Exhaust manifold straightening

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Model T Ford Forum: Forum 2018: Exhaust manifold straightening
Top of pagePrevious messageNext messageBottom of page Link to this message  By Noel D. Chicoine, MD, Pierre, SD on Sunday, September 02, 2018 - 10:36 am:

Reading Chris and Jerry's account of their speedster trip and the problems with their exhaust manifold makes me wonder a solution I've thought of but have never tried. It likely wouldn't work but here goes. As I've gotten the manifold glowing from lack of advance or too lean a mixture, could you intentionally do that and place a small jack under the exhaust or manifold and slowly tweak it up, since that is the apparent cause of it warping in the first place?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Sunday, September 02, 2018 - 10:44 am:

http://mtfctulsa.com/Tech/manifold.htm

http://dauntlessgeezer.com/DG82.html

http://www.mtfca.com/discus/messages/331880/342833.html


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Shirley on Sunday, September 02, 2018 - 12:50 pm:

You got to think about how hard that heat is for the block and valves. 50 something years ago I would sometimes retard the spark and light a cigarette. I wouldn’t do that today.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Sunday, September 02, 2018 - 02:32 pm:

I've used the first method twice. It's amazing the weight of the wrench does it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Sunday, September 02, 2018 - 04:17 pm:

Sorry but why would you want to subject the engine to that much heat and stress if you don't have to? When rebending the exhaust manifold, generally you used a lot more heat anyway and it does not work all the time, many are cracked/broken in the process.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Warren on Sunday, September 02, 2018 - 07:48 pm:

Second Larry, It works... Just take your time and don't spot heat it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Carnegie Spokane, WA on Sunday, September 02, 2018 - 08:48 pm:

I've never had very good luck using methods such as those above for a manifold that was more than just a little bent. The problem I find is that the holes, although in alignment, are no longer spaced correctly. As such, the manifold still will not fit onto the block if you use close tolerance rings. I built a straightening jig that uses a series of wedges to force the manifold into the exact correct attitude in regard to both straightness and spacing. It works a treat. Only problem is it takes about half a bottle of acetylene to straighten a badly bent manifold.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Neil Kaminar on Sunday, September 02, 2018 - 08:49 pm:

Use the rings. Cast iron grows when heated. The growth is a function of temperature and time. You can keep the exhaust manifold straight just by remembering to use the rings.

I think a torch is a better way to heat the manifold rather than running the engine too hot. And I would do it off the car in a fixture or on a scrap block. As Mark says, you need a bit more temperature anyway.

Old cast iron wood stoves are warped all to hell by the action of too hot a fire for too long a time. Some are warped so bad that cracks open up in the fire box pieces. For some reason steel doesn't seem to have this flaw. Formula 1 steel headers are run yellow hot and as far as I know don't warp.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A Bartsch on Sunday, September 02, 2018 - 09:48 pm:

Are formula 1 steel exhaust manifolds available for the T? Who has them for sale?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Joss sanderson on Monday, September 03, 2018 - 04:19 am:

No formula 1 for Ts to my knowledge. Formula 1 manifolds cost hundreds of dollars. Not worth it and T owners not like to pay about $1000 for a manifold.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Monday, September 03, 2018 - 09:51 am:

If you straighten your manifold with the torch and wrench method, DON'T push down on the wrench or your time is wasted.Otherwise I think the method would have worked for me.


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