VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 manifold heat control valve

Hello. I just purchased a 1946 Stylemaster business coupe. It's very nice, runs great. However, the manifold heat control valve is stuck...it does not move at all. Any advice as to how to unstick it with out breaking it of course ? I looked in past questions, did not see anything about this. Thanks.

My first attempt to free it up would be to pour some ATF through the carburetor with the engine cold and running at a fast ide. This will soak the shaft from the inside. The spray the outside with a good penetrating oil like PB Bkaster and let sit over night. The using a medium sized hammer gently tap the heat riser fore and aft.....brass hammmer prefered. This might work depending on how rusted it is.

Ok.....thx...it is stuck in the " upside down " position. How bad is it to have this stuck ? The car seems to run just fine...but it does bother me it is stuck.

Not quite sure what the up-side position is but if the straight bottom of the counter weigt is at an angle it is in the warmed up position. This will be providing no heat to warm up the incoming "gas" and cold enging performance may be a little bulky but will not hurt anything for summer driving.

The straight bottom of the counter weight is on top ! It is completely turned over. Ok....well that's good...I will work on freeing it. I always remember my dad had a 1950, and told me put a drop of oil on this frequently and make sure it moves.

Perhaps you have been working on it for days. It doesn't really matter if it is stuck so long as it isn't stuck where it diverts heat up onto the carburetor all of the time.In that case it may not run that well. The problem with unsticking one that has been rusted up is that they then tend to leak and you get an irritating noise.That device was also fitted to Holden engines and we really didn't need it much. Often the valve was simply removed and the hole tapped and bolts inserted. I look forward to a follow up, like how did it get to be upside down?

try Aerokroil

My 48 has a bolt through the holes. It was that way when I bought it. Run just fine with out it. Of course I am in Northern CA and it doesn't get to cold here.

Thanks for the feedback. I have not done anything for several days. Car runs just fine. I still will try to unstick it....if I fail I won't worry about it. I have to tell myself...is it really worth so much time and effort ? ha

Happens a lot..If the car runs w/o overheating..It ain't really broke...don't fix it.

Got it to move....trying to put it in the correct position. ( flat part on bottom ) It is completely turned upside down. Is it possible someone re installed it in the upside down position ? Hmmmmm But they would have had to take it apart ? How is the " flapper" part installed on the peg ? Pressed on from the factory I am guessing ??

I would guess the damper valve is loose on the shaft + the shaft is frozen.
Would be best to remove the manifolds and split them apart to see for sure.

hmmmmmmm ok the shaft and the " flapper" moves about 1/16 of a turn...it's very interesting....never saw anything like this before.....and the flat part is on the top...it is completely upside down as stated before. When you are looking at the engine while standing in front of the car, my flapper moves clockwise.....so in real life, it is supposed to move about not quite 1/4 of a turn counter clockwise ( I have a 1950....same engine, and everything is correct on it ) I am glad it moves, but now I want to get it to be correct...it's the principle of the situation now. hahahaha

All I know is the previous owner said at some point the head was removed, they did some valve work , etc. I am hoping this 1 dumb thing is not making the car run crappy.....according to previous posts, it won't. I just hate things that are not correct.....my OCD and ADHD and all the other things I have aren't helping either. hahaahahah

Hi clement,

Thought I would post some pictures to help with the discussion. If you decide to take the manifolds off then you need to read the following post about leaking issues caused by reassembly problems.

41 Exhause Manifold pictures

Exhause Manifold Leaks

As you can see in the pictures the flap (internal part) is welded onto the shaft. It is possible that the weld is broken, or the counter weight (external part) was installed upside down. The weight is held in place by a dowel. All the cast iron parts are prone to rust so it is common to have things freeze up. Usually the flap freezes in the open position so engine performance is not a problem except in cold weather as mentioned in previous posts. The best lubrication is remembering to move the counter weight up and down every few months if your car is not driven regularly and stored in a high humidity area of the country. Friction works to keep everything working well.

It is also common for the spring to break or fall off. The spring keeps the flap closed until it expands from the heat of the engine and causes the flap to open. It has been my experience that the spring is usually the cause of most problems.

Good luck, Mike

Hi, Mike. great pictures !!! Thanks. I do not have a spring...one on the way from Chev's of the 40's. I think someone re installed the external flapper upside down. I see in the pics it looks like a small pin or nut/bolt assembly holding the flapper to the shaft. Mine doesn't have that. I will keep working with it and see if I can get it eventually fixed. Perhaps I can get the flapper to free from the shaft and re install it correctly. Yes, I did read all the posts about warm weather not really effecting it, which is good. On my 1950 everything is correct from the factory...I always put a couple drops of oil on it regularly and make sure it moves. Learned that from my father. Not sure if I want to go to the trouble of taking off the manifolds, etc. Thank you EVERYONE for the advice and thoughts, again, Mike, those are awesome pictures !!! Have a happy and safe Labor Day all !

sorry...I meant to say counter weight instead of flapper. I think someone put my counter weight on upside down. The shaft is on there correctly...the " cut" into the end where the thermostatic spring would slide into is on the correct side.