Hi the valveguide in my -65 425 are worn in exhaust valve nr 8 , i looked in the Olds chassies manual and there are valves with oversize stems in 4 different sizes and it,s possible to ream up the valveguide. There are no digits stampen at heads intake area so maybe guides are original.

Is it possible to buy these valves 60 years later ?

 

A lot of valves are available oversize like that. They are known as "rebuilder" valves because it is a quick and less expensive way of saving cylinder heads. But .....I just looked in my normal suppliers online catalog and they do not have them available for the 425. Probably not enough demand, if any. To be honest with you it is almost as easy to just machine the heads for new valve guides and be done with it and a much nicer job.

 

Ok Bill , thanks for answer , yes the market for 425 rebuild valves maybe not so large.

 

If #8 valve guides are worn that badly, you can bet the others are worn beyond specs. The "right way" is to replace all the valve guides.

 

Yes Ralph , should let a machine shop check the heads.

 

I wonder what are the stock valvehead and stem dia , Olds chassies manual says :
Intake head : 2,000" - 1,990" , Intake stem : .3425" - .3432"
Exhaust head : 1,629" - 1,619". Exhaust stem : .3420" - .3432"

Is the first numbers stock sizes ?? Have measure some of the exhaustvalves stem
and can read approximately 8,71 mm / .3432" at the top end with no wear. Maybe
i got the valves with oversize stems in the engine and need a new set of valves.

 

Glenn,
Those are the stock dimensions. They do vary slightly from batch to batch. Also the exhaust valves are usually tapered slightly from top to bottom.

The oversize ones would be .003" or .015" oversize so approximately .346 or .358 Also the oversize valves are still the same size at the top so the stock valve locks can fit. They get larger below the lock groove on the stem.

Take a look at the picture below and you can see the line where the stem gets .003 larger just above the part number. Notice the part number says +3 That indicates the oversize.

 

I dont know what capabilities the shops over there have but I would probably install a set of bronze guide liners in the heads. That is the easiest fix. You will still have to machine the valve seats afterwards.

 

Great info BillK , thanks. Here is a pic of my cyl 8 valves. Can not se any digits on the stems. Should hear what the machine shop says about this.

 

Yes those are just standard valves.