JohnSchiavarelli

finished the annual leakdown test this weekend of my 540 NA motor. all cyl were great yet again but the #8.

#8 is at 20%.. pulled the exhaust. Looks like water has been getting past the Pyrometer bung into the cyl.
pressure the cyl with air and I cal feel it coming past the exhaust valve.

What to do? The valve looks like it has light rust on it. I would like to get one more summer out of the motor before a rebuild..

MILD THUNDER

iTrader: (3)

When you did your leakdown, did you try giving the valve stem a few smacks with a rubber mallet? Sometimes the rust/carbon buildup on the valve seats can give high leakdown numbers. 20% isnt all that bad for a used engine. Obviously the leak should be fixed asap. Your valve might be tuliped a bit. Get a straigtedge and run it across all your exhaust valves and see if the #8 stem is higher than the rest.

JohnSchiavarelli

Excellent idea.. I will tap the top of the spring today.. 20% is not bad, but the rest are all under 10%.

I have a feeling the valve is a bit tuliped (justa gut feeling)

I will run the straight edge also.

If the valve is a bit out of sorts, is it the worst thing in the world to run it like that? with a small leak? Could the leak be from the valve seat?

MILD THUNDER

iTrader: (3)

I would tap the valve, and not the spring. You want the valve to kinda go down and smack against the seat a couple times. Only issue i can maybe see is more of a chance of reversion with the leaky valve, but as long as the leak in the tailpipe is fixed, i'd doubt you would have problems. Probably tons of guys running around with valves that have higher leakdown % than yours.

Then again, now would be the time to tear it apart for a valve job.

JohnSchiavarelli

When you say tap the valve, you mean the "top" where the retainer is correct? Nice and hard (but obviously not too hard) with a light-medium rubber mal?

Now is the time for a valve job. Too many other things to do.. (i.e. new intake, new lifters new cam, ect). that is all in the budget for next year! :-) i will tap and see what happens

JohnSchiavarelli

Tapping the valve didn't do a darn thing.. (other then make a lot of noise). So.. Pulled both heads last night. Took them to the shop today. #8 ex valve was slightly bent. not even visible to the naked eye. Time for a new valve job.

Having Bob make a new cam shaft for me as well.. so some performance upgrades..

FIXX

iTrader: (2)

wouldnt be suprised that 8 valve had a problem..that cylinder usually runs lein..up the jet size a little when you change the cam,the egt probably was not giving you the proper temps with the water in that cylinder..Try running cooler temps on the egt,better safe then sorry