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RV Bits Plenum Fit

SeanB

Well Known Member
Hi. I?m getting close to the paper clip trick with trimming my RV7 baffles, so getting close. I plan to install my RV Bits carbon plenum, so I put it on the plane for a look. Love the carbon! But...the fit fore and aft is not good. Probably half an inch off. Also, there is the piece that steps out by the oil cooler brace. Not even close to fitting. Finally, where the vertical baffles bend at cylinders one and two, the carbon plenum does not match with its contour. Anyone have experience installing one of these plenums on a 7 or 9? Pics? Thank you very much!
 
I had the same issues to start......

I wrestled with this for a good amount of time. I even had multiple e-mails with Jan in South Africa. What "did the trick" for me was to remove "both" the forward and aft baffle braces, then it started to seat in much better. Any small gaps will be filled with the weather stripping you choose to make the seal. And also when you actual screw it in tight. The next, and much bigger issue will be the cowl inlet to plenum seal. I designed a strip much like what Vans normally uses in the area but, that comes up much higher and wraps up and around in between the cowl and the ramps. You install them "after" the lower cowl is attached. I also used the oversized oil cooler. I'll get a few pix posted here later. All worked great in the end! Engine temps are good and no issues so far........

Are you using the "stock" Vans cowling?
 
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Tim, thanks for your reply. I also elected not to install those two brackets. Seems the plenum will provide more than enough support. I'll need to investigate futher, but I believe the plenum flanges may be at a slightly different angle compared to the face of the baffles. This could be causing the plenum to "push" away. I also don't know if I am supposed to cut off the little extension for cylinder number four area of the oil cooler brace. Yes, using Van's pink cowling.

I too am installing a remote cooler, just behind #3. It's the Showplanes setup with large cooler and shutter. Using an IO-375 with squirters, so need the help.

The outboard baffles get a vertical bend on #1 and #2 to taper the form for the intake area. The plenum doesn't match well here either.

Appreciate seeing your pics and ideas. Thanks!

https://www.flickr.com/photos/188844155@N06/49988654556/in/dateposted-public/
https://www.flickr.com/photos/188844155@N06/49988654546/in/dateposted-public/
 
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Oh no...........

Tim, thanks for your reply. I also elected not to install those two brackets. Seems the plenum will provide more than enough support. I'll need to investigate futher, but I believe the plenum flanges may be at a slightly different angle compared to the face of the baffles. This could be causing the plenum to "push" away. I also don't know if I am supposed to cut off the little extension for cylinder number four area of the oil cooler brace. Yes, using Van's pink cowling.

I too am installing a remote cooler, just behind #3. It's the Showplanes setup with large cooler and shutter. Using an IO-375 with squirters, so need the help.

The outboard baffles get a vertical bend on #1 and #2 to taper the form for the intake area. The plenum doesn't match well here either.

Appreciate seeing your pics and ideas. Thanks!

https://www.flickr.com/photos/188844155@N06/49988654556/in/dateposted-public/
https://www.flickr.com/photos/188844155@N06/49988654546/in/dateposted-public/

Yea, I see what you are talking about. I'm not gonna be of any help there. I have the "stock" Lycoming IO-360. No bends out on the sides.... or a jog back at the oil cooler site.... thats way more than I had to deal with. Other than the inlets but, you are gonna have way more to do to even get there,,,,you may try to get in contact with Jan.... I tried them a few weeks ago and got the message they were down for Covid......
 
Inlet Baffle Seals

Tim, would you mind sharing the pics of how you sealed the inlets to the plenum as you may save me some aggravation & time. Kindly PM me and I will send you my cell number or email address.

Thanks / Ron B
 
Tim,
I may have caused some confusion. My engine is a stroked IO-360, so it's now an IO-375. Same foot print as yours I believe. The bends on the sides are only in the baffling. Instructed to do this in the baffle kit directions to narrow things toward the intakes. Would still like to see pics if you don't mind. Want my e-mail? Thanks.
 
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The plan view of the baffles for the sides and back is a rectangle. The sides are parallel and the back is square to the sides, the notch notwithstanding. The back of the plenum should be square, like check it with a framing square. I make my plenums tight and it looks here like you should shove it straight back. The flange should be at an angle to match the baffles as the plenum will slope downward matching the slope of the cowl.

As a general comment, I would bend the sheet metal on the front to fit before cutting the plenum. That would be a PITA with that carbon.

Make it fit AND pretty!
 
Bill,
Thanks for your reply and suggestions. Agree about the baffling being square in the back and on the sides, until the prescribed vertical bend midway thru the #1&2 side baffles. Maybe I can massage the top part of the bend out some and help it conform to the plenum. Yes, the plenum needs to go aft some more to fill that gap. I?m getting interference to do that and suspect the plenum flange being the culprit. It gets worse with positioning the plenum for the slope of the cowl. I?ll need to investigate that further. Appreciate everything! Thanks again.
 
Square peg, round hole, etc. Build a new one. A leaky plenum lid is useless as a leaky boat.
 
BL plenum!

The plan view of the baffles for the sides and back is a rectangle. The sides are parallel and the back is square to the sides, the notch notwithstanding. The back of the plenum should be square, like check it with a framing square. I make my plenums tight and it looks here like you should shove it straight back. The flange should be at an angle to match the baffles as the plenum will slope downward matching the slope of the cowl.

As a general comment, I would bend the sheet metal on the front to fit before cutting the plenum. That would be a PITA with that carbon.

Make it fit AND pretty!

Bill makes plenums that fit and are pretty!



 
Thanks Dan and Krea. I will end up doing this correctly...whatever it involves. Bill...sending a PM.
 
for what it's worth......










Keep in mind this is a rough fit of the stripping to see if it would work in flight. It works.... I'll tidy things up and make them look good when I slow down.....
 
Tim...thanks for the pics! This is helpful and gives me some hope. Your install and what I see of the rest of the plane looks very sharp! Appreciate it!
 
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