Seized engine?

Ok guys, here's what I have. A Ford 302, 1978 I think, that has been sitting for 20+ years, maybe. Project was started in 1988. Engine was supposedly rebuilt, installed and then car was stored. I removed all spark plugs and sprayed cylinders with fogging oil. Trying to rotate engine via bolt on front pulley. I get a slight turning (not a full turn) then stops, will turn back then stops. I didn't want to put to much pressure on bolt as this point. I figure it's got some rust inside, maybe a stuck valve? Thoughts on how to free up short of disassembling?
Thanks, Ron W

You will have to disassemble it. Usually they are assembled using lube on all the parts, some people just use oil thinking they will be installing and starting it right away. It is not just the rings that stick. It can be the crank or rod bearings etc... It obviously has a problem and by just fogging rusty or improperly assembled parts you are not addressing the issue. Leave fogging for junkyard motors that you are trying to band aid. If there are any questionable parts in there just get something better, that old block is non roller and chances are has some cheap cast pistons in it. At least get a newer roller block to work with, they can be found for next to nothing as I have picked up a few decent ones for as little as $50 and $200 for running roller 302 HO.

If you insist on trying to band aid it: pop the valve covers first and see if one of the rockers is not coming up all the way due to a stuck valve.

Not what I wanted to hear, but I know it's the right thing to do. At least this way I'll know what I have. When you buy from someone else, you never know for sure what you have. You gotta love "a good deal"....
Thanks for the reply!

Hey Ron, This sounds just like the engine situation i had. I had to take the main bearings off to get mine to turn over. They used some oil product that gelled up and all the piston rings had to be replaced and cylinders honed to get it off. i went ahead and put all new bearings in and put GT40 3 bar style heads on for better flow. Not to expensive for a fresh new motor.

More than likely I'll probably have to do the same. Even though I didn't want to do this now, I'm looking forward to having a fresh motor done the way I want it. Thanks for the info!

If you are interested, I posted it in the new classifieds section, I have a new Mustang Coyote motor complete swap with the 6 speed available. Stock it makes more hp than even a very built 302 and that is just its starting point. I have the complete car so everything is available with it, headers, wiring harness, gas tank with pump, driveshaft, wiring including the gas pedal as it is drive by wire etc.. asking $8800

That would be sweet, but well out of my budget.
Thanks, Ron

Here's my 2 cents. My MX came with a 66 model 289 that was originally installed in the late 80's but never started since. My motor did the same thing as yours - turn almost 1 full revolution then stop (manually turning the crankshaft). Then when I turned it back the other way - again it stopped just before making a full revolution.

I pulled my heads to see what was going on. With the heads removed, the engine turns 360 deg no problem at all. In my situation, the problem turned out to be some engine crud that formed over the last 25+ years on top of the piston. The 289/302's used a very small combustion chamber (i.e. closed chamber), part of the head squeezes almost flush with the piston head. Too much buildup on the piston or head in this area will cause the same issue that you and I experienced. On mine, I found what looked like carbon/dirt on top of the piston. I don't know how it got there but it did. The piston would travel all the way around until it got to the point where this trash came into contact with the head and piston -- then it stopped like the engine was seized.

I gave my pistons and heads a light wire brushing and then reinstalled the heads using the same head gaskets. As I suspected, the engine turned over all 360 degrees very freely. I probably could have replaced the head gaskets and called it done, but where's the fun in that. In my case, I opted to tear the engine all of the way down and freshen up bearings, rings, etc. Btw, during the teardown I didn't find anything else that could have caused the engine to have these problems - no galling, tight bearings, shavings, etc.

I'm not saying this is definitely the case with your engine, but if you're fond of that old Ford and are on a tight budget, a SBF gasket kit is only about a $100.00.

SD

That sounds like positive light on this story. If you go on Amazon you can get a $20 bore scope that uses your phone as the monitor. I have one and it works surprisingly well, stick it down the spark plug holes and you'll know what you are up against before you turn a wrench.

Ron, try squirting kerosene in the cylinders and letting it sit overnight. you will have to change the oil but it is a cheap fix.

Thanks to everyone for all the replies. I have not had any time to work on the Healey, I moved to a new home. As it turns out the engine was not seized. I have a friend who is a classic car restorer come over to check it out and he got it turn over by hand and then we got it turning out via the starter. Since I'm moved into the new home now. I going to try and get it fired up this weekend. If that all goes well I can start assembling. And so the fun begins!

That sounds really good, it is always nice to find out you don't have to do a whole bunch of work you didn't budget for time or money wise.