Engine swap!

The tranny won't take a 258 without an adapter I believe. The bell housing is different for the 4 banger and the center shaft size is different although the pilot bushing in the CJ crank can be swapped with a YJ pilot bearing.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos:

Check if you will have problems with emissions laws. Swapping an older engine into a newer car (Jeep in this case) may or may not be legal in your area.

Thanks for the warning, fortunately I only drive the Jeep in northern Wisconsin and the UP and am not required to get my emissions checked. As it is running with the 4 I probably wouldn't even pass an emissions test, and my plan with the I6 would be to rebuild it with a custom EFI system with a Turbo. The reason I am interested in the older engine is cause I am on a budget and its cheap!

Thanks Mike,

Do you know if an '88 258 would match up or am I looking at the same issues with that as well?

Keegan

It's the 4 banger bell housing that is the issue. You might want to try places like advance adapter to see what the adapter plate runs. The pilot bushing to bearing swap is simple.

Mike

Sure is nice to be in such an area! In general few adapters are made for the AX5 that comes with the 2.5 4 cyl engine. The adapter companies stay away because they consider the AX5 to be weak and not worth keeping for most engine swaps. But who knows, there might be something available.

The AX-5 transmission is rumored to be weak for six cylinder use. In fact, the earlier carbureted engine Wranglers used the 258 that Jeepster is thinking of using in front of the AX-5 and similar transmissions. Newer ones use the heavier duty AX-15. This conversion could be done using OEM parts. If you can identify and find the right bell housing then you are well on your way. That said, no conversion is as easy, and an "easy swap" just does not exist, not when you get done with exhaust, clutch linkage, motor mounts and all the rest. The 2.5 engines are all fuel injected and the 258s are carbureted. That means a different fuel tank and all the plumbing that goes with. If you can get a wrecked or rusted through Wrangler or Cherokee of the same year, you might do this conversion with a minumum of fuss.

I have driven a four cylinder Wrangler for fourteen years and am well satisfied with it. "custom EFI system with a Turbo" and "I am on a budget and its cheap!" just don't go together. What do you think that custom EFI and turbo are going to do to a thirty year old essentially junk yard engine? I have a pretty good idea myself. In this guy's place I would keep driving the vehicle as is, and maybe give the four cylinder engine a ring job, bearings, valves, whatever it needs.

Earle

Hell, I just pulled the 2.5 outa my Wrangler...driving to work one day and for some reason it just ate a piston. Swapped in a junkyard motor with only 96k on it for just under $900. This included all new gaskets and seals as well as a new w/pump and t/stat, but doesn't count the tank of gas to go get the motor.

-- Old Crow '82 FLTC(P) '95 Wrangler YJ BS#132, TOMKAT, SENS, SLOB#13

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In this case they might, I already have an EFI setup I just need to adapt it to whatever manifold the engine I get has and program it, as for the turbo, a guy I work with has an old turbo off of an old diesel rig that I would use. I am well aware that just throwing this stuff on an old engine would be potentially disastrous, I would rebuild the

258 stronger and the 8:1 compression ratio of this particular year 258 is desirable for implementation of a turbo. This engine would be a project engine, something for fun! I plan on running the jeep with the 4 until it gives up then swap it out, maybe with something even better.

Keegan

Projects are fun! Keep us posted. You should be able to find the right bellhousing. Lots of folks swap out trannys and that age of Jeep is also junkyard fodder as a parts source.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos:

Two things here, one is that not all 2.5's are FI, 1991 was the first year that the 4cyl's (or YJ's in general) were fuel injected. The other thing being that in an '88 there is a very good chance that he has the BA-5 (french) tranny, which makes it even less favorable for a swap.

Earle is correct. All 2.5L YJs were fuel injected. 87 - 90 had Renix throttle body injection. 91 and later had Chrysler's system on them.

Huh, I would have sworn I saw carb'd uns.... thanks for the correction.

Matt

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