Saving an old 12a
 

I bought a '85 s model a couple years ago as a project and am finally done getting it ready for the track. I had the engine idling nicely about a year ago but have had trouble with it lately. Did a compression test using the leading plugs:
Front 75, 75, 75psi
Rear 65, 45, 45psi

Car has sat for over 10yrs and has 138k miles. Should I even try to unstick the seals or just tear the motor down for a rebuild and hope the housings are ok?

Did you add any oil to the chambers when you did the test? Was it a hot engine?

Normally you want to do a compression test on a hot engine or at least with oil in the
chambers and spin it some by hand so that things will seal.

I think TF is correct, and that the motor will respond well to some tlc. Tlc being run time.

No oil, engine was cold. Can't get it to idle right now so warming it up first wasn't in the cards.

Obviously I didn't get concrete numbers given the less than ideal conditions but it sounds like its worth getting running again before making the decision to tear down?

I just don't want to waste time polishing a turd.

it's totally worth it to try to get it running. does it run while on choke? is it firing up consistently, but just won't hold an idle?

Based on what you've said I would turn the idle speed screw til it held 2000 or so and let it run, making sure I had lots of Lucas or MMO in the good gas in the tank. My current car I bought with 125000 and had sat 6 years. It was crotchety at first but now is sweet. I did have to do the alumaseal coolant seal fix, which works like a charm. And a carb rebuild, of course.
The best thing you can do for a 12a is to run it.

Thanks for the input guys. I'll tackle it after the holidays. I reset the idle and mixture screw to factory base settings but will lean towards a high idle as suggested.

Good luck. If she's not streetable, just let her run in the driveway and loosen up. I'm optimistic. 12a's are just getting good at that mileage.

Yeah, even engines I replaced due to excessive oil consumption on decel started nicely and idled well. I'm very hopeful that my current 7 with just over 100k miles will last for quite a few years before I need to think about an engine replacement/overhaul.

I had a 12a that sat for 10 years also when i bought it. It ran after i fixed carb,(by fixed i mean throw carb out of anger into concrete and build new carb.) never overheated, however did blow smoke. The oil rings inside are just rubber and they dried out. So when i got on the interstate, it looked like a smoke trail. james bond style. It did help when cars were in my bumper. Smokee screen ftw.

Thanks again guys. She does smoke a bit but as long as she gives me a year or two of fun I'll be happy. Merry Christmas