[AMC-list] 195.6 leaky head gasket

[tom jennings <tomj@xxxxxxx>]

Popped the head off today, and what a mess! Evidence of oil and water leaks.
The head gasket didn't seal for crap. I suspect the head isn't cracked, just
the leaky gasket, but I won't know for sure til I get it magnafluxed.

When I last assembled it, summer? 2007, the head was resurfaced, and the
block I got clean with razorblades and lacquer thinner. Copper Permatex
(brush on I recall now) decent thin coat. It's evident I didn't use too
much.

It's one of those old fashioned composite gaskets with the steel lip around
the combustion chambers etc. You can tell where it did seal -- the steel is
shiny, with bits of Permatex visible. But in the portion between the
cylinder pairs (the pairs w/o a crank journal between) the steel is
blackened. There was foamy oil near #2 and #5, and those two, the typical
light carbon/coke on the piston top was soft, steamed soft. (It wasn't oil;
plugs and valves are white). I had those clean (photos) in 2007.

The most likely thing I can think of is my torque wrench is WAY off (I'll
get it checked or a new one depending on the cost to check) and/or the lube
I used threw torque way off. Do gaskets go bad sitting on the shelf? Hard to
imagine. You can do bad things with too much Permatex, but that's not it
here. Block deck could be not-flat, but I checked it with my Starrett 18"
straight edge (as best I could in the car).



I got the 2nd donor motor all apart for cleaning, and I now have a
near-perfect rocker assembly (in parts of course). MAN was this (donor)
dirty! I had to drive the rockers and stands off with a hammer and block of
wood. (Solvent, steel wool, oil, Kroil, etc). Miraculuously the shaft is not
worn. No harm done, it was just hardened goo: no oil filter, cheap oil, many
decades. I have something like 4 dozen rockers etc to pick through and get
cherry ones. Gotta buy new valves though, mine are all crap. Depending on
$$$ I may just disassemble, clean, reinstall my current head with it's
cleaned up used valves. Some lips are too thin, but I can get a few years
out of it and when the time comes, build a new head and swap.

Related to that: I absolutely will do the full-flow hack to a stock oil
pump. It's gonna be easy! I might simply make a new end cap for the pump. A
flat chink of 1/4" steel with four holes and one milled grove to oil one
gear. And tap and plug the pump body outlet. The 2nd donor's pump looks
good, I'll feeler guage it and hopefully I won't have to buy a new one. Pump
will output through the top plate, to the remote filter, and return to the
block at the 3/8" pipe plugged hole in the main gallery right above the
pump. I even have a remote kit but I probably need some hose fittings. Drop
dead mission critical, don't want the main oil feed to pop off!




The ARP studs came today (fast! they're in Ventura) and those fit fine and
will work out great. It will go together with ARP moly. Was $125 total.
Sigh, I suppose I should get new conn rod bolts, maybe (not for certain)
main bolts. Yeah, it's a slow-turning motor, but it's a long stroke and high
mass -- accell. forces are probably as high as a 6000 rpm motor. That's 12
bolts and nuts (ouch) but I can use their lowest-end products. No other
mission-critical fasteners I can think of that warrant $5 each in this
motor. I want to be able to run it at 4000 for a minute or two at a time.
Sounds slow, but redline is 4500, and if you're in the car when you do that,
you'd understand why! It's a lot of mass flinging around!

I have 18 conn rods to choose from, so I will do what I did on my 232,
mix'n'match balance. I have a good scale at work. Again, slow turning, but
long stroke, large mass. If I can afford it I'll get the crank balanced
after I get all the rods+pistons the same weight.
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