Engine Rebuild Part I (The Break Down)

Time to start working on the engine!

258 cu in (4.2 L) Jeep AMC 6-Cylinder 99.4 PS (73 kW; 98 hp), 261 N·m (193 lb·ft)

Obviously, the first step is to break everything down.  The engine ran before I parked it, but did leak oil really bad.  Everything I looked up states that these old CJ7 258 engines are one of the most dependable engines.  Since this engine is the original, I decided to rebuild it rather than replace it with a crate engine.  This is my first attempt in rebuilding a engine, so bear with me on this.  I do not have a set plan with this engine.  My only plan is to figure out what needs to be replaced or upgraded as I go.  

I needed to take a bunch of pictures of the engine before I started breaking it down.  It could help when I put it back together.  

I started to take pictures of all the electrical wires that I was removing and then decided that a lot of the wires and connections all needed to be replaced, so I just removed the wire harness without taking anymore pictures.  I hope I don't regret that decision.

Here is the wire harness after it was all removed

After all the wires were removed.

Next was removing the carburetor.

After the carb was removed.

Next I removed all the rubber hoses.

After most of the hoses were removed.  You can see in the background the pile of hoses.

I then removed the valve cover.  This was done by just removing the bolts surrounding it.

Oil used to leak like crazy around this cover.  Looks like the gasket needed replacing.

I then removed the alternator.

Alternator removed along with the bracket that held it on.

Next was removing the fan.  All the bolts holding this on came off fine except for one.   

I had to be careful, but I was able to cut the bolt off. 

The fan pulls right off.

Next I removed the Power Steering Pump and bracket.  All this was just held on by a few bolts. 

I then removed the fan pulley. 

My neighbor was kind enough again to let me borrow his cheery picker.  With this I was able to get the engine up on the engine stand that I bought off Craigslist.  

It is a dark picture, but I first drained the oil that I had in the engine while it was stored.

I then lifted it off the homemade engine stand I had made.

I got it all bolted up to the stand with some grade 8 bolts (I know this is a little overkill, but I was just being safe)

Notice the old golf club I used on this side of the engine to stop it from falling over when it was on my homemade engine stand. 

I used this 4x4 and small piece of plywood for this side.

Now that it was on the stand, I continued to break everything down.  Removed the valve cover again to get started on the head.

I removed all the bridge pivot arms off the rockers.  I made sure I marked the location on all of these.

Rocker arms removed.

Here is how I kept track of the location of all the parts on the head.

Next I removed all the push rods and also marked the location.

I then moved onto the distributer cap.

The cap was just held on by a few screws

Distributer after the cap was removed

It is only held on by a couple bolts.

Removed distributer.  This will probably be replaced with a new one.

Engine with the distributer removed.

I then removed the ignition coil which sits just the the left of the oil filter.

Removed coil

This too, will probably be replaced.

This is the bracket that held the ignition coil onto the engine.

Removed this part, which I have no clue what it is called.  (If you know what this is called then please post it for me.)  It sits to the left of the ignition coil.

I then removed the fuel pump which is only held on by a couple boils.

The dip stick then came off.

I then removed the thermostat housing.

Next, I removed the manifold which was held on by a bunch of bolts that were hard to get to.

This is just a shot of two of the bolts that sat under the manifold.

Manifold removed.  I might be replacing this with a four barrel carb manifold.  Not sure on that one yet.

I then removed the exhaust.  I believe I will replace this with headers.

Manifold, exhaust gasket.

Here are all the parts so far.  I have them laid out in the same location as they were installed.

Now it was time to remove the head.  All the head bolts were first removed and marked for location.

When all the head bolts were removed, they had tons of old oil on them except this one singe bolt.  When removed, it was covered in surface rust.
(If you know what this means, then please let me know by making a comment below.)

After all the head bolts were removed and a few taps with the rubber mallet, the head came off the block.

Water pump was next.  This came right off with no problems.

Next I removed the camshaft pulley/ damper/ harmonic balancer.

First I removed the three bolts holding the pulley on.  The pulley came right off after the bolts were removed.

Next I removed the harmonic balancer.  Autozone did not have the correct puller at the time I went there, so I tried removing it with this jaw puller.  It did not work at all.  The teeth on the puller kept slipping.

I went back to Autozone a couple days later and got an actual harmonic balance puller.  It worked perfect.

Pulled it right off with no problems.  I guess it helps to have the right tool.

Next I removed the timing chain cover which was just bolted on.

Cover removed.

I'm pointing at the worn out oil pan gasket.




There was A LOT of play on the timing chain.  You can see how much I was able to move it in these next two pictures.

Pulled this washer off the crankshaft sprocket



Trying to point out the two markings on the sprockets 

Removed the bolt holding the camshaft sprocket.

Removed the camshaft sprocket and timing chain

Pulled off the crankshaft sprocket.

The wife came out and took a picture of me working on the engine

Rolled the block over so that I could remove the oil pan.

Oops.  Rolled the block over and a couple of the lifters fell out.  I rolled the block back over and removed all the lifters.


Also forgot to remove the engine mount brackets.

I then pulled the camshaft out.

Next, I rolled the block over (again), removed all the bolts holding down the oil pan, and then removed the oil pan.  The oil pan was on the block pretty good.  I had to gently use and putty knife to break the seal.

I then removed the oil pump.

(There is the wife keeping me company.....with no interest in the engine!

These are the two bolts holding down the oil pump.

I got everything broken down minus the crank and pistons and loaded it up in my truck to take to the machine shop.  As you can see by my set up, I did not have access to the engine hoist at this time.  I made it work though!

I took the block and head over to Strickland Machine Shop in Wendell to see if they can check everything out for me and do all the machine work.  From what I was able to fine out from asking around, this is a very good machine shop.  Its a family owned shop which is always nice!  Glen Jr. (the owner) was very nice and took his time explaining what needs to be done to the engine and why.  I'm excited to see the work he will do to this engine.



Strickland Machine shop suggested that I go ahead and take the crankshaft and pistons out myself to save me some money.  That very cool of them to advise me of doing that instead of just staying quite and charging me for it.  He even gave me some good advice on proper ways to do the work.  So, I brought the block back home and finished disassembling the engine.

First I removed the caps holding the piston rods in.

Its hard to see in this picture, but both the cap and the rod are marked 1 through 6.  #1 is at the front of the engine (the fan side).  The numbers and everything else marked is read on the oil filter side of the engine.  Hopefully I remember this when I put it all back together.

Here are the markings on the caps holding the crank shaft down.

Removed the first piston and placed the caps back onto the piston.

Here is a shot of the engine after I removed all the pistons and bearings.  Yes, there was a little bit of wear in the bearings and crankshaft.

Just incase the machine shop is able to reuse the pistons, I marked all of them in there own bag.

Next, I removed the caps holding the crankshaft down.

You can see in the top right of the picture where I was placing the caps in the same order and position as they were before I took them off.

Crankshaft removed.

Here are a couple shots with the crank out and all the caps put back on (minus the 3rd one).  I left all the bearings on it incase the machine shop needed to see the wear.

I took the block back to Strickland's Machine Shop to get this baby like new!  I guess that will be the next post.