Siezed motor? how to free it up?

[03mach1]

Hey guys so I traced down the original 351 motor to my 71 mach 1 and its all there except for the A/C and power steering pump. But it has sat outside for over 30 years! when this car was parked they yanked the motor and put it on the ground and did not move since 1975. Now i am sure this thing is siezed up. what is the best way to free it up with out causing a lot of damage to it. It will undergo a complete rebuilt of course.

[POPPAJ]

Re: Siezed motor? how to free it up?

Take it to your engine builder for dis-assembly. You may very well cause further damage after 30 years.

[03mach1]

Re: Siezed motor? how to free it up?

i am the engine builder lol just never delt with a siezed motor

[Fly Bye]

Re: Siezed motor? how to free it up?


If you were to pull all of the plugs, it should turn, but like the others have said, that would not be advisable. The engine block will need an acid bath.

[03mach1]

Re: Siezed motor? how to free it up?

Sweet hopefully that will work

[Fly Bye]

Re: Siezed motor? how to free it up?


Alex, where in the Nor Cal are you?



Tony

[Paul S]

Re: Seized motor? how to free it up?

Learned this ages ago from another old timer. A friend had a 140 hp MerCrusier (4cyl Chevy) that sat for a couple of years without a motor cover or air cleaner.Figured we would have to pull the motor since it was froze up.Pulled the head off and took a large hammer and piece of 2x4 and tried to free up the pistons to no avail. On the advise of the old shade tree mechanic friend of mine we filled the cylinders with vinegar which I honestly thought was a waste of time and money. We let this sit overnight and returned the next morning. Reached in and hit the starter button expecting to hear a click - click . The short block assembly spun freely like a electric motor. I since have been told that unlike metals kind of seize together (Piston rings and pistons to cyl walls) and the acid in the vinegar helps dissolve the crud created by the various surfaces. I have shared this method with plenty of other gearheads with plenty of success stories being shared. Now keep in mind this is no cure for the motor with a seized crank bearing (rod throw or main bearing). If too much torque is required to spin the motor then further investigation and or tear down will be required.So good luck and please share your findings with us as things progress.

[Fly Bye]

Re: Siezed motor? how to free it up?


You could pour the vinegar down the spark plug holes to bypass tearing the head off.

[03mach1]

Re: Siezed motor? how to free it up?

@ Tony im up in Placerville
Thanks for the advice. As for the vinegar did you just use a basic cooking vinegar? Ill pour some down the plug holes and let it sit over night and take my 18 inche breaker bar to the front crank pully and see if it spins at all

[Paul S]

Re: Siezed motor? how to free it up?

You could pour the vinegar down the spark plug holes to bypass tearing the head off.

Any access would be OK. Intake,spark plug hole etc. We had the head removed while in the process of removing the motor from the boat.

[Paul S]

Re: Siezed motor? how to free it up?

@ Tony im up in Placerville
Thanks for the advice. As for the vinegar did you just use a basic cooking vinegar? Ill pour some down the plug holes and let it sit over night and take my 18 inche breaker bar to the front crank pully and see if it spins at all

Yep. White distilled vinegar from the local grocery which I keep on hand for cleaning bathroom tile , adding to my Bissel LGM for heavy stains on carpet along with Folex and glass mirrors.

[03mach1]

Re: Siezed motor? how to free it up?

Thanks for the help Pual

[Fly Bye]

Re: Siezed motor? how to free it up?

im up in Placerville

Isn't there anyone in the North Bay Area???

I'm not gonna drive 2 hours (one way) just to hang out with someone

[AllenB]

Re: Siezed motor? how to free it up?

You can fill the engine full of diesel fuel. Not EPA approved I'm sure but it will work. Drain the oil that may be in the crankcase, pull the plugs, fill each cylinder, fill the crankcase and fill the intake. This is going to make a mess so you will need an area that you can actually do this. Leave is sit a day or two and it should free up. I have also seen transmission fluid poured down the spark plug holes work too.

I wouldn't worry to much about hurting anything. This engine is going to have the cylinders bored, new pistons, crank at least polished if not turned, heads will be rebuilt. When you get it apart the first thing will be to get in a hot tank and clean the block and heads.

Have fun with this one! Sounds like a great project.