Acceptable Valve Pitting

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Yesterday | 09:07 PM

AussieEffy

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Acceptable Valve Pitting

G'day all. After some advice. I bought used E7 heads to replace the E6 heads on my 1990 351. This is an intake valve from the used heads. My question is, if lapping cleans up the sealing surface okay, would these be okay to use? Keeping in mind this is a stock, low budget exercise.

Today | 05:20 AM

DaveMcLain

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Lapping won't clean up the sealing surface on that valve. It'll have to be ground. Otherwise it's probably ok to use from what I can see in the picture. Question is, what does the seat look like?

Today | 06:20 AM

AussieEffy

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That's the seat. Haven't touched it other than home-brew evaporust.

Today | 06:22 AM

AussieEffy

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I think I know the answer, but.... What do you think about using new valves in these old heads? Will they lap enough to seal?

Today | 07:06 AM

DaveMcLain

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Quote:

Originally Posted by AussieEffy

I think I know the answer, but.... What do you think about using new valves in these old heads? Will they lap enough to seal?

No. While that seat doesn't look terrible it should be ground to make it concentric but more importantly to make the surface flat and to narrow it back down again for proper sealing. What will be done is hit it with a top angle first, most of the time I use a 30 or a 37 degree to shrink it back down. Then the 45 degree can be ground and it will probably clean right up. Sometimes what you'll see is a small area where there's a pit from corrosion or something getting in there one time or another and you have to top it again.

Lapping doesn't have much to do with a proper valve job it is used mostly just to check width and position of the seat on the face of the valve.