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E: Engine Checking Valve Grinding


Website User
VOC Member
After lapping in both Valves they are tested with water ( NEVER Petrol ) and a drop of Engine Cleaner , which turns the water pink so that any leak can be easily seen .
The seats and Valves are cleaned and the Valves are inserted in the head with NO Valve springs fitted and the Top Guide in place.
Any other ways of doing this ?2651026511

Nigel Spaxman

Well Known and Active Website User
VOC Member
I guess there are a lot of ways of doing this. I usually do it the opposite way to you. I put the valve springs in and put some kind of solvent in the port and then look for leaks in the combustion chamber. Sometimes I use gas (petrol) If I had an even grey colour on the seat and valve it never leaks. You can do this test before you take the valve springs out.


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VOC Member
VOC Forum Moderator
I usually put the test fluid into the port as Nigel does, less likely to make a mess when emptying too. I tend to use paraffin as the test fluid. It searches out leaks, is less volatile than petrol and so less of a fire risk.

roy the mechanic

Well Known and Active Website User
VOC Member
Six or eight vertical pencil lines on the seat, fit valve and upper guide, rotate valve by hand, if the marks are cut or blurred you have it sorted. No fuss or mess.


Active Website User
VOC Member
Engineers blue on the valve seat and rotate valve I do the same to the head after lapping to the barrel.