O-200 Motor Mount Bolts

[6478]

Does anyone know what motor mount bolts to use with an O-200 with Lord mounts? Fresno Airparts sells a C-150 O-200 bolt kit with one AN6-43A, one AN6-44A,and two AN6-55A bolts and I'm trying to verify that is correct for 120/140 use as well. I went through the Technical Forum archive but the bolt P/Ns mentioned there are all over the place.

Thanks in advance

[6597]

I got the same kit, but I ended up using 2 AN6-44As on the lower mounts, probably because I have 2 grounding straps. AN363-624 stop nuts with witness paint. Randy may have a better idea, there is a squish factor on the Lord Mounts.

[6298]

I have been thinking about this for a while. The question about two different lengths of the 43 and 44 bolts was confusing. Dave answered that question about the ground straps. The only thing that would be concerning about the Fresno Airparts kit would be that some mounts could have different bolt hole length than others. I’ll measure the ones on two of my airplanes and update if they are different.

[6643]

The 140A parts manual calls for 2 each AN6-44A and AN6-54A. If you're using the 140A mount, I'd expect the O200 to be the same, as it uses the same mounting cushions, etc.

[6298]

I took a look at mine, and found a few interesting things. I use bolts with castle nuts and cotter pins, and they are a little longer. More like -57 on the upper two. The lower ones are -44’s The ones from Fresno Airparts are probably correct using nyloc nuts. Another interesting thing is that the spacers in the lord Mount kit that Fresno markets are longer that some others that I have removed. Might cause the bolt length to be longer. I find a lot of those spacers squeezed shorter due to over torquing.
Like John said the Mount is the same on a 140A if the engine is a C-90-14. That Mount is also for an O-200A. It is part number 0451111.

[6478]

Thanks Randy, John, and Dave for the info. This explains the P/N variations I was seeing in the Technical archives. My mechanic prefers we use the castle nuts instead of Nylocs so looks like I'll follow Randy's lead there and use two -57s and two -44s. Hadn't considered the need for a longer bolt to use a castle nut but that makes sense.

Appreciate the help!

[6643]

Hadn't considered the need for a longer bolt to use a castle nut but that makes sense.

If that's the reason, then wouldn't it stand to reason the -44s would have to be -47s, too?

The grip length of a -44 and -44A are the same...