Brought home the 8CM and poured marvel mystery oil down the chambers last night. What's my next step if she refuses to free up? Take off the heads or the intake? Just some guidance I'm seeking from the flathead pro's. I'm new to the flathead and want to do it correctly. Thanks.
depends on how "stuck" it is... might take a few weeks of soaking, might only take a few days... be patient
There is no set sequence to free up a stuck engine but before you screw something up internally its a good idea to know the exact condition of the engine. Since it wont turn over something is stuck, Piston, valve whatever? Anyway since you dont know about the prior condition of the engine the safest way to check to see what you are going to encounter is removal of the cylinder heads. This will show you if you have a rust problem in the cylinder walls or just some stuck rings. If you just have some stuck rings Marvel should have freed them up but a better chemical is Kroll Oil, its an aircraft use chemical that is a corrosion penetrant , expensive but works well. In any case DO NOT try to turn the engine using a big wrench on the crank pulley nut, shear of the nut stud and thats more problems. Further suggestions based upon what you encounter.
If you open it up and it's a rust bucket, you can try melting the pistons out with acid...be very careful.
Another way is to put a solid block in one of the cylinders ( or 2 traveling in the same direction) and use a heavy angle or Chanel iron with holes drilled to match the head bolts. Tighten it down then use your BFH then re tighten and reBFH it. I have used this method on recovered marine engines.
Yes, very hazardous. Hydrochloric acid will eat the aluminum (bubbles a lot) and clean the steel...but it needs to be a block worth the trouble. I've got one, but haven't done it yet. 2x4 sledge on the pistons just crushes the crowns - won't move the pistons. Already got the 4" crank out...I soaked it with everything I could think of - Mavel, Kroil, Diesel, PB Blaster - you name it. But if the block is crack free...everything can be cleaned, machined, or replaced...
I had a severely rusted one that I only wanted to salvage the crank and rods from. After trying all the Kroil, ****** fluid and kerosene tricks I knew of, I finally took a big hammer and long chisel and knocked the tops off of the offending pistons from the bottom. Broke the skirts out and finally got the crank and rods free. What you do just depends upon what overall condition the engine is in...
Marvel works good you just have to not be in a big hurry......go get a sandwich,go to the movies .......have a beer.......do that for about a month and it should come loose...we did a 560 international that was froze solid I mean it wouldn't budge even trying to pull it in gear....soaked it and forgot about it for a month.....give it a 2ft tug and there it went ........
As suggested, I pulled off the heads and measured the stroke. It's definately 4 inches, so I've confirmed its a merc. That's the good news. The bad is that I broke a total of 4 studs getting off the heads. Also, two cylinders were rusted, one one each side of the engine. On the p***enger side, it looks like the water may have come from the two valves on top and just leaked down into the piston bore. It could be the same thing on the drivers side. Can anyone help explain some possibilties? One important fact is that the anti freeze in the engine was in perfect condition. No rust at all....Is it possible that rain coming thru the carb and intake could go through the valves that way. This motor has been in the open and uncovered for the last 10 to 15 years. That's the only thing that makes sense to me, but what do I know. That's why I'm here seeking your ***istance. Thanksl.
Mine was stuck the exact same way. Rain down the carbs. Finally after a couple of weeks of no luck with all the above mentioned oils... I took the heads off and used the old 2X2 wooden block and hammer trick. After just 2 days of lightly tapping, it broke loose. Now the rings are still stuck in the pistons and only 30-35 lbs. of compression. So it won't fire. Everything else is ready. Is there any way to get the rings loose without taking the pistons and rods out? Thanks, Kevin Ooltewah Speed Shop
You can oft weasel out the crank by removing all bearing caps and just working it on out. Better access to everything that remains.
Vinegar will soften aluminum while also attacking the ring's rust lock into the cylinder. Eventually the piston will free up by one means or the other. You wanna be careful with the BFH and 2x4, as it's easier than one may think to split a cylinder wall on any engine, flathead or not. Dry rust can act as a wedge The biggest thing to remember is it took years to get there. To undo it safely may take weeks of soaking. With the MMO try dragging it out into the sun so it has more extreme day/night heat cycles. good luck
Ive used brake fluid, eats the rust up pretty good. Get it to start turning, roll the worst cylinder pistons down and take a bottle bruch and clean up the bores. Fill the cylinders up with ****** fluid and spin it over a few and should be good
Lifters might indeed be adding some drag to the ***embly, so pop the 4 bolts on cam and remove the timing gear. Attack one shaft at a time...
Apply a mixture of 50% acetone and 50% transmission fluid to loosen it up. BE PATIENT and don't destroy or crack anything.
Mine was stuck when I opened her up. It ended up being the oil pump was locked up. I could not get the oil pump to come loose from the block eather. While taping on the oil pump with a ballping hammer, the oil pump busted, and cam out. After that it spun over freely. Be patent and you will get her free.
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