valve lapping??

If they vacuum tested OK they should be fine. I think the theory is that modern machining methods are precise enough that lapping really doesn't accomplish anything.

nate

I only lap valves in heads that do not really need valve grind work. IE, if one is replacing the seals, might as well lap the valves/seats.

JT

If they passed the vacuum test,all will be fine. I'm a bit peculiar, I hand lap lightly with fine compound to check for a perfect sealing surface.

Freddy

Grumpy AuC>

Shops are getting away from hand lapping. Typically they use an interference angle of ½° difference, which allows them to fully seat within a few miles. If you still have the heads off the car, you can wet-check the valves by pouring solvent in the intake and exhaust ports. If the fluid runs out, you have an unseated valve. Some dampness around the head of the valve after a couple of minutes is OK.

Yea, the wet method is more accurate.

Using vacuum, "IF"...they actually did it is actually pulling the valve toward the seat...plus if they don't have very accurate gages...they won't see any leak. Using vacuum to seat the valve AND check for leaks is cheating. If they are listening...for a leak..use a new shop!

I normally don't bother checking the heads I have done. I'm not gonna admit how I do it but the shop I use has never given me a bad valve grind. I do my own assembly when I port heads, he just does the grinding.

He uses (as noted above) a 45 degree head cut and a 46 degree valve cut on his street stuff. On hot rod or race heads, it's 45 - 45.

Mike