Engine 1978 King Cobra Engine Seized From Sitting 25yrs.

colorado cobra · Jul 23, 2018

Just bought a KC that has been sitting for 25 years. It was in a frontend collision in 1993 and never ran since. I pulled the spark plugs and shot in some lubricant but the crank wouldn't budge. I then poured tranny fluid into the plug holes and let set for a couple of days but had the same result. Does anyone have another idea before I pull out the 302?

Adieu · Jul 24, 2018

auto or stick?

colorado cobra · Jul 24, 2018

stick

Adieu · Jul 28, 2018

You can try soaking down all the cylinders with the plugs removed with wd40 or pblaster overnight and then using a drill to drive a socket on the shaft of the oil pump (it'll either be 1/4" or 5/16" if I remember right) to pressurize the oiling system and lubricate all the other moving parts.

Lastly, make sure the cluth isn't stuck.

Neuron · Jul 28, 2018

Sitting (if outside even worse) for 25 years, time for a rebuild.

jozsefsz · Jul 29, 2018

I've heard Marvel Mystery Oil soaking for a few days works very well, I've just used WD-40 in the past on a really stuck 2.8 in my II (sat for I have no idea how long). Kerosene / diesel fuel is also supposed to work well.

Make sure you can get a breaker bar on the crank bolt, and that you try and break it loose by 'shocking' it (instead of prying really hard, smack the breaker bar back & forth as if you were having an angry seizure to see if you can make any headway) . If you can budge it even a tiny bit, soak again, let sit for a couple of days, and try again. It'll eventually come loose this way unless something is completely seized or melted, it can take some time & patience though (often a few weeks of this process).

It might be easier to move the fan / shroud / radiator out of the way so you have enough room to try this without hurting yourself.

If it's really messed up inside (water-logged or other stuff rusted together), running 302 HO's can be had for not all that much money, I wouldn't even bother rebuilding one that's rust-seized myself. Unless originality is super important to you. But I'm also a big cheap-skate and I'd keep at it until it broke loose. Time, patience, and shock-motions should be able to do it unless it's mechanically seized (which is unlikely).

Adieu · Jul 29, 2018

Neuron said:
Sitting (if outside even worse) for 25 years, time for a rebuild.

Not necessarily.

In 2004 a 1958 Chevy Apache pickup was brought to me at the shop that had been sitting in a field since the 70s with instuctions to get it running.

Filed the points, changed the oil, plugs, wires, battery, belt, hoses, and coolant. Then I rebuilt the carb and wheel cylinders, washed out the gas tank, and replaced the master cylinder.

After that I pre-lubed the old stovebolt and fired it up. Last I heard, the ol' girl is still running.

Neuron · Jul 29, 2018

74stang2togo said:
Not necessarily.

In 2004 a 1958 Chevy Apache pickup was brought to me at the shop that had been sitting in a field since the 70s with instuctions to get it running.

Filed the points, changed the oil, plugs, wires, battery, belt, hoses, and coolant. Then I rebuilt the carb and wheel cylinders, washed out the gas tank, and replaced the master cylinder.

After that I pre-lubed the old stovebolt and fired it up. Last I heard, the ol' girl is still running.

So the engine was locked up solid too?

Adieu · Jul 30, 2018

Neuron said:
So the engine was locked up solid too?

Wouldn't turn over before we soaked it down.

Neuron · Jul 30, 2018

74stang2togo said:
Wouldn't turn over before we soaked it down.

You got lucky, good job. My Uncle owned a junkyard and in my youth I worked there a few summers and one of the tasks I helped with was trying to get seized engines unseized. We did have a few successes in getting them rotating but never got one good enough to sell. My favorite was when after soaking and trying to turn the engine over(dampener bolts are not that strong you can break them with the right leverage I found out)for days my Uncle wanted to try pushing the car and popping the clutch. I am not sure how fast he was going but it dropped the driveshaft in front and almost pole vaulted the car, pretty much gave up after that.
I guess I should have said I would rebuild that 25 yr old engine but maybe its my OCD that keeps me from doing most Mickey Mouse things on a car.

Adieu · Jul 30, 2018

Neuron said:
I guess I should have said I would rebuild that 25 yr old engine but maybe its my OCD that keeps me from doing most Mickey Mouse things on a car.

You're trying to shotgun diagnose what could be a simple problem over the internet without all the facts by throwing the kitchen sink at it.

I work on cars for a living; have since high school (in my 30s now).

This is why I don't give BS recomendations and ask a lot of questions and give advice that can lead to an answer instead of assuming I know a lot about a car I can't even see. That engine could very well have a set of wiped out main bearings causing it to be mechanically locked up, or a broken piston, or any of a dozen other things... or it could just be locked up due to hardened and dried oil film and flash rust in a cylinder that'll be resolved easily enough with a bit of a penetrating oil and some time to soak. There's no point in yanking it out and tearing it down to rebuild it until you're sure it's necessary though.

Neuron · Jul 30, 2018

Yea but that is why it is so much fun.

jozsefsz · Jul 31, 2018

Yeah, there's no right or wrong answer here, except any answer that is definite. It could be anything, and there's no harm in trying to unseize it. The worst that can happen is you end up rebuilding it (though as I mention I wouldn't if it's that seized up). I usually add "if it were me" to my opinions, causes less friction.

colorado cobra · Sep 10, 2018

I tried the tranny fluid and thinner mix trick but after a week it still didn't budge so I decided to tear the 302 down. As soon as I pulled the valve covers I found the worst sludge build up I have ever encountered. Stripped down to the short block, I unbolted the rods and knocked out the pistons with not too much issue; hopefully the rust rings can be bored out. When I dropped the parts off at the machine shop they considered charging me an extra cleaning fee. I guess I can't blame them.

Neuron · Sep 12, 2018

Well it was worth the try, but the outcome is as I suspected. I think in the long run you will be happy you did it right(in my opinion of course).

colorado cobra · Sep 12, 2018

Yeah, I thought how good the engine looked externally, i.e. no modifications, and all the smog equipment still intact, that the engine internally would be sound and could be revived. At least limp by for now while I worked on other parts of the KC, but that wasn't the case. Now I have to start a new thread on building a souped up 302.

Engine 1978 King Cobra Engine Seized From Sitting 25yrs.

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