Help with RV-7 Lower Cowl Hinge/Pin

I have read several posts about this already but couldn't find exactly what I'm looking for -

I need to replace my hinges on my lower cowl at the firewall (bottom ones next to the exhaust, not on the sides). I ordered what I thought would be the correct size from A/C Spruce but obviously I was wrong. So I decided to take one of the hinges off, take a buddy's RV-10 down to Spruce yesterday (great excuse to fly the -10 ) and get them to match it while I was there. Well after bringing out what seemed to be every hinge they had I left there without new hinges. The common theme was that the hinge pin was the same size on all the MS parts but the surface sizes were different (well at least this is what the nice ladies said behind the counter). The other difference that I noticed is that all of the M/S hinges were the nice extruded ones but my hinges for the bottom are not the good extruded hinges, they are open end and probably why some have broken off. But they are a much large pin hole.
So I figured looked on Vans this morning and now I'm confused even more.
For those who have built their -7, do you remember if the plans called for a heavier/larger hinge or was this something that each builder did differently. I found in a couple of post that some of the RV-8 builders had used MS20001. I'm not sure which size or even how this is sized. What should I be measuring?
My plane is 12 years old with just over a 1000 hours so going back to the builder and asking him may be a much tougher task than just figuring this our myself.
BTW, i'm not interested in replacing it with fasteners. I love the clean hinge look and want to stay with that. Plus the hinges that riveted to the plane/firewall are not broken, just the ones on the cowling so I'm only going to replace that half hence the reason I'm trying to get an exact match.

Thanks in advance for your help

BCP Boys said:

I have read several posts about this already but couldn't find exactly what I'm looking for -

I need to replace my hinges on my lower cowl at the firewall (bottom ones next to the exhaust, not on the sides).

Click to expand...

They are the same as the side hinge. The 1/8 piano hinge.
https://www.vansaircraft.com/cgi-bin/store.cgi?ident=1544709170-66-42&browse=hardware&product=hinge

BCP Boys said:

For those who have built their -7, do you remember if the plans called for a heavier/larger hinge or was this something that each builder did differently. I found in a couple of post that some of the RV-8 builders had used MS20001. I'm not sure which size or even how this is sized. What should I be measuring?

Click to expand...

Here is dwg 45 for the -7's with the the cowl instructions for reference.
https://photos.google.com/album/AF1QipMwcmY9gv4A11c3UMqOj_avdeVhjIvwdnebdtrF/photo/AF1QipNo4CFZHYEaX9Z0I_8bEaZMqz66qDLgYX4bH1si

thx

Thank you for the info. This is a ton of help.

Amir - I riveted a piece of angle on the firewall to allow a screw with a large area washer to hold the cowling up on the inner side next to the tunnel. This provides enough support for the hinge to keep it from eating loops.
The screw is inline with the hinge, just a bit inside of the first loop. I put a nutplate in the angle, so it is easy to unscrew and put back in.
It has held up great.

Do yourself a favor and only use the extruded hinge material for the lower cowl (MS20001P).

I replaced the bottom hinges on the RV-10 with this as the left side had repeated hinge loops breaking off. Trouble free after this change. Using this on the new RV-8 project.

Carl

I believe the ACS part number would be. Unless going extruded, then you'd want the MS20001P4 part number. These have the .090" pin.

Part #: 03-00050-x (x = 3 or 6, depending on length)
Mfr Part #: MS20257P4

My plan is to cut the loops off of the lower hinges, then rivet 2 pieces of .062 going forward from the firewall side, on top of what's left of the hinge metal strip. This forms 2 ledges on each side. The outer on each side would be an inch or so inside the gear leg and the inner on each side another 4.5 inches inboard. Match drill and nut plate. The inner 3 or 4 inches before the tunnel is not flat/parallel to the bottom lip of the firewall so I'm not going to attach anything in this area.

I figure 4, #8 machine screws would be much easier to install than the hinge pin. They would be less likely to fail.

The failed portion of the hinge loops in my case was the inner 4 or so inches on the cowl side where the hinge was shimmed to make up for the slightly downward curve of the inner 4 inches before the tunnel.

#8 screws

I replaced the hinges with 3 screws on each side. I trimmed the loops off of the hinge on the firewall and left that as a shim for the plate with nut plates attached.