Sticking Valve

Just an update on my sticking valve issue. To date, I have soaked the offending cylinder valves with penetrating oil, MMO, and Sea Foam. Not all at the same time, but several days apart with short engine runs inbetween treatments. The last treatment was to fog the engine with Sea Foam per the instructions on the can through the wiper vacuum inlet. All to no real change.

What I have noticed is that the engine runs better cold, and progressively gets worse as it warms up. I found the #3 spark plug was not firing at all, so installed a spare plug with a slight improvement. This weekend I did find a vacuum leak at the carb. mounting flange. I am not sure how long this may have been leaking, but in pulling and inspecting all 4 plugs, they were all found to have a carbon build up at the end of the plug thread about 1/64" thick. I have been running the carb. high speed mixture control about 1/4 turn off the seat since day one, which is where it seems to want to run.

I have not yet pulled the valve cover, and may have to go there. I would like to avoid pulling the head if I don't have to, but things are not getting any better. The compression on the #3 cylinder is down to around 50 PSI, give or take. When I checked compression in September, it was running 65 PSI (the others were within 3 PSI). The engine vacuum is vibrating between 17-18 In. Hg at idle.

Any ideas?
 
if you have bronze valve guides eventually more will stick. The solution is to replace them all. If not, and you are certain its a valve, bite the bullet, pull the head and offending valve and repair it.
 
If you're just starting to lose compression on that one cylinder, I'd recommend pulling the side cover [ the manifold doesn't have to come off] and checking the valves and clearances.. It sounds like you may have a sticking/lazy valve or that you are just starting to burn one..
 
Thank You Genelemen. After tossing and turning last night I have come to the conclusion that I am going to have to pull off the valve cover and have a look and see what is going on in there. I may have to bite the bullet and pull the head. I was wanting to avoid that because the exhaust manifold is one of those heater type manifolds and I can not get the distributor off without pulling the manifolds. I will have a look at the valve guides. The engine was rebuilt sometime in the '80s and I am not sure what might have been used when rebuilding back then. Thanks again.
I will post again on what I find.

Chris
 
50/50 ATF/acetone is one of the best penetrants and gum cleaners you can use. Maybe with the tappet cover off and the plug out you can access most of the stem to get it in there.
 
Why do you have to remove the manifolds to remove the distributor ?? All the heater manifolds I've seen have a hole cast in them so a screwdriver can get to the retainer screw and there is plenty of room for the wrench.. There are several different manifolds and there certainly could be some without the hole,, I just haven't come across one..
I'd look at the valve lash first,, are yours adjustable ?? Once a valve starts to burn, its goes pretty quick.. But, sometimes they can be saved if caught in time..
 
Sometimes when you try to remove the valve cover with the manifolds in place,you find that the upper rear VC bolt is too long & will hit the manifold before its fully unscrewed.I always make sure there is a shorter bolt in that corner.
 
I removed the valve cover today. As luck would have it, the valve lifters are not the adjustable type. I am going to take a look at the valve clearances tomorrow and see how they look. If there is a hole in the heater manifold to remove the distributor, I have not found it, yet, anyway. I will take a closer look tomorrow. (It would not be the first time that I have missed the obvious.)
 
Well, I took a good look at the manifold and it is an Otwell heater manifold. There are no holes in it to poke a screw driver through. I checked the valve lash on most of the valves, and found the lash to be quite a bit larger than recommended. I am now suspecting that my cam is worn. The valve lifters are the non adjustable type. No broken springs, and the two valves on the offending cylinder are showing about the same valve lash as the others. Looks like I am going to have a larger project than expected this summer!
 
It shouldn't too difficult to figure out how the measure the camshaft lift to see if a lobe is badly worn.. But, if the lift turns out be OK and the lash is OK, it looks like you probably have a burnt valve..
As for removing the distributor, you might be able 'warp/bend/make' a 90º screwdriver to get at the retainer screw without removing the manifolds..
 
There's only 4 (four) nuts holding manifold to the block, loosen and pull manifold towards you a half inch for access. Replace manifold gasket with late 31's. You're probably going to have to pull manifold anyway if dist stuck, and you're also probably going to have to pull the head to ck for a burnt valve. JMO
Paul in CT
 
Thanks, guys. I have come to the conclusion that I am going to have to pull the manifolds and head and find out what is going on. I have been hitting the manifold nuts and head bolts with the acetone/atf mixture every day. Will pull the manifolds first and take a look before removing the head. I was wanting to install a stock exhaust manifold anyway, so now have a good reason. Maybe get a little paint on the engine.

Ok, I have another dumb question, can the cam & lifters be pulled and replaced without pulling the engine? (I know the oil pan would have to be removed.) It looks like the cam shaft would clear. Looks like getting the lifters to stay in place while installing the cam might be a real trick. Just wondering.
 
