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tpbruce

Exhaust Manifold Repair

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While waiting for parts to be returned from rebuilders started to clean up intake and exhaust maifolds. Intake bead blasted nicely. The exhaust manifold had a heavy coating of red "paint". Very thick and lumpy. What ever it was it was tough. But the discovery under it was not good. The manifold has been cracked. The cracks are like a spider web. Several of the webs have been brazed. Other webs have not. Also there is a coating of black "paint" that requires extreme time to blast a quarter size area clean.

How best to repair the cracks. Contine the brazing or "?".

This is a 31 buick series 90. The flanges of both the intake and the exhaust are very flat having been checked on a surface plate.

Thank you

Tom

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Cracked manifolds are a real problem. Mine actually cracked into 3 pieces. They cannot be brazed. They need to be welded with cast iron with someone who knows what they are doing. In order to weld cast iron, the entire manifold has to be heated. I recommend you contact Tom Sparrow at Prairie Auto Porcelain. He can get the job done right. Otherwise you'll be shopping for a new manifold like I did.

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The black "paint" you mention is quite possibly porcelain, as many early manifolds (particularly on higher dollar cars, such as the Classic Buick 90) were completely coated in porcelain.

I agree with Michael, if you try a quick or cheap fix, guaranteed you'll be doing it again. Not only is cast iron tough to repair, but remember that this is cast iron that has been subjected to extremely high temperature fluctuations, and it's poor material to start with.

You also might check to see if anyone has reproduced that model manifold, new cast is greatly prefered to old repaired cast.

Good luck

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About 2 years ago, a guy in Texas was advertising new cast exhaust manifolds and heat riser valves in the Buick Bugle. I haven't seen the ads recently.

Cracked manifolds on the early straight 8's are often indicative of improper tightening of the mounting studs with their odd washers. Make sure to follow the instructions in the technical manual. Look at past posts on manifold problems.

Bob Engle

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Hi Tom: Someplace I have a name of a company just outside of Ames, IA that welds blocks and manifolds. They actually weld it while it is still in the oven. They did one for me, cost was about $150 and it looked great when they were done. I watched them doing one for someone else. these guys are pro's and very nice to deal with. Let me know if you need their name and I will dig it up.

Ercell

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The place in Texas, here to be un-named, did a lot of advertising for replicating parts, and in particular cast manifolds. I've not heard a happy story about that place, many people sent parts and money and lost same.

Welding old cast is a true art form, and welding it hot is, as I understand it, the only way to have a chance at success.

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I have a couple of thoughts regarding manifold cracks.

First, take it to a professional. I would love to have the name of the person in Ames, IA that repairs them the right way so I can have mine done by them. The first time I had mine worked on, it didn't work out so good-endedup with more cracked parts and lots of brazing everywhere.

The fellow in Texas unfortunately has priced himself out of the average person's budget. He is somehwere in the $2200 to $2300 range for an exhaust manifold. When my car is done, it might have a value of $15,000 to $18,000 so his pricing is just out of proportion for my car in my opinion. It would a different story if I was restoring a Duesenberg or a high dollar sports car. He is not set up to make manifolds at a price the average car owner can justify spending on a rather ordinary car. He has a niche market for his product. I know the molds are expensive but if he amoratizes the mold cost over 15 to 20 exhaust manifolds, he might be able to lower the price to an amount that means multiple sales. There are street rods being made from old Buicks all the time. I suggest buying their exhaust manifolds. They never use the original engines.

Happy Motoring!!

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The black "paint" you mention is quite possibly porcelain, as many early exhaust manifold (particularly on higher dollar cars, such as the Classic Buick 90) were completely coated in porcelain...

Aren't black paint or porcelain as you mentioned and ceramic coats the same thing?

Edited by gordonjj (see edit history)

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My 90 series had two cracked manifolds. One welded perfect with proper preheat/postheat with my tig welder with cast rod. The other one wouldn't weld. The cast was of such poor quality it would just fall apart as soon as the torch touched it. Old cast will either weld good if it's decent cast or it will just melt away and blob because of impurities. Stay far away from that place in Texas. I know several guys in the ACD that were completely ripped off. Deposits given and parts never recieved.

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Update on Exhaust Manifold repair and running lean problem.

The carburator was rebuilt by Old Carb Doctor in NC, Thr Heat Riser Sleeves were installed by Bill Boyce in NY ( after talking with several local machine shops who lacked confidence in pressing in and out) and the badly cracked Exhaust maifold was welded by Charles Clemont and Ceramic Coated by Tom Sparrow of Prairie Auto in MN and new throttle shaft was carved out of stock by a local machine shop. Every one of these folks were most helpful and all the work (while not inexpense) was super. Would recommend any or all for any work required.

Finished assembly of all the components yesterday and she fired up and is running. First road test will be on Sunday (have company all week end). But could not contain my satisfaction and had to report current progress.

That old feeling of hearing an engine fire up after disassemby just nevers goes away!

Tom

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Update on Exhaust Manifold repair and running lean problem.

The carburator was rebuilt by Old Carb Doctor in NC, Thr Heat Riser Sleeves were installed by Bill Boyce in NY ( after talking with several local machine shops who lacked confidence in pressing in and out) and the badly cracked Exhaust maifold was welded by Charles Clemont and Ceramic Coated by Tom Sparrow of Prairie Auto in MN and new throttle shaft was carved out of stock by a local machine shop. Every one of these folks were most helpful and all the work (while not inexpense) was super. Would recommend any or all for any work required.

Finished assembly of all the components yesterday and she fired up and is running. First road test will be on Sunday (have company all week end). But could not contain my satisfaction and had to report current progress.

That old feeling of hearing an engine fire up after disassemby just nevers goes away!

Tom

With the exception of the heat tube guy, all of my work was done by the exact same people and I totally agree. Expensive, but great work and worth it. If you go cheap on the manifold you'll be doing it over and over again which will end up being more expensive yet. Good luck on your maiden voyage!

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I have a friend who welded my 320 center exhaust manifold and he used 99 nickel rod. He wouldn't even consider castalloy. Yes he heated it very hot before welding it up. He chopped off the ends and welded pipe in their places as well as fashioning pieces to repair the rest. We just got the engine running and have about 150 miles on it. So far so good. It looks amazing. He tells me I am lucky that the cast iron still had plenty of metal to it? This guy has been welding for well over 50 years and the local welding shop wouldn't touch it. We still have to reinstall everything with new gaskets, but I believe it should be very quiet after we complete this on Friday. What would porcelain coating do to help - if anything?

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