4.0 to 4.5 question

Swaping 258 to 4.0, 4.0 parts to 258 etc!
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Joined: May 22nd, 2019, 6:20 pm
Vehicle Year: 1995
Vehicle Make: Jeep
Vehicle Model: Wrangler

4.0 to 4.5 question

Post by Blrmkr1 »

Have a 95 yj with 4.0. Has a bad rod bearing.
Also have a 258 short block, in excellent shape. Was pulled for v8 swap at 83k.
If I do a crank swap to 4.5, will I run into lean mixture issues.
4.0 has 140k and almost no ridge on cylinders. Removed pistons without reaming. No oil loss between changes or smoke.
Maybe naive, but was just planning a hone and valve lap on the 4.0. Machine work on either crank (10/10) should be same, except for slight shortening on 258 crank?
I've researched so much the last few days, but most threads are about 3 to 4 thousand rebuilds.
Can(or maybe should) the 258 crank be installed in a refresh style build?
Stock refresh can be done locally under a grand. And can I expect a moderate degree of reliability.
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Vehicle Year: 1990
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Re: 4.0 to 4.5 question

Post by Sailboy42 »

The ECM should be able to compensate, assuming all your sensors are operating properly.
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