Salt water siezed

[robert644]

Hello, I work at a small boatyard and recently acquired a pair of 41 series Volvos in a boat. The boat had sunk and remained in the yard for several months before I got my hands on it. i managed to get one engine freely turning, but not so much with the other.

Currently I can rock it back and forth a couple millimeters by the flywheel. After 10 days of sitting with liquid wrench / PB Blaster / Knock-off it hasn't improved or noticably gotten worse. Well, I want this thing to go !

At this point I have two ideas that I gathered from the internet. One is to drain all the coolant and replace with boiling water. Sounds like a good idea. The other is to pour hot engine oil down into the cylinders. I think I want to make the cylinder expand, rather than the piston, but it is an easier task and the desired result is to break up the corrosion holding the piston rings.

Failing that I am faced with a more difficult job. At the end of it all I have a 10 ton forklift with a 20 foot extension boom, just for these kinds of tasks, but I am not sure I want to draw on that resource quite yet. The idea with this being to remove the oil pan and try to knock the pistons free using a brass bar on the crank.

Pulling the head is why I am posting this though. I have some questions.

- When pulling the head I start with the last bolt in the tightening sequence (#26) and work incrementally towards #1 ?

- Is my initial un - torquing done with the 90 degree turn and then in following 4 steps of loosening it ? Much like when I torque it ?

- When I get the thing off, is there any way to ascertain which cylinder is the one frozen up ? I can look at the valves and see which ones were open, or I can try to get a thin piece of metal down the side and see which rings move ?

I am going to get the machine shop to make me a wooden plug to hammer on and hopefully that, and a crowbar on the flywheel will break it free. When I'm rich I can redo the job correctly, but for now it's just important to me to have a working boat, and not a limper.

Any ideas would be appreciated. Thanks !

[captainbri]

Pulling the head. .just tske the bolts out with a impact gun. Your not going to warp the head. Then pull the pan pull all of the caps off off the rods and then look for rust at the bottom of the cylinder of the piston that is all the way to the of the cylinder. Soak it with oil turn the crankshaft with all of the rod caps off then put rubber hose over the rod bolts then tap the piston down it should move with very little effort. Mark the piston hole and direction. Do not mix up any of the parts when you put it back together. Example do not put piston one in to piston cylinder. When you tap the piston down this will allow you to see the cylinder. If there is rust get the proper size cylinder hone lots of oil and hone enough to get rid of the rust.. then remove the piston. If the cylinder has deep pits you might get stuck doing acset of rings and honing all of the cylinders

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[captainbri]

Make sure the pistons..rod caps bearings go back in to the cylinder they came out of.. if it was my engine I would get a set of piston rings new main and rod bearings.

Sent from my SAMSUNG-SGH-I537 using Cruisers Sailing Forum mobile app

[robert644]

Thanks for the response. I should add that I'm trying to avoid engine removal. Once the engine is out of the boat, I got that. But I'm trying to do the job without removing the engine or even the head. If I got to, I got to. But I would rather not.

I'm just fascinated. I was able to turn the motor for about 1/32 of a revolution and now it's stuck and I can only move it back and forth the distance of 1 flywheel tooth. I'm guessing this is the play of the rings in the pistons ?

[socaldmax]

I've heard that a 50/50 mixture of ATF and acetone, left to sit in the cylinders, is an excellent way to free up rusted cylinders.

[SoloBob]

Marvel Mystery Oil..... In the states you can find it in just about any auto parts house. I've had good luck with it in the past.

[robert644]

Originally Posted by socaldmax

I've heard that a 50/50 mixture of ATF and acetone, left to sit in the cylinders, is an excellent way to free up rusted cylinders.

I have read this one as well. Currently I have the cylinders full of liquid wrench, chosen because it was available in a pour bottle. I think I will need to have a wooden plug turned, pull the head, and try to knock it loose that way.

Pulling the engine is something I want to avoid.

[gjordan]

Instead of pouring boiling water into it, you might rent a steam cleaner and run steam through for a half hour or so, and then hook a vacuum cleaner to the same spot and pull cool air through for a similar time. Since you must have the injectors out, rent a bore scope and maybe find out which cylinder is the problem, and make an adapter to fit an air compressor to the injector hole. After a good soak of ATF/acetone, put 100lbs of air into the cylinder and see what happens. Be sure to put rags or old towels over the other injector holes because if it comes loose, it will blow crap all over your engine room. OH, I forgot, depending on what stroke the cylinder is in, you might have to undo the rocker adjustments to make sure the valves are closed, and you are not just sending air out through the exhaust. Best of luck. _____Grant.