Jeep Enthusiast Forums banner

Life of a 258

1K views 12 replies 11 participants last post by  1986cj 
#1 ·
I am curious how long a properly maintained engine has lasted folks? I hear people brag about low mileage on an original engine all the time; heck my '77 CJ5 has 41K original and runs like a champ. But what have some of you been able to squeeze out of a 258 when properly maintained?
 
#2 ·
I am convinced that after the end of WWIII the cockroaches will be driving around in I-6 Jeeps! If AMC could've figured out better gas mileage and emissions for them they'd still be around. The EPA was the only thing that could kill them!
 
#3 ·
I had my first CJ for about 6 years and had 215,000 original miles on it when I sold it. Still ran perfect never had any issues with it. That was in 2002 from what I understand the guy still has it and has not replaced the engine. Not sure of the miles now.
 
#9 ·
The 4.0 is known to last 200k to 300k miles.
The 258 was never known to be a Lemon, just an oil leaker.
I would expect 200k+ from the latter year models,
and the early ones 100k to 150k reasonably.

Why the difference?
Research and Development a lot changed in metallurgy and
engineering from 1972 to 1987 (last year the 258 was used if I remember right)
engineers learned more about why some parts fail and improved them
they learned better bore shapes, such as being wider at the top than bottom,
Better rings and aluminum alloys for the pistons, and the list goes on.
I just want to know why on the 259 and 4.0 they could not make a timing chain
that that didn't have 15 to 20 degrees of slop new.
 
#12 ·
The 4.0 is known to last 200k to 300k miles.
The 258 was never known to be a Lemon, just an oil leaker.
I would expect 200k+ from the latter year models,
and the early ones 100k to 150k reasonably.

Why the difference?
Research and Development a lot changed in metallurgy and
engineering from 1972 to 1987 (last year the 258 was used if I remember right)
engineers learned more about why some parts fail and improved them
they learned better bore shapes, such as being wider at the top than bottom,
Better rings and aluminum alloys for the pistons, and the list goes on.
I just want to know why on the 259 and 4.0 they could not make a timing chain
that that didn't have 15 to 20 degrees of slop new.
I have soaked the new timing chain in hot oil for hours, let it cool down, then install them. After about 1,000 miles (nothing really) re-degreed the cam and found at least 15 degrees of stretch or retarded cam timing. I used a Morse chain with little bushings. The cheaper timing chains have much worse stretch to them. (Dynagear)
My two cents.
UPTILLNOW :cheers2:
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top