[lostpilot28]

I started digging through the forums hoping to find some detailed info on what others have done with this setup.

I'm getting ready to start on my baffles, and I was wondering if I just "cap" it as a last step with the James plenum. I've heard that the Van's baffle kit needs very little modification to fit the plenum properly, but what are those mods?

Any help is greatly appreciated.

 

[Radomir]

Front inlet ramps.. the aft side is pretty much same (leave off that one little bracket on middle aft...) so the only "challenge" is front inlet ramps..

Oh yeah, they won't be as tall.. you'll trim them a lot more than going with stock baffle seal material..

 

[lostpilot28]

Thanks Radomir...I hope that's it...sounds pretty easy. Why do so many people have trouble getting the baffles to fit?

 

[yakdriver]

Yep, everything fits great with just a few mods to the inlet ramps. Don

 

[aparchment]

Pics?

Pictures would be great guys!

 

[Radomir]

I've got some here:

http://picasaweb.google.com/n777ty/Baffles

 

[nucleus]

James Plenum Baffling Pics 4 U

Basically it is about trimming the baffling down so the plenum sits nice and low in the engine, then tying it down, and making airtight connections to the inlet rings. My example is likely different than yours because I adapted a James angle valve plenum to a straight valve engine. First I cut the plenum down so it fit inside the plenum:

Then I marked the baffling and timmed the baffling down:

Then we fiberglass a lip that went over the baffling and drilled holes through both that lip and the baffling with nutplates on the inside side of the baffling for mounting screws.

I ended up needing to build in a bulge for the fuel divider on the top of the engine.

Now I am finalizing the connection to the inlet rings.

I have more pictures in threads here and here.

Reminder: James uses polyester based resin, not epoxy. Old school!

I hope that helps,

Hans

 

[lostpilot28]

Thanks for everyone's reply...but I have a few new questions.

The Van's baffling kit is going together pretty well. I have the back and sides done (still need to trim them down for the plenum, though). I can see that I'll be trimming off at least 2 inches all the way around.

Here are my new questions:
1. The bracket that mounts on the engine case (aft) and connects the 2 aft baffling pieces together...is it still required with the plenum? I'm thinking that after I trim it down, there won't be enough baffling material to get but maybe 1 bolt connected.

2. The Plenum itself seems a bit long. Mainly, the intake holes on the front touch the aluminum rings when i have the bottom cowl in place. This is a shorty cowl, so I'm thinking I should trim the plenum holes back an inch or so. What do you think?

3. Oil cooler area. The plenum (aft left) has a "tab" that fits in the recess that goes back about an inch for the oil cooler. Did that make sense? The plenum is a little short and doesn't go all the way back into the oil cooler recess. Maybe 1/4" or so gap. How does that get covered or filled in?

Thanks for all your help.

 

[osxuser]

Basically it is about trimming the baffling down so the plenum sits nice and low in the engine, then tying it down, and making airtight connections to the inlet rings. My example is likely different than yours because I adapted a James angle valve plenum to a straight valve engine. First I cut the plenum down so it fit inside the plenum:

Then I marked the baffling and timmed the baffling down:

Then we fiberglass a lip that went over the baffling and drilled holes through both that lip and the baffling with nutplates on the inside side of the baffling for mounting screws.

I ended up needing to build in a bulge for the fuel divider on the top of the engine.

Now I am finalizing the connection to the inlet rings.

I have more pictures in threads here and here.

Reminder: James uses polyester based resin, not epoxy. Old school!

I hope that helps,

Hans

I don't have any answers for the OP but Hans, are you using Polyester/Vinylester resin? I thought that you couldn't use it with Carbon? Maybe I'm wrong.

 

[lostpilot28]

Thanks for everyone's reply...but I have a few new questions.

The Van's baffling kit is going together pretty well. I have the back and sides done (still need to trim them down for the plenum, though). I can see that I'll be trimming off at least 2 inches all the way around.

Here are my new questions:
1. The bracket that mounts on the engine case (aft) and connects the 2 aft baffling pieces together...is it still required with the plenum? I'm thinking that after I trim it down, there won't be enough baffling material to get but maybe 1 bolt connected.

2. The Plenum itself seems a bit long. Mainly, the intake holes on the front touch the aluminum rings when i have the bottom cowl in place. This is a shorty cowl, so I'm thinking I should trim the plenum holes back an inch or so. What do you think?

