F134 Re-build

[81 CJ5]

I got all the bolt holes for the exhaust cleaned up. No helicoil(s) needed




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[81 CJ5]

Removed the pistons from the rods. Torqued the rodcaps (45 ft lbs) and hopefully I’ll get the time to throw them on the precision gauge tomorrow. Also media blasted some fasteners and opened up the oil pump.




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[81 CJ5]

Drove out the rod bolts after measuring the big end of the rod so I could start resizing them.


Media blasted


The caps after some grinding.

[81 CJ5]

Ground the rods and honed them.




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[81 CJ5]

If you're wondering why and how resize Connecting rods,,,,,

The connecting rod supports 4-5 tons of pressure during combustion so load stress forces of the engine combined with heating and cooling of the engine deform the big end bore of the connecting rod. The majority of rod stretch is mostly vertical and occurs in the rod cap. Using a precision gauge you can accurately measure out of roundness to .0001.

Usually, you'd check rod alignment first and for cracks but I didn't notice abnormal wear with the piston skirts so I let mine ride.
Here's how I honed my connecting rods and pretty much any other engine.

1. Remove pistons and torque rod bolts
2. Measure the connecting rods on the precision gauge
3. Take Connecting rod cap off, place the connecting rod in a rod vise, and drive out rod bolts using a brass hammer (if using rod vise)
4. Gently run a file over the connecting rod and rod cap parting faces to show high spots
5. Apply blue dye to the connecting rod and cap parting faces and place them on a rod and cap grinder
6. Start grinding material off the cap and rod until all the dye is gone
7. Remove any burrs or sharp edges with a file to remove any possible stress risers
8. Reassemble the Connecting rod and torque to spec then measure with the precision gauge
9. Start honing the rod to bring it within spec. (I usually do 3 strokes flip the rod and do 3 strokes again and measure then rinse and repeat until I'm within spec and correct Ra.)

If I missed anything, made a mistake, or you have anything to add please do so. Thanks for viewing folks.

[Reserector [Veteran Member]]

That is a very important, but often overlooked part of a good rebuild.

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[81 CJ5]

That is a very important, but often overlooked part of a good rebuild.

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Aye. Cost me nothing and it's peace of mind.

[81 CJ5]

I forgot to update the thread.

Did some valve seat work and CC'd the cylinder head. I came up with 75cc

I did some guesstimating and came up with a 6.94 CR in stock form. Pretty close to advertised specs.
I'll be playing with the numbers more to see what I can come up with.

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Picked up the crank today. 30 on the mains and 40 on the rods. Started making some spacers to mount the head to the mill. I’ll take .010 off the head and re cc the combustion chamber to see how much of a difference it made.

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Alright I took .020 off the cylinder head and got one combustion chamber cc'd so far. (#1) Drum roll please,,,,,, 73 cc; so my baseline is pretty much 1cc per .010. The head is completely usable right now but I'm slapping it back on the mill and running it down more. I layed the straight edge across the head and end to end it was .012 low.


Here it is at .020. All cleaned up.