Exhaust Valves

[fmartenies]

So I pulled the head tonight and disassembled the valves. All of my intake valves were great. None of my exhaust valves would come out. They don't appear to be bent, and my digital calipers say the ends are not mushroomed. however, when I slide them down, they bind and stick at the top of the grooves for the keepers. No budging.

I'm not too worried because I have a spare engine waiting 10 feet away. However, I'd prefer not to put valves out of the other engine or new valves in and have the same thing happen. Anybody else experience this and know what I should check? My first thought is a PO messed the timing up. It's not immediately clear to me though because the apparent bend is so close to the end of the valve and everything else looks otherwise fine.

[fmartenies]

No advice?

[Cocacolakidd]

Once had the same problem my self - one bent valve and two others that would not come out. Usually it is the head end of the valve that bends, but not always.

I used epoxy and glued a bolt (3/16" x 2") to as close to the center of each valve as I could and straight with the stem. When the glue was cured, the next day, I put a drill motor chucked onto the valve and spun it slowly (Variable speed drill) and could see one of the exhaust valve wiggle around - I replaced it with guide still attached. Two others that would not slide out I polished with fine emery cloth on the upper end while spinning with the drill and they slid right out.

Note: A little heat from a map gas/LP torch and the epoxy wipes right off

[Cocacolakidd]

Almost forgot - One can also go to the local auto parts store and get a Valve Grind Kit that allows one to spin the valve in the head - this kit is usually used with the valve grinding compound to seat in valves on rebuilds - it will also work in your situation.

[fmartenies]

Any worries unique to the 944 that should be taken care of to avoid damaging the replacement valves? Or is this normal for the engine? 83 w/just under 100k.

[Cocacolakidd]

Things that are not that normal still happen. The valve guides are all machined to the same specs, but because the exhaust valves are exposed to much more heat the machining on the stems is different than that of the intake valves. Usually this is .002 to .008 thinner section depending on the valve property. It is always possible to get an expanded stem with close tolerances and add a minute burr where the keepers join and this is often a problem. Also a work expanded stem sometimes out of round will also be extremely hard to remove. With the closer tolerances sometimes it doesn't take much especially in an area not worked by the valve guide.

If you can polish them and have easy removal, then inspect them thoroughly along with the guides they may well be OK to re-assemble as is. Otherwise new valve and guide may be the solution.

[fmartenies]

If I can just work (or have worked) the section above the keepers so it can exit the guide, that would be great news. That portion never enters the guide anyway and everything else measures within tolerance.

I go to the machine shop tomorrow to see what they recommend and at what price. I also have a complete second engine so that is also an option.

I looked at the early engine/late engine differences thread but didn't see a straightforward answer to this question: Can I put a late 2.5 head(not sure of the year) on an 83 block?

[fmartenies]

Good call on deburring/polishing. Took it to a local auto machine shop to get everything measured and checked and they are going to do a full valve job and rework the exhaust valves for a song and a dance. I pick her up on Friday.