 105 <----Did this one a couple times and 105 was the best it would do.
3. 150 7. 145
4. 150 8. 140

I have a bore scope but it wouldn't fit through the spark plug hole but I couldn't see anything out of the ordinary. Not sure if I have a bent valve or if the rings are shot...I have around 2k miles on this Aluminator with 44cc 2 valve TFS heads.

What are your guys thoughts? Should I put the plugs back in and take it to a shop to have a leak down done on that cylinder?

 

[Cobra03SC]

I would say yes to the leak down, and possibly a shop might have a smaller bore scope. I use a Milwaukee and it fits in there with room to spare. Most on the market are too big to fit in the hole.

http://www.mscdirect.com/product/de...__15557577904_c_S&026=-99&025=c&item=45434875

 

[Blueline]

Sucks, but a leak down test will tell you where your issue is. GL

 

[Stanger00]

After talking with a builder and tuner he explained that the o-ring may have not of seated. I didn't have any lube to help the o-ring seal and it could have binded. I was using a cheap O'Reilly rental.

Car still has issues but I have a good lead to what happened. Found some vapors on a hose behind my intake manifold near a high failure rate location in higher boosted 2 valves with stock intake manifolds.

 

[Ourobos]

I had similar on my 03.. Thought a stuck exhaust valve.. Then I noticed my plug gap had 'closed itself' somewhat.. Further inspection was a broke ringland on #7 due to a lean condition..

I'd do the leak down test for sure. How did the plugs look, any oil on them?

 

[Stanger00]

Plugs are perfect. Look good on heat no signs of detonation. I was more concerned on the passenger side since I heard a loud pop coming from that bank a while back.

On my next day off I'll be pulling the intake manifold to see if there is a deviation of some sort that would leak boost. That cylinder being that low doesn't make sense to me. I'll stick with it being good as I chase down another problem.