YJ Motor Mounts (4 cyl to 6 cyl)

Granny

Granny

One day at a time...
Joined
Jun 12, 2007
Location
Cabarrus County (Rimertown)
This question will probably be the first of many... and I have searched the forum. I have a '95 YJ with the 4-cylinder engine. I m going to to replace it with a '75 (258) 6-cylinder engine. Can anyone offer some specs and/or info as to the best way to tackle the motor mount project? :confused:
 
check Trans-Dapt. When I had that YJ and swapped the 4 cylinder for the 4.3 Chevy Vortec, Trans-Dapt had exactly what I needed.
 
I've done this swap. I'd never do it again. It's easier and cheaper to sell the 4cyl jeep and buy one with a 6 cyl.
 
We spoke about this up at The Flats the other weekend. I have personally done this swap. Here's what ya do:
Cut old 4 cyl frame mounts off and save them, bolt 4.0 YJ motor mount brackets onto your 258, use 2.5/4.0/258 YJ or TJ motor mounts (they are the same), move the frame mounts where they need to be, weld them in and call it a day. Easy stuff.

I'm sure you can find all of the needed brackets on here, cheap.

Or...(I have done this too). Bolt 4.0 MM brackets to the 258 block. Locate the engine in the engine bay where you want it. Use leaf spring bushings and some .250" DOM for sleeves and just make your own frame mounts.

I say keep it simple and go with my first example.
 
Don, I like easy and strong.
Cut all the brackets off, make you a mount out of schedule 40 pipe, spring bushings and tabs and a piece of metal plate
David Minton and I made some for his LS swap and they have worked just fine. Cheap, easy, and strong
 
x2 on the bushings. I used 1/2ton chevy leaf eye bushings (polly) and some 2"x.25" wall DOM for the inserts.

Don i have some of the perfect size inserts for the jeep motor mount width. I'll send em to ya if you will use em. Just weld on a tube or plates to secure it to your frame rails.
 
ThanX Guys! I'm still pondering over all this, and will definitely keep all of it in mind for when I get down to actually doing it. Jody, both of your examples look good. The "easy & strong" idea looks good too. I have no doubt that I can make a motor mount as good as any on the market. Right now I am just worrying myself over getting them located properly. :confused:
 
I got the advance adapters weld in brackets. Then I made the DOM mounts. I would not mess around with any other type of mount. I got the DOM and bushings from Barnes.
 
I used DOM, poly bushings & 1/4" plate, solid, and easy... For placement, is the tub in place? Or... Use trans,mount skidplate & use the skid plate to locate the engine in correct forward place. I centered mine between the tails, measuring off the harmonic balancer...
 
Steve, when I search those different sites (Advance, Brown Dog, Trans-Dapt, etc.) I can't find anything that specifically describes what I am looking for. Mounts for Chevy V8s, 4.0s, etc. are easy to find, but the old 258 is really not clearly mentioned.

The tub is still on the vehicle. For clarification, I am replacing the complete stock YJ drivetrain with my old '75 CJ 258, T-18, Dana 20. Both axles will be Scout 44s which have worked well for me for years. Like everything else, once I get down to doing it I will probably find it really isn't a big deal, but keep the suggestions coming anyway. They are all interesting... and I'm not too old to learn something. :)
 
I don't know your fab skills...so

For simplicity sake, if your fab skills aren't great, my first option is best and it's off the shelf OEM parts.

If a grinder and welder is like additional limbs on your body, then make set out of leaf spring bushings and DOM tube for a sleeve. Place the sleeve between the OEM YJ/TJ MM brackets on the block, center the engine, cut some 1.5" or 2" DOM to length, notch, weld to the sleeve and the other end to the frame. Gusset as needed, call it a day. To do it this way, you'll need YJ/TJ or even XJ 4.0 MM brackets since they have "ears" that easily accept bushing/ sleeve type of mounts.

Make sense?
 
Jody, my fab skills will probably work OK. Right now I'm gathering all the info, ideas, and suggestions that anyone will offer. Thanks again for your support, both here and at The Flats where you allowed me to bend your ear. :beer:
 
Don.
You have granny as a template. IF you want the same location for your shifter as you have now, and you have enough room for an upgrade cooling like a Taurus fan or the like, then you can bet your measurments off of her, using the fire wall as the reference point.
pull the front clip off of both Jeeps. Pull the entire drivetrain, engine, tranny and t case out in one piece.
using the engine crane, slide it all up under the YJ. When you have it about where you think you want it, shove some blocks up between the t case and floor pan, and a jack with a wood block under the oil pan. Tweek the position until you have the desired engine location. make sure the frame is level, and the tail shaft is centered in the rear. raise or lower the tail shaft for the correct engine angle. once it's all where you want it, then you can start making the mount.
Here's the ones we made on Davids

Photo024.jpg

Photo025.jpg
 
I wish it was that simple... there's a big difference... and the mounts are welded, not bolted, to the frame.
 
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