Valve Clearance Question...odd finding

Jay Auskin · 02:30 PM

I'm buttoning up a top-end rebuild on my 3.2L, and when putting the #4, #5, #6 intake side valve cover, I decided to wiggle the #5 intake rocker. It seemed like there was excessive play. A dial indicator confirmed this. The engine at the time was at TDC for #1 with both valves for Cylinder #1 closed.

So, I rotated the crankshaft so I get to the right spot to adjust #5. I re-adjust intake rocker #5 clearance to 0.10mm, as confirmed by feeler gage + dial indicator. I go back to TDC, and the clearance grows to 0.24mm.

Is this OK? I'm thinking the valve clearance, as set at the proper position, is the max clearance. Why does it grow to 0.25mm for this one?

My cams/rockers were reground and rockers refaced/rebushed by Dougherty Racing Cams, so I'm fairly certain these are in good shape.

Eagledriver · 06-03-2007, 04:20 PM

Something is wrong. Maybe your cams aren't timed properly and the intake is just starting to open on number 5 when at TDC. Are you maybe on the overlap stroke instead of the compression stroke.

You can look at the cam lobes and see when the rocker is not on the lobe.

Only other thing it could be is out of round base circles and I can't imagine that would be it.

-Andy

Jay Auskin · 06-03-2007, 04:57 PM

Well, it was confusing the heck out of me because it was only one valve. I was thinking timing too, but it would be on more than one, if so. So, after several rotations, I decided to "wipe" the cam surface before it got into position on the #5 rocker pad. Then I checked it, and the clearance was big. I re-adjusted it, checked it again, and all was good. It appears as if there was something stuck on the lobe surface that was making the clearance off.

I checked several more, and all look good