Valve lapping

V8-Ninety · Jun 29, 2015

Ive finally been forced to begin lapping my valves as i need the heads on my v8 soon but ive been at this one for ages and im not sure if its going to work

I think the black line at the bottom should disapear butbi havent got a clue... anybody here care to advise?

freelance · Jun 29, 2015

If they are really bad you should get the valve seats cut and the valves ground and then they will only need lapping in, to help you should hope to have a nice smooth rings out 2.5-3 mm wide on the valve, and obviously mat he in the valve seat, too narrow and it can burn through, too wide and your springs need to be a lot stronger.

V8-Ninety · Jun 29, 2015

freelance said:
If they are really bad you should get the valve seats cut and the valves ground and then they will only need lapping in, to help you should hope to have a nice smooth rings out 2.5-3 mm wide on the valve, and obviously mat he in the valve seat, too narrow and it can burn through, too wide and your springs need to be a lot stronger.

Thanks freelance... is the picture clear enough for you to gues what state my valve is in?

biketeacherdave · Jun 29, 2015

That's looking OK to me I recently did mine when I swopped my heads over try fitting the valve spray and putting some petrol over the valve seat n see if its fluid tight

discool · Jun 30, 2015

But we are not look at the seat but at the valve head, valves are harder than the seats so if your having issues with the valves but not the seats replace the valves. You could end up destroying the valve seats.
Mind you the last time I had to do that and also did a decoke on an engine was 1970

listerdiesel · Jul 1, 2015

We ground our valves in at the rebuild and they were about the same, still going fine 80k miles later.

Peter

V8-Ninety · Jul 3, 2015

Can anyone give a rough estimate as to how much seat recutting and valve grinding would cost?

SmileySteve · Jul 3, 2015

TBH I think that valve looks ok, if the seat looks shiny too and not pitted its probably fine.

listerdiesel · Jul 4, 2015

lANDYbrownlee said:
Can anyone give a rough estimate as to how much seat recutting and valve grinding would cost?

About £45 a head to get seats and valves done, plus VAT. Another £30 per head if they need skimming.

Peter

V8-Ninety · Jul 4, 2015

I had asked a small engineering firm abojt skimming.... pete you guessed the skimming price to the penny.... so about 150... and then id just need a v8 r380.... can i interest any of you in a kidney?

Valve lapping

V8-Ninety

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freelance

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V8-Ninety

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biketeacherdave

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discool

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listerdiesel

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V8-Ninety

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SmileySteve

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listerdiesel

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V8-Ninety

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