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Drilling holes in firewall
- Thread starter RVdreamin
- Start date
alpinelakespilot2000
Well Known Member
You can probably do it anytime before installing the engine mount. Thereafter it gets a bit hard to access and definitely limits the tools you can use to make the holes. Also, definitely worth drilling the cabin heat hole now while the firewall recess is not yet riveted on. Nice to be able to reach inside to use a backing plate/board while you are drilling. Good luck.
bruceh
Well Known Member
No problem deferring this. I used a cheap Harbor Freight punch set which has a 1 1/8" hole punch. It is perfect for the control lines and electrical pass throughs.
Start the hole with your step drill out to 3/4", then use the punch to finish the job. As long as you can get the punch in the starter hole and put a wrench on the end of the punch, you can create firewall holes in fairly tight quarters.
Start the hole with your step drill out to 3/4", then use the punch to finish the job. As long as you can get the punch in the starter hole and put a wrench on the end of the punch, you can create firewall holes in fairly tight quarters.
BillL
Well Known Member
No problem deferring this. I used a cheap Harbor Freight punch set which has a 1 1/8" hole punch. It is perfect for the control lines and electrical pass throughs.
Start the hole with your step drill out to 3/4", then use the punch to finish the job. As long as you can get the punch in the starter hole and put a wrench on the end of the punch, you can create firewall holes in fairly tight quarters.
Cheap HF it may be but, - I tell ya, that 4 lobe penetrator makes a better hole than my Greenly two lobe penetrator. Pretty good looking result. Your pass through is almost exactly where mine are - I must have copied you!
BTW - To the OP - i installed the mount to the hanging engine, a singe person job and it took 20 min. It is super easy to then mount the engine w/mount back to the firewall. It will allow you to do lots of things that are much more knuckle busting with the engine on the FW. Then, you can punch those control holes. I did mine by the drawings had no issues.
And - yes there is room to do those later. I added some eyeballs for a couple of cables and it was no problem with tools.
sglynn
Well Known Member
Drilling Firewall holes
I just hung engine. Waiting to drill firewall holes is good idea and no problem waiting until you are ready to hang engine. But then there are a bunch of things to do to firewall before you put on engine mount and engine for the last time. You can research that under different thread.
I just hung engine. Waiting to drill firewall holes is good idea and no problem waiting until you are ready to hang engine. But then there are a bunch of things to do to firewall before you put on engine mount and engine for the last time. You can research that under different thread.
