SBC Motor mount question

[Scott R]

Spent the last 1/2 hour searching though the arcivies and did not quite find what I was looking for., so here goes: I finished welding in the scab plates yesterday for the AA motor mounts, and I am about to install the "L" brackets this afternoon, however it looks as if they should be bolted though the frame rail as they have two drilled holes in the lower half of the "L."

I am thinking weld and bolt? It's gonna be pretty nasty drilling though that much steel, but I have a pretty big drill that's probably up to the task. Also I used 6013 ARC rods to weld the plates, if I should use something different please let me know before I get to much farther in. Thanks!

 

[FJ40Dude75]

I just welded them on drilling holes in frame sucks and the weld is strong enough

 

[Pytbool]

If you welded vertical up and they are good-looking welds, don't bother bolting.

If not, bolt them also. Depending on where your scab plates are, you may be able to bolt through just one side of the frame rail. If you have to go through both sides of the rail, you should sleeve the holes to keep from collapsing it.

-Tyler

 

[woody]

hate to say it, but I ran my engine and t-case AA plates bolted-only for about 15 years....never once had an issue with them, just those two stock bolts in there. I did retorque the bolts each year, but don't ever recall them being loose.

I would only weld verticle tho if you decide to do that.

 

[Scott R]

I think I'm paranoid, I almost want to bolt them for saftey reasons, I'm a stellar mig welder, but so/so on arc.

I mounted the plates 9" inches back from the rear of the front shock tower, and since the plates were 10" long I but the middle of the plate 5" on the 9" mark.

I smacked the plated with a 20lb sledge a few times after I welded them in to make sure they were tight welds, I did have some issues with the lower weld since the gap between the plate and the rail lip was a bit large.

 

[FJ40Dude75]

mine are mig'ed on no problems yet

 

[HI^C]

I have had one of mine done both ways, mig and now bolted. I removed the welded mounts from a frame with nothing more then a 6 lb hammer and a chisel every now and again. The mounts came off with chunks of frame still stuck right where they were welded !!!! I really wasnt swinging hard, the 6 lb just takes less swings< LOL I assumed and still think that the heat and such from welding caused the metal to become weak. Since i removed them, i decided i would bolt the drivetrain in, which i did. Every hole is sleeved (just slid a chunk up the frame openings) and where i could i ran a saddle ( like a C) over the top of the frame rails to to the hole on the other side.

 

[dgangle]

On my most recent SBC to FJ40 conversion, I welded the scab plates to the frame and then bolted the 'L' brackets to the engine and rear transfercase support. I then positioned the engine/trany/TC where I wanted it and tacked the 'L' brackets to the scab plates. I then unbolted them, removed engine and welded everything up. No misalignment on these!

 

[Scott R]

Thanks for all of the suggestions, I am suprised that you guys did MIG, maybe I should have. I just figured that due to the thickness of the steel on the plates and frame I would use ARC, maybe thats why I don't like the welds very much.

 

[greencruiser]

I welded the rear mount for the trasfercase crossmember

I had everthing where I wanted it , clamped it tacked it the removed the scab plates with the angle brackets and welded them fully to the scab plates then I welde the scab plates to the freame under the rig

for my front mounts I fabbed custom AA style mounts and the frame bracke is 1x4 angle I think with the angle bracket welded to it then i bolted it with two bolts thru the top of the frame rail ( two layers of frame steel) and bolted two bolts thru the side aswell lots of drilling also used 1/2 inch grade 8 bolts with nylocks and lockwashers

If I redid it i would probably bolt the rear mounts on too but I was a bit lazy

 

[HI^C]

"I am suprised that you guys did MIG" well your only working with 1/4 or 3/16" thickness, which most migs are able to do. BTW 300 amp mig is not uncommon,

 

[Scott R]

I just always did sheet metal of course with my wire MIG, and figured plate steel was probably a little to much. I'm no pro welder for sure, far from it in fact. We are talking "wire mig" right?

 

[HI^C]

Mig i have only seen in wire feed. it is all based on amps, 135 amp will do 3/16. 135 amp is really the smallest or most basic mig for most manufactures.