super A exhaust manifold

Mon Jul 11, 2011 3:25 pm

hi guys,
i have a question. thinking about replacing my stack on my super A. now the pipe that connects the stack to the manifold has pretty bad threads from heat, elements, age etc.
should i use a new pipe with my new stack, and if so, the threads would probably have to be chased. but i worry about getting shavings down into the manifold.
without taking the manifold off, what is the best way to install my new stack?
thanks a bunch :)
mark in pa

Re: super A exhaust manifold

Mon Jul 11, 2011 3:46 pm

I would definitely take the manifold off. Not that big a deal. It will give you an opportunity to clean all the carbon out of it.

Start soaking the 6 manifold nuts in Kroil now. :D

Re: super A exhaust manifold

Tue Jul 12, 2011 11:14 am

With the exhaust manifold, it is very unlikely that chasing the threads for the exhaust pipe will get any debris into the engine unless one blows into the manifold with compressed air. Using compressed air is absolutely unnecessary as the engine will blow out any loose material as it runs. Due to the in-block valve design of the Cub (I know this thread is about a Super A), it is even less likely that debris would get into the Cub engine.

Re: super A exhaust manifold

Tue Jul 12, 2011 12:11 pm

once you have the old pipe out stuff a shop rag down the opening before you chase the threads. If you don't have a tap for the job take a piece of threaded pipe and with a hacksaw cut about 4 to 6 slots in it about 1" down the threads. Use that to clean the threads then pull your shop rag out.

Re: super A exhaust manifold

Tue Jul 12, 2011 12:26 pm

Bigdog wrote:If you don't have a tap for the job take a piece of threaded pipe and with a hacksaw cut about 4 to 6 slots in it about 1" down the threads. Use that to clean the threads then pull your shop rag out.
For Cub...but same idea works. See.....Homemade exhaust pipe tap

Image

Re: super A exhaust manifold

Thu Jul 14, 2011 11:23 pm

good suggestions guys.
just curious, what size and thread should my super A be?
thanks
mark

Re: super A exhaust manifold

Fri Jul 15, 2011 6:47 am

1.5 NPT.

Re: super A exhaust manifold

Sun Jul 17, 2011 3:49 pm

that's 1.5", 11.5 threads per inch...correct?

Re: super A exhaust manifold

Sun Jul 17, 2011 4:08 pm

dolphins wrote:that's 1.5", 11.5 threads per inch...correct?

Yes, 1.5 npt has 11.5 threads per inch.

Re: super A exhaust manifold

Thu Jul 21, 2011 7:26 pm

thanks again guys.
mark