VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 Stuck valve

So after adjusting the points and timing, there was still what I call mini back fires from the carb. So I decide to take the valve cover off only to find that one of the push rods just sitting in the hole and not touching the arm. The valve spring on the other side stuck in the down position and not returning. I just recently bought this car and the engine was rebuilt in 1981 but practically just sitting and never on the road. So I am assuming that the valve is probably just gunked up and stuck. What do you guys think the chances are of me freeing it up or should I just break down the engine?
Thanks,
Ken

I would try freeing it up. You may want to remove the rocker arms and then use penetrating oil and tap on the valve with a small hammer to see if the spring will pull it up. I have had success doing it this way, if they are not stuck to bad. Old gas can cause the valve stems to gum up and stick.

Apply penetrating oil to the valve stem several times over a day or two time period. Then tap the top of the stem gently with a brass drift or soft headed hammer. If there is a solid sound and no apparent movement then stop and apply more penetrating oil. I like PB Blaster. If there is any movement then tap gently. The valve spring will eventually push the valve stem upward. However, if after several attempts to free the valve without success, you will need to remove the head and free the valve.

First attempt with PB Blaster no good. Hopefully setting over night and after work. Fingers crossed.

Ken

I had the same problem with my 48.
The only think that helped was warming the valve stem with a hot air gan ( a hair dryier`so it should not overheat ) and then used penetrating oil and taping softly with a coper hamer.The warmth makes oil penetrate deeper.
Try it it might work for you too.

Jianis

By actual tests (on a motorcycle forum "Honda SOHC") a 50-50 mix of ATF and Acetone is by far the best penetrating oil you can use. Try it, you'll like it.

Funny, brings back memories. In the mid 50's my ol' 47 coupe stuck a valve - never knew why. I poured a quart of MMO in the tank and smothered it, at a husky idle, every night with MMO (and let it soak all night). It took a week to free that valve.

The advantage of pouring the MMO or ? through the carburetor with the engine running is that it gets to the lower part of the valve guide, the area the deposit on the valve stem contacts. Doing it from the top dosen't allow much to get down that far.
If it is a 1948 or newer engine the top of the guide must be oiled by going through the valve spring as the valce cap seal would prevent it from reaching the guide if oiled from the very top of the stem

Well the good news is I got the valve unstuck, the bad news is whenever the valve became stuck it must have put a hairline crack on the rocker arm which decided to break off after I just fixed the valve. So I ordered another rocker arm and hopefully I can just replace it without re-adjusting all the others?

When you get it running you may discover that you also have a bent intake valve on that cylinder.....and push rod.

Sticky valve is what I must have had...I was lucky enough to end up with just a bend push rod...Of which I straightened on my lathe and a dial indicator...an inch at a time...

niken,
Now that you have the valve free be sure to either add ATF or MMO to the gas. It provides lubrication to the intake valve stems to prevent sticking. A glug or two to a tank full.