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1949 BUICK ROADMASTER HEAT RISER


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Wondering if any of you have had any issues with the heat riser on the exhaust manifold?  Can any of you send me a picture by any chance?

On left is the heat sensor coil but there isn't a place for the spring tab to fasten against.  Also on the right side is a spring on the lower part of the lever but it is just a short spring with again nothing to hook to.  Plus that fact that it is completely froze up and these are very difficult to free up again.  I have had some experience with another vehicle and this one the manifold was off the car and still had great difficulty in freeing up again. I am wondering if any of you have any advice?  Hate to remove the manifold if at all possible naturally.  Can anyone send me a picture of their heat riser and where both ends are suppose to connect to?  That would help but to free the valve is going to be a problem I'm sure. Did spray it with anti-rust spray but doubt if that is going to help much. Tough problem!!! Open to any and all help.

Autonut Lee

p.s.  Also I have one missing zerk fitting on one of the control arms.  They usually screw in on most cars but looked at these and they do not appear to be that type.  There is no hex on the fitting in order to put a wrench on it and screw it out.  Are they pressed in or what???  Why should one be missing if they are pressed in etc.  I wouldn’t think they would come out easily.
Autonut Lee

Edited by autonut (see edit history)
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Mine was frozen solid so I gently tapped the shaft back and forth until it was free, gradually turning as you tap. It takes a while but will free up, after I got it moving I drilled a small hole on each shoulder just in as far as the shaft to make it easier to get graphite into the joint. The small spring on the arm should attach to a metal tab held by a bolt in the exhaust flange.

good luck and have patience.

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Thank you "My047" for the pictures. Kind of clears up the situation.  But of course mine is VERY FROZEN!  Attaching picture of mine on the back side.  Can you tell me whether the valve is open or closed from the position it is presently in??  If open, I think I will just leave it alone.

Heat Rise2r.JPG

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If the riser was closed you would know it after she has warmed up.  No power. Pinging. It would be similar to running with a hand over your mouth every time you exhaled. 

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Get some Mopar "Rust Penetrant" and spray a little on the shaft at both sides. It is really heat riser solvent from the days when heat risers were common, just renamed to "Rust Penetrant". Keep doing it before and maybe after you drive the car. Heat cycles help it penetrate. After a few days or trips like this the heat riser will probably be more receptive to unsticking. Don't force it. If eventually it moves with a little tap on the end, put more solvent on and heat cycle it one more time before you get carried away trying to free it.

 

Edited by Bloo (see edit history)
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Really? I was under the impression neither Ford nor GM sold it anymore. I asked for GM heat riser solvent at a Chevrolet/Buick dealership in the mid 1990s and was told it had been discontinued for ages. It seemed to me back when you could get all three that Chrysler's heat riser solvent worked better than Ford's or GM's anyway. Maybe just perception. I can't prove it. The Chrysler one (Mopar 4318039AC) is available on Amazon.

 

Edited by Bloo (see edit history)
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9 hours ago, Bloo said:

Really? I was under the impression neither Ford nor GM sold it anymore. I asked for GM heat riser solvent at a Chevrolet/Buick dealership in the mid 1990s and was told it had been discontinued for ages. It seemed to me back when you could get all three that Chrysler's heat riser solvent worked better than Ford's or GM's anyway. Maybe just perception. I can't prove it. The Chrysler one (Mopar 4318439AC) is available on Amazon.

 

Do you have a link?  I cannot find it on Amazon searching by that number.

 

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Autonut,

 

If you can free it up with penetrant, great. But I had to remove the manifold, apply heat w/ a propane torch and repeatedly hit the shaft with a hammer drill to free it up (it took people) while spraying with Kroil penetrant. Finally it budged.

The words "open" and "closed" are relative terms, easily confused, at least for me.

 

No expert here but it looks like your is partially closed (for a cold engine). Before I bought the car, mine was frozen partly closed and caused the intake manifold chamber to crack open due to continuous excessive heat.

 

1rst photo show closed position (heat going into intake heat jacket).

 

2nd photo shows a fabricated steel plate welded in to repair and close off the cracks. Luckily I didn't need a new manifold.

Mine is now fully closed when cold, then gradually opens (clockwise movement of weighted shaft) when warming up, diverting away exhaust heat, as designed.

 

I suspect most people keep them wired open to keep exhaust heat out of intake manifold, since we mostly drive in warm weather.

Bought the AC Delco stuff online and I obsessively lube the riser every 2-3 weeks.

 

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IMG_2343.JPG

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Today's fuel is more volatile (too volatile!) than in the past.  Leaving it open or removed will not affect driveability unless you regularly drive in cold damp weather.

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On 4/8/2021 at 7:56 AM, Bloo said:

I bought some but is it better than Kroil?  Probably no way to objectively know outside a laboratory test but I'm a sucker for a potential solution to freeing rusted-stuck car parts.  The bane of the hobby!

 

I doubt I can free my rusty riser flap but it's stuck wide open so I will leave like that.  Perhaps I can free the bolt on my trunk latch chrome!

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  • 2 weeks later...

Kestral thank you for the photo.  If you say that your riser is CLOSED in the picture and ifyou compare that with the picture that I posted, they look almost the same do they not?  Thus my riser is stuck in the closed position and that is something I DO NOT WANT.   Thus I guess I will have to do more work on it and drop the exhaust pipe. Maybe I can burn the valve out with a cutting torch. I am not sure I can ever get the valve freed again but I suppose worth a try.  Do you agree that it appears that my riser is stuck in the closed position???

Lee

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I replaced the manifold valve body on my 1949 Super 51 many years ago because of a frozen flapper. It had froze most of the way closed, but enough hot exhaust gas passed through to rot out the intake manifold and ultimately cracked it. The replacement newly cast manifold valve body unit has no flapper, just a rod, and the weight and coil thermostat for looks.  Having your weight over to the right is where it should be. Mine froze just partially open and that caused my problems.  Earlier, my manifold valve body developed a hole, probably because of the partial opening. I had a welder braze the hole, but not knowing about how it all worked, the braze only took care of the hole and not the stuck flapper. (The braze would have impeded movement of the flapper if it were functioning.)  I ended up also replacing the intake manifold with a used one.  No problems since with the repro manifold valve body and the used intake manifold.

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IMG_20210419_173152408_HDR.jpg

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Thanks fellows for all your posts as you are very helpful with the pictures etc.  Have not completed this project as yet, but at least I know now how to proceed.  Thanks much!

Lee

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The new reproduction riser I ordered for the Special a few years back didn't come with the "damper" flap installed, simply for the reason of warm weather driving.
 

The shaft can be worked out and you could put the damper onto the shaft, if you really felt the need. 

706F5BE7-810A-460F-B660-05A6896EAFBE.jpeg

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