I purchased a 79 BRAT because I'm a sucker for the 70s look. The gentleman who sold it to me said it had a semifresh rebuild...whatever that could mean. Anyway, after checking fluids I brought it home and virtually parked it to replace leaky radiator and front brake system. After I got all things repaired I ran the Sooby for a few days and realized that coolant was finding its way into the motor oil...not milky but fluorescent green!

 

I then proceed to remove the EA71 from engine bay, relocate engine to work bench to remove heads and intake from block. One of the intake gasket was split which probably allowed coolant into combustion...which accounts for the weird carbon build up in piston and etc. HOWEVER, when fluid sat in top of piston, none of it would seep through which tells me those piston rings are in great shape not allowing fluid into case. I also don't see any cracks in head or around cylinders.

 

So here is my dilemma... should I consider the case half seal which would inevitably force me to do a partial re-rebuild? Is there something else I should consider?

At this point, you're far enough into it you might as well go for a full rebuild. That way you'll know for sure everything is ok. Coolant is a terrible lubricant so the condition of the bearings may be questionable.

 

I bought my '80 Brat sight unseen and it turned out to have a blown head gasket, so I replaced them. Very soon after the thrust bearing let go. Every time I pushed the clutch pedal the engine would knock. Wish I would have done a full rebuild the first time I had it out.