Thanks John. I'm always in favor of retaining engineered components/systems. I was just checking to see if there was something I missed in regards to efficiency, or well documented failures, etc.

I think I have a plan, and a clear path at this point. Only thing left to do is get the motor apart, and see what I'm working with.

Thanks to all for the helpful replies.

The balance shafts ARE a documented failure point, or at least the bearings are (probably because they're a PITA to replace and get skipped during a rebuild). Plan on installing new balance shaft bearings with your overhaul, as well as a new oil pump. You might also want to search for the thread on oil pump relief valve shimming as described by FastEddy - good knowledge there.

The bearings indeed can be a failpoint. A guy on starquestclub has over 300k miles on his motor with original balance shaft bearings. His motor is meticulously maintained.

My motor has maybe 100k, and the bearing looked like crap. Case by case, check and assess what you have. Then make a call, but based on the motor your describing, I doubt the bearings will be ok as is.

I haven't ever heard of needing to replace oil pumps. From what I read, most of the time, it's still perfectly in spec.

I too should read Eddys article.

Got the motor out and mostly disassembled. This is what I've found so far;

between cyl. 1 and 2



between cyl. 2 and 3



Might be difficult to see, but there are cracks bridging the three small passages to the head bolt seat. Although these don't appear to be bridging the cylinders themselves, they look ominous. What are your thoughts?

The cylinder walls in #1 (cylinder with poor compression) look to be in good shape to me. No major scoring or gouges etc. Although the piston can "wiggle" a bit. Not sure of the tolerances here yet.

Another update:

two of cylinder 1's piston rings were destroyed. No major scoring on cylinder walls. Oil ring was ok. Block, crank, and head are at the machine shop to get cleaned, tested, and machined as needed.

Machinist doesn't think that the cracks will be a major setback. After testing the block, he will make recommendations.

One of the timing chain guides was bent. Because of this it was worn through to the metal backing.

Balance shaft is already deleted, presumably by the previous owner's mechanic.

Head looks to be in good shape, and all jet valves are intact. We'll see what the test results reveal.

Well then... Looks like your one of the better off ones, you had the balance shaft out and never even noticed excessive vibration. I didn't either.

Lets see what the machinist says.

Well, there definitely was vibration. But I'm unsure as to what the greatest cause of vibration was; no balance shafts, or one cylinder not working... <img src="/forums/images/graemlins/lol.gif" alt="" />

Thought i'd update...

Machinist said everything was a GO, the cracks around the head bolt seats weren't critical, and that the block is sound otherwise. So I had him bore it out (.040), deck it, and install new brass expansion plugs.

The head also checked out, so I had him install new valve seals, valve job, surface it, etc.

Crank just got a polish.

Got all the new parts in; Pistons, timing components, gaskets, bearings, rings, etc.

Everything went together as planned. I continuously second guessed myself, because everything was just so simple (in comparison to other projects i've done in the past). I primed the oiling system by removing the spark plugs, and cranking it over for a few minutes. Then fired it up... or attempted to. It hadn't occurred to me that the distributor is not "keyed" like most newer cars. It's been a while since I've worked on something this old After a few backfires, I figured it out. Sorted it, and it fired right up.

After running it a while I took it for a gentle test run. All was well, aside for a little necessary carb tuning. Then a coolant leak developed from somewhere. It was very difficult to track down, as it was dripping from the bell-housing. Long story short: I have an exterior crack in the block on the passenger side, connecting the front-most and middle expansion plugs.... Gotta love it.

Still waiting on a call back from the machinist...

In a desperate attempt, I took the recommendation of my wife to find a "special glue" to patch it up. I went down to the local NAPA and got a bottle of Blue Devil block sealer...

Now let me preface this by saying that buying and trying something like this, is the absolute last thing I would ever resort to. I'm always a proponent of fixing something the correct way, or not at all. But in THIS case, I thought I had done just that, only to find that due diligence was not thoroughly performed.

So I follow the directions, get it in my cooling system, and it starts seeping from the crack. After about fifteen minutes or so, the crack turns greenish white (from blue), then white. And the leaking ceases! I shut everything down and check the coolant to make sure that this hardening is not systemic. Everything flowing good.

It's been two days now. Coolant level static. Temps good and cool (even on highway). unbelievable... But I don't yet trust it to hold for good.

In the meantime I'm researching possible repairs, and I've come to stitching (due to the block being cast iron). Anyone have experience doing this? Looks pretty straight forward, but more research is needed.

Dude, have a similar situation in the 88. Before disassembly, I decided to try a product called Steel Seal. Alchemy I say. The 88 is living in TX, and I ran the crap out of it. Still runs cool, no leaks nothing. Better living through modern chemistry.

Wow... That's horrible man. A machine shop should have caught that - unless they caused it during the machining process at some point.

Those stop leak type products can work, surprisingly, but I'm with you in doing it correctly. You might be able to find a good core block and make the machine shop re-do the work on the core block for free, and just swap everything over. There are also specialty welding shops that would weld the crack for you. There is also a process called pinning (probably the same thing you called stitching) that works. All just depends on what YOU want to stick into it effort and $$$ wise.