Chris H said:
Thanks, guys. I have come to the conclusion that I am going to have to pull the manifolds and head and find out what is going on. I have been hitting the manifold nuts and head bolts with the acetone/atf mixture every day. Will pull the manifolds first and take a look before removing the head. I was wanting to install a stock exhaust manifold anyway, so now have a good reason. Maybe get a little paint on the engine.

Ok, I have another dumb question, can the cam & lifters be pulled and replaced without pulling the engine? (I know the oil pan would have to be removed.) It looks like the cam shaft would clear. Looks like getting the lifters to stay in place while installing the cam might be a real trick. Just wondering.
Click to expand...
If you are thinking of changing the cam, why not drop the pan at the same time and install adjustable lifters. Actually it would make the job a bit easier in my opinion. I really think the cam is OK but like any 80 year old part, it is worn some. Do yourself a favor and get a Stipe IB330 and find some horsepower you didn't know you had.
 
If you were going to replace only the cam shaft,you shouldnt have to drop the pan.The original lifters are hollow & have a horizontal hole that takes a gulp of oil every time the valve opens.just stick a nail in the hole when valves are open,& you should be able to pull the cam.If the valves need the seats ground,that will lessen the clearance & if you replace the valves You will likely need to grind the stems to get correct clearance.
 
sorry to hijack the post with a different stuck valve issue, but someone else may need the info...

29 A engine. #8 valve (exhaust in #4/firewall side) is stuck open. the difference is that my engine has been sitting for god knows how long and i haven't been able to afford everything to get it running yet. i turn the engine with the crank and every spark plug hole pushes out massive amounts of air, but not the #4. felt around with my finger to find the exhaust valve stuck open. before discovering this, i put oil and pb blaster in the plug hole. since discovering it, i've put seafoam in. most of it seems to run out the exhaust manifold, though.
i do want to try running the engine as-is when i've gathered the electrical parts, but i figured if there's a way to get this valve moving and putting out decent compression while i'm waiting, more power to it (no pun intended). as stated, money is tight at the moment (no income), so it's implied that i can't throw out money for gaskets yet, either. SO... are there any fantastic methods i can use to attempt to free this valve without spending any money or pulling anything... before running the engine?
 
pyrodork said:
sorry to hijack the post with a different stuck valve issue, but someone else may need the info...

29 A engine. #8 valve (exhaust in #4/firewall side) is stuck open. the difference is that my engine has been sitting for god knows how long and i haven't been able to afford everything to get it running yet. i turn the engine with the crank and every spark plug hole pushes out massive amounts of air, but not the #4. felt around with my finger to find the exhaust valve stuck open. before discovering this, i put oil and pb blaster in the plug hole. since discovering it, i've put seafoam in. most of it seems to run out the exhaust manifold, though.
i do want to try running the engine as-is when i've gathered the electrical parts, but i figured if there's a way to get this valve moving and putting out decent compression while i'm waiting, more power to it (no pun intended). as stated, money is tight at the moment (no income), so it's implied that i can't throw out money for gaskets yet, either. SO... are there any fantastic methods i can use to attempt to free this valve without spending any money or pulling anything... before running the engine?
Click to expand...
First thing you want to do is pull the valve cover and find out what is stuck. The valve might be ok and the tappet stuck. If this is the case, no amount of lubricant will unstick the valve because the lube can't reach the tappet. Sometimes it takes money, no matter how much you don't want to spend it or, how unavailable it is.

A roadster with suicide doors?
 
First, determine the source of sticking via James' method. If its just the valve, you can tap it with a drift through the spark plug hole. If its really stuck, you risk bending the stem this way so be careful. Use penetrating oil and time to loosen it.
 
I had a few stuck valves in this AA engine. The truck had sit for an unknown number of years and the stuck valves had the engine stuck. I removed the valve cover, manifold assy and the spark plugs. I sprayed PB Blaster on the upper valve stems through the ports in the block. I sprayed PB Blaster on the valve springs so as to hopefully coat the lower valve stems. I poured copious amounts of Marvel mystery oil and WD 40 mixed in the spark plug holes because that is what I had on hand at the time. I used the valve spring compressor tool pictured on page 157 of the 2011 Brattons catalog. The part number of this tool is 9280 . I could hook part of the tool over a manifold stud and slide the other end at the bottom of the valve spring and pull up. This tool came in very handy to unstick the valves. I could prise the valves up and down and continue to apply PB blaster untill the valves would move freely. I hooked my jump start to the starter switch and grounded the positive cable to a head nut and spun the engine with no battery. When the valves unstuck the engine had good, pop your thumb off the spark plug hole compression. If you don't have the tool, this won't help you but may help someone else that does.
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