LarryC wrote:
doped304 wrote: , I removed the schrader valve from my compression tester and introduced 120 p.s.i to the cylinders ,With the cams removed, and heard a very audible leak from each and every cylinder. Mostly from the exhaust valves but an intake or two just to switch things up. .
That leads to a couple of logical questions. The click sound was caused by something moving and coming into contact with something else.... What's the source of the problem there?
a] stuck vales....binding in the guide for some reason
b] slightly bent valves....how did they get that way?
What I have seen guys do numerous times is incorrectly install the cams and turn the engine over. That leads to bent valves...that leads to the leakage...
In the past, they used stones to cut the seats at PP. Stones will cut a nice straight seat. The likeliness of 8 valves having non concentric seats are pretty slim to say the least....
Are there other things that could cause a problem? Yes there are. One being that the valve job needs a top cut because the 45 cut is now larger than the valve...
Pull the valves out, put them in a drill an spin them... If they're bent, you'll see it in a heartbeat.
If none are bent,, clean the valves and seats free of oil. Take a black magic marker and mark the valve face about 5 or 6 spots equally spaced on the 45. Put the valve down in the guide and spin it with a lapping stick. Pull it back out and inspect the marker and the seat. You'll see where the contact points are.
If you're running the PSP3x cams, you have far less room for incorrect cam timing that with the stock cams. They have a ton of duration, especially overlap duration. You'll bend valves real quick if the timing is off...
Am I defending Joe here? Yep... because I'm in the same business and I know what happens. I did not read anything about a phone call or email to Joe informing him of the situation and discussing it with him. THAT is truly the first thing that should have been done....
Hey Larry,
Not quite sure where you got "click" from. All I read was "very audible leak". But I know where you're coming from if a noise was heard while cranking.
You're the expert, and by all means doped304 should perform the procedure you recommended to determine the cause of the problem.
At first hearing no compression and 100% leakdown, I thought the same thing -- either inaccurate testing, or bent valves due to incorrect cam installation or timing. But the fact the leaks were heard with the cams removed, eliminated a testing problem.
In my years in automotive I've seen a lot of bent valves, ether by incorrect chain install, or a belt jumping time. In all instances, I can remember, something always held true. There were visible marks (nicks) on every valve (intake or exhaust) and piston, and the damage held true across the board. Meaning there was a nick on every intake (and/or exhaust valve), and every piston. Doesn't have to be a big gouge, sometimes just a little nick. And the damage I've seen has always been universal. Every valve made piston contact, and leakage was pretty much the same at each cylinder.
So the things that caught my attention were no visible contact marks on any valves in the pictures (doped304, carefully examine the top of the pistons also), and the fact that cyl. #1 valves held fluid consistently, others not at all, and another marginally.
My engine had about a 25% leak past two intake valves.
Got a good story on a V6 engine, The alternator belt broke, drive belt came off, battery light came on and customer kept driving, The drive belt got caught behind the crank pulley, bore a hole though the plastic timing belt cover, derailed the T-belt, jumped time, bent all the valves. Needed an engine after that.
