Had one of those "DUH..." moments today. I've been working on a Stihl 62cc from a chainsaw for my 28% Wild Hare Extra. I thought, "Hey, I just won't mount the cylinder until I have the engine located on the firewall." "That way I won't be fighting the cowl/cylinder interference while I am getting the engine located properly on the firewall!!" Don't know why I never thought of that before. I guess because I am always anxious to get the engine all done and running on the test stand.

So anyway, for those of us that take our engines apart, which is probably most of us "engine converters", just leave the cylinder off, get your engine spaced properly for the spinner, and centered in the cowl front hole. Get your bolts, mounting, spacers if needed etc., all figured out, and bolt the engine to the firewall. Then you can mount the cylinder, and proceed with your favorite method of mapping out what parts of the cowling need to be cut. This method also has the added advantage that without the cylinder weight, the engine will usually sit on the firewall without falling over. (Fuselage standing vertically on its tail.)

I know, somebody is going to say they've been doing it this way all along.... right?

AV8TOR

How about some pics of your Stihl engie conversion and mounting? Ihave a Stihl 038 Imay use someday.

Ok, I am not done enough to have pics to show yet, but I will post them when I am.

AV8TOR

I think I've done that before but usually end up missing some stupid detail, like when I test fitted my 32cc Mac engine on my USL and didn't account for the muffler spring contacting the firewall... simple 3/8" long spacers was all it took, which also let me use the stock firewall hole for the fuel lines and ignition wire and such.