Heat riser leaks!

[Roadhog]

My '56 Buick special has developed an anoying exhaust leak at the heat riser bushings, I used to work at a dealer (non-GM) and they had rebuild kits for heat risers, are these available for my old Buick? I also worked for a delivery co. and we would remove the heat riser and plug the holes with bolts, these trucks were started in the morning and run for 8-12 hrs. straight so warming the manifold was no problem. Has anyone ever tried this with their Sunday afternoon cruiser? I rarely run it in cold weather. THANKS! Ed

[RocketDude]

I'm not aware of a kit to rebuild heat riser. Hopefully some one here has a lead on one.

As far as disabling the one on your car, I would rather see you bite the bullet and pay the outragiously high price being asked by the company's that supply them. I think I've seen new ones for $60-75 dollars.

I am aware that blocking the old one open, and putting weld or bolts in the shaft holes, is a very commonly done.

That practice is what seperates the men from the boys. If you want to do Mickey Mouse, back alley work, go for it!

The way I look at something like that, if the factory put it there, put it back. If you can improve on something, fine, but to alter it like you suggest is criminal.

I'm sorry to sound like an ol' meanie, but......

One man's opinion. Keep it stock

[old-tank]

Ed

Get rid if the heat riser! You don't need it for a fair weather car. These old ones either leak around the shaft like yours or stick in the closed position leading to driveablity problems. You will need to remove the manifold to cut it out and plug the holes. On those that are stuck just cut out the butterfly. Even on a restored car you cannot see the riser and probably will not get a point deduction.

Willie

[NTX5467]

Well, both orientations have merit.

I concur that if it was put there for a reason, even if that reason belongs in a part of the country with much colder climates than where you now appear to be.

For example, in a Chrysler factory heat riser rebuild kit for mid-'60s Chrysler B/RB (383/440) engines, there are two bronze bushings that the butterfly shaft rides on as "bearings" for it in the exhaust manifold. In many cases, the new bushings have a nice "press fit" in the exhaust manifold holes for them, but the internal diameter was too small, yet the shaft would fit. As the prior one (from the factory) had hung in the 1/3 open position, the service manager got an appropriate-sized reamer and "clearanced" the i.d., of the bushings so that the shaft fit tight, but was loose enough to allow the thermostatic spring to do its job. No exhaust noise, as many people have noted that many of those valves had, if they didn't also rattle at idle, but it worked for a good while and was easier to free-up with penetrating lube.

My gut suspicion is that all of those kits, regardless of manufacturer, have pretty much the same stuff in them, but with different counterweights and thermostatic springs for particular applications. Plus having new bronze bushings in them.

Knowing that they CAN be made to work reliably (with a little care and effort in assembly to make sure they will work), I'd be inclined to possibly increase the judging score if I knew it worked (rather than being a "dummy"). As judges are not supposed to touch anything on the car, IF the technician put the counterweight (with a valve "gutted" or dummied up) in the "hot" position , that could well be a dead giveaway of what had happened--IF the judge knew what they were looking at, with all due respect. Of course, cars sitting on the show field would all tend to have "cool" motors by the time the vehicles were judged ("cool" being defined as the ambient air temperature around the motor which would heat the air temperature to cause the valve to open). In this case, putting the counterweight position in something near the "cool" side of things, it might look more appropriate and not raise any questions. Once the engine was hot and somebody might look at it, they could then presume that it was stuck in that position and not worry any more about it.

So, as both orientations (remove/defeat the valve's functionality or recondition the valve mechanism) are valid and have reasons for being desired, it might be advisable to make it look as if nothing had been done to it if it's internallly removed. To me, the less eyebrows raised on the judging field, the better.

It might not matter to you, but it could very well matter to a future owner. A future owner/buyer that when finding one thing "not as intended", might start picking the car to see where other shortcuts might have been made.

If the valve shaft is "leaking", then I suspsect the valve might still be functioning? If that's the case, possibly finding a bushing supplier (somewhere!) that could supply the bushings of the necessary inner and outer diameter might be all that's needed--but this could also be wishful thinking.

Your car, your time and money, your judgment call.

Just some thoughts,

NTX5467

[Roadhog]

Thanks for the replys, I have a "NO", don't remove , a "YES" remove it and a "it's up to you"!! I did work at Chrysler garages from '69 to'79 and replaced and reamed many a heat riser bushing. I have a lathe and could make the bushings but as I recall the riser had to be cut out, then I would have to find another shaft and butterfly. I think I will look for another manifold, maybe I can find one with the riser stuck and then free it up, might not leak as bad as mine/. I am not really worried about "show" points as I enter very few showns with my "driver". Thanks for the replys!!!

[RocketDude]

I'm not familiar with Buicks, but is it neccessary to locate another manifold? Finding a used manifold you will just end up with one as worn out at the one you have.

I'm an Olds guy, and you can purchase a new heat riser, which just fits between the manifold and the head pipe, it's not part of the manifold No need to get a whole manifold and go through all of that. Check with your Buick supplier, I bet you can find a new one for under $100., and it's easy to change, much easier than rebuilding your old one.

When I said leave it in the system, I wasn't refering to points and judging either. To me, it's like cheating at solitare. If you can live with yourself and sleep at night, knowing you mickey moused something on your car, then go for it. To my way of thinking, if you're willing to cut corners in one area, where will it end.

My car will probably never get close to good enough to appear in a car show, but anything I do to it, will be perfect, or it won't be done.

The next owner may wish to do a frame off. If he does, he won't have to worry abour correcting any short cuts on my part.

Good luck...

[NTX5467]

Chevrolet has also used separate "unit" heat riser valves rather than valves internal with the exhaust manifold. Some are still available (1960s Corvettes and musclecars where restoration correctness can drive the market) whereas the later model vacuum-operated "early fuel evaporation" versions are discontinued (and were pricey when available).

Key thing, which would also be "the hard part", would be to find a Chevy heat riser gasket/seal that would match the Buick (or other GM makes') internal diameter and bolt pattern and then see what valve it would take to mate with it. By the time that research was finished, the time expended could have already been used to effect some fix or whatever, with all due respect. A good thought, though.

Enjoy!

NTX5467

[Roadhog]

Buick heat risers are IN the manifold, not in a seperate housing like a shivvy or an Olds If I were to find one of these would'nt that be worse than disabling my own? I would be "modifying" my BUICK with a SHIVVY or OLDS part!!!!!!!! HOW COULD I SLEEP AT NIGHT!!!!!!!!

[NTX5467]

In reality, I suspect a Chevy or Olds heat riser valve would never bolt up to a Genuine Buick-designed engine of any kind. Even if it might be modified to do so, there's ALWAYS the possibility of "tissue rejection" happening, resulting in a even greater exhaust "leak" than before.

Enjoy!

NTX5467

[Guest]

Check out this site....

http://www.buickfarm.com/

[Dynaflash8]

What would the driveability problems be like if the heat riser were stuck shut?

[JohnD1956]

Dynaflash, Assuming you are aware this is a 7 year old thread, and were looking for opinions on your question, I think the first drivability issue would be an engine overheat. In a V8 with dual exhaust all the exhaust would be routed through the intake manifold resulting in localized intake overheating and loss of power. On a straight 8 or a V8 with single exhaust I believe the engine would eventually stall when enough exhaust could not pass the valve.

[Ben Bruce aka First Born]

On a straight eight, there would be no more back pressure, just always hot exhaust heating the carb.

Ben