un-sticking Chevy (OMC) 350 V8

[Valmika]

Originally Posted by travis_farmer

that may be an option for this weekend. at least i will know what i am dealing with, internally.


~Travis

It may be a little more expensive but I have used Marvel Mystery oil twice to unstick a small diesel. Just put it in and let it soak. Try to turn a bit with starter every couple days. If you take he heads off use a wood dowel and tape with a hammer

[flyingfin]

Originally Posted by Randall M

Try Marvel Mystery Oil in the cylinders.

Randall M

Second vote for Marvel Oil. Pull plugs and put about a tablespoon in each cylinder. Put plugs back in loosely
Repeat every other day for at least a week. DO NOT USE STARTER
Remove all plugs and try to turn over by hand rocking the bottom pulley. If no move, repeat for another week, then remove plugs and this time try to turn by putting wrench on front pulley. If no luck, then try starter as last chance

[wayne.b]

Originally Posted by hellosailor

PBlaster or Kroil will chemically attack the rust, follow the instructions, it may take 3 applications but that should free the rings. It may take a large breaker bar to get any rotation. After twelve years of sitting...I'd assume it will need a rebuild, or at least a thorough tear-down to confirm what condition anything actually is in.

===


PB B'laster and Aero Kroil are both excellent products - much better than WD-40 for freeing suck parts. PB B'laster is more widely available however. Some people have reported good results with a home brew mixture of 50/50 transmission fluid and acetone. Acetone is highly flammable of course and should be used with caution.

[Greg Mason]

A lot of comments about the rings and cylinder walls. If, as Cheechako says, you pull the heads, you will know tons about the cam, valves and won't have any compression in the cylinders, so spinning the crank should only take 1 gorilla. If the oil is good, you can also use a drill after pulling the distributor to turn the oil pump and lube the upper end at least, and get some on the crank too. It may all help. Good luck.

[travis_farmer]

a semi-local auto parts store suggested Marvel Mystery oil, and with the second, third and fourth votes here, i used an oil pumper to squirt a couple tablespoons in each cylinder. the guy also said that if i take the valve core out of my compression tester kit, it threads right into the spark-plug hole, and fits an air compressor fitting at the other end. i put a regulator in between, set to 40PSI, and added air pressure to each cylinder in turn to sort-of force the MMO into the rings. now i will let it sit for a few days, or week, and try to turn the crank by hand now and then.


as a point of optimism, i turned off the oil fill cap and looked in the valve covers, and was pleased to find it was pristine, with a few little puddles of oil (no water). this was a happy discovery, and gives a little credit to the seller's story that it was rebuilt, with a little over an hour on it when it was put in storage.


~Travis

[Jesse]

Until you have disassembled and made certain the engine is reliable you can't trust it. Failing that, in all probability it will only get you and whoever else is aboard just far enough to wish you hadn't left the dock. Consider what it will cost to get towed back, and that can be a real shock.

[travis_farmer]

Originally Posted by Jesse

Until you have disassembled and made certain the engine is reliable you can't trust it. Failing that, in all probability it will only get you and whoever else is aboard just far enough to wish you hadn't left the dock. Consider what it will cost to get towed back, and that can be a real shock.

I will very likely get the engine checked out. at this point, i am just trying to see if i spend my very limited money on re-building this engine, or a salvaged engine. if this engine can be saved, that is the route i would like to go.


well, to be honest, i would like to drop in a new crate engine, but that is way beyond my funds.


i only make about $13k a year, minus bills, so available funds have to be planned very carefully. once i have the engine rotating, i will feel better about saving the engine. if i can get it running, as is, at least i can work on some of the lower cost projects the boat needs, while i save up for the big items. i still have yet to open up the sterndrive and see if that needs to be replaced, or if it can be rebuilt.


~Travis

[jimbunyard]

Have you tried a long breaker bar on the crankshaft bolt? All this talk of stuck rings and such are just guesses; a single stuck valve can seize an engine just as well as 'rusted' rings; using the starter to try and 'unfreeze' it is definitely not a good idea.


Don't get to carried away though...maximum torque for a 7/16 20 grade 8 bolt is about 80 ft lbs.


Given the relatively low humidity in southern California, I'm guessing that the engine may be runnable as is if you get it freed up. I don't think you're planning any round the world trips with the boat, if you can get the engine running, it doesn't smoke, it starts easily and has good power, there's no reason not to trust it for the general recreational purposes for which it was intended.

