You can soak it more. Thats about all you can do without pulling it out. Maybe fill the crankcase with mystery oil and prime the oil pump by yanking the distributor. I would yank it out at this point but you can keep trying
Try and soak it some more. If it still doesn't turn, admit defeat and remove the engine before you do damage something. Likely it's a stuck valve that is better dealt with with the head removed and in a solvent bath. Worst case it's actually a seized piston. I had one in an old Nailhead that once it did let go, it took out the back wall of the piston to the first ring land, boy did that thing smoke! And it repeatedly tried to siphon the crankcase dry as the busted piston went up and down. Not a great scene. One engine we tried to start was an old tractor from the 30s. It gave a 1/4 turn and then stopped fast; the mice had packed so much rapeseed into one cylinder it created something more than hydraulic lock. The only way to fix it was to open it up.
Soaking it more is the easiest, quickest, so I’ll try that. Working on borrowing a borescope to look in the cylinders too. Thanks for the advice- this car is my baby but I wasn’t planning on spending Invicta money in large chunks on it just now.
Keep it wet. If itll move at all, keep on it ; you'll gain 1/8 turn every day. Back and forth without too much pressure. You can also bar the ring gear if accessible, but you need to be gentle with the aluminum bellhousing etc. Up here a rusty frozen motor is not really a big deal if thats all it is. Mice and trash not withstanding! ws
What he said. I have found using a large prybar on the fly wheel ring gear allows the best control and leverage to work the crankshaft back-and-forth. I’ve done this more than a couple of times carefully working it back-and-forth gaining about a 16th of an inch at a time. A very slow go but you will eventually get your full rotation. As I mentioned in a previous post definitely pull the valve covers and completely remove the valve train. Once you are putting that kind of leverage on the crankshaft it is very easy to bend a valve that is stuck open and not even know it. Steve weim55 Colorado
Today's results: • Disconnected all belts, not that I thought they were a contributor. • Obtained a borescope, cheap Snap-On piece of crap. Had to rig up a secondary LED AND use a circa 30" monitor to see anything, and even that was pretty poor, image-wise. But what I did see down the left bank looked like some clean cylinder walls, some spotty oxidation, and a lot of crustiness on the pistons. Could not contort to see the valves, despite having a 45-degree attachment and angling the scope. Not impressed with the scope in the least. • Also tried to turn the motor counter-clockwise with about a 16" breaker bar on the crank pulley, but it didn't budge. • Inside the oil fill port in the valve cover, things look fine (no rust I could see). Still probably going to put more Marvel into the bores, but if there's loose, 'flakes' in the bores, is anything other than a rebuild possible? If it breaks loose, is it possible to pop the heads, 'clean things out' & reinstall heads? At this point I see 2 options; find the funding for a rebuild or sell.
Option 3- buy a used poncho motor and drop it in.. cant be to hard to locate something comparable. Keep the #s motor of course.
I had a very nice running Olds 455 that I took apart to upgrade. To my surprise, a couple of cylinders had very deep rust pits. Never burned any oil or had any noticeable blow-by. Go figure.
I've done that, popped the head, broke loose the offending piston that was seized, and then put it back together again. The results were less than stellar, in fact, they were lousy. The car was a 70 Chevelle with a clapped out old 6 banger in it. It leaked like there was no tomorrow and it had run out of oil. I got it into the yard and shut it down, and it locked up. The next morning I took the head off, got a block of wood and a sledge hammer, and beat down the bad piston. Didn't take too much ring. That engine was pretty loose and burned up anyway. The I bolted it all back up using the old head gasket, and surprisingly, it held. The other gaskets leaked anyway, so it didn't matter. I was dead broke and desperate as I had a job coming up in a few days and I needed a working car. The car smoked, vibrated, ran terribly, but it ran. And it leaked, boy did it leak. There was no way in hell I could ever seal that car up and I tried. But that engine was so burned out there was no winning anymore, it really needed to be rebuilt. So I got a couple of paycheques under my belt and bought my first Buick, and never looked back. Now for my 2-bits, for what it's worth; I think you're better off soaking it for a while longer, and then if it doesn't break loose, spend the few hundred and get a gasket kit and take it apart. Likely you could get away with only doing what is necessary to fix the issue, those engines are pretty forgiving and I have seen it done, but a car like that should probably be saved and done right. Just as an aside, it's worth more resale wise if the numbers all match, particularly if it still needs work. If you want more proof of how a shoestring budget repair can work, there were some you-tube videos circulating on this site (in the Bench, I think) that details how a bunch of Alberta rednecks got an old 50 Buick and a 52 Packard running again after being in a wrecker's for 50 years. They faced some interesting challenges and spent more on beer than they did on the engines, and they both worked and drove again.
Update : 389 has been soaking in 8 oz of Marvel Mystery / bore (minus the slugs nearly at TDC) for about 2 weeks. Since the motor turned about a half inch on the pulley and stopped before all this, I try to rotate it both directions, thinking it may 'back off' the obstruction. Tried to turn it yesterday and I loosened the crank nut. I feel like the next step is opening the motor. Take the heads off? Any reason to bother with the timing cover too? Anyone have a coffee can of good vibes they can spare?
Well at least ya got the pulley bolt loose! You never mentioned if its a stick or automatic. Stick? In gear and get a few guys to rock it back and forth. Itll go. Turbo? Bar on the ring gear BOTH ways till its free. If a valve was stuck, pop the valve cover and exercise each valve with a wood block and a mallet. Some PB blaster on each valve will help. It WAS running when parked right? Edit: Pull the rockers off and get a full face tap on the valve stem. If from the side you can bend a valve, or crack a guide. IIRC, Ponchos valves are like Chevies... individual on studs?? If so take a machinist ruler and measure the thread showing above the nuts to get a rough setting when re-installing. I think you have a stuck piston. ws
On another note, I sincerely doubt a stuck valve will hold it back. Ive been on board at least 3 389s and a 400 that blew the cam gear with zero piston interference. start with the simple stuff. Got a pal to help bar it over from each side back and forth? ws
I was taught by a great mechanic as a boy, to never put anything but oil into the crank case, and I have lived by that credo.
With marine power, its not unusual to fill the crankcase and then top it of to the carb with kerosene. Especially if its been submerged. That stuff helps dissolve rust. ws
Car is an automatic, and did run when put in the garage. A buddy wants to jack it up & turn the ring gear, but someone explain how turning one end of the crank differs from turning the other.
Yeah he is a bit off center But his vids are interesting, seeing what he does on the cheap. UTG is cool too.
