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  #1  
Old 11-17-2020, 11:46 AM
f14av8r's Avatar
f14av8r f14av8r is offline
 
Join Date: Apr 2012
Location: Tampa (Wimauma actually)
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Default RV-8 Vetterman Crossover Exhaust

I bought my RV-8 about 18 months ago and have struggled a little with the Vetterman crossover exhaust system. I had a crack at the number 2 cylinder attaching flange and, a few months later, a crack at the number 4 flange. Then, just a few weeks ago, a crack at the crossover tube just before the exhaust outlet on the right side. I was also repeatedly breaking the crushed tubes or the adel clamps at the attach points on either the exhaust or the engine mount.

When I got the repaired pipe back from Vetterman last week, I was determined to get the system better support to avoid future cracks! After doing a lot of reading here, and consulting Vetterman's installation package directions, I decided to rework the entire support system.

Previously, I was attaching the support system to the engine mount and the tying the two pipes together horizontally. This time, I decided to attach the supports to the engine and make no attachments to the engine mount. I attached vertical supports from the sump to both pipes. Then, I tied the two pipes together horizontally.

I have attached a link to a video which shows the new support system and my test flight. The startup and shutdown parts of the video are slowed down but the rest of the video is full speed. The indications for speed, vertical speed, and G are unreliable but I did put 5.5 positive and 2 negative on the airplane during the aerobatic portion of the flight.

As you'll see, that exhaust system has a lot of movement during startup and shutdown. For me, this video is clear evidence that attaching to the engine mount is probably not a good idea. The exhaust system moving with the engine seems to make more sense to me.

Hopefully no more cracks! Thanks to Clint at Vetterman for his help and for his quick and expert repairs of my pipes!

Enjoy - https://photos.smugmug.com/RV-8-Exha...t_mp4-1280.mp4
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  #2  
Old 11-17-2020, 02:48 PM
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Default

that is how Vett did it previously on the two-pipe x-overs. Tie it to the sump bolts so everything shakes together. That is how mine is mounted and no issues.
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  #3  
Old 11-18-2020, 01:55 AM
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Default seems to work

Quote:
Originally Posted by fl-mike View Post
that is how Vett did it previously on the two-pipe x-overs. Tie it to the sump bolts so everything shakes together. That is how mine is mounted and no issues.
I really thought this method was very hokey, and tried several other ways but none worked right. I ended up doing it the way Vetterman recommended, and it does seem to be working fine. Only have about 40 hours, so time will tell.
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  #4  
Old 11-19-2020, 08:21 AM
BobRV7 BobRV7 is offline
 
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Thanks for the video, it shows a lot of shacking going on back there and no wander it was cracking the tubes, I guess I'll have to change mine.
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  #5  
Old 11-19-2020, 11:40 AM
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Ha ha! Looks like you had a lot of fun "testing" your new exhaust system!
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  #6  
Old 11-19-2020, 12:46 PM
scsmith scsmith is offline
 
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Good that you made the change. I think the attachment to the engine sump bolts so it can all shake together is crucial.

I have found that the little lugs that attach the mounts to the sump bolts can fatigue over time and crack, so keep an eye on them.
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  #7  
Old 11-19-2020, 04:58 PM
Bcone1381 Bcone1381 is offline
 
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Location: Chelsea, MI
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I installed my Vetterman exhaust recently. I thought some photos might spice up this topic.

The first document is a Vans drawing of the factory installation I think on an RV6 or 6. The second is the Vetterman drawing that came with my exhaust system which is a Lycoming O-360 cross over exhaust made for an RV I think but being applied to a non RV experimental application.

Note worthy is the Factory has all attachments connected with the engine. The Vetterman drawing has two of four points attached to the engine mount.
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  #8  
Old 11-19-2020, 11:46 PM
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Default Interesting test

Quote:
Originally Posted by Bcone1381 View Post
I installed my Vetterman exhaust recently. I thought some photos might spice up this topic.

The first document is a Vans drawing of the factory installation I think on an RV6 or 6. The second is the Vetterman drawing that came with my exhaust system which is a Lycoming O-360 cross over exhaust made for an RV I think but being applied to a non RV experimental application.

Note worthy is the Factory has all attachments connected with the engine. The Vetterman drawing has two of four points attached to the engine mount.
This does spice things up. I don't have my vetterman drawing handy, but either it is different from yours, or I misread it. I did mine the "van's" way with the pipes connected together and each to the sump. Neither picture captures it perfectly.

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  #9  
Old 11-20-2020, 07:37 AM
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Quote:
Originally Posted by f14av8r View Post

What happened at 2:53? Smoke on? Crankcase vent burp on the exhaust? Or do you have an air/oil separator that vents to the exhaust and dumped at that point?
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  #10  
Old 11-20-2020, 04:39 PM
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f14av8r f14av8r is offline
 
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Quote:
Originally Posted by 1001001 View Post
What happened at 2:53? Smoke on? Crankcase vent burp on the exhaust? Or do you have an air/oil separator that vents to the exhaust and dumped at that point?
Inverted oil system canister vents onto the exhaust pipe.
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Exempt and gladly donating anyway - Current through March 2025
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