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I've had valve issues since I bought the car in April 2019; I was never able to get it idling smoothly and starting it was an issue. Today I took the deep dive, after fruitless attempts to get the valves adjusted to spec, and decent compression across all cylinders. The car had been sitting from probably 2009-2015, and after fluid changes, plugs and points started up with a little hesitation, understandable due to the hibernation. We've put maybe 30 miles on it in 2019-20, when not rebuilding the suspension, brakes, etc.

What I discovered:

--Intake valve stems in #3 and #5 were gunked up something fierce, obviously keeping them open enough against the guide, it appears. Others weren't much better. Exhaust valves were all gunk-free, but had wear from the guides.

--Most of the valves are "Packard" script with a slot in the center--one valve has been replaced and is in nearly perfect shape. The other valves have wear on the stems than is significant--I think I'm replacing the whole set as a result. Some have pitting on the stem; other serious scratches and wear at the spring retainer. The seats all look fine, and no evidence of burned valves. The engine at some point had been rebuilt, but no idea when. The cylinders still show hone marks.

--The guides have a little bit of play. What is 'acceptable' in terms of play?

--The adjusting bolt on the valve lifters as I recall is supposed to be convex. Mine have worn to the point where they are concave where the stem meets the bolt. I assume I can recondition these to a convex condition with some careful work on a grinding wheel. Given the condition that they were in, it's easy to see that it was impossible to get an accurate adjustment with feeler gauges since the stem was sitting in a 'hole' in the adjustment bolt.

Any advice?

For a driver, just changing the valves will probably tighten up the fit in the guides sufficiently unless they are waving like flags. It is much less than fun to change the guides with the engine in the car.

I just went through something similar on my car, and can report that after reshaping the tappet screws, the valve train is much quieter.

Ross actually helped me, and we chucked each tappet up in a lathe and ground the tappet screw convex while it was rotating.

I think your plan to decarbon, new valves, and fix the tappet screws should provide good results.

If you look at the service manual, it discusses a modification to the exhaust valve guides that reduces carbon build up. It may be worth seeing if you have the newer or older style valve guides.

If you do end up driving out the valve guides, put a block over wood over the valve seats!!! Several years ago, I was driving out valve guides, the hammer slipped, and I ruined one valve seat - turned a ring and valve job into a complete overhaul!

Good luck!

Thanks, guys--Ken, I'd read your adventure previously and PDF'd the pages. Great write up. I planned on refurbing the tappet screws by putting them in a cordless drill in a vise, and use a Dremel for some creative re-shaping. Not the first time I've done something like that!

After further review, the guides do not appear to be all that bad--they are original style, so I will probably modify them per the shop manual. There's a dash of slop in them but using the "one" obviously newer valve and it's perfect stem, the movement is negligible. I'll order up replacement valves for those that are worn out, and call it good.

Due to fumble-fingers, I'll be dropping the pan to retrieve one of the valve keepers. Slipped out of my oily fingers, right down the drain hole where my rag plug had slipped out, and 'tunk' hit the pan.

It's always sumthin'.

Refurbed the tappet screws this afternoon, and looked again at the valve guides--several of them have obviously been replaced as they are not all a matching style. None of them though have been cut down or drilled with the countersunk void in the shop manual.

Interesting.