Stove Pipe Warning!

[Guest shadetree77]

So I took my car on a second test drive yesterday. This was the second drive since I restored my engine compartment. One of the parts I replaced was the choke stove pipe. This pipe goes from the automatic choke on the carb. down to a small hole in the exhaust manifold. It provides hot air for the choke to open. On the drive yesterday, I began to hear an extremely loud exhaust leak. It sounded like I wasn't running a muffler. Well, I thought my manifold gaskets had blown out.

Today, I investigated further and noticed that my stove pipe was loose. I removed it from the carburetor and discovered that.....IT MELTED!!!! Holy crap!! :eek::eek: It melted right in two! This allows an open hole right into your exhaust system. When I plugged the hole with my glove covered thumb the noise stops. This stove pipe came in a kit that I bought from a well known vendor of old buick parts. The tubing appears to be made of aluminum. It promptly melted when the engine came up to operating temp. This was a serious part failure and could have potentially allowed my choke to be filled with molten metal. Let's hope that didn't happen.

I am going to contact the vendor and inform them of this serious part defect. I'm going to the auto parts store for some steel tubing and I'm going to make my own. I'm still in shock that this happened.....

EDIT: The part failure was my mistake and not the fault of the vendor. Please read the entire thread before passing judgement.

Edited August 31, 2013 by shadetree77 (see edit history)

[rick60]

Exhaust gasses should not enter the choke assembly. I'm not familiar with the Buick design. All of the hot air chokes that I've seen have a fresh air source that is heated by the exhaust. Be sure there is no exhaust gas entering your choke or damage will occur to the carb. Check your service manual for the proper operation and design of the hot air choke. I'm sure the Buick guys can explain the operation of your specific vehicle. I enjoy all of your posts. Good luck and keep up the good work!

[Guest shadetree77]

Thanks Rick and you are correct. Exhaust gasses do not enter the stove pipe. On my car the pipe leaves the carb. and goes down through a hole in the exhaust manifold and out a hole on the bottom of the manifold. The hot exhaust passing around the pipe inside the manifold heat the air inside the tube providing hot air to the choke. But when my tube melted away the hole in the manifold was left wide open allowing for a VERY loud exhaust leak.

[rick60]

Thanks for the explanation of the Buick design. It should be a simple fix with a steel pipe. My Ford draws air from a baffle bolted to the outside of the manifold. There is no chance of exhaust gasses entering the choke housing. I've seen a few choke housings melted from hot exhaust gasses when the heat transfer tube rotted away. Keep up the good work.

[Ben Bruce aka First Born]

Robert, the pipe in the manifold that the stove pipe connects to SHOULD not leak exhaust gasses. In your first post, you said that when you covered the hole, the exhaust leak went away. THE PIPE IN THE MANIFOLD IS BAD, causing hot gasses, that were not supposed to, to flow into the choke pipe.

Ben

[Guest shadetree77]

Ben, are you saying that there are supposed to be TWO different pipes connected together to form the stove pipe?? My replacement kit only had one piece of pipe that was just long enough to go from the carb, through the manifold, and out the bottom of the manifold. There is no other pipe in the manifold. There used to be a broken off piece of rusty pipe in there but it was driven out when I refurbished the manifold. I assumed the kit I got was complete and was meant to be one solid piece of pipe all the way down.

Edited August 31, 2013 by shadetree77 (see edit history)

[Mr Riviera]

There WAS a sleeve in the manifold that the stovepipe went into . I think you removed it when you refurbished it . You can leave the stovepipe out and there should be NO gases coming out of the hole where the pipe goes into . It is a closed unit .

[Ben Bruce aka First Born]

Robert, that "broken off" piece should have been a permanent fixture. Protruding about 3/8 inch at top and bottom. Your manual should have a picture of it. I tried to take pictures of one I have on the bench, but due to operator error, they are fuzzy. Will try again if you need for me to. The aluminium pipe attaches to the top off the pipe sticking out the top.

Enjoy

Ben

[Guest shadetree77]

Crap. That piece I removed was severely rusted and broken. It's long gone now. Any ideas on what I should do to replace that? Hammer a piece of steel tubing in there?

Edited August 31, 2013 by shadetree77 (see edit history)

[JohnD1956]

Steel tubing will eventually rot out again. You probably need a piece of copper tubing but I would investigate why you have exhaust noise there if others are saying you should not have that.

