[crm318]

I am tearing down my Pontiac 400 due to coolant in the oil (it only has 2000 miles since rebuilt). I noticed that the intake valves on the number 1 and 3 have an odd chip missing from the outer diameter or margin. Upon closer inspection, is appears to have a flow path viable in the chip and looks to be washing out. The divot is not effecting the valve face, but it seemed it would if it continued to erode. These are stainless 5000 Ferrea valves with a 30° face. The seats are in perfect condition.

[mgarblik]

If possible, I would like to see some better pics. I would like to see a straight on pic of the margin and face where the defect is. Couple of things to look at. 1. Check the stem to guide clearance on those valves and the mating exhaust valves. 2. Look super close at the mating exhaust valves for any chance of tiny similar damage to them. It is possible that the valves are contacting each other at some point during the cycle. You didn't mention anything about the camshaft, valve sizes , cylinder heads used or anything else, but it is possible under the right conditions and with detonation. Also check the chamber walls for any chance the valve is just touching something in the chamber. Remember to look everywhere around the valve as it is rotating during operation. 3. Check the block chamfers to make sure the valves are not just kissing the edge of the chamfers as well. Let us know if you find anything. Pics of valves in the head might be helpful as well.

[PAUL K]

Is it possible those nicks were there before the engine was started? I've had Ferrea valves nip each other when in use but they didn't look like that and both valves had witness marks. Fwiw they were 2.125 and 1.8 valves in a factory head.

Is it possible a foreign object went through this engine?

[steve25]

That does not appear to be a chip, but it looks like marks from a poorly maned valve spring compressor during the assembly of the heads.

Some better pictures of the overall head of the valve would help greatly !

[Half-Inch Stud]

Just maybe the Exhaust valve has a similar feature on the sealing side.

[STEELCITYFIREBIRD]

More pictures, or more speculation.

[crm318]

Heads are small chamber 1968 #15 with mild porting, 2.11/1.77 valves and bronze valve guides. Cam is a summit 2802 with 1.5 rockers (soon to be 1.65). Other than the valve damage, everything looks to be in order. No contact or witness Mark's on the head or block.

[crm318]

More

[crm318]

More pics

[STEELCITYFIREBIRD]

Picture 1 of last set looks like foreign object hit it, edge rolled back.
Likely burning because of resultant sharp edge

Valves sure are buried deep!

Find or know how water is getting in oil yet??

Was valve job done with stones and lapped in heavy?

[hurryinhoosier62]

Originally Posted by STEELCITYFIREBIRD

Picture 1 of last set looks like foreign object hit it, edge rolled back.
Likely burning because of resultant sharp edge

Valves sure are buried deep!

Find or know how water is getting in oil yet??

Was valve job done with stones and lapped in heavy?

That’s my guess as well; foreign object damage.

[crm318]

I forgot to mention, hardened valve seats were installed, same as screw in studs. Everything that can rebuilt or replaced was. As far as the valve job, I'm not sure how they did it. I did lap the valves myself before assembly and they had perfect seating / contact.

[dataway]

Way long spark plug installed and clipped the edge of the valve?

I know, a silly guess

[hurryinhoosier62]

Originally Posted by dataway

Way long spark plug installed and clipped the edge of the valve?

I know, a silly guess

No, possible.

[crm318]

Or a compression tester, which I have used before...hmmmm. as for the water in the oil, I had a very corroded timing chain cover and also, the deck of the block looked like it had seen better days. Also has slight surface rust on two conjoining combustion chambers, so it may have been a head gasket. New timing cover and decked blocked on the way.

[steve25]

Well both valves where still sealing well as seen from the contact pattern , but the question is if the valves went in the gead not looking like that then what was eroding them.

At this point you have no choice but to replace them and continue on with the rebuild and addressing the other issues.

In that first photo in post # 9 of that valve I for sure do like that line / ring pattern seen above that valve seat area ( not sure what that's from ), nor the unclear seat contact area that looks pebble like, as if lapping compound was left in the pores of the valve seat area of the valve and or head.

["QUICK-SILVER"]

Originally Posted by crm318

Or a compression tester, which I have used before...hmmmm.

For peace of mind...Screw it in now and see if that was it. Long thread reach adapter would get awfull close.

Clay

[shaker455]

I looked at those pics closely,
Area in question appears to have an inclusion in the raw material rod stock before it was finished machined.
They may have let it go thru inspection as it may not have affected fit or function.

You can chuck up the valve and see if there is any runout.

[Skip Fix]

I felt a valve bump a TDC stop screwed in the spark plug hole so a long plug or compression gauge could have.

[mgarblik]

Lots of good suggestions of things to check in this thread. Compression gauge kissing valve is possible and easily checked. One other thing to look at along the lines of the foreign material is the valve guides. When bronze liners are used, they sometimes chip the end of the OE iron guide area during installing, or crack them slightly if they use a ball broach to size them. Then a little piece of the guide breaks off in operation. Look very closely in the pockets at the guides for cracks or a little piece of the original OE guide that is missing.