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Firewall mounting problems

slngsht

Well Known Member
I have two problems after drilling the firewall brackets (sigh).

Problem #1 - pure carelessness by me... the lower left edge of the firewall is 1/16" further back than it should've been. The others are all correct. Root cause of this problem is I missed the centerline of lower angle bracket when I drilled it on the left side.

My options are:
1. order another lower weldment bracket, drill out old one, put new one in (at this point I have only drilled the outside 2 holes on the angle bracket on firewall.
2. live with 1/16", and shim corresponding engine bracket with 0.060"?


Problem #2 - on the lower right weldment - the aft hole edge distance is 0.225 which is slightly less than the required .25". Edge distance is fine on the 713 longeron. the problem is in the weldment. what's puzzling me on this one is I don't see how I have any control on where this hole is - it is positioned by hole in skin and position of weldment.

Any advice on either of these is appreciated.
 
Sure.

shimming is done all the time for the mounts. The hole placement I would guess is acceptable, but without seeing it I would ask you to call Van's and get their take on that one. Hope this helps, R.E.A. III # 80888
 
I had a similar edge distance issue on the weldment, and Vans said that the edge distance in steel in that case was a bit more forgiving, and to build on. You are right, it is hard in this area to get edge distance everywhere, especially with the variance in welded parts. I figured the edge distance was more critical in aluminum, and built accordingly. Not saying you shouldn't check, but I think you will get same answer as I did.

Regarding the shim, the engine mount will probably not be perfectly flush with the firewall anyways due to welding variances. I had to shim my lower right mount apr 1/16". Shouldn't be an issue for you.

Chris
 
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