Calling all Gen 3 subframe into Gen 1/2 guys?

[JEM]

BTW, JEM should have his big bore Honda bearing stroker engine up and running in that car as well. Because I just have one project car, I can get my similar projects on the street a bit quicker, but JEM does his absolutely correct the first time, every time

Yeah, right...but you're going to be at the convention and I won't

 

[excidere]

Can I bother one of you for a pm or a post on the process of making the jig to get the tranny mount in the right place? I think I have it in my head on how to go about it... but a push in the right direction from somone who has done it would be awesome... Thanks

 

[ManySHOs]

Can I bother one of you for a pm or a post on the process of making the jig to get the tranny mount in the right place? I think I have it in my head on how to go about it... but a push in the right direction from somone who has done it would be awesome... Thanks

Ohh, I second a post!

I have a spare gen2 SF that will be donating the trans mount- I can use this for measurements but any advice is appreciated. I should have my gen3 SF in a few weeks.

Ian

 

[JEM]

Ohh, I second a post!

You need to be a passable welder to do this.

Come up with something that locates tightly to the bushing pads on the subframe. I used a sandwich of a couple big square foundation anchor-bolt washers with a (3/4?) fender washer in between that was a reasonably close fit in the bushing hole. Make some steel tabs that'll bolt to the mounts on the subframe. Weld up a framework to connect the tabs to the locating pads. Take your time so that the whole thing doesn't warp all over the place. +/- 1/8in in this application isn't critical as long as you don't have a bunch of 1/8in errors that all stack up the wrong way.

Transfer the frame to the Gen3 subframe and you'll see where your mount locations need to be.

What this *doesn't* get you is how big the pocket in the left subframe rail needs to be for transaxle clearance. I tackwelded the trans mount on the subframe, dropped a transaxle on the mount, marked and measured, pulled it all back off and commenced massaging the rail. Some folks just cut a hole in the rail and leave it at that but that struck me as taking too much strength out of the rail, I cut an L-shaped section out of a piece of 3x5x.180-wall rectangular steel tubing and boxed it in.

The front mount was a head-scratcher but worked out very cleanly, mark the location of the stud on the crossmember and drill a 1/4in hole through both layers. Put a piece of 1/4in shaft 8in long in a holesaw arbor and run a 1 3/4in holesaw through the crossmember, piloting on the hole. Push a piece of 1 3/4in rollbar tubing up through the hole, weld it in place top/bottom of the crossmember, put a plate on top for the motor mount to bolt to. Nut goes right up the tube from the bottom.

 

[Ishodu]

I should have took a pic of the jig I had made, it was quite simple. I will try and explain. I first took an old front motor mount and bolted it in the gen 2 frame. I had made a 4 pieces of flat bar that were 4 or 5 inches long with 1/2 holes close to the one end to bolt on the tranny mount. I bolted them on there. Now I took a piece of angle iron that was long enough to cross the front of the sub frame. Clamped it on there straight across. Then flipped the sub frame over and transfered the holes that are in the frame for bolting the bushings to the frame. After drilling these 4 holes 5/16 I used 4 5/16 bolts to hold it down in that spot. Now I took a piece of flat bar that was long enough to connect the angle iron to the front motor mount and welded it on there. Next step I used another piece of angle iron that was very close in width of the tranny mount. And long enough to reach over the rear bushing mount location. I clamped it at the front. Once it was aligned up with the bars I had bolted on the tranny mount. Then I installed a leg of sort to hold this piece up from the other end. I just rested it on the rear bushing mount. Added a piece of flat bar so I could clamp it there as well. Then I tack welded the angle iron to the other angle Iron to complete the L shape across the frame. Then I tacked in a cross bar to make sure it stayed ridged and didn't move. I then slowly went around and welded it up solid the rest of the joints. Leaving the 4 tabs to locate the tranny mount last in case a small amount of warpage was present. Once it was all welded up you can unbolt it then remove the jig leaving the tranny mount there. Then its time to do some cutting and pasting. Its been a while so I hope I didn't forget.

 

[groove83]

OK, I know I am bringing up a old post, but I was just thinking about this...(cause I want to do a 3rd gen swap and convert my 94 ATX to a MTX..)

What about using the tranny mounts from a 92-94 v6 5 speed tempo? instead of having one mount for the transmission, you would have one on either side of the tranny, and since you have to weld it all together for the tranny mount anyway, you can just make holders for the mounts for the tempo.

