81 CJ7 258 is dead - Advice on replacement
- I am going to ramble... will try to keep it to a minimum -
- I have 5 Jeeps
81 CJ7 - bone stock with 258
81 CJ7 - bad block... lots of mods - this thread is about this jeep
86 CJ7 - Nice trail jeep, Mopar EFI, several other moderate mods.
94 YJ --> rollover - bought for the 4.0 - MPFI
08 JK --> not relevant to this thread... but didn't want it to feel left out.
I have a CNC Mll ... and CNC plasma ... relevance is I can make some parts if needed.
... I have several "orphaned" Engines (mostly chevy small blocks)... (I do have a 396 big block... but can't see it being a good choice for my jeep)
- I originally purchased the 94 YJ to put the 4.0 and FI in my stock 81 cj7... but the 258 and carb in it just won't mis-behave ... I mostly just use it around the farm.
- I just (last week) purchased another 81 CJ7 (setup for rocks)...
--- 37" tires
--- Dana 44 front and rear (Detroit in Rear, EZ Locker in front)
----- I do not yet know the gears in the Diffs...
--- Has the Dana 300, twin stick, (was told it has 4:1 conversion)
--- T-176 transmission
--- The 258 in it was fairly fresh... but it broke a piston skirt, and damaged the block cylinder beyond reasonable repair... Previous owner removed the 258 and dis-assembled... about 6 months ago.
--- the bad 258 had been fitted with a TBI ... I have that on-hand
I have several options for the replacement engine .... I am leaning toward using the 4.0 from the YJ (it had 122,000 miles ... and ran good... I think it had some intermittent PCM issues though).
- 4.0 from the YJ Rollover
- 1994 RAM 1500 truck I have, with either 318 or 360? (FI) 94,000 runs good.
- Chevy small blocks.... 305, several 350's, one 400 SB, and.. one of the 350's is from a 98 truck... MPFI .. but the engine would need a rebuild.
Over the last couple of days, I have removed the Fenders, Hood, Tub from the YJ .... the PCM and Wiring harness removed as well.... I am now ready to dismantle and remove the 4.0 .... Plan to clean it up, run compression tests on each cylinder... and probably crack open the Oil pan and take a look at the bearings??? (I am old school chevy engine experienced... this will be my first time in a jeep engine)..... From those tests will decide if internal work is needed..... clean it up, paint it nice.... then put it in the (new to me) 81
- I have read a couple of threads about the viability of swapping in the 4.0 .... I don't see anything there that scares me much.... I am interested in feedback from those that have been there ....
Attaching 3 pictures -
1.) the YJ a couple of days ago before I started on it
2.) the YJ tonight
3.) the new to me 81 on the trailer...