VintageBonanza Forum

[James Rodie]

I am looking for information and/or drawings that may be available reference the exhaust system bushings that Norm Colvin discusses on page 15 of Colvin's Clinic. Would also be interested in related experiences other members may have had with exhaust flange bypass and any real world solutions that address this 2 stud flange installation.




Jim Rodie

[Bryan Wells]

I don't have information on Colvin's clinic but if you are asking about exhaust leaks in the area where exhaust stacks mate up with the cylinder, here is what I can offer.

It's important to start off with good components, the face of the cylinder head should be smooth and in good condition and have a flat and level mating surface. The studs in the head should not be rusted and worn. The exhaust mounting flange should each also mate up with each cylinder head flat and level with not gaps. Even with all those conditions met, I sure the spiral wound no blo gaskets.

www.vintagebonanza.com/images/TCM-627429.jpg

I have seen some people that will go ahead and coat these gaskets with thin layer of hi-temp red RTV silicone. When attaching the exhaust make sure that you do not over tighten as this will bend the exhaust mounting flange and cause leaks. Many people will over tighten trying to stop an exhaust leak and bend the exhaust flange and once you have some leaks, its best to take the exhaust off and start over. A old set of worn exhausts should be replaced or sent off and let a exhaust repair center rebuild them.

[Glenn A. Belson]

Several years ago I saw a Bonanza that Dawley had modifed the center exhaust flange and made a slip-joint on the center contact. This stopped the leak and it has been happy ever since. FYI. Works good! And the stress is left at the gate!