I'm planning to go with a Rotrex kit down the road. I might even be upgrading it a bit (200 - 220 whp). So, I did a compression test (thanks for the help, Kuksi).

Front to back:
#1: 203 psi
#2: 199 psi
#3: 182 psi, 188 psi after a bit of oil
#4: 199 psi

We were a little short on time, so we only re-tested #3 with oil since it was a bit low. From what I understand, these figures are still within factory specs but what are your thoughts on that 3rd cylinder? Is it a problem and if so, what is likely the issue? If I decide to fix it, what else should I consider doing at the same time?

Thanks,
- Tom

 

There can be up to 28psi difference between cylinders within spec.

 

Its not horrible but its not good either. if you're going to go in there id freshen all gaskets/seals/bearings and possibly throw in some forged rods

 

Do a leakdown on #3. I betcha it's a leaky exhaust valve.

If while applying pressure into #3 with it at TDC, and you listen to the other cylinders' spark plug holes with a hose, and you hear the hissing in #2 and #4 and not #1, it's the exhaust valve. If you hear it in #1 and #2, it's the intake valve.

It's loudest in the oil filler cap, it's the rings.