Spinner Cowl Centering

I am just about to "nail" my cowl and thought I had it pretty well spaced and aligned until I did the final gap trimming on the front edges. As every thing snugged up and the gaps closed the assembly twisted slightly and the front of the cowl moved down and right relative to the spinner back plate - not by much but enough to notice. I have the upper and lower firewall hinges clecoed and the front holes on the joggles drilled as #30 pilots. The vertical firewall hinges are not drilled yet. What are my options for tweaking it back to center or is it good enough?
Jim Sharkey

Camloks.....

Hi Jim,
Hinges on the top are really difficult to insert and remove because of the tight radius on the top cowl edges. We used camloks and never looked back, plus you won't have the hinge pins sticking up out of the cowl. All you do, is rivet a wide length of .062 to the firewall upper lip and install camloks at 4" spacing. With the upper hinge removed, move the entire cowl assembly over to where it should be and drill and cleco the vertical hinges on the lower cowl. You may want to lower the cowls so that the top cowl is close to even with the top of the spinner since the engines often sag an 1/8" or more within the first 100-200 hours from the motor mounts compressing.

It's usually easier to mount the lower cowl first but the top cowl should also be attached to the lower cowl for centering and vertical alignment.

Regards,
Pierre

If you think it is close enough, it is close enough. It does not look that bad and only you will notice it when your done. Your airplane wont complain and it will fly just fine.
However, you might be able to retrim the back edge of your cowling, change the spacing on you hinge rivets, and redrill. Fill in the old holes and you will never now they existed. This will change the spinner backplate to cowling clearance and make that gap a little wider, which is not necessarily bad. I would assume that if things shifted, your gap is not consistent between each side now anyway, so you may want to redrill that hinge to accomplish this.
Dont be afraid of the hinge pins. Some people seem to have trouble with them, but mine work well and I prefer not seeing a bunch of fastners on my cowling. That is personal preference. I think Vans got it right and hence used that method on all of their models. I can get my cowling off in minutes, despite very close 3/16" - 5/16" spinner backplate gaps (settling in nicely). It goes back on just as easily. I would use camlocks on the bottom firewall attached points if I was to do it again for other reasons, but not on the vertical sides, top, or between the upper and lower cowl. The hinges work very well. I would not switch to camlocks to fix your problem unless you where commited to using them instead of the hinge. I think redrilling the hinge would be less work.
Regardless, if you commit to fixing this, you will probably find it takes less time to fix than you have already spent worrying about it.

Thanks for the feedback Jon and Pierre.
Jim Sharkey

I feel your pain

I had exactly this same question and fortunately, I live on the
Florida gulf coast about an hour from Lakeland. I went over to Sun-n-Fun and looked at a lot of the RVs and found that probably half of them looked like yours (and mine). I was driving myself crazy over my cowl fit and after looking at the cowls on the RVs there, mine was about average (some looked better some worse). My advice is to make it look the best you can and move on.

It's Fixed!

I took JonJay's advice and retrimmed the firewall edge of the cowl and redrilled some of the holes. It seemed to do the trick.

Now I am trying to decide if I should cut off the foremost eyes on the cowl upper to lower joint hinges since I am strugging to get the pin around the first little curve. I haven't even tried to get the pin around the tighter upper firewall joint. Any advice short of camlocs which will be a last resort?

Jim Sharkey