Starting-cowling rub

[RV6KalGal]

I'm new to the forum and uncertain whether this belongs in the maintenance or general discussion area.
I purchased a 1998 RV6 in Aug of 2009 with 440 hours on it. At that time I noticed a dime-sized bump in the lower cowling with small cracks emanating from it. Now with 560 hours on the airframe red silicon has started showing through the bump and it is clear that the starter is rubbing through the cowling. An RV6 builder friend told me that it may be due to the engine mount settling over time. The question is whether this happens to other RVs and what to do? My builder friend thinks that he saw some RVs at AirVenture with bumps built into the cowls for clearance. Has anyone seen this? He is willing to work on the fix for me, but said rather than trying to make a smooth bump from scratch, it would be easiest if there is something already on the market, suggesting that a tear-shaped 1 inch piece would be fine. Is there such an insert available, even if not for this specific purpose, something that would work?
He also noted that the engine mounts could be changed but it would be a laborious process.
Any insights or suggestions are more than welcome.
Thank you.

[Rick6a]

Oftentimes, builders mold a blister into the cowl to assure positive clearance with a starter or alternator. Certainly, you can use/bond a variety of materials in the local area to facilitate the process though it seems to me simply laying up additional cloth around a temporary mold would be the way to go. Others who have done so can likely provide you with the specifics. Bottom line: Your problem is not unique and there are many RV's out there with a blister molded onto the cowl to assure positive clearance with a starter or an alternator. Someone good with fiberglass can easily do the necessary rework or you can bite the bullet and purchase a lightweight starter or Plane Power alternator or similar and possibly avoid cowl rework altogether.

[Mike S]

Originally Posted by RV6KalGal

I'm new to the forum -----

Karen, welcome to the force

Good to have you aboard.

I agree with Rick, lots of folks use a blister------

Have you checked to see if the spinner is showing a droop where it aligns with the cowl??

If the engine mounts are starting to sag, it is pretty noticeable at the spinner.

[pierre smith]

...Quite possibly the easiest fix might just be a shorter belt. We 'borrowed' three from NAPA auto parts when we installed our engine and ended up with plenty of clearance with the shortest belt...kinda tucked the alternator up close to the engine block,

Best,

[RV6KalGal]

Thanks to all who responded with ideas, much appreciated. The cowling had not dropped. Someone who knew the plane told me that the starter had noticeably begun creating a bump in the cowling at only 70 hours. Rather than put a blister in the cowling, I decided to replace the automotive starter that was in it with a Skytec. Problem solved, weight saved, better starter, smooth cowling.

[Mike S]

Originally Posted by RV6KalGal

I decided to replace the automotive starter that was in it with a Skytec. Problem solved, weight saved, better starter, smooth cowling.

Karen, looks like you made a good decision there.

Thanks for reporting back with the solution to the problem, maybe someone else will benefit from your efforts.