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Exhaust
 | 2011.08.18:
My exhaust pipes are the standard crossover configuration for the
vertical induction IO-360 as supplied in Van's firewall-forward
kit. While bolting these on should have been a quick and simple
task, at this stage it seems that very few things are... The
crossover pipes for cylinders 1 and 2 fit perfectly onto the studs,
but those for cylinders 3 and 4 did not. It seemed that the one
or both of the flanges on the pipes was ever so slightly rotated
relative to the studs on the cylinders. Long story short...
called Van's, who redirected me to Larry Veterman, who actually makes
the pipes. I sent my pipes back to Larry, who found that they
fit ok on his jig. So... either the studs on my engine are a
little off, or his jig is, or there is just more slop than tolerance
between the two... In any case, Larry offered a relatively
simple solution of adding a ball joint in the riser for cylinder 4 to
give the necessary freedom of rotation. This he did for a very
nominal fee that I gladly paid, and indeed it solved my problem.
The exhaust hangers also did not fit well, but that's a known design
problem, not a manufacturing issue. The problem is that with the
-A model (i.e. tri-gear), the exhaust cross-brace, if installed as
specified, interferes with the nose gear socket. Larry's
instructions also list an alternate method of supporting the exhaust,
from the airframe instead of the engine. But I didn't like that
idea because of the relative motion. So I kept the original plan
(support by the engine sump bolts), but just moved the cross-brace a
little further forward to clear the gear leg socket. I also
adjusted the tabs on the collars that attach the braces to the
pipes. I adjusted them such that the ends of all the brace tubes
can be kept perfectly straight, thereby keeping them intirely in
tension, no bending loads. This should prevent breakage of the
tube ends, which has been reported by some RV owners.
The right side pipe comes from clyinders 3 and 4, and also hosts the
cabin heat muff:
The left side pipe comes from cylinders 1 and 2. Also visible
here is the ball joint that Larry Vetterman installed for me on the
riser for cylinder 4:
Hard to get a good shot of them, but here are the exhaust pipe support
braces:
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