PA12 Muffler Shroud Removal Problem

I must have done something wrong with my muffler shroud and the placement of the fresh air intake and exhaust ports. I have an O-340 with PA20/22 exhaust pipes and an original PA12 muffler and shroud.

I cannot remove the shroud without removing the exhaust pipes. The scat tube attach points hit the motor mount preventing removal of the shroud. The shroud won’t clear the motor mount no matter how we turn it.

That cannot be right.

Please, HELP!!!

I tried to use the PA-20/22 crossover pipes with my PA-12 per the Kenmore STC and couldn't make it work. Went back to the old exhaust headers from my old 0-290 installation. They are the same diameter as the crossover pipes so should not impede the exhaust efficiency and everything fits.

I think there are some differences in crossover pipes that we aren't aware of.

Upgraded from I-235 to O-320. Had to cut and weld a few degree bend it the right side exhaust where it goes into the mufflers to get it to fit. This is with the x-over PA-22 pipes per the Kenmore STC. This is with a long mount, but still a tight fit.
I have heard you won’t get rated HP if you use the old O-235 exhaust.
Mikey


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This just cannot be right: having to remove the exhaust pipes in order to remove the muffler shroud every 50 hours?

There must be a better way, or I really screwed up the installation. Maybe Univair put the air intake and outflow bungs on in the wrong position.

Does anyone have photos of a 12 with an O-320 installed in accordance with Kenmore’s STC? The more detailed; the better.

Please?

Oh, and the downpipe of the muffler also inhibits removing the shroud.

Paul
I can send a pic, but I think I see the problem.
I never remove the shroud for the AD inspection, just remove the long slide keeper at the top. That allows for getting it spread far enough to get a mirror in to inspect the exterior of the muffler which I believe satisfies the AD. You can do the interior via the tailpipe.
Hope this helps.
Mikey


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