The things you've done so far are all good. Additionally, I'd pull the valve covers and make sure all the valves and lifters were free; wouldn't hurt to squirt some oil down into the lifter bores as well.

If it turns out that the engine is badly seized from rusty rings and cylinder bores, it may still be possible to do a 'shade tree' overhaul for less than 3-500.00 in parts. If the cylinders are so rusted they need boring (rather unlikely in my opinion), depending on the going rate (15.00 a hole around here), a long or short block may begin to look more economical.

If the boat was run in salt water, and is raw water cooled, I'd be at least as concerned about the block water passages and the manifolds as the rings and cylinder bores...

[captlloyd]

Go on YouTube to get ideas and see many engines unstuck and running well.

[travis_farmer]

Originally Posted by jimbunyard

Have you tried a long breaker bar on the crankshaft bolt? All this talk of stuck rings and such are just guesses; a single stuck valve can seize an engine just as well as 'rusted' rings; using the starter to try and 'unfreeze' it is definitely not a good idea.


Don't get to carried away though...maximum torque for a 7/16 20 grade 8 bolt is about 80 ft lbs.


Given the relatively low humidity in southern California, I'm guessing that the engine may be runnable as is if you get it freed up. I don't think you're planning any round the world trips with the boat, if you can get the engine running, it doesn't smoke, it starts easily and has good power, there's no reason not to trust it for the general recreational purposes for which it was intended.

The things you've done so far are all good. Additionally, I'd pull the valve covers and make sure all the valves and lifters were free; wouldn't hurt to squirt some oil down into the lifter bores as well.

If it turns out that the engine is badly seized from rusty rings and cylinder bores, it may still be possible to do a 'shade tree' overhaul for less than 3-500.00 in parts. If the cylinders are so rusted they need boring (rather unlikely in my opinion), depending on the going rate, a long or short block may begin to look more economical.

If the boat was run in salt water, and is raw water cooled, I'd be at least as concerned about the block water passages and the manifolds as the rings and cylinder bores...

"southern California" ??? who is in southern California?


i have tried gentile rocking with a breaker bar on the crank bolt, a bit forward, and a bit back. all that did was break the crank bolt loose (not off).
and no, i don't plan on any round-world trips. just fishing in large lakes. the previous owner used the boat much the same. freshwater.


~Travis

[jimbunyard]

Originally Posted by travis_farmer

"southern California" ??? who is in southern California?


i have tried gentile rocking with a breaker bar on the crank bolt, a bit forward, and a bit back. all that did was break the crank bolt loose (not off).
and no, i don't plan on any round-world trips. just fishing in large lakes. the previous owner used the boat much the same. freshwater.


~Travis

Oops...still wouldn't be overly pessimistic just yet...

[Imprezza72]

Another vote for Marvel however if you get it to turn over then crank it for a while DO NOT start it. Drain the oil and check it for metal bits, if found do the heads thing and check the cylinders, if not fresh oil and a Hail Mary.

[Lepke]

I've freed a bunch of engines, mostly gas. You need a lube with acid in it or something that dissolves rust. The best stuff I've ever used is Kearney Rust Cutter. Besides lube it contains an acid. About a half can on a v-8. I never had diesel, marvel, etc., give any help on breaking loose an engine. Another product that dissolves rust but doesn't hurt base metal is Archoil 5100. It's water based. Online here: archoil.com
Whatever you do, the oil has to be changed.

If all else fails, remove the heads, put a block of wood, big enough to just fit in the cylinder and stick out. Hit each piston with the wood and a sledge hammer. Do all the cylinders then try the crank. I never had to do more than 3 passes with the wood. It's not as much pressure as ignition puts on the piston tops.

You will have some pits in the cylinder and some damage to the rings. But the engine will run. It may smoke a little and use some oil. If you're not going on the ocean, it doesn't have to be perfect. It would help to change the rings and hone the cylinders for longer life. The 350 is a descendant of the 265, 283, 327 and the design was in production for about 50 years. Sort of the Detroit Diesel of gas engines.

[Bdozz]

We freed up an old tractor motor with ATF, pull the spark plugs out and fill the cylinders, and fill the crank case, leave it sit for a few weeks, car motors and marine engines are not the same, the cams are different to keep water from being pulled in from the exhaust.

[Bdozz]

I would agree with the pessimists though. If the rings rusted into the cylinders it will do more then burn a little oil.