8 cylinder front engine iconic vehicle
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By Dawid van der Walt
I see on Youtube people test valve seats by filling the combustion chamber with water. They also claim to to this without fitting the valve springs?

Is this how you test that your valves are seating properly after lapping them?


Example -
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By worf
Short answer: yes.
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By Schocki
An old mechanic checked it the same way but did it with fuel. I think fuel is better due to the fact that the surface tension is a lot lower. If it seals fuel, it's good to go.
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By Dawid van der Walt
So why can't I get mine to seal? I have lapped them three times, with course, medium and fine past.
I did this by hand, and can hear them go smooth as I go.
The seats and valves are not pitted, and show an even slightly gray surface.
Any suggestions?
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By h2pmr
if the valves and seats are both an even grey colour all round after you have ground them in with fine paste they should be good to go.

you could try hanging a weight onto the valve stem i.e GENTLY clamp mole grips onto the stem where the collets go to hold the valve to the seat.

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By Dawid van der Walt
So after a weekend spent lapping each valve again, and testing each combustion chamber before moving on, I have success :beerchug: .

All 32 valves are sealing well. I'll check again when I have installed the valve springs.

Came across this trick that worked well for me.

Remove the suction cup from the lapping tool, and fit it to a socket adapter for a battery powered drill / screwdriver. With some fiddling you can center the cup so the valve doesn't experience to muck side to side forces.

Made the job much easier. My seats weren't badly pitted to start with but still required a fair amount of work.

Now the assembly can get started. I plan to have the car at the last Cars and Coffee here on the first Saturday of December.
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