Given everything I encountered with taking the pistons and cylinders off, it was clear that I need to address the engine fully, and nut just clean it up and hope that new pistons, new cylinders, and new or rebuilt heads would give it the longevity it needs.
So I cracked the case.
Compared to the breakdowns of the 74 AH engine, the 72 AE engine, and the first AR engine I bought, in some ways it is worse than all 3 of those. And the AH engine was pretty dirty!

It was immediately apparent how bad it is, with the oil return gallery at the front pulley clogged. This could actually be why so much oil is out the front if it is getting past the oil slinger since it has no place to return to.

Pretty much anywhere oil is it is grimey with sediments. You’d have thought I never changed the oil or never did so on a regular basis.
The AH engine may have been cleaner. I’ll have to go back through the photo galleries and posts to compare.

The mating surface looks rusty, but I assume this is breakdown of a case sealant.
It looks like this everywhere, bust combined with oil and sediment.

I do suspect that a lot of the oil “seepage” I would constantly see at the bottom was due to the case sealant being in such poor condition.


Even the cam plug groove just had so much debris around it that it was probably seeping.

The oil pump housing mating surfaces are and odd color, and the surface above where the pump resides looks like it may have gotten some kind of rust at the case bolt.

Every exposed oil return gallery is clogged, which makes me really worry about the internal ones.
I had no plans to drill and tap the oil galleries but I’m thinking perhaps I should do that after the initial cleaning tomorrow.
That way, I can be sure that the solvent bath gets into all of those internet bits and pieces and I can get all of my case brushes deep into the receceses.

There’s wear on the distributor gear. Not a lot but it is more noticeable that I’ve seen on other older engines. Perhaps it will polish up and be reusable.

I don’t know how such debris got into the case around the upper rear case bolt’s o-ring. I have no seen this before.


I only took a brief look at the crankshaft. I’ll know more tomorrow after a complete breakdown of the rods, rod bearing inspection, etc. I’m dreading that dam circlip removal. I so hate them!

The 3rd lobe from the gear has a large nick in it.
I also noticed that the lobe metal is relatively discolored. Every other cam I’ve seen has been bright silver so this probably should be replaced. This is good in a away, since I was thinking of that mild cheater cam by CB Performance.