[Marty Roth]

Robert,

That broken, rusty piece which sealed the manifold, and allowed the choke stove pipe to carry heat (not exhaust) to the choke..

it may be the same as what was used on Chevy manifolds, and should be readily available from Chevy vendors.

Another less pretty, but still functional option would be to drive plugs into the top and bottom holes to seal the leak..

and then Fit a length of copper tubing to the choke, and make it long enough to reach, and to wrap around the manifold to pick up its heat, and to transfer the heat to open the choke...

or just adapt a manual choke cable like many others have done...very functional !!

[JohnD1956]

Just checked the Master Parts catalogue I recently acquired. The general illustration shows a straight piece of pipe going through the manifold. Their are three different part numbers however, depending on which carb you have. The book lists:

1308020 for a Model 40 with a single carb.

Then it lists :

1339798 for a Carter

1338268 for a Stromberg.

I am making the assumption the 1308020 is the pipe through the manifold. The other two may be the riser pipes to the choke housing on the carb. In any case, it appears you can simply insert a new piece of steel pipe in place of the rotted piece you drove out, just like you originally thought.

[old-tank]

The aluminum tubing 'might' have functioned if the steel sleeve was in place, but it is still a poor choice for this application...if it didn't melt, it surely would corrode in place. Don't aggravate yourself further by calling THAT vendor.

[Ben Bruce aka First Born]

Crap. That piece I removed was severely rusted and broken. It's long gone now. Any ideas on what I should do to replace that? Hammer a piece of steel tubing in there?

Robert, I checked the "pipe" in an old manifold I have. It is non-magnetic, not copper or brass. Probably s.s. of some kind. It looks like a straight piece, extending ABOVE the manifold about 3/8 in., and BELOW about i/2 in.. The below part is cut at an angle, with the opening pointing back. Hope this helps.

Enjoy

Ben

[JohnD1956]

Stainless steel make a lot of sense in this application.

[Guest shadetree77]

Thanks for all of the help guys. I inspected the hole in the manifold today and it looks to be 3/8" diameter. I have some 3/8" steel tubing. It's not stainless, just regular steel. I think I might try to gently drive it in there. It's a tight fit but then, it's supposed to be to seal off the exhaust. My original piece had that angle cut into the bottom too so I'll recreate that. How important do you think it is for that piece to be stainless? I could order a piece of stainless line if you think it's necessary. I guess the regular steel could rust but I would think that wouldn't happen for a very long time. What do you guys think?

[Marty Roth]

If you had to take a daily driver off the road, and could not get to work for a few days, then a temporary fix might be OK.

In this case, I would surely get a length of Stainless Steel, do the job right once and for all (or at least until your grandkids inherit the car), and be satisfied in doing it right - not having to do it again in several years.

Just my 2 cents...

[buick840]

If you had to take a daily driver off the road, and could not get to work for a few days, then a temporary fix might be OK.

In this case, I would surely get a length of Stainless Steel, do the job right once and for all (or at least until your grandkids inherit the car), and be satisfied in doing it right - not having to do it again in several years.

Just my 2 cents...

X 2

[1953mack]

.....I could order a piece of stainless line.....

A hobby store or a well-stocked hardware store item.....K&S Precision Metals.....3/8" or 7/16" O.D. x 12" long.....< $10.00.

Al Malachowski

BCA #8965

"500 Miles West of Flint"

[old-tank]

Robert

Stainless would be best and will certainly keep the tube to the carb from corroding to it. On the other hand, with that car destined to lead a more sheltered life (stored out of the weather, driving around puddles) it will probably outlast you. Being impatient, unless I had the needed piece of stainless laying around, I would fix with regular steel. Drive it!

Willie

[Ben Bruce aka First Born]

Robert

Stainless would be best and will certainly keep the tube to the carb from corroding to it. On the other hand, with that car destined to lead a more sheltered life (stored out of the weather, driving around puddles) it will probably outlast you. Being impatient, unless I had the needed piece of stainless laying around, I would fix with regular steel. Drive it!

Willie

I agree with Willie.

Enjoy

Ben

[51dyno]

What ever you use make sure it's seamless.

[49_buick_super]

Robert,

Some photos from a manifold off a 248:

...if they may be of any help.

