fiberglass cylinder head wraps

[chopperpilot]

Hi all

Can anyone give me some info on these I've heard that you use high tempeture (RTV) silicone mashed into bid with a rolling pen or somthing like that. My question is do you also use epoxy or do you just use plain high temp silicone?

Thanks
God Bless
Scott

[John Slade]

If you're talking about the baffles people make out of BID and RTV, I believe there's no epoxy involved.

[--D--]

Bill James said he used regular ol' BID and EZ-Poxy. His trick to avoid turning the plenums into goooo was to post cure them in 50 degree increments. Not sure what his max temp was... but I'm pretty sure he published it somewhere on ez.org. Here's the link:

http://www.ez.org/ezcron05.htm

D

[Lynn Erickson]

Originally Posted by --D--

Bill James said he used regular ol' BID and EZ-Poxy. His trick to avoid turning the plenums into goooo was to post cure them in 50 degree increments. Not sure what his max temp was... but I'm pretty sure he published it somewhere on ez.org. Here's the link:

http://www.ez.org/ezcron05.htm

D

One of the best and ezeist ways to post cure an engine plenum is to start the engine and get it warm. Then leave the plenum in place until the engine cools. remember the epoxy is being cooled by the air flowing into the engine. the plenum gets the hottest after shut down. I have built many with ezpoxy and non have melted.

[Dust]

Hey lynn - the ones you have built - do they lay on the fins? I know the answer is yes, just makin sure

[Lynn Erickson]

Originally Posted by Dust

Hey lynn - the ones you have built - do they lay on the fins? I know the answer is yes, just makin sure

No, there is an aluminum baffle all the way around the engine in contact with the cylinder and cyl.head. the baffle extends down under the cyl. and warps around with 2" open area on the bottom center of each cyl. the top of the baffle is just above the top of the cyl. heads and the plastic plemun is overlaping the metal by 3/4" and fastened by screws all around. the plastic top can be removed easily to check the plugs and wires while the metal baffle stays put.

[Dust]

So, the glass is attached to the aluminum and that is touching the cylinder fins, sooooooooo, altho not touching, they are exposed to the same heat.

[bferrell]

The standard velocity cooling plenum is of all glass construction, and is attached directly to the tops of the cylinders. I'm not sure how thick it is because it's a standard kit (engine install kit) part, but I'd say it's 2 or 3. Here are a few pics, more at my site.

[Lynn Erickson]

Originally Posted by Dust

So, the glass is attached to the aluminum and that is touching the cylinder fins, sooooooooo, altho not touching, they are exposed to the same heat.

They are somewhat but when the engine is running the cyl. are 400 degrees or so and there is cooling air flowing which cools the alum. and when stopped the engine is in the 300 degree range and the alum. baffle is only 250 degrees and cools quickly.
The main advantage is that the top is easily removed without removing the ducting and the intire plenum. the alum stays put and sealed to the engine and just the top is removable for inspection

[Dust]

Well, the conti i have has stepped fins, to get the shape i want for the cover would be much easier to make from glass,carbon or kevlar than aluminum.

i will install a flange for easy removal of the ducts to the cylinder wraps