I have a 12a, very stock, out of a series 3. About 120,000 miles. I ran the it was pulled out of the car it came out of. It lived its life stock. No headers, stock carb. Is there any benefit of rebuilding and replacing at least the soft seals. clean the carbon, and reassemble assuming the hard seals are in spec. Most likely I would replace hard seals, but depending on wear I'm leaving that one open. Or should I keep it sealed. Im kinda concerned about 32 year old soft seals. Yes, opening would allow for some porting.

 

If compression is good then you could probably get away with leaving it as is. However, I figure you would be better off to rebuild it BEFORE something fails, that way you can replace all the soft/hard seals and bearings as needed. Considering the age of the motor I'd guess that you're on the right track.

I would rebuild it if it were mine, but that's just me

 

i would just rebuild it

 

12A's rarely failed for the same reasons the later series engines did. if you want it looking new and don't want to worry about the very slim chance of a coolant seal going out then rebuild it.

 

Rebuilding is where I was at also. thanks for all the opinions!