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Knisely or Acorn for PPonk 470-50?

J

JohnnyR

SPONSOR
AK, ME - what time of year is it?
Which do you recommend?
Mechanic coordinating build and install of a PPonk 470-50 for my 180 is saying Knisely, because the systems are cold rolled with minimal welding compared to Acorn’s. He’s also stating Knisely’s flow just as well.
Ideas?
Johnny
 
Acorn makes a nice muffler but the rest of their stuff is most certainly not airworthy, as in it doesn't fit by a country mile.
 
skywagon8a said:
Acorn makes a nice muffler but the rest of their stuff is most certainly not airworthy, as in it doesn't fit by a country mile.
Click to expand...
Dont they make the Seaplanes West engine mount? Are you asserting that because of the issues you experienced with your swing mount, or do you know of others having recent problems?
J
 
I'm talking about their exhaust systems. I bought a complete new system from them which failed three times because it wasn't built correctly. Finally had it repaired by Dawley and it fits perfectly.
 
Approaching 2000 hours on a Knisley exhaust built by AWI, zero issues. Well, other than the flame cones burn out within 200-300 hours...not a big deal IMO though.


Sent from my iPhone using Tapatalk
 
Are you building the engine in AK? Reeves stocks AWI, Atlee stocks Knisley, and Seaplanes North stocks Acorn. I used Acorn and bought it from Acorn. Fits perfectly. I think their fab method makes the most sense. I like their seaplane muffler. I like that they provide a new muffler shroud (Knisley didn’t make a shroud). I had Atlee’s modify the new shroud to add a carb heat source. Way better than the silly heat robber on my old exhaust. And the #1 reason I switched? To eliminate clamps. My old clamped exhaust left gray leak streaks on everything. It was a constant battle even after Atlee worked on the joints. Not a hint of a leak with my Acorn. I’m happy with their parts and happy to provide good pireps. Great customer service, too.
 
stewartb said:
Are you building the engine in AK? Reeves stocks AWI, Atlee stocks Knisley, and Seaplanes North stocks Acorn. I used Acorn and bought it from Acorn. Fits perfectly. I think their fab method makes the most sense. I like their seaplane muffler. I like that they provide a new muffler shroud (Knisley didn’t make a shroud). I had Atlee’s modify the new shroud to add a carb heat source. Way better than the silly heat robber on my old exhaust. And the #1 reason I switched? To eliminate clamps. My old clamped exhaust left gray leak streaks on everything. It was a constant battle even after Atlee worked on the joints. Not a hint of a leak with my Acorn. I’m happy with their parts and happy to provide good pireps. Great customer service, too.
Click to expand...

Yes, I am considering having Mark Campillo/Black Sheep Aviation assemble the engine, as he feels he will equal or better the build by the other shops in the area. He is pushing for the Knisely due to less weld joints/less prone to cracks
 
I have a Knisley dual exhaust on my 54 180. It is a modified K model Beech exhaust with a slip joint on the middle cylinder and no clamps. Over six hundred hours and 20 some years and still looks good. Did replace one muffler since the flame cone was going to plug the outlet as it was letting go. I'd use them again.
 
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