Scuffed & scored Valve shims faces......Any input- Please??

[johny brando]

Just put my motor back together after fitting a few new (OEM) valve guides , having all valve seats cut , all new Stainless Steel valves , new OEM valve seals , new NPR Rings & a Hone. Runs good ...I'm using a 15w40 purpose blended Running In Oil to help bed the rings in. I went to check valve clearance after first 100 miles ( they were set at 4 to 6 thou) found I found several Shim faces badly marked with many revolving circular lines on the face that the cam strikes & a couple of them you could you could actually just feel & see deeper scoring with a scriber point .....Aaaaahhh
When I built it I did (as is quite normal ) have to tip all the new valves to be able to stay in the 230 + plus shim range ...they were spun in lathe with a Dremal held perpendiclar to the valve stem ....I was very,very particular when doing this but maybe it just wasn't good enough ! & I can only think this problem is caused by the underside of the Bucket itself not sitting square enough on the end of the valve stem tip ...which is then allowing the bucket to float unevenly on the stem tip causing the Cam Lobe to load up on one side of the shim face which would then cause it to have a digging in effect on the shim & also cause the shim & bucket to SPIN instead of just revolving as they should do normally, and as such this is causing the damage ????? The question is this .........................
Has any one else experienced this or have heard of it's cause & cure before ? if so I'd appreciate hearing from you..... also is there a trick or a proven better method to ensure a perfect square tipped stem end ??
Thanks guy's, Johny B

[zed1015]

The shim wear you describe is common but usually takes many thousands of miles to occur.
If this has happened to a good or new shim in a very short time frame then un-square stems may be the problem.
If this is the case then the cam follower will also get skewed in its bore which will result in excessive skirt and bore wear.
I should also note that if you have used pattern shims I have had some that I discovered not to have been hardened to oem quality and have worn quickly.
Personally the Dremel method of tipping the valves does not sound accurate enough.

[needaz1100r]

[Personally the Dremel method of tipping the valves does not sound accurate enough.[/quote]

Ditto