3. Oil cooler area. The plenum (aft left) has a "tab" that fits in the recess that goes back about an inch for the oil cooler. Did that make sense? The plenum is a little short and doesn't go all the way back into the oil cooler recess. Maybe 1/4" or so gap. How does that get covered or filled in?

Thanks for all your help.

Anyone? Bueller? Bueller?

 

[yakdriver]

Sonny, I filled the gap in the oil cooler area with some micro balloons and flox. Worked great. You will have to do a lot of work around the front of the plenum to get a good fit to the engine cases also. Don

 

[ArVeeNiner]

Closing the gap up front

I've been playing around with installing baffles to my SJ plenum. My airplane building grinds to a virtual halt during the holidays but that doesn't stop me from thinking about what I'm going to do project-wise after Christmas.

Anyway, I see from Radomir's pictures that he has whacked the inlet ramps pretty good from the Van's version. I have a couple of questions though:

1-How do you plug the gap between the plenum/baffle and engine located directly above the starter and alternator?

2-I assume that the nutplates on the front inlet ramps are to secure the plenum to them with screws located in the air inlets. Is this correct?

3-It doesn't look like the Van's Air Dams (parts CB-1002C and CB-1010C) are present. I've been told that these are to keep the cold air from directly hitting the front two cylinders. Are the fiberglass ramps that are inherent to the plenums enough to do this job?

Thanks!

 

[nucleus]

Re: More Questions

I've been playing around with installing baffles to my SJ plenum. My airplane building grinds to a virtual halt during the holidays but that doesn't stop me from thinking about what I'm going to do project-wise after Christmas.

Anyway, I see from Radomir's pictures that he has whacked the inlet ramps pretty good from the Van's version. I have a couple of questions though:

1-How do you plug the gap between the plenum/baffle and engine located directly above the starter and alternator?

I put some slippery stuff (mold release compound) on the engine and then filled it in with RTV, worked great. I also used some masking tape to make sure it did not drip out overnight. Best to let it cure for a few days if it is very thick. You do want to leave a gap or put in a hose to cool the alternator.

2-I assume that the nutplates on the front inlet ramps are to secure the plenum to them with screws located in the air inlets. Is this correct?

On mine I the screws ended up on the outside of the inlet, both medially and laterally for each. There is a little lip there that is perfect for a screw.

3-It doesn't look like the Van's Air Dams (parts CB-1002C and CB-1010C) are present. I've been told that these are to keep the cold air from directly hitting the front two cylinders. Are the fiberglass ramps that are inherent to the plenums enough to do this job?

No. You definitely want some sort of dam up there, even aluminum tape will do the job.

Thanks!

You're welcome.

Hans

 

[CNEJR]

I made this plenum.......

for a friend's RV8. Layed it up with Carbon/kevelar. It uses standard Van's Baffles. You just bolt up the side baffles, lay it down inside, mark the sides, cut them and install nut plates on the plenum. Very tight & lite. fits Ly O360 parrell valve. I was wondering if anyone would be interested in one of these for reasonable price? Transitions well to standard Van's Cowl.

http://img96.imageshack.us/i/img0130op.jpg/

 

[ArVeeNiner]

I've got some here:

http://picasaweb.google.com/n777ty/Baffles

Radomir:

From your pictures I see a couple of nutplates on the pilot side of the engine, outboard. I assume you secure the plenum to the ramp with a couple of screws accessed from the inlet right? On that same side but close to the engine case, I see no nutplates. How do you seal that area? Is it with RTV as Hans described?

On the passenger side of the engine, I think I may see a single nutplate inboard near the case but nothing outboard. How do you secure this?

Do you have any photos of your plenum secured in this area?

Thanks

 

[Radomir]

There are two platenuts on the pilot side.. accessed through the inlet... fairly easy to do. Nothing on the pax side.. the plenum ramp was re-done where it was laid up on top of actual ramp (see plenum photos on my Picasa album).... so there was no need for any serious sealing... It's a perfect fit..

I'll be honest -- this can be done a bit "cleaner" and tighter, with more sealing.. The thing is -- my cylinder temps are so good that I never bothered closing up every single little hole there may be.. Heck.... yesterday my hottest cylinder was 285...(coldest was right at 250)... why bother?