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View Full Version : HOW -TO UNSEIZE A SEIZED ENGINE!!


GRUP
12-06-2000, 07:08 PM
I PICKED UP A 360 LAST WEEK FREE!. IT HAD BEEN OUTSIDE FOR A COUPLE MONTHS AND WAS FULL OF WATER. I PLANNED ON JUST USING THE CRANK IN A .040 340 BLOCK TO BUILD A 375. THE ENGINE IS SEIZED REAL GOOD. WHAT'S THE BEST WAY TO FREE UP THE ENGINE WITHOUT DOING TOO MUCH DAMAGE TO EVERYTHING? IF I CAN SALVAGE THE BLOCK I MAY JUST USE THE 360 COMPLETE. WHAT WOULD BE THE MAX'M OVERBORE ON A 75 BLOCK?
THANKS!!

ChristianCuda
12-06-2000, 10:52 PM
Well first things first oil it down with trans fluid al the bores
let it soak for a while and keep it oiled.then loosen up the rod bolts and main bolts With emphasis on Loosed only. Do not remove any ov them. Then work the rods loose off the crank. Then work the crank loose off the mains. This should allow you to turn motor to remove pistons as the rods allow for each turn. Remove as many pistons as possible before turning the crank to free up tension.

Christian

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ChristianCuda
12-06-2000, 10:53 PM
Oh and you should eb able to go .040 over to 340 size but I would only go .020 and then have it sonic checked too. Going .020 gets you more rebuilds down the road.

Christian

jammiejeanne
12-07-2000, 12:27 AM
I've also had good luck with Marvel Mystery Oil. Used Trani fluid and I like the mystery oil best, tho trani fluid works.

MJD
12-07-2000, 01:16 AM
Use diesel fuel. I have done this several times and it worked each time. The key is to be patient and let the diesel do the work, be prepared to give it a week or two depending on how badly siezed it is. I have also heard of the Marvel Mystery Oil, but have no personel experience with it. A good friend of mine swears by it though.Good Luck!

72Challenger
12-07-2000, 02:46 AM
To answer your other question, that block was cast with the 340 water jackets, so you can safely bore to at least 4.080" (the same as a .040 over 340). So you have no real reason to change blocks unless the 360 cylinder walls are ruined. That way you save on the crank grinding. But ChristianCuda is right, don't take more than you need to, gives you more for later, and the extra couple inches won't be noticable in the performance.

GRUP
12-07-2000, 01:04 PM
THANKS FOLKS!!! I GUESS PATIENCE IS A VIRTUE I DONT HAVE. I'VE DESTROYED MORE PARTS (I DROVE A FLAT SCREW DRIVER RIGHT THROUGH A THERMOQUAD ONCE!) THAN I CARE TO REMEMBER DUE TO LACK OF PATIENCE... BUT I'LL BE PATIENT THIS TIME. I'VE GOT LOTS OF TRANNY FLUID. 72 CHALLENGER CAN YOU REALLY BORE A 75 360 .080 OVER?? I'VE ALWAYS HEARD THESE WERE THINWALL BLOCKS. HOW MUCH MEAT IS THE MIN'M YOU CAN LEAVE IN THE CYL. WALLS?
THANKS, GC

72Challenger
12-07-2000, 07:47 PM
Actually, if there's no core shift, or if the shift is in the thrust direction, you can go up to 4.100". That's the same as a .060 over 340, remember the early blocks have the 340 cores. I'd never go that far without sonic testing first. I'll need to look it up to be sure, but I believe the minimum thickness is about .125". The factory recommends a maximum of .040" over, but crazy horespower freaks go over that all the time, seemingly without too many problems.