I would like to know the series of the Camloc's on the engine nacelle side cowlings. I plan to change them to stainless steel phillips head. Some of them are very tight and difficult to turn, so I think the lengths are incorrect for some reason, perhaps the changing of the lower cowlings.I put a drop of ACF-50 on each Camloc about a week ago to help them turn. Tje heads are depressed below the surface on some of them.
I would appreciate any other information that would help me figure out the correct stud lengths to order and how to remove the retainer rings. I plan to order the correct pliers. I assume the Camlocs are 4200 series, but I don't know much about the Camlocs yet. Removing the studs with the special pliers looks easy. I would imagine installing a new stud would be easy were I not also trying to change the retaining ring to stainless also. I've never tried this before. I saw some videos where the depth is measured and the number written on a piece of tape above the line of Camloc holes as some studs are different depths (lengths) by the nature of the beast.
Clear Skies

Replacing both is relatively easy. Check out the Skybolt website, http://www.skybolt.com/ For information. They make everything you will need, including a the pliers and an installation tool for the snap ring on the retainer. I did this several years ago on all if the fitting on my Aztec.

Hi Jim, It's reassuring to hear the process is not too difficult. Did you change your CamLocfasteners to the Skybolt CLoc fasteners, or did you order CamLoc's from them? If you did use the Skybolt CLoc's did you have to change the receptacles? I think that would involve drilling out all the rivets for the receptacles and riveting new receptacles on , so I assume you did not. How did you measure for the correct lengths, or did they already know the correct lengths?

Edit: I called SkyBolt and they do have a kit along with the tools for the 4000 series fasteners. They are -6 and -7 in length. Only 16 are -7. I am calling them back later to find out the difference between the 302 & 304 stainless head. I imagine one of them is harder than the other to resist wearing of the slots from screwdrivers. Thanks again!
Gomer

Edit: All of Skybolt's 4000 series SS CLoc's are now 304 stainless (no more 302 stainless) with hardened "Diamond" heads to prevent galling. I ordered one each of the -6,-7, & -8 studs in phillips head, along with the pliers and clip install tool. I plan to remove some of the very tight Camlocs and replace them with one of the SS studs to see what length I will need in general as I suspect the new lower cowlings that were fabricated just prior to me purchasing the plane are constructed of a slightly different thickness aluminum than the originals. I was told the dash numbers represent 0.030" difference in length for the studs which is not much thickness at all. They said even paint can sometimes change the thickness.

No, I did not change the Camlock receptacles. I did replace the rings the Camlocks go into with new stainless to get a better look. Phillips head are the only way to go. No more scratched from slipping screwdrivers.