7aull

iTrader: (2)

Okee doke-
Quick recap:
-80 12a in storage; cooling system stored empty (3 yrs); filled up with water (pure tap to flush) and water filled oil pan! ie catastrophic leak from water jacket into oil system.
Forum members and Atkins Rotary (who originally rebuilt this engine) suggest that the CENTER IRON failed and caused the leak (there is apparently a thin spot that can fail if water freezes inside). Others suggested puling the oil pan and check to see if freezer plug had burst.
So:
Pulled the oil pan today - while engine still in car (Man, these are NOT designed to come out this way )
Results viewed from UNDERNEATH engine:
1) no obvious damage to BOTTOM of center iron
2) no visible freeze plug or failure in FRONT housing, tho I would guess the freezer plug can only be seen if front cover removed... (FIRST photo is of this area, below)

So: how to trace the water Route to pan?
-pour water down HEATER HOSE that is attached to REAR iron (2nd Photo)
-observe water coming into pan from below
PICS ATTACHED:
Note water is draining in from Rear Iron at Rear Passenger side (exhaust side)!!
(3rd Photo)
NO water observed coming from center iron.
NO water observed coming from front cover/freeze plug.

Thoughts??
(failure of REAR iron seems to be the obvious...)

NOTE: Engine water jacket NOT filled entirely (cooling system, rad, etc removed) - just whatever water poured into the rear housing at the heater hose point - Should note that water began draining into pan area almost immediately! ie. did not take time to fill water jacket BEFORE starting to leak.
NOTE: car front end jacked up for access and pics

Thanks All - look forward to ideas!!
Stu Aull
80GS
Alaska

Jeff20B

iTrader: (13)

Hmm...

gsl-se addict

iTrader: (3)

Now maybe I am off my rocker here, but I'm pretty sure there are 4 freeze plugs on the back of the rear housing. Looking at the pic in the FSM for the tension bolt tightening sequence, there appears to be one just to the right of the e-shaft (exhaust/intake side of engine). That appears to be consistant with where the water is coming from.

It has been some time since I have had my engine out, but I'm pretty sure on the freeze plugs being there. I suppose you probably popped one when the little bit of water left in the system froze. The good news is that if it is a freeze plug on the rear, you won't need to tear the engine down to fix it. Just pull the engine and replace the plug. Even if the rear housing is cracked, then you'll only have to remove the tension bolts and pull the rear iron and replace. You will only need to replace those few coolant seals and button it back up.

Good luck.

Whizbang

yea but look real close and it looks like its coming from between the rear iron and the rotor housing, not between the rear iron and bell housing mating surface.

The coolant seal is build into the rotor housing. Aluminum is not known for its durability, but generally cast iron doesn't like tension forces. I'd say pull the engine.

Whizbang

okay, i looked up the expansion coefficients of cast iron and aluminum.

Al - 12.3 in/in.oF x 10-6
Cast Iron - 5.9 in/in.oF x 10-6

Example, if the aluminum was a rod about 6 inches long, the temp difference from room temperature to -80 being about 150 degrees, the aluminum would contract about 0.011 inches. doesn't sound like a lot but when your talking about things that are held together tightly that is A LOT of force.

The iron piece the same size will only contract about 0.0053 inches.

j9fd3s

iTrader: (3)

yep, motor has to come out....

7aull

iTrader: (2)

Hi Guys-
yeah I concur - talked to Atkins about the freezer plugs and he also sez they would leak OUT side, not in. And If I pull the rear housing "only", I gotta figure the very act of pulling all the tension bolts will likely screw some/all gaskets or seals thru-out the block, so I would think just hoping to pull the rear iron and re-seal it is a pipe dream... ;p
But some of you are thinking its a HOUSING - NOT an IRON?? eww.
So I guess me-and-my-instructional-DVD will be tearing 'er down...
Thanks for having a look and sharing-
Stu Aull
80GS
Alaska

gsl-se addict

iTrader: (3)

Yep. The freeze plugs would leak on the outside. Anyway, you probably have a crack in either the rear housing or iron. I suppose that it might be also possible that it is a pinched outer coolant seal.

Let's hope it is the seal or the iron as they are a lot cheaper to replace than the housing.

7aull

iTrader: (2)

Seals?
Wouldn't THAT be nice!
Positive thoughts for the Patient appreciated (and for the "doctor" too )
Stu Aull
80GS(s)
Alaska

Jeezus

iTrader: (4)

If you got a cracked Iron, I got one here if you need it.

7aull

iTrader: (2)

Thanks Jeezus - appreciate the offer - likely will need one; will let All know what is up when I pull it apart
Stu Aull
80GS's
Alaska

Jeezus

iTrader: (4)

Good luck on it man. I hate to see another 7 down, but love seeing one up

gsl-se addict

iTrader: (3)

I also have a front/center/rear iron from my old '80 SA if you need it too. No housings, though. That engine tossed an apex and tore up the rear housing. I think that I might have the front one, but had a lot of chrome flake.

7aull

iTrader: (2)

Thanks Addict - looks like its the Rear I'll need, but have to pull her apart to be sure - Atkins will sell me a checked-out (read: used-but-useable) iron for $100, so that should cover me.
Stu Aull
80GS's
Alaska