Calling out to the 258 gurus
jamesweed
Jeeper
- Posts
- 112
- Thanks
- 0
- Location
- Orlando, FL.
- Vehicle(s)
- '85 cj-7, 258, T-5, dana 300, stock diffs; 1967 Chevy Nova 2d HT
Ive just finished a 4.0 head mod with Mopar MPI kit on a mid 80s AMC 258 i6 / 4.2l block. The block has been totally rebuilt, as was the head, all new parts. The jeep runs great, good throttle response cruise up hills no problem(had carter bbd previously), idles smooth. its got about 200 miles on it since rebuild.
However,
I've got an annoying ticking noise seems like coming from cylinder 6, been there since the begining but seems to be getting louder. Leaning over the engine at idle you cant here it, but at around 1500 rpms you barely pick it up. Its very apparent from the INSIDE of the jeep when driving with a load on the engine, and more so during deceleration with engine in gear(engine braking).
I set lifter preloads at about ..055, at the upper tolerance, because I hate valve lifter noise, thought I would avoid that by going on the high side.
I used a stethoscope and probed around and Ive got the loudest noise on the exhaust manifold tube at head, but I can still here faintly on passenger side of engine down by the cam and lifters.
Im thinking exhaust leak, it's a used cherokee header, But Id like your input. Im pretty worried about it.
The back of the head is hard up against the firewall, even more so than the AMC 258 i6 / 4.2l head that was on there, so I hear EVERYTHING from inside.
PLEASE GIVE SOME INPUT!!!!!
thanks, James
However,
I've got an annoying ticking noise seems like coming from cylinder 6, been there since the begining but seems to be getting louder. Leaning over the engine at idle you cant here it, but at around 1500 rpms you barely pick it up. Its very apparent from the INSIDE of the jeep when driving with a load on the engine, and more so during deceleration with engine in gear(engine braking).
I set lifter preloads at about ..055, at the upper tolerance, because I hate valve lifter noise, thought I would avoid that by going on the high side.
I used a stethoscope and probed around and Ive got the loudest noise on the exhaust manifold tube at head, but I can still here faintly on passenger side of engine down by the cam and lifters.
Im thinking exhaust leak, it's a used cherokee header, But Id like your input. Im pretty worried about it.
The back of the head is hard up against the firewall, even more so than the AMC 258 i6 / 4.2l head that was on there, so I hear EVERYTHING from inside.
PLEASE GIVE SOME INPUT!!!!!
thanks, James