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View Full Version : Valves pitting and marks


Iain
02-10-09, 05:05 PM
First off, pitting on the face, ok or renew? It's an inlet valve.

http://iainel.co.uk/images/forums/Valve1.JPG

Next up, exhaust valve, there's a dark shape on it that doesn't seem to come off with the wire wheel. Is this normal?

http://iainel.co.uk/images/forums/Valve2.JPG

Thanks!
yayoboy
02-10-09, 05:09 PM
not 100% sure but i remember my head builder syaing something about replacing the valves if they are pitted, i would inagine the exhaust valve marks are heat marks?

edit: replacement of the valves that are pitted makes sense actually as you aim to get it smooth in the chamber..
Iain
02-10-09, 05:10 PM
I can understand replacing it if they're pitted where they meet the head, or on top, but wasn't sure about it just on the face.
AlexW
02-10-09, 06:45 PM
Face shouldnt matter much, the black marks will just be heat marks problery, main reason for cleaning the bottom is to make it so the valve lapping tool will stick correctly.
philip
02-10-09, 11:43 PM
id leave it matey, will be fine. usually the valve seat pits, which would then need re-cutting.
Will F
03-10-09, 01:00 AM
Both will be fine, although for the prie of two valves ( a few £) why not change them?

Also need to ask yourself how that valve got the marks on it - should be fine if its a rebuild though I spose....
Iain
03-10-09, 09:23 AM
What, you suggest change them all? Or just the 'damaged' ones?

Can I ask you how they got the marks on them? lol I'm not sure what would cause it.

Cheers all.
Nova_Tek
03-10-09, 09:57 AM
If you're gonna change them mate I'd change them all tbh, especially if they are only a few £. You dont wanna end up having to crack open the engine to replace ones that weren'T should something happen.
Adam
03-10-09, 10:47 AM
Are there any pitting marks on the chamber itself>
Iain
03-10-09, 10:48 AM
The head looks okay.
AlexW
03-10-09, 11:35 AM
Valves are at least £5 per valve, anything up to around £15 per valve.

If your worried, replace them, if not, dont worry. But they look fine.
burgo
03-10-09, 12:06 PM
wow never seen pitting like that on the face before. what are the seats like?
Iain
03-10-09, 12:12 PM
Seats are fine. The other inlet valve on #4 is also fine?! There's some lighter pitting on the first valve of #1 too. I'm sure I placed them in the right order upon removal.
burgo
03-10-09, 12:17 PM
for it to be one of the two valve instead of both then surely it has to be a valve defect
philip
03-10-09, 12:34 PM
ive seen a couple. i wouldnt worry ive built maybe 20xe heads this year so far and a couple had some very slight marks. and alls been fine.

as said if the seating faces were pitted then its just a matter of getting them re-cut, which isnt an expensive job. for all you know if could of been caused from a tiny bit of guide or something previous to you owning it.