Checking valves are grinded in correctly
Turbo Mini Forums

Is there a way to check valves are grinded in correctly?

I've saw tests with liquid in the chambers, tests with liquid in the exhaust / inlet ports and tests with an airline put into the ports and blown from behind the valves while the chambers are full of liquid to show bubbles

Which is the best to use?

water, petrol, brake cleaner, thinners, vodka....choose your liquid.

Pour either direction really with valves shut. If it leaks it leaks, if it doesnt all good.

Although water probably isnt the best choice.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

water soluble cutting fluid no rust and its not to nasty to deal with good for the chamber/cr also

You can see when you lap them in if they are OK. You just have to look for the darker witness mark on both seat and valve to be continuous. Any gaps of thin bits and there's somthing wrong. Engineers blue may help too.

Definitely worth bluing/ marker pen.

If they've been lapped too much, both seat and valve surfaces start to become concave. The lapped surface may look uniform at first glance and it may seal too, but if the valve doesn't make full contact over the full seat width it could reduce heat transfer.

Of course other option is simply light. Shine a decent light at either end and if any gets through...it aint sealing.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Thanks well I filled each chamber with paraffin and left it over night. This morning I checked and they were all still full but the exhaust and inlet port for two of the chambers were slightly wet so its seeping through but not by much

Do you think this is ok as the chambers looked identical to how I left them last night

Thankd

Based on a description...hard to tell

But as long as they seal over a short period and arent pissing anything through they should be fine.

Valves only need to maintain compression for milliseconds at a time !

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Freddie Dixon of Brooklands and Riley fame always said they were on their seats so little it didn,t matter !

did you have springs on when you did the test?

Yes springs were on.

After 14 hours they were still full with very little loss, before grinding them in two chambers completely emptied after 1 hour!!!

When you turn the engine over by hand setting the valve clearance they are constantly opening and closing so when the engine is running at 1000 rpm they are going to be closed for a very short period

I think I will stop fiddling with it and just put it on, I bet my stock head on now leaks more

sounds good,

lets face it, more is going to get past the rings,

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will