Forum

[Beezabryan]

No amount of guesswork by the board members will get you anywhere.
Why not just pull the head off and have a look.

[papasmurf]

I hope I am not breaking forum rules but Wurth oil and Wurth petrol treatments save a multitude of problems like valves sticking, oil leaks and so on.

[pd110961]

the head is coming off tonight.. cant do it at the weekend as off to London to see AC/DC!!

[Geoff B in Kent]

Pd - read the earplug thread!

[pd110961]

well, taking the head off didnt take long, had to remoe crash guards etc, .

its the exhaust valve liner, it has slipped out of the head about 3mm.. the push rod had taken advantage of the situation and jumped out from under the rocker, but no damage done that i can see.

i have had to order a valve spring compressor, then i can take stock of the situation. has anyone here removed a valve guide from the head and installed a new one?

the piston tapped the guide and made a small mark in the crown, perhaps 1mm at its deepest.. do you thing it will be ok to smooth file this out as much as possible and nor replace the piston?

[pd110961]

looking at the parts diagram, its the valve seat INSERT that has been pushed out into the head.. what would be the cause of this?

[papasmurf]

It is called the coefficient of linear expansion, of two different materials, overheating overcame the press fit the seat is supposed to be.

[Les]

dl = L0 α (t1 - t0) (1)

where

dl = change in length (m, inches)

L0 = initial length (m, inches)

α = linear expansion coefficient (m/moC, in/inoF)

t0 = initial temperature (oC, oF)

t1 = final temperature (oC, oF)




Just use the above formula it will be fixed in a jiffy

[pd110961]

thanks for the explanation, Gents.. I di dmy engineering Degree in 1984.. my memory fades!

I spoke to our Hosts this morning.. the valve SEAT dropping is not so common but it happens.. then cant fix it but I found a company locally, Mansfield Engines, that can do it no problem.

they said they would machine out the head and fit an oversize seat, and it could be about £45 all in, so not too painfull after all.

the removal of the head was easy ... thank god for indian technology!

[Adrian]

I would also treat the head to one one our hosts' oversize exhaust valves, which is intended to be a better fit for the valve seat than the standard item.



A.