CJ5 frame dimension nightmare...

[rixcj]

Hi, all..

I have a 1979 CJ5 that's a "daily driver" in the nice weather (I don't ever put a top or doors on it). I know that this forum is about engines, but my questions are two-fold...about the engine and frame.

Anyway, I'm also building another CJ5, from the ground up...bought and restored a frame, some axles, an engine, tranny, TC, etc., all from different sources. I go through each component, then install it. I have my DD to use as a reference.

Here's my problem...right now, the jeep is at the stage of a rolling chassis, with M.O.R.E. BombProof motor mounts bolted to the frame.

http://www.mountainoffroad.com/_e/Je...V_8_Mounts.htm

I have a completely rebuilt 401 that I attempted to install, yesterday. I suspended the engine over the mounts, and lowered it into place. I attempted to get the engine side of the mounts bolted to the block, finger tight. There was no way, no matter what combination of bolting this-to-that , that was going to work.

I measured my DD (AMC 360) from the lip of the oil pan, to the inside edge of the frame, on the driver's side. It was 7.125". The new motor mount, bolted up, measured the same thing. I thought, "Great!", and bolted it all up, finger tight.

Now, the passenger's side was off. I decided to fabricate a new engine-side portion of the bracket that would work. I'm a self employed metal fabricator.

So, I made a new bracket. It's currently hanging to cure, after painting it.

Well, I went back and forth, between my DD and the new frame, and started comparing some dimensions. I thought that I read somewhere that AMC V8's were offset to the left side by about an inch or so, but now I can't find that info. So, I measured the right side of my DD from the lip of the oil pan, to the inside of the frame, and it measured about 8.25"

Went back to the new frame, same measurement was about 7.5" (???) Then, I went back to the DD and measured the total ID of the frame width in front of the crank pulley. It was 26". New frame, in the same spot is 25.250". That's a .75" difference. No wonder the mounts wouldn't bolt up!

So now, I'm afraid that my new bracket isn't going to suffice. I have to move the engine to the left some more, then modify both brackets. The tough part is that I have to prop the engine at all the correct angles, at the right location, to know exactly how to modify the brackets. I wish that it was as easy as elongating some holes, but that won't work.

I have a few questions... does anyone know the correct centerline location of the engine, in the frame? I feel as though I may have to bolt up the tranny, and t/c to the skidplate (crossmember), to see how/where the t/c output yokes line up with the pinion yokes. I don't want them to be at a lateral angle.

Also, how about other engine angles, like side-to-side (level?, I'm thinking not...), and front-to-back.

Has anyone else ever heard of "same" CJ frames being different dimensions? There are several other different "non-similiar" dimensions that I didn't mention...

Well, thanks for reading all this. I don't typically like to get long winded, but I figured that I needed to explain all this to get some answers.

Rich

[tufcj]

Is there a metal rod between the motor mounts? There was from the factory on 76-up CJs. If it's gone, chances are the rails have flexed. I've seen variances of more than 1" in vehicles with the rod removed.

Bob
tufcj

[rixcj]

Is there a metal rod between the motor mounts? There was from the factory on 76-up CJs. If it's gone, chances are the rails have flexed. I've seen variances of more than 1" in vehicles with the rod removed.

Bob
tufcj

That's interesting. I bought this frame (frame only) used, and it did not have that crossrod that you mention. So, that's what those rods do?

Didn't those rods only come with 6 cyl. engines? Did the 304's come with them?

Anyway, if that's the case, and the frame DID flex inward, I could possibly porta-power it back out and bolt up the engine.

Thanks, Bob!

Rich

[tufcj]

My 77 CJ was a factory V-8, it had the rod. There's a lot of rail between the radiator and the skid pan, so the rod was put in to keep the rails from bowing.

Bob
tufcj

[86CJLA]

Rich,

Here are some pictures of the tie in rod, I had them saved from when keith posted them on JF.