Sonex aerovee cowling

[Rynoth]

Wow... that difference is.. remarkable. I doubt I'm the only one who still has all that casting in their heads, and I can see how that alone could cause a significant variation in cylinder head temps.

Steve Bennett from Great Plains A.S. discusses this in his EAA video. The video is a must watch for anyone building a VW aircraft engine regardless of the "brand".
https://www.eaa.org/videos/2117083972001

Nice link, he talks about those passages about 36:30 into that video.

[mike.smith]

Here is a before/after photo of rework done on a VW cylinder head.
Not sure if this is the exact same head as used on AeroVee engines, but it should serve to illustrate the issue with casting flash.

Hmmm. I never gave those crevices a second thought before. I don't have CHT issues, but these photos sure make me want to clean up my heads anyway!

[John Usher]

Those are great pics! Thanks Waiex49 for posting! Do you know what brand head is in the right side pic? The one on the left appears to be the head from Mexico that Mr. Bennett talks about in the EAA video. I think the part # may be 043101355H. (?)

[Waiex 49]

Got the photo from a web site on motor gliders.
Not sure what make or model of cylinder head, other than it is from a VW.
Said to be the same head, left is before clean up, right is after.
Quite a difference!

Don (Waiex 49)