[matt167]

Went to the nearest open hardware yesterday ( sunday ) to get grade 5 or 8 7/16"-14 bolts for my custom motor mounts, to hold the 2 1/2's togther. being that they needed to be 6" long, and they didn't have any. I ended up with some allthread and a couple nuts. I figured this stuff was good enough for mock up purposes.. As it turns out, due to the orientation to the frame mount 1/2 not being flipped like the actual engine mounts are ( 1 left, 1 right ), the nut insert on it ( inner plate ) has to thread thru it on 1 side, and thus the bolt would have to be fully threadded, and seems like a hard thing to find.. Didn't think grade 8 allthread existed, but I searched and it does.. Is grade 8 allthread as strong as a grade 8 bolt?

if anyone is wondering. The mounts are correct for a 1975 Ford Elite or Lincoln Continental, and the lower 1/2's are the top plate to a 1974 Plymouth barracuda mount. The spacer is a 3/8"x1 1/2" pipe nipple, which puts the engine at 1 1/2" setback. This could be adjusted any way with different spacers. The allthread needs trimmed, but being it's just the mock up allthread/ bolt, I wasn't worried, and just cut it as close as I could with the small chop saw

[35terraplane]

Originally Posted by matt167

Went to the nearest open hardware yesterday ( sunday ) to get grade 5 or 8 7/16"-14 bolts for my custom motor mounts, to hold the 2 1/2's togther. being that they needed to be 6" long, and they didn't have any. I ended up with some allthread and a couple nuts. I figured this stuff was good enough for mock up purposes.. As it turns out, due to the orientation to the frame mount 1/2 not being flipped like the actual engine mounts are ( 1 left, 1 right ), the nut insert on it ( inner plate ) has to thread thru it on 1 side, and thus the bolt would have to be fully threadded, and seems like a hard thing to find.. Didn't think grade 8 allthread existed, but I searched and it does.. Is grade 8 allthread as strong as a grade 8 bolt?

if anyone is wondering. The mounts are correct for a 1975 Ford Elite or Lincoln Continental, and the lower 1/2's are the top plate to a 1974 Plymouth barracuda mount. The spacer is a 3/8"x1 1/2" pipe nipple, which puts the engine at 1 1/2" setback. This could be adjusted any way with different spacers. The allthread needs trimmed, but being it's just the mock up allthread/ bolt, I wasn't worried, and just cut it as close as I could with the small chop saw

Matt grade 8 threaded all the way is just as strong, they are rolled threads that is a much stronger thread than a cut thread, also that is how they get up to the head.
With a rolled thread you remove no metal just move it around, cut threads of course you remove metal.

Bob

[MRTS33]

I have little experience with Ford and even less with Mopar motor mounts. It looks to me that those motor mounts aren't going to take to much torque to snap that bolt. I think I'd look for a better setup. Please correct me if I'm wrong.

[matt167]

It shouldn't be any weaker than the setup the Lincoln it came out of had, which used the same engine mounts. The only diffrence is the mount sat over top of a saddle with a locator pin. I don't see it snapping a grade 8 bolt, altho I could weld a thick steel washer to each side of the mopar mount, so it doesn't rip out the metal, just to be sure.

[MARTINSR]

That is WAY wrong, it WILL break. The mount ears need to be next to one an other. With that one floating out in space it WILL break or at least bend that bolt. Grade 8 means nothing when you have those forces, zero grade garden gate bolts would hold just as good.

Correct the design and don't try to make up for what you have with "stronger" bolts.

Brian

[da34guy]

4 words ---
THAT AIN"T GONNA WORK !!!!!!!!!!!!
Sumthin Mickey Mouse would do.

[matt167]

I was just looking at/ going by the listed bolt strengths. But I see what your saying, and after thinking about it, I would tend to agree.. I'm thinking, if weld the spacers to the inside plate, then it would eliminate the load forces on the bolt. Or I could get another set of the 460 mounts, and seperate them from the rubber and use those for the bottom plates. that would put both ears side by side, and probably work best... I have the mount towers for the 4cyl, which I was hoping I could get the engine to bolt onto them and into the chassis. I might fabricate a saddle on the towers, just like the lincoln had

[matt167]

Originally Posted by da34guy

4 words ---
THAT AIN"T GONNA WORK !!!!!!!!!!!!
Sumthin Mickey Mouse would do.

Lol yea. I'll figure somthing out tho. The Mopar mounts were $6/ each so it's no big deal to chuck them. make good brackets for somthing or other anyway.. I was trying to do it cheap. but cheap and good doesn't always work out

[da34guy]

Now yer thinkin right.
Leave the MM stuff to Disneyland

[oldred]

Originally Posted by 35terraplane

grade 8 threaded all the way is just as strong, they are rolled threads that is a much stronger thread than a cut thread,Bob

True and an often misunderstood factor. I think extending the thread by cutting on a lathe or with a thread die loses about 20% to, in some cases, as much 30% in strength as opposed to the correct rolled threads. Basically if a thread die is used to extend the threads on a grade 8 bolt shank it can no longer be considered as a grade 8.

[boatbob2]

Hi,basically what everyone is trying to tell you is,the 2 motor mounts (engine half,and chassis half) need to fit inside each other,then the bolt holds the 2 halves together,,, thats the way the factory designed them,dont try to re-invent the wheel.

[matt167]

Ok, trying to find somthing else to work.. I thought about splitting the Mopar mounts in the center and making them wider. It could work but would need fish plated to retain the strength, and by the time I got done splitting and welding, I could have just fabbed somthing.. I don't want to use another set of 460 car mounts and try to cook them, as I'm only 50% sure they would work once I seperated the 'hoop/ear' half from the engine mount 1/2. There a bit too expensive for a 50% chance at $30/ each just about everywhere.

If I bend a bracket out of steel stock, what is a good way to keep the holes equal when drilling both sides equal? my drill bits are not that long.. Otherwise is it kosher to weld the right size mount tab to a base plate cut to the right width?