Rocker cover to cowl clearance?

[szicree]

I'm fitting (cursing) my cowl and am finding that the rocker cover on the number 4 cyl is very close to the upper cowl. Assuming they are far enough to not bump at startup/shutdown should I be concerned? All opinions are very welcome. Thanks.

[Ironflight]

My opinion is that as long as it doesn't bump, it's not a problem - these are very tightly cowled engines!

Paul

[pierre smith]

Originally Posted by szicree

I'm fitting (cursing) my cowl and am finding that the rocker cover on the number 4 cyl is very close to the upper cowl. Assuming they are far enough to not bump at startup/shutdown should I be concerned? All opinions are very welcome. Thanks.

Hi Steve,
We just went through the same thing on my buddy's -4. Be sure and fit the rear cowl cheeks while the forward top and bottom cowls are on and check the height to be sure that the cheeks don't cover the screws of the top skin. Aligning all four cowl pieces was a lot tougher than on my -6.

When the time comes to mount the oil cooler, I'd suggest that you lay it back about 30 degrees and use a short length of 3" scat tubing. A flat mounting plate can be attached to the upper motor mount tubes for this with some Adel clamps. If you mount it on the rear baffle, half of it will be blocked by the cylinder when it's low enough not to rub the cowl.

Regards,
Pierre

[RudiGreyling]

Good Question, can I add a question?

What is typical minimum clearance? Who had what clearance, and then had it touching?

Thanks
Rudi

[pierre smith]

Rudi,
If you have an opportunity to watch an 0-320 or 0-360 start up and shut down without the cowl off, you'd be surprised at the amount of rolling/shaking as the engine either comes to life or shuts down. Obviously, the rocker box covers will move the most, as will the airbox....furthest from the center of the engine. I'd try for at least 1/2 an inch.

Regards,
Pierre

[RudiGreyling]

Thanks Pierre!