Alright so I have decided to replace the valve stem seals on my 250 I6. Now I have looked over the forums on how exactly to do this, I also check my Chilton's. But neither has been very useful. However the forums did mention that an air compressor and special fitting may be necessary along with some other special tools. Is this true? Can anyone provide a step by step process in changing out the valve stem seals? At the very least a general outline, I am pretty sure I can figure it out just by looking at it.... whats the worst that can happen? I blow up my engine? It will give me a reason to get a 302.
You'll need an aircompressor, spark plug hole fitting to connect the air hose to, & a spring compressor tool. Remove the spark plugs, do one cylinder at a time. Screw in the plug fitting, hook up the fitting to the compressor, Compress the valve spring retainer with the spring tool. Remove the valve keepers (don't loose em, they're small boogers) remove what's left of the old seals. Install new seals and reinstall the spring, retainer and keepers. make dead certain the keepers are seated when you release the spring compressor tool, otherwise you'll drop a valve and have a perfect excuse to swap in a V8.
I don't want to dis your idea of just doing the seals. But I think you will be way ahead of the game if you take the head off completely and let a machine shop go over eveything. Older heads most likely have worn guides which is the biggest reason for oil burning. At least with a fresh head, you know all is well again. Guides, valves, springs, head gasket, seals - all nice and new tollerances again. Good time to repair the rocker shaft too. As far as doing just the seals with an air compressor spark plug adaptor - that should be in the manuals someplace. I will have to go look and if I find it - cut a paste a picture of it for you.
if you do just replace the seals,have a soft face hammer handy or a hard wood dowl and a hammer.You may have some keepers that wont release,if this is the case,with the valve still assembled give the stem a whack with the hammer and dowl to loosen the hold of the keepers.Mushroomed valve stem tips will also give you a problem when it comes time to pull the keepers.if you find any mushroomed tips(check em before you start)just pull the head and get it re-done.Mushroomed tips can cause rocker noise and other problems down the road.(namely causing the keepers to fall out and drop a valve on a piston)this only happens while the engine is running(of course)good luck.
You don't need an air compressor or special fitting. To hold the valves up while changing springs or seals I prefer to just shove clothes line rope in through the spark plug hole then move the piston up to the top of the cylinder.
That is a great tip. I have done that on countless small engines to remove lawn mower blades, minibike clutches, pulleys, ect. I could only add to use all cotton rope - if little bits of rope get left behind they will burn up and go out the exhaust. Poly rope bits could melt and burn onto the cylinder walls and rings if left behind.
