High Mileage 12a
 

I have a question for experienced board members (one of which I am not). My father / son 85 FB 12a project has over 169,000 miles on it. I believe we are the fourth owner. We have owned the car since 2006 and have put only 1000 miles or so on it. Back in 2006 I put some Autolite plugs in it to tune it to see what I was working with. When I pulled the plugs today they were perfectly normal. I still have the plugs that came with the car and they were normal.

This got me to thinking. The engine makes no smoke, it runs dead smooth and quiet, seems to have ample power for what it is, but from everything I have read, 12as should not last this long. However, there is no indication that the engine was rebuilt as nothing looks particularly new. In fact, some things look particularly old. Is it that unusual to have such a high mileage 12a?

I don't know where you heard that 12As won't last that long. Maybe some FD people got confused and scared.

It is normal for 12As that have been driven "normally" to run 200-300,000 miles. They don't tolerate high revs much, but given that peak power stock is 6,000rpm then they won't see high revs anyway. (And in the case of Series 3s, every stock tach I have seen was at the extreme optimistic side of tolerance - 7000rpm on the tach was about 6300-6400 actual)

My last 12A sufferered many loss-of-coolant events until the one that finally killed it. At 211k. The interesting thing was, the thing that killed it was not a blown coolant seal, it was warped housings by the spark plug hole that caused the apex seals to crack. Apex seals, what was left of them, were still in tolerance, and the housings were chattered and flaked but they admittedly lived a hard life and I've seen a lot worse come out of running engines. In short, it probably would have made it to at least 250k.

By this time, the car's shell was in such sad shape that I scrapped it. The lower link mounts were held in place by chunks of angle iron that bolted through the floor to reinforcing plates, because there wasn't any solid metal left. The upper link mounts were long gone, the reason I did my first 3-link actually. (The wheelwells were window screening with a heavy slathering of undercoating)

My 85 fs. Has......253,400 miles on it I've owned if for a year I got it from my brother in law that owned it for 5 years. I don't think its been tore down and rebuilt it just don't look "clean enough"

Thx. Any tips for timing? My sons will be running their first autocross in it next weekend.

the most i've heard of for a 12A is 420k, car came into the dealership with a seized shock....

we used to see gsl-se's with 250-300k all the time. my friend used to have one that went 250k and was still on the original clutch.

Mine went 213,000 miles. Combined daily driving and weekend autocrossing. :)

Seafoam in the tank, and Lucas in the oil, and you'll be good for another 100k or so...




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I have a 82 gs 12a with 180,000+ miles and still running strong! Taking out the smog stuff and the ac helped revive the motor a bit for me. Its a daily that sees occasional hard canyoning. Wanna start autocrossing if I can find some good condition 12a rotor housings! If I can rebuild it the motor will see some street porting too :)

I have a lill over 110K. Body is in decent shape. Trans is shot. New clutch though. Still have the stock water pump. lol. Seafoam seems to be whats keeping her alive

I'm at 160K and have no problems. Runs like a champ, and I know guys that have 250K on the original engine. Just keep it full of oil and coolant and replace the heater hoses for no cooling system "surprises" and you should be good to go.