18 April 2019

Cross bar dimensions

I keep forgetting to make a post about my engine mount crossbar dimensions, so while this is old news I still want to document it. With my cold air induction (Thunderbolt) I had to lower my crossbar in order to gain enough clearance for the engine.  The short of it is that the rear of the sump on the cold air setup is about ~3/4 lower than the standard sump.



This is a pretty standard modification and Barrett sells these crossbars with their cold air induction. The dimensions of my setup are in the photo below.


I unfortunately measured once and cut/welded twice. The first time I welded one in, I more or less eyeballed in the dimensions while the engine mount was on the weld table and not on the airframe. After I mounted the engine and allowed the mounts to sag a bit, I was not happy with the clearance I had remaining (1/16"). As such, I removed the engine off of the mount and welded a new cross bar in place. The tubing was pretty easy to find and I just ordered it from: McMaster Link


With the Thunderbolt IO-540 setup with Cold Air, .82" of cross bar drop got me a little over 1/2" of clearance on a mostly settled engine.