New valve seats,and new valves. The seats are 3 angle. Valves are new. From all the YouTube videos I have seen, from bmw, porsche,gm.ford.. they dont lap in the valves at the factory( as I can see) . And there cars off the assembly line run just fine. Any help here? Thanks
Just read in pelican parts forum, that not necessary any longer,with new.metals,etc.
I would do it on principle but that's me.
It's pretty much free and will tell you instantly if the machine shop did the job right or not.
It would suck to get the head on and find out you've got a valve that isn't sealing.
+1 on checking to make sure things are correct. I have gotten valve jobs back where there seat to valve sealing surface (the center of the 3 angles) was all over the place.
As I have learned a few times..."New" or "Rebuilt" means that the part has never worked before.
Assuming the head is in pieces now and your are assembling, two minutes with some paste on the valve and some dye on the seat will tell you how good of a job was done on the valves.
Only caveat with valve grinding paste is you really want to wash the stuff off cause if it gets in the engine oil it will eat the bearings.
A good machine shop will check the sealing of the valves with a vacuum. You can check it using grinding paste IF you do it correctly. The correct way is to turn the valve only 3/4 of a turn. Turning the valve more than one revolution can cause any high/low spot to disappear.
As I have learned a few times..."New" or "Rebuilt" means that the part has never worked before.
That's pretty good, and i agree with it but my slightly different take is new is made by a machine and rebuilt is something a human has had a chance to berkeley up.
It all new, but will check with blue,and paint thinner for leaks
Alfaromeoguy said:New valve seats,and new valves. The seats are 3 angle. Valves are new. From all the YouTube videos I have seen, from bmw, porsche,gm.ford.. they dont lap in the valves at the factory( as I can see) . And there cars off the assembly line run just fine. Any help here? Thanks
If the valves and seats have a cut, lapping them will only ruin the cut. You also get the possibility of not removing all of the embedded grit which will greatly accelerate wear.
If you need to verify seal, use something like a Sharpie on the seat surfaces and give the valve a spin. If it's off, have the seat or valve recut.
Also, had new valve guides installed at same time of valve seats and valves.
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