 

[JEM]

What about using the tranny mounts from a 92-94 v6 5 speed tempo? instead of having one mount for the transmission, you would have one on either side of the tranny, and since you have to weld it all together for the tranny mount anyway, you can just make holders for the mounts for the tempo.

Given that I have no idea what the mounts for an MTX Tempo look like, I can't say. I'd guess the odds are pretty good that it'd work, and might even fit better than the SHO mount. Pictures?

 

[groove83]

I will get some better pictures of how teh mounts and thier setup tommorow, but on either side of the tranny in the picture you will see a black setup, those are where the mounts go/are. the front mounting plate/mount can come from a 4 cylinder tempo, because the MTX-3/4 have alot of similarities. (MTX-3 was used in the tempo/topaz, ******/lynx....4 cylinder cars)

however the rear mount has to be from a v6 tempo, because the V6 has a notch in it for a bolt thats on the tranny that the 4 cylinder didn't have. last time I bought a rear tranny mount, I paid 30 bucks brand new.

thought of this because every MTX SHO mount I have seen has separated, and with it like that, that side can have alot of movement. With 4 mounts total on the motor/tranny, at each corner, there will be alot less movement, and wouldn't have to worry about the bobble struts that the MTX use.

and if you have to add the MTX mount, why not in a way upgrade to two mounts instead of one.

 

[JEM]

however the rear mount has to be from a v6 tempo, because the V6 has a notch in it for a bolt thats on the tranny that the 4 cylinder didn't have. last time I bought a rear tranny mount, I paid 30 bucks brand new.

You may be onto something with a different transaxle mounting arrangement, but I'm not sure if the Tempo pieces are the right way to go, I don't think that rear mount is going to adapt very easily.

 

[groove83]

one more question...(am picking up another SHO and my current one can be a little project..) are the ATX motor mounts the same between the v6 and v8, as in location on the frame?

 

[JEM]

one more question...(am picking up another SHO and my current one can be a little project..) are the ATX motor mounts the same between the v6 and v8, as in location on the frame?

When you say 'ATX mounts the same between the V6 and the V8' - do you mean between the Gen 3 SHO and SLO, or between the Gen 2 SHO ATX and the Gen 3 V8?

I think both answers are 'no' but my knowledge isn't exhaustive.

Does that indicate you're trying to put a Gen 2 ATX powertrain on a Gen 3 subframe?

The Gen 3 SHO transmission mount is considerably different (and significantly more elaborate) than either the Gen 1/2 MTX or ATX setups, or the Gen 3 SLO setup.

The amount of surgery that other swappers have had to do on the rear motor mount tower when using a Gen 3 SHO subframe indicates to me that the rear mount on the Gen 3 SHO subframe is substantially different from the earlier cars as well as the Gen 3 SLO.

Mine ('91 MTX) uses a late '98 Sable subframe, the stock rear engine mount tower is close enough (right height, hole needs to be slotted slightly) but the other two were a fabrication exercise. The car's not running yet (next week, really, just plumbing up the coolers and hooking up the exhaust and a couple last electrical connectors in the left front corner) but the engine is right where it's supposed to be in the engine compartment and everything fits nicely.

With the Gen 3 subframe and the ATX coolant bottle up in the fender and the two-row radiator the AC plumbing comes out a bit ridiculous too, it's got all that open space right in front of the compressor for plumbing but (to clear the MTX coolant bottle that isn't there anymore) it hooks over behind the fan shroud (where there's barely room because of the two-row radiator) then down and under (where it's likewise tight 'cause the Gen 3 crossmember's fatter and a bit further forward) to the accumulator. I'm debating whether I want to do something about that as well, cut up a set of compressor manifolds and shorten the pipes to move all the couplers/hoses over directly in front of the compressor and have my friendly local TIG artist put 'em back together, but then I'd have to find an AC shop to crimp new hoses on the hard lines...

 

[groove83]

more like I want to take a 94 ATX, get a gen 3 subframe, pull the 3.2L and bolt on a MTX (leave the acc. drives)

I wanted to know if the motor mounts them self's on 3rd gens (mounts on the passside front and rear) were close to the same location at the 2nd gen mounts, since I know tranny mount will be different then everything else.

 

[JEM]

more like I want to take a 94 ATX, get a gen 3 subframe, pull the 3.2L and bolt on a MTX (leave the acc. drives)

Ah, now that sounds like an idea.

How far further forward do the Gen 2 ATX mounts locate the engine than do the Gen 1/2 MTX mounts? Somewhere between 1-2 inches? You'd have to move the stud holes rearward a compensating amount.