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 Post subject: un-seizing a rebuilt but seized engine
PostPosted: Tue Mar 03, 2015 12:40 pm 

Joined: Thu Jun 14, 2012 9:43 am
Posts: 81
Location: West coast Canada   
hey JNC,
I'm the proud new owner of a 1973 4M that was rebuilt about 15 years ago, maybe 20. New pistons, bearings, seals, &c &c. It's been bored 1mm over and it's looking really great. New oil pump too. It never ran. The previous owner got it back from the machine shop and was going to put new timing gears on it, but then lost momentum.

The engine sat in a heated, dry basement since it was finished. The head was loosely attached but not torqued down. It was filled with a thick oil and left there.

So, what's the best way to get this to spin again? I've got penetrating oil and WD-40 all over the pistons and crankshaft. There doesn't seem to be any corrosion on it at all. I've got a pry bar I can bolt to the flange side of the crankshaft, but before I put a lot of strain on it, what else should I do?

I know there's a pile of info out there about various un-seizing techniques. Basically I'm wondering if there's any special gotchas about un-seizing something that's pretty much new but never-ran.

To get the camshaft going again I undid the bearing caps, but I'd like to avoid undoing and re-torquing the crankshaft bearings.

Thanks,
Mike

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 Post subject: Re: un-seizing a rebuilt but seized engine
PostPosted: Tue Mar 03, 2015 7:41 pm 
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Joined: Thu Apr 15, 2010 3:00 pm
Posts: 44
Location: St. Augrida, FL
diesel makes a good solvent to clean the surfaces of the gummed up oil. use a soft brush to agitate it. you will probably have to take the head off if there is really a lot of that stuff in it.


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 Post subject: Re: un-seizing a rebuilt but seized engine
PostPosted: Sat Mar 14, 2015 11:25 am 

Joined: Thu Jun 14, 2012 9:43 am
Posts: 81
Location: West coast Canada   
In case anyone searches this thread in the future...

I ended up undoing the main bearings and the connecting rod bearings to finally get the 4M to spin freely. In all of them, the oil used when it was first assembled had turned into a very thick, very sticky coating almost like not-quite-dry varnish. There was no way this thing was going to turn over without pulling it all apart and cleaning it out.

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'70 MS55 Crown & an '81 BJ42 LC
(ex: RK41, RT85, MS55x2, MX13, TE25, TE27, BJ40, FJ40x2, BJ60)


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 Post subject: Re: un-seizing a rebuilt but seized engine
PostPosted: Sat Mar 14, 2015 4:33 pm 

Joined: Sun Jul 25, 2010 12:44 am
Posts: 58
Location: Chattanooga, TN
Most of my projects are long and drawn out so I use engine assembly lube, the red stringy stuff. It has stayed pliable in one of my engines for about six years as it sat in a bag in the corner of the garage waiting for the rest of the car to be ready.

Kane


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 Post subject: Re: un-seizing a rebuilt but seized engine
PostPosted: Mon Mar 16, 2015 8:47 pm 
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Joined: Mon Jul 30, 2012 4:36 pm
Posts: 421
Location: Coarsegold California (around fresno)
Any pics of your project?
I ahve done many things to unszise an engine. I once rolled a motorcycle down a hill and put it in 5th and let the clutch out. It actually worked. Most the time with an engine I dont care about, I put trans fluid down spark plug holes for 3 days, put a breaker bar on the crank, crank till I get a tad of movement, then ram back and forth to get all the rust off the cyl walls. :twisted: I have never done this to a toyota, just hondas. :lol:

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 Post subject: Re: un-seizing a rebuilt but seized engine
PostPosted: Mon Mar 23, 2015 6:16 pm 

Joined: Thu Jun 14, 2012 9:43 am
Posts: 81
Location: West coast Canada   
pics:
Image
Image
Image

A lot of lighter fluid got almost all that gunk out. Next, starting to tear down the 2M for its timing gear.

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'70 MS55 Crown & an '81 BJ42 LC
(ex: RK41, RT85, MS55x2, MX13, TE25, TE27, BJ40, FJ40x2, BJ60)


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 Post subject: Re: un-seizing a rebuilt but seized engine
PostPosted: Mon Mar 23, 2015 10:04 pm 
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Joined: Thu Apr 03, 2008 2:38 am
Posts: 73
Location: Moreno Valley, California 92551
palatine wrote:
pics:
Image
Image
Image

A lot of lighter fluid got almost all that gunk out. Next, starting to tear down the 2M for its timing gear.

If in doubt, get the crank polished and magic mystery oil would have been my choice to free the rings.

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 Post subject: Re: un-seizing a rebuilt but seized engine
PostPosted: Sat Mar 28, 2015 12:10 pm 
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Joined: Wed May 18, 2011 5:09 pm
Posts: 168
Location: Netherlands
free the rings is not easy but can be done. Let it soak few days in a gasoline/diesel mixture. Then heat the pstons some with a blowtorch, so the aluminium widens to the steel of rings. Heat on piston dome. Then spray a lot of WD40 and try to get them loose. Best is to work with some warmed pistons as this expands the aluminum and soaks the WD40 better

If no success, try t break off the rings because a new set is not expensive and easy to find i guess. tick out the pieces of ring with an old screwdriver, and carefully with the soft alu ringlands of piston. Good luck !

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