RV14A Lower Cowling Revision for 4 into 2 Exhaust

[77bonanza]

Does anyone have any photos/guidelines for altering the lower cowling on a RV14A from a 4 into 1 exhaust system into Vetterman's 4 into 2 exhaust systems for a IO390-EXP177 A3B6 Thunderbolt engine? Photos would be especially appreciated.

Thanks.

[jeffw@sc47]

Start with an approximation of the cutouts that you know will need to be enlarged by way of successive cuts, i.e. start knowing the cut outs will be tight.

I enlarged both of the cut outs at least twice after the first cuts. The cowling is off now to do my first oil change and I will be enlarging the left side exhaust cut out, the photo of the cut out with the line of dots. That cut out is clear of the exhaust pipe but I want more. It should be my last cut out adjustment.

[Nova RV]

I started out with the sizes in this pic and made the final a little larger to make sure the engine shake didn't cause the pipes to contact the cowling

[Bsquared]

Here is how I did mine. I started out with 1/2” clearance all around but opened that up to 5/8” after my first flight due to rubbing at start up and shutdown. FYI this is a 390 EXP60

[Jetmart]

Not a 14A but this is what I did for he 14 taildragger. Pipes and outlets are more visible in the 3 point position.

[DanH]

Originally Posted by 77bonanza

Does anyone have any photos/guidelines for altering the lower cowling on a RV14A from a 4 into 1 exhaust system into Vetterman's 4 into 2 exhaust systems for a IO390-EXP177 A3B6 Thunderbolt engine?

Just to clarify...the "EXP177" is the 210 HP version with a one-piece intake plenum/oil sump?

[77bonanza]

Yes, it is that version.