F

fred gassit

Member
Hi guys

I am about to rivet all the various angles and engine mount brackets to the firewall.

The engine mount brackets all have a hole on the reinforced boss that doesn't have a matching hole in the firewall.

It would seem logical that it should be drilled through for 1/8 like the others but there is no explicit instruction to do so or any rivet call out for that hole.

The link below shows the hole I am talking about.

https://picasaweb.google.com/101730537441770437828/February152012#5709327364166874514

Curious to know what others have done or if newer/older plans versions had more detail.

Thanks in advance
 
This is a tooling hole used to hold the parts during welding. I was advised by Vans to abandon the hole.





Ariel
Rv8 under construction.
 
I just installed the engine mount on my RV8 last night. Previously I had drilled through the tooling holes and the firewall to 1/4 inch and used these as the mounting points for my fuselage rotisserie. After removing the rotisserie I used the same 1/4 inch bolts to temporarily attach the engine mount. The 1/4inch bolts were not centered in the engine mount but with hand pressure I was able to get all 4 bolts in the engine mount. I was very concerned that the holes were out of alignment enough to cause a problem. I decided to follow the instructions and use the engine mount as a drill guide. I removed one of the 1/4 bolts from the mount and with a 3/8 inch drill attacked the lower right (looking aft) mounting point. I found that the flexibility of the mount allowed the drill to "find" the 1/4 hole and use it as a pilot so I continued drilling. Once complete I installed the 3/8 inch mounting bolt finger tight. I them moved to another hole and did the same thing removing the 1/4 inch bolt and drilling with the 3/8 inch drill. Each time the flexibility of the engine mount allowed the drill to "find" the 1/4 inch hole. So basically the upshot is that my installation used those tooling holes. The engine mount was easy to install with only minor hand pressure to move the mount around to achieve alignment. This was my experience so take it for what it's worth...measure the tooling holes and compare to the drawings and the mount you have...maybe I just got lucky...hope you do to...
 
Thanks guys, only early days here so I will reserve the tooling holes for possible future use as suggested.

Tooling holes the same size as rivet holes= confusion (for me)
 
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