Just recently changed the motor out of my 87', and finally found some time to do a write up.
The motor didn't necessarily need replaced, but I did it because I had the time and a newly rebuilt engine to put in it.
First I'll start on how I come across the new motor.
I was at the local machine shop a while back (getting front wheel bearings pressed in I believe), and I was wondering how much they would charge me to do the machine work on my Eagle's 258 (Boring, crank grinding, head work, etc.), and as we were walking through the shop, I saw what looked like a 258 setting there. Asked if it was for sale, man said that it belonged to a former employee that did all the machine work to it to put in his CJ-8 Scrambler Jeep, but died in a car crash. So he said he would sell it to me for the work they had in it, so how could I refuse. So I went home with new wheel bearing, and a 258 bored .030 over, crank ground .010 under, and a head with new valves and everything.
I built up the short block with:
Sealed Power Pistons
Clevite 77 Bearings
Hastings Piston Rings (Top Ring: Chrome)
Cloyes Double Roller Timing Set (Set to 4 Degrees Advance)
ISKY Camshaft (.450/.450) Lift (256/256)Duration
Crane Cams Anti Pump-Up Lifters
Melling Oil Pump
The rest of the components were original/stock.
Such as:
Distributor
Coil
Rods
Rockers
Pans
Carb
Water Pump
etc.
Here are some pictures I took along the way.
With valve cover, manifolds, and rockers off.
All the parts removed
Head off
Old Engine out, had to borrow my friend's hoist.
Let the transfer of parts begin.
Oil pan removed, to reveal some SLUDGE.
Even more SLUDGE under the timing cover.
Engine bay cleaned up waiting for the new motor.
New double roller timing set.
Everything ready to set back in.
After the short block was set in, the head was laid on.
Rockers and Manifolds
Valve Cover and Carb, and the rest was history.
The whole process took about 3 weeks, but that included a few days waiting for parts.
I thought I had all the parts I needed, until I went to put the head bolts in, and realized that AMC switched sizes, from '87 to 85' engine years. And the that 1/2" bolts from my Early 87' (Actually 86' date marked motor), would not fit into the 7/16" holes on the 85' head or block. After that was sorted out, everything went together smoothly, and the new motor fired up after the second crank.
I first set the timing to the factory recommended 9 degrees, then went on a test drive after a 20 minute warm-up/break in period. It ran with a lot of hesitation, like late spark timing. So I rolled it up to 13 degrees advance to match the 4 degrees advance I had in the Cam timing, and then the motor came to life. Had more get-up then it ever did before. I ran Non-detergent oil for the first 500 miles to help break things in, and everything seems to be doing just fine.
I am impressed with the performance the ISKY cam gave. I now have better throttle response, more power across the engine rpms, and most importantly better GAS MILEAGE. I'm not sure if there were several factors in gaining mileage, but I went from around 12-13 MPG to 17-18 MPG. And that's driving the same roads and driving habits I had before, so overall I can't complain at all.
I am considering doing the Ford TFI cap/rotor and coil upgrade next time I need a cap and rotor, to see I can get any more out of the 258 (now 262). But that's for another day. Now to just enjoy what is pretty much a new Eagle (Drivetrain and Suspension wise).
Feel free to ask questions
Enjoy
-TC