Well I don't know about the SJ Cowl but ...
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I don't know a thing about the SJ cowl but It is a tight fit in the Van's cowl as well. I had to modify the Vetterman exhaust and put some very expensive thermal blanket in the left side of the lower cowl (after I repaired the burned cowl) to eliminate the heat problem. The initial problem was intensified by incorrectly set timing from the Lycoming factory but it remained a problem to a lessor degree after that problem was finally fixed.
Bob Axsom
Follow-up: Larry Vetterman read this post and contacted me via e-mail right away to get to the bottom of the situation. I appreciate finding out why I had so much trouble and that it has been fixed. As you can see in the e-mail trail he offered to fix my system after all these years but I declined because the system works fine now. Here is the e-mail between the two of us explaining that the problem came up when Van's Aircraft went to the new (at the time I bought my finishing kit) cowl. The change ... well you can read for yourself below. It is cut and pasted right out of the e-mail so you have to read the last message listed here first to get the proper order.
Larry,
I will post this on the web and thanks for the generous offer to modify my
pipes after all this time but they work OK now.
Thanks again,
Bob Axsom
----- Original Message -----
From: "Larry & Cathy Vetterman" <
[email protected]>
To: <
[email protected]>
Sent: Friday, November 10, 2006 1:50 PM
Subject: Re: exhaust
> Bob, This is what I thought the situation was. We exchanged almost 50
> systems for the new style back then and sent them back out for the -8 as
> they would work on that model.. The new style system was raised up so the
> #2 pipe now comes in on the side as #3 does. Since that time there has
not
> been a problem such as you have, using a Van's cowl. My concern with the
> picture on the web is that builders will think they will have the same
type
> of problem with our system when in fact that is not the case. I believe
an
> expanation of this should be placed on the web. If you would send us your
> system, we would modify pipes one and two to the design needed for the
> prepreg cowl. Larry
> ----- Original Message -----
> From: <
[email protected]>
> To: "Larry & Cathy Vetterman" <
[email protected]>
> Sent: Friday, November 10, 2006 1:19 PM
> Subject: Re: exhaust
>
>
> > Yes it is. I got one of the new cowls just after Van's Aircraft first
> announced they were available. I had a severe problem with the ignition
> timing set by Lycoming on the LASAR ignition that I'm sure was due to
> unfamiliarity. Part of the modification I made was to cut off the pipes
at
> the slip joint under cylinder #2 to bring the crossover up as far away
from
> the cowl as possible and replace the link with one made out of hardware
> store steel. The cowl was still very hot to the touch. It seems to be
> doing OK with the aluminum backed silica thermal blanket (from Aircraft
> Spruce) glued to the inside of the cowl with 3M thermal strip adhesive. I
> have about 270 hours of operation on it and the outer surface is now cool.
> In the last 20 hours or so I have added a baffle between the pipes and the
> cowl to direct the cooling air to the cowl outlet. This seems to help as
> well.
> >
> > Bob Axsom
> >
> >
> > ---- Larry & Cathy Vetterman <
[email protected]> wrote:
> > > Bob I noticed on the web that you have a burned area on the lower
cowl.
> The only reason I can think that the exhaust is too close to the cowl is a
> new style prepreg cowling and the original exhaust system. This
combination
> make the exhaust pipes too close. When we discovered this about 8 years
or
> so ago, we changed the exhaust as 2 inches of clearance was taken out of
the
> prepreg cowl compared to the old original style. Let me know if this is
> what you have. Larry @ Vetterman Exhaust
> >
> >
>
>
