I've found a 1984 RX-7 with about 90K miles with a 12A engine that's been sitting since 1997. Before deciding to sell, the seller tried starting the car and the engine seized up. It's locked solid and won't budge. As far as I know, last time it was run was in 1997. Don't know whether they flushed the fuel tank or took any other precautions before making that attempt. After 19 years, I'm not surprised that it didn't start. My question is whether this car is worth buying as a project, with the potential of the engine needing to be rebuilt or replaced, or should I just walk away? I can imagine a lot of issues on a car that's been sitting for that long, aside from the engine, but at least it was garaged the entire time. Any thoughts?

 

From a technical standpoint, expect to replace the engine. Just giving worst case scenario given the analysis/symptoms. From a financial perspective, where really not suppose to do that in this section, but a rebuilt may cost $1000+ depending on what parts might be good or used engine at ~$500-$1000.

 

The first question I would have is how is the rust if any? If its rusty then no, walk away. There are clean examples out there.

Expect to replace the engine. Its most likely carbon locked. It can be freed and the carbon can be cleaned away and it can run, but that is rare. If you are looking to buy and sell for a profit, look elsewhere. You will be not only doing the engine, but the brakes, tires, clutch, clutch hydraulics, fuel tank, filters, hoses, plugs, wires, cap, rotor, radiator cleanout or replacement, bulbs... The list goes on.

 

Sitting that long you'll have to go through the whole car and make sure everything is in working order. If the engine is no good maybe look for a 13b to put in it.
If you want to buy as a project car and keen to put a bit of time and money into it then buy it, if it's not rusted out badly like mentioned above.

 

It's called carbon lock.

 

ATF treatment= automatic transmission fluid pour it into the spark plug holes assuming you can remove the plugs.

I never tried it, never had to, but I've heard stories here. I've used WD-40 on a frozen motorcycle cylinder .

 

Use MMO in a carbon locked engine. Never use ATF.

 

Jeff is right, MMO = Marvel Mystery Oil and will work better than ATF without the issues of ATF dissolving the "good" carbon otherwise sealing the engine. Sometimes, rocking the engine back and forth from the flywheel can help free it up, but obviously a lot more work.

Don't force it, or you'll fracture a seal and then it's done.

 

oh no!! not another Marvel Mystery Oil love fest in here again.

"smells organistic" "cleaner than a hound's tooth" "I take a teaspoon with breakfast every morning"

 

Its because MMO works so well in rotary engines. I recently used it over a 30 day span to clean a used Renesis 13B replacement engine for my RX-8. After using the MMO, the rotors looked fantastic and the compression numbers raised each week until install. The MMO works and many club members use it religiously. I've saved multiple rotary engines with the stuff.

 

so now I have a a quart of 14 year old ATF that is useless laying around!