Thread: 2.25 diesel valve stem seals, advice pleeeease!!

Originally Posted by chazza

I haven't heard of the oil method before but I have heard of people using compressed air to hold the valve up and also synthetic twine.

Disconnect the battery first - accidental turning of the starter during this operation might damage the engine badly.

With the twine method do as Dave does, then feed the twine - the sort that is synthetic, about 3mm in diameter, not furry and won't drop bits - into the cylinder through the spark plug, or glow plug hole. When a goodish length is piled on top of the cylinder use the starting handle to carefully ease the piston up as high as it will go. If enough twine has been fed into the cylinder it will bear on the valve face and hold it up. Make sure that a good lengthy-tail is hanging out of the head, so that it can be retrieved and to avoid all of it disappearing inside the cylinder. Advantages are: no mess; a positive lock; no leak-down; no fear of the engine running on oil.

I also use this method on my chainsaw to seize the motor, whilst undoing the nut on the centrifugal clutch, for servicing of the bearing behind it. On a 2-stroke engine the piston needs to be quite high before inserting the twine, so that it doesn't get caught in the ports,

Cheers Charlie

the twine trick wont work on a 2.25 diesel (unless your combustion chambers have fallen out). and I dont trust the compressed air.

I replaced my stem seals without using oil, air or rope. Quick and clean.

Aaron.