[Dark_Horse]

I am rebuilding my 454. I just got the heads back from the machine shop where I had the seats ground. I have brand new valves for it. Springs will remain stock. Cam is only a step up from stock (Edelbrock 2162 with matched intake manifold).
My question is - is it worth lapping the valves? I have searched here in the forums and cant seem to find a definitive answer concerning new valves.
I know how to lap them having done it a few times over the years, just wondering if its even necessary given the valves are new and the machine shop done by a man I trust completely.
Opinions?
Thanks:hurray:

 

[SMALLBLOC]

I would just to make sure everything will seal properly.

 

[tonkas69]

I would just to make sure everything will seal properly.

x2

the machine shop done by a man I trust completely.

:noway::noway:
Then there should be no ?'s ??? :noway: :thumbsup:

 

[Dark_Horse]

Not a matter of ??s - more a matter of "is it required" ? I have both schools of thought searching the forums. At first I figured just put the new valves in - after all, new valves, fresh seats but then after searching, Im wondering if I should lap the valves. Many have commented its a waste of time only adding wear to the valves ("like pouring sand down the carb") and other have commented "its a must". Just looking for a push one way or another (altho Im leaning toward doing it - what can it hurt)

 

[tonkas69]

It can't hurt, but if your willing to put in the extra work, to give you a peace of mind, then I would say have at it. It just seem a waste of time (if you trust the machine shop) to tear the head down keep track of all the parts, re-clean the heads and put them all back togother again.

Is all I'm saying

 

[engineguy]

Lapping the valves is not necessary and can be detrimental to the valve face and the seat. However it is my opinion that new valves should be put into a valve grind machine and checked, just to be sure. I have seen some new valves that are not exactly concentric and touching them up on the valve grinder will guarantee that they are OK.

 

[pdvanocudadave]

Put head on bench with exhaust ports faceing down.Fill intake ports with liquid and watch around valve face for leakage.Then fill exhaust ports.Lap the ones that leak.It is a good idea to grind new valves.jmi