Dan

[Guest shadetree77]

Thanks for the advice guys. I tried all day to locate a piece of stainless tubing. On the advice of Al above I called every hobby store, hardware store(small and big), pipe supply, and industrial supply within a 50 mile radius. Not one of them had stainless tubing in stock. Only two of them could even order the piece but it wouldn't be here for a week. I gave it the old college try but I'm not waiting around for another week+ of driving season to pass me by. The only thing keeping her from being road worthy is putting the bumper/grill back on and fixing this choke pipe. If I use the steel pipe I can be back on the road by Labor Day. I'm going to go for it. Nobody has ever accused me of being too patient. I'm going to paint the piece of steel tubing with some of that flame proof VHT paint, stick it in there, and go cruising!

[Erik]

Personally I have been running with an aluminum tube for years "from a well known vendor of old buick parts" without any problems, but then again I haven't messed up my manifold and exposed the tube to highly acidic hot gasses.

Shadetree, the fault is your own and not "from a well known vendor of old buick parts"

I know that everyone in this forum loves to blame everything incl. climate changes on that vendor, but If your man enough to throw blame your man enough to apologize.

[Guest shadetree77]

If you've read through this thread then you know that when I started it I did not know that the manifold was supposed to have a second, separate tube in it. So yes, the part failure was due to my own mistake and not the "vendor of old Buick parts". I considered going back to the beginning and editing this thread to express that but I thought that anyone that came upon this would read through the whole thing and come to the correct conclusion as I did.

Now, that being said I do FULLY believe that a reputation has to be earned somehow. From what I've seen and heard the MAJORITY of folks have had a lot of the same experiences that I have had so I won't apologize for my attitude towards them. I also believe that the choke stove "kit" should have come with ALL of the parts needed to replace it. Right or wrong, strictly my opinion. I have gone back and added a message in red on the initial post to future viewers of this thread. I have also removed any remarks that may have been considered even slightly malicious.

Edited August 31, 2013 by shadetree77 (see edit history)

[Erik]

I also believe that the choke stove "kit" should have come with ALL of the parts needed to replace it.

When I order a complete brake line kit I do not expect the kit to include the car frame although the brake lines pass through it.

Do you really believe that a kit from California would include the center piece of the manifold, that the sleeve is integrated with???

From what I've seen and heard the MAJORITY of folks have had a lot of the same experiences that I have had so I won't apologize for my attitude towards them.

So your opinion of the vendor is totally biased, prejudice and based on hearsay??? And that gives you the right to bad-mouth them???

[49_buick_super]

...Do you really believe that a kit from California would include...

Funny. I thought Robert was referring to the right coast, not left.

[retirednow]

That's what I thought as well

Funny. I thought Robert was referring to the right coast, not left.

[Guest shadetree77]

Is it so wrong to believe a complete kit should come with all of the parts needed for the job? It's a small piece of pipe described as the "lower choke pipe" not "a piece of the manifold". The kit only came with the upper choke pipe. Don't you think it should either come with both or be listed as ONLY containing the upper? A frame? Really? Come on now. That's just being ridiculous. The comparison you are trying to make is way out in left field and argumentative.

Based on your comments I don't think you know who I'm talking about. And you must have missed the part where I said "experiences I have had". Many personal experiences. So yes, that does give me the right. Even though I don't believe that I did "bad mouth" them and I never named anyone. If I did say anything that might even be considered "bad mouthing" I went back and deleted it.

I freely admitted my mistake and edited the thread. What more do you want? To argue with someone on the internet? I advise you to visit another popular automotive forum for that. There are plenty of hot rodders over there that will argue with you. I'm not taking any of this personally Erik but you do seem to be coming at me aggressively for some reason. I'm sorry if I have offended you in some way and hope that we can still help each other in the future. That is what this forum is for is it not? The friendly sharing of information? That's all I have to say about this. I won't comment further.

I would ask that this thread please remain open to provide future information for people that might run into the same problem and make the same mistake that I did. If any moderator needs me to edit anything further and/or delete a few of the last posts (including this one) please let me know. I have no problem doing such.

Edited September 1, 2013 by shadetree77 (see edit history)

[Erik]

Maybe I did come at you a little strong, but then I am tired of everyone (specially in my country) always blaming someone else for own faults. But enough said on this.

