What liquid to test for valve leakage

[Kevin.payne.15]

Help please

 

I've had to replace two valves in the engine and hoped that I had cut them in sufficiently with coarse then fine paste. I've managed to get a even gray colour but if I drag my nail over the surface I can still feel some surface roughness - it's as if I have concentric rings. Not sure this is right nor how to remove them because we've been going with the fine for ages

 

I've reassembled the head and have tested with petrol to see if it's leaking and kinda think it is. Is petrol too tough a test or should I use a more viscous liquid?

 

Suggestions please on removing the concentric rings if this is the cause?

 

Thanks

 

Kevin

[Pete Lewis]

The only way would seem to be have the valves ground and seat recut to the correct angles

 

maybe time to fit exhaust inserts as cutting will remove some lead memory

 

Reckon once the rings have formed paste will only keep them generated

 

re facing the seats is looking a possible solution

 

I often regring with paste using a reversing battery drill on the stem and you have to watch out for

making rings ,

 

Petrol maybe a bit thin, and would creep through a reasonable seating , parrafin was an old gag

oil is a bit thick ,

[Kevin.payne.15]

Pete. The inserts were new a year ago and the valve was new from moss. I managed to get a reasonable gray line about 2 mm wide all around the valve so it must have been pretty close to the seat to get the wear mark .....but I've got groves

 

The worry is that if I carry on with grinding paste do I just perpetuate the groves now that they have started ?

 

Kevin

[Pete Lewis]

I feel the answer to that is ....yes

 

out the box idea, you dont have a seat cutter but could you erase the rings if you cut a disc of

wet and dry it would not follow the developed rings being on a stiff backing ???? To sit in the seat and rotate with the valve

[Pete Lewis]

are you using UL exhaust valves ??  and what engine is this for  

 

Pete

[Kevin.payne.15]

Yes I believe they are. Seats replaced 2 years ago

 

Engine is actually a 2000 me 2 converted to gt6 compression standard. You can see all the posts on the site in recent months. Must be the longest rebuild in history!

 

Kevin

[Kevin.payne.15]

Nope no valve cutter available. Headache pills issued every time I step into the garage as preparation for the next set of woes.

[Pete Lewis]

If you are getting concerned about the grooving have you a local machine shop that could cut the seats and face the valves for you its normally quite a cheap job

 

if you have hard seats and two exhaust have burnt then theres a problem somewhere

soft valves , retarded, tight tappets etc. come to mind

 

pete

[Kevin.payne.15]

This is what the valve currently looks like. I think it's a case of a trip to the local valve cutter for me!

[Pete Lewis]

i would have thought a fine paste would flatten the grooving , its not  so bad 

 

what do you use to turn the valve with   stick and plunger or a drill ,  do you reverse the direction frequently  ??

 

Pete