When do I rivet the bottom of the firewall?

[Trevor778]

I've drilled the motor mount to the airframe and have done all the firewall penetrations. I would like to mount the motor mount permanently and get this thing standing on it's own 3 legs. Im just looking at the bottom rivets on the firewall thinking that they look a little tough to buck after I attach the motor mount. Should I squeeze these now? How does the bottom cowl attach there?

RV 7 slider 0-360A4M vertical induction.

Thanks for the input everyone

Trevor

 

[bret]

I did mine when I installed the skybolt brackets for the last time, and that was after the engine was temp installed and cowl fitting was done. no need for the gear to be on, I still have the fuse on the rotisserie doing wiring and windshield skirt fitting.

 

[NYTOM]

Been there. ( few weeks ago)

Trevor I just did mine a few weeks ago and on the 6 anyway it's pretty tight trying to buck those rivets in a few places. A small tungsten bucking bar fits in there and works well on most of them. I believe there was two rivets directly under the center motor mount bolts that were particularly tough and I loosened the mount up a bit and pulled it forward to allow the bar to fit.

 

[Raymo]

Should I squeeze these now? How does the bottom cowl attach there?

RV 7 slider 0-360A4M vertical induction.

Thanks for the input everyone

Trevor

You will need to wait until the cowling is fit for the piano hinges on each side. if doing skybolts, the same applies, as mentioned above.

Doing the same engine but using an elbow out of the vertical sump to point the servo forward and get more room in that area for cowl fitting.

 

[bret]

I also used firewall sealant on all the skins that attach to the firewall, if you shine a light from the inside, you can see all the gaps, don't need any possible CO entering inside.

 

[Dan B]

I would suggest quarter-turn fasteners on the bottom cowl. The eyelets on the piano hinge on my 9 started breaking at about 100 hrs. They started breaking nearest the exhaust stacks first. You will still need to consider having room to rivet along the bottom firewall.