What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Angle Valve Cowl Clearance

plbarrett2004

Active Member
Hello All,

I’ve encountered what I believe is a fairly common problem but I’m having a little trouble wrapping my brain around the best option.

I have an IO-360 A3B6D angle valve engine. I just installed the cowl and am about to start the baffles. The clearance from the forward top of cylinder 2 to the cowl is about 1/2”. Searching the archives I’ve found reference that this is fairly common. One thread recommended moving the baffle to the inboard of the cylinder flange. It seems I have three options 1)just make the baffle super low (I suspect this is asking for cracks) 2) bend the baffle inboard (maybe a challenge with the baffle reinforcement there) or 3) relocate the baffle inboard of the flange.

Searching the archives produced a few threads but all the pictures have since been lost to time. What have others done here? Does anyone have any pictures?

Thanks!
 

Attachments

  • D6D802C8-BCB7-4971-8BEB-5465AB349966.jpg
    D6D802C8-BCB7-4971-8BEB-5465AB349966.jpg
    344.1 KB · Views: 186
It seems I have three options 1)just make the baffle super low (I suspect this is asking for cracks) 2) bend the baffle inboard (maybe a challenge with the baffle reinforcement there) or 3) relocate the baffle inboard of the flange.

Incorporate all three and be happy.

A conventional plenum doesn't help much. Mine would bang the inside of the cowl on starts, when the engine flails around due to torque reaction. The issue more or less went away as the original Lord mounts sagged, but not before cracking a short 0.060" attach plate across the top of the cylinder. You can see it in the original fabrication photo below.

I eliminated the baffle plate by adding attach ears to the fiberglass plenum lid itself, with clamp plates over the ears.

That worked fine...until I replaced the mounts with new ones from VIP. With the engine back up where it belonged, the plenum lid was bumping the cowl again. The latest iteration added "soft spots" to the lid, so it doesn't matter if it bumps.

Look close at that last picture. Things are so tight in the front corner that I'm using a truss head screw rather than the fillisters in the other locations, so the screw head clears the cowl. And look at Scott's baffle plate above #2, which doesn't stick up any higher than the clamp plate on mine. It's tight.
 

Attachments

  • PC210002.JPG
    PC210002.JPG
    254 KB · Views: 247
  • New Plenum Attachment3.jpg
    New Plenum Attachment3.jpg
    223.3 KB · Views: 227
  • Plenum Soft Spot left.jpg
    Plenum Soft Spot left.jpg
    106.3 KB · Views: 245
Last edited:
I went with option #1. 13 years and 1800 hours, it’s still going strong. I may go to the hangar later. I’ll try to remember to snap a picture.

Hello All,

I’ve encountered what I believe is a fairly common problem but I’m having a little trouble wrapping my brain around the best option.

I have an IO-360 A3B6D angle valve engine. I just installed the cowl and am about to start the baffles. The clearance from the forward top of cylinder 2 to the cowl is about 1/2”. Searching the archives I’ve found reference that this is fairly common. One thread recommended moving the baffle to the inboard of the cylinder flange. It seems I have three options 1)just make the baffle super low (I suspect this is asking for cracks) 2) bend the baffle inboard (maybe a challenge with the baffle reinforcement there) or 3) relocate the baffle inboard of the flange.

Searching the archives produced a few threads but all the pictures have since been lost to time. What have others done here? Does anyone have any pictures?

Thanks!
 
Here it is. Disregard missing valve cover screws. I just did a wobble check.
 

Attachments

  • 4P71PkFaRMOgb6v+JqVBuw.jpg
    4P71PkFaRMOgb6v+JqVBuw.jpg
    481.4 KB · Views: 165
  • l92PlTU4QCyqSTFCTAUuJg.jpg
    l92PlTU4QCyqSTFCTAUuJg.jpg
    474.1 KB · Views: 132
Scott, Dan, and Jerry - thank you all for the photos and input. Definitely helpful. I haven't quite decided which option I'm going with, but i'll be starting to trim soon so... I'll have to make up my mind.

I will post photos when I get it sorted. Thanks again!
 
Back
Top