I was unsure if it was best to weld my motor mounts using a Mig (which I have) or a stick (which I don't have) What would be best????? or does it matter???? If I use my mig, is it ok to use my .024 wire or should it be larger?

 

Joe -

The answer depends on the power of your MIG setup. If it can push 100 amps and you're working with .18 or lighter plate, that would be fine. My MIG does 88 amps and I have made good welds in 1/8 thick steel using .024 steel wire and gas. In .15 thick material, I used the flux core wire and got a great weld.

Stick welders make great structural welds. They just also make quite a mess and require a lot of cleanup later, but so does the flux core wire on your MIG.

 

I have a Hobart 180 Mig using .024 steel with gas. No flux core

 

I think it all depends on the talent/competency of the "weldor". A good weldor with any machine can get good results... multi pass maybe, but for engine mounts you're not usually dealing with anything thicker then 3/16" material

a 180 should handle that with no trouble... though I'd try for at least .030 wire and gas shielding... a rookie weldor (like me) could make a mess of anything with more than adequate equipment.

John (certified dauber in both stick and wire)

 

SJ, your MIG should do the job, but I would question welding the mounts directly to the frame. I'd weld them to doubler plates and bolt them to the frame. It will be much easier to build and get a quality weld on them on the bench whereas it would be near impossible to do it completely inside the frame and you won't take a chance on warping or crystalizing the frame in the most critical area of all, plus future owners will thank you.

 

Hey, thats a darn good idea. I will definately look into that,
but how come I hear a lot of negatives about bolting on motor mounts?
Also is the doubler plate for reinforcment, instead of just bolting the mounts
themselves? How thick should the plate be???

 

By a doubler plate I was refering to a plate that is part of the mount and goes flat against the frame with bolt holes in it.It's meant to be an attachment point, a reinforcement and to spread out the load. For the best results make the plates a close fit top to bottom inside the rails x 4-5" long and stagger the (4) mounting bolts. Use hardened bolts of at least grade 5, and the same grade largest and thickest washers you can get on the outside of the frame. I'd use 3/16" plate depending on what you will be using for the rest of the mount. I'd expect that the bolt in mounts that are complained about used too small a plate or lined up the holes across the frame creating a weak point. I've seen a LOT more bolt in than welded MMs. For extra strength you could consider tieing the two mounts together with a tube under the engine. Don't forget to use a rubber mount insulator don't bolt the engine in solid.

 

what kinda motor are you putting in?
i dunno about the need for some huge reienforcement for motor mounts the shells themselves are pretty thin, but i would definately make sure it was well thought. staggeredare not needed if you leave ample room around the hole but thats when we get into a thing called safe edge distance! oh yea i forgot use whatever you want if you use mig i would bevel one edge to get more penetration and use atleast 3/16 for mounting ears and 1/4 for the actual part to mount to the frame. you want the ears to bend inwards when you torque the bolt

 

I have a 302

 

The major reason for the wide plates are so they cannot move or work against the bolts. As a matter of principle I don't like to line up multiple bolt holes directly across the frame so as to not give a place for a crack to start if I have a choice, hence the staggered bolt arrangement.

 

Well the lip of the frames, top and bottom, are 2 1/2 inches(roughly. Should the plates extend passed that, or exactly flush with the frame lips. A great amount of zigzagging would also be minimal, giving the measurements. Should the hole sizes match something similar to the rivits on the frame, or bigger?

 

I guess I wasn't very clear. The plates would be flat. If the height of the frame is say 6" between the flanges on the inside (I don't know the actual measurement) at the point where the motor mount will go, then I'd cut a plate 5 7/8" (to give room for the small radius in the corners of the frame) by long enough to drill mounting holes on either side with at least 3/4" all the way around the holes (this will depend on the shape and size of the mount) This plate simply goes against the vertical surface of the frame on the inside, and bolts thru that surface.
If I still am not completely clear email me and I'll send you a sketch.

 

I believe I understand, but send me an email anyway. I'm a visual person. You know how guys are. heheheh

 

So AXRacer, you meant something like this???

 

That's it! just make the plate a snug fit between the flanges and use two 3/8" bolts @ the top and one or two at the bottom as well as large thick washers on the outside of the frame and you won't have ANY problems with those mounts being bolt ons.