How to repair a cracked heat riser?

[Alexander C.]

My heat riser cracked in half in my hands AFTER removing from the collector. From the looks of the inside of the cracks, it's been cracked for decades. Long story short, turns out it's irreplaceable. It can't be found used, NOS or reproduction. If you know where I can get one, PLEASE let me know! It's from a late '56 so it's a 3 bolt, 2", for welded flanges, not the 57+ style that uses the donut for the slip type flange. Repros have TOP raised, missing the M, and they are too thick. I thought about having a machine shop cut a 57+ repro for me but it still would not pass judging because of the TOP and M stamped into it would be missing or wrong.

I'm hoping you guys can take a look at the pictures I attached and tell me how to go about repairing it? If I soak it in Evapo-Rust and clean it with acetone, can a skilled welder get a good penetration and grind down the welds so it's as good as new? The issue is that the crack is where the shaft is and I'm worried heat from welding might distort something enough that it won't operate correctly, which I want it to.

Ideas? Thank guys! Alex

[Richard M.]

Re: How to repair a cracked heat riser?

Hmmmm, it might work on a heat riser?....take a look at this process I used to fix a '556 exhaust manifold. After the process the screw heads could be filed down, filled with a high temp filler compound, and high temp paint coated. That's what I did on the manifold.

https://www.forums.ncrs.org/showthre...=6211#poststop

When you go to the photobucket page, just click slideshow. Each photo is not described, but I think you'll get the idea.

Rich

[Joe L.]

Re: How to repair a cracked heat riser?

My heat riser cracked in half in my hands AFTER removing from the collector. From the looks of the inside of the cracks, it's been cracked for decades. Long story short, turns out it's irreplaceable. It can't be found used, NOS or reproduction. If you know where I can get one, PLEASE let me know! It's from a late '56 so it's a 3 bolt, 2", for welded flanges, not the 57+ style that uses the donut for the slip type flange. Repros have TOP raised, missing the M, and they are too thick. I thought about having a machine shop cut a 57+ repro for me but it still would not pass judging because of the TOP and M stamped into it would be missing or wrong.

I'm hoping you guys can take a look at the pictures I attached and tell me how to go about repairing it? If I soak it in Evapo-Rust and clean it with acetone, can a skilled welder get a good penetration and grind down the welds so it's as good as new? The issue is that the crack is where the shaft is and I'm worried heat from welding might distort something enough that it won't operate correctly, which I want it to.

Ideas? Thank guys! Alex

Alex------

Even before I saw Richard's response, I was going to suggest repairing this using screws after drilling and tapping. You'll have to carefully evaluate the piece for the best location for the drilling and tapping and subsequent installation of the screws.

Personally, I would not consider welding unless there were no other option and I think there is.

[Edward M.]

Re: How to repair a cracked heat riser?

I think part of the goal is to make the repair undetectible once the heat riser is installed. I think the screw idea is a good one, but some sort of "dressing " to cover the screw heads will also have to be done.

Alex, I really think a repo 57 can be made to look correct, including the "TOP" and "M". I would do whatever I could to restore this original, but I would like to also look at the possibility of making a correct looking reproduction.

[Gary C.]

Re: How to repair a cracked heat riser?

Alex, spoke with Pete Sawatzky, a fellow NCRS member who sells a lot of Tri 5 Chev parts this morning about the '56 3 bolt heat riser. Pete said he has not seen nor had one for sale in many years. Pete also said the '56 3 bolt heat riser wasn't cast iron like the '57, but powdered steel and that its surface was very smooth compared to a '57.

Duke or Joe might comment on high heat adhesives like http://www.cotronics.com/vo/cotr/rm_adhesive.htm

Gary....

[Alexander C.]

Re: How to repair a cracked heat riser?

Thanks guys for the information. Good to know it's powerdered steel! It totally looks like that and not cast iron now that I have cleaned it up.

I also sent and email to www.locknstitch.com as I'm told he might be able to help me. He's in CA right up the freeway from me a couple hours.

This seems to be the closest reproduction I can find, but at that price and still not correct, I'll even resort to an adhesive as mentioned if I have to so I can reuse mine.

This sucks lol.

[Edward M.]

Re: How to repair a cracked heat riser?

Alex;

I think this one could be modified by a machine shop to look like your part. Not saying it will be cheap, but I think it is doable.

http://cgi.ebay.com/ebaymotors/57-58-59-60-61-62-63-64-65-CHEVY-V8-EXHAUST-HEAT-RISER-/310293910267?pt=Vintage_Car_Truck_Parts_Accessories&hash=item483ef552fb

I really want the dimensions off of your heat riser so I can draw up a set of blueprints. Do you have a set of micrometers or a vernier caliper? I do need precise measurements.

Ed

[Kevin G.]

Re: How to repair a cracked heat riser?

This is an interesting question! I have an original cracked heat riser valve that I removed from my 71, and would love to learn the method of repair. This valve has cracked straight down the line of the shaft, in half. I'm worried that even if repaired it will still end up leaking threw the shaft/bushing? Perhaps a combination of drilled, epoxied, tapped and screwed? There are replacement valves available but I would really like to reinstall the original. Please post your results!

[Alexander C.]

Re: How to repair a cracked heat riser?

I really want the dimensions off of your heat riser so I can draw up a set of blueprints. Do you have a set of micrometers or a vernier caliper? I do need precise measurements.

Ed

I actually don't have anything better than a measuring tape