Do not use stainless or copper for the sleeve. The manifold is cast iron so the sleeve should be plain steel. Else you will create a galvanic battery which with the acidic gasses will corrode the joins. So what if the sleeve only lasts another 35 years. The stove pipe i aluminium is also correct as aluminium does not retain heat well and will react faster to temperature fluctuations.

[Ben Bruce aka First Born]

Erik MAY be right on the S.S.. I don't know. BUT I DO KNOW the two on my work bench are not magnetic.

Enjoy

Ben

[Erik]

The cast iron of the early '50s contaned just about everything BUT iron. During the years sulpher has built up, which is also why it is virtually impossible to weld or repair. A 60 year old manifold contains currently mud, sulpher and hope. Don't think to much about it :-) Stainless steel contain a certain amount of chrome and nickel changing its galvanic charge. And what you really don't want is the manifold corroding around the sleeve edge letting the sleeve drop out or welds loosen

[Guest shadetree77]

I tried to put the piece of 3/8" tubing in the manifold today. It would not fit. When I began to tap with the hammer the tubing split every time I tried it. I tried the next size of tubing down (5/16") but it is too loose. I was able to flare the top part of the 5/16" tubing enough to seal it but I cannot do the same to the bottom. I don't have enough space to swing the hammer hard enough. I can't find a tubing that is a size between 3/8" and 5/16". What should I do now?

[Marty Roth]

Just a thought:

Flared one end?

Insert that end from the bottom,

and then expand the potentially shortened end now sticking out from the top?

Use an extremely high temperature Exhaust Manifold Sealer on both ends

Maybe that will work?

Good luck

[TexasJohn55]

Robert, Just remember that whatever you use, the upper tube must fit in it after you are done. You may have to get an original lower tube. ???

[JohnD1956]

Considering that a lot of these manifolds seem to crack, I would not strike anywhere close to it no matter what. Marty has the right idea about flaring the end first, but I would not make a V flare. I would insert the tube for the lower stove pipe in the flaring tool at the maximum length you could to get the die onto the tool. Then use the flaring tool to essentially push the pipe as if you were going to flare it. In theory this should bunch up the pipe in the area next to the flaring tool, but leave a piece for you to connect the upper choke stove pipe to.

Use the smaller diameter tube and install your flare from the top. Then when you put the aluminum tube on top it will keep the lower choke stove in place. The bottom I would try to seal by inserting a thin screwdriver up from the bottom and then rotating it to expand the pipe below the manifold. Don't forget to cut your angle on the bottom.

Chances are that in a short while exhaust carbon gases and rust will seal the lower choke stove to the manifold.

[Marty Roth]

Not to be picky, but flaring could work, my thought was to EXPAND, rather than to FLARE... kind of like the way you expand a section of tailpipe to fit over another O.D. of the same diameter

[old-tank]

All good solutions so far!

Assuming that the original tube was 3/8" and the manifold has rust, crud and remnants of the old tube still in the holes. Measure the actual diameter of the 3/8" tube you have on hand, then pick a drill bit 0.005" smaller to drill the holes so you have an interference fit.

[Guest shadetree77]

Thanks for all of the suggestions guys. All great solutions. I think I ended up using a bit of advice from each post! I'll try to explain what I did.

I cut a piece of 5/16" tubing to the correct length. I then flared it (or expanded it, not sure which term would be correct here) by clamping the tubing into the hold down device used in a tube flaring kit, putting a tapered punch in the end, and hammering it into the tube. This flared/expanded the end of the tubing. I then put the pipe down through the manifold from the top. I should have put it through from the bottom as this would have made it a lot easier for me in the end. Anyway, I then tapped the top part with a hammer and large punch to seat the flare into the manifold. I attempted to do the same to the bottom part while my Dad pushed down on the top to keep it from unseating but that just did not work. It kept popping loose. So in the end, I ran a bead of fire place cement around the bottom part of the pipe to seal it.

This did seal everything up just fine. Will it last? I'm not sure. I may end up working on it again. Next time I'm going to either try putting it through from the bottom so I can better see what I'm doing with the fireplace cement OR try Willie's suggestion. By the way Willie, I did thouroughly check the hole in the manifold and I did not see any remnants of old pipe or crust. I also cleaned up the piece of 3/8" pipe so it was slick and smooth. I greased it too. I even tried putting it in the freezer for an hour so the metal would contract hoping that would give me the little extra room I needed. No dice. Hopefully, the solution I used will last. Thanks again for all of the help guys.