I bought a 258 from a friend who will be installing a 302 in his CJ5. It appeared to be a rebuilt long block so we checked compression and it was 160-165 on all cylinders, checked two times per cylinder with the carb opened full throttle.

I pulled it down to the short block last night and determined that it is bored .040 over, the valve train was very clean, almost like new and the cylinders had no detectable ridge.

I grabbed my telescope gauge and micrometer and found maximum taper and out of round to be .002, Haynes calls for .001 max.

I have a huge amount of work to do to the Jeep before I can get it on the road. With the compression readings and bore and taper measurements, should I hone and install rings and bearings?

Or, should I torque the main and rod caps and put it back together?

Most likely I will put less than 5K per year on the Jeep.

I do plan to install a cam, lifters and timing chain while it is on the stand.

Unless the cyl walls are stained or funny looking from sitting or have some other problem, I personally would just reassemble it, clean and lubed like a new motor. It sounds fairly recently rebuilt, and with your usage plans, it sounds great as-is.

I too get the temptation to make things perfect even when they're close-to-perfect, but I've learned to resist! Unless there's other factors, the net gain here sounds too small to be worth the effort and cost.


Or if you don't want that terrible old motor, give it to me, I'll dispose of it properly for you, no charge... :-)

Thanks for the reply.

I looked at the cylinders in the daylight and the crosshatch is easily visible in all the cylinders. The timing chain is new and so are the valve seals. I realize there is a lot of differences in the quality of work and this long block may be straight from the Azone but it will be fine for my needs.

I ordered a Fel-pro full gasket kit and plan on putting it back together as is. It will get two coats of SPI epoxy primer and three coats of TPC acrylic urethane to match the trans and xfer case.



I have not owned a straight six since my 60 Belaire in 1982 and I loved it. Can't wait to get another inline on the the road in a vehicle I have always loved but never owned.