Click on image for the lowdown. 
====
| | | Forums66 Topics128,052 Posts1,055,729 Members48,426 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Aug 2011 Posts: 60 Wrench Fetcher | | Wrench Fetcher Joined: Aug 2011 Posts: 60 | I have a supposedly rebuilt(owner id dead) 54 235 block with a 56 head in my 49 1/2 ton. I have tried everything and cannot get it unstuck. I was wondering if it could have a piston or valve hitting somehere to lock it up. I wanted to see if anyone had any idea before i tear it down???
| | | | | Joined: Dec 2004 Posts: 1,897 Shop Shark | | Shop Shark Joined: Dec 2004 Posts: 1,897 | It is very comon for the valves to stick on these motors, espeacially if one was cranked with old gas in the system.
If you suspect stuck valves, pull the valve cover and rocker assembly. This will eliminate the valves as suspect.
If it is still stuck it is likely the usual piston rings rusted to the cylinder walls. Some diesel fuel squirted into the cylinders through the spark plug hole might help free it. I have had success using ATF. Let it sit for several days. Try spinning the motor both ways untill it will spin freely for a couple revolutions.
If you still can't budge it, it's time to pull the head and have a look inside. There are spy camera tools availabe that might let you look into the cylinders through the spark plug hole without pulling the head. Harbor freight has one that works well according to a trusted source and I have seen one recently at Costco. | | | | | Joined: Mar 2008 Posts: 1,775 'Bolter | | 'Bolter Joined: Mar 2008 Posts: 1,775 | Pull the spark plugs out and use some penetraiting oil on the cylinders.
Take the side cover off and shoot some penetrting oil on the lifters too. They can get varnished in the bores also.
Good luck.
Last edited by Whitedog; 01/16/2013 7:41 PM.
| | | | | Joined: Mar 2005 Posts: 1,636 'Bolter | | 'Bolter Joined: Mar 2005 Posts: 1,636 | If it won't budge, it's likely rusted cylinder walls. Keep putting a mixture of atf and diesel in it. Let it set a few days, then try to turn it. You may can remove the flywheel dust cover and use a pry bar to see if it will move any in either direction. Just be mindfull if you try too hard and it does move, you may break some rings.
There is also a sliim chance a bearing (could be rod or main) that is too tight. Has this engine ever been run?
If you can find it in your area, a lot of folks swear by "Kroil". Put some of it down the spark plug holes and let it set a few days.
| | | | | Joined: Mar 2011 Posts: 1,146 Shop Shark | | Shop Shark Joined: Mar 2011 Posts: 1,146 | This might sound a little strange. A old timer said they use to use coca cola in the cylinders, They would let it sit for a couple of days. Frees up rusted piston rings. Or gun powder in the cylinders.
Thanks
| | | | | Joined: Sep 2010 Posts: 1,705 back yard wrench turner | | back yard wrench turner Joined: Sep 2010 Posts: 1,705 | Billm, Kroil, ATF and diesel, penetrating oil, molasses, coca cola, or some mixture there about put into the cylinders will help dissolve rust on the rings. Remove the valve cover and loosen all the valve settings so you don't bend pushrods when it does turn over. Remove the flywheel cover and pry on the flywheel with a crow bar gently in each direction. It will eventually break loose. Wayne1938 1-Ton Farm TruckStovebolt Gallery Forums1989 Silverado 1996 Mustang GT convertible When I die, I hope she doesn't sell everything for what I told her I paid for it! | | | | | Joined: Sep 2003 Posts: 200 Shop Shark | | Shop Shark Joined: Sep 2003 Posts: 200 | Billim, All good advice here. I have never heard of using coca-cola, but that doesn't mean it won't work. I have to ask, because it hasn't come up. Is it out of gear? Could the clutch be stuck? Just askin. Mark
1951 Chevy 3100 Some days you get the bear. Some days the bear gets you.
| | | | | Joined: Jun 2011 Posts: 1,901 Shop Shark | | Shop Shark Joined: Jun 2011 Posts: 1,901 | Coke = phosphoric acid = rust is under attack = point of inertia is over come and you motor spins round and round So there is truth in advertising after all.... Coke makes the world go
Give me ambiguity or give me something else
| | | | | Joined: Mar 2010 Posts: 1,660 Curmudgeon | | Curmudgeon Joined: Mar 2010 Posts: 1,660 | Shift manual transmission into neutral. Remove rocker assembly (as was suggested before) or remove pushrods. Check that lifters spin or move and are not stuck in the galley. Remove the starter, distributor, spark plugs and loosen fan belt. If the engine still doesn't rotate it needs to be removed from the truck. Remove the timing gear cover and gear and see if the cam can be turned. If the crank doesn't turn, for a rebuilt engine, it needs to be taken apart to see why. If this was an engine from a worn out old field truck, I'd put a 6 foot lever on the end of the engine and go for it.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM." | | | | | Joined: Aug 2012 Posts: 566 Shop Shark | | Shop Shark Joined: Aug 2012 Posts: 566 | I just went through this with my 1956 235. It sat for 20 years. I could not budge it even with the methods above except the coca-cola idea. I only used coca-cola for drinking and cleaning the terminals on the battery when they were gunk up with corrosion.
It took me a while to remove everything minus the cam and lifters. Since the engine would not rotate I could not remove the clutch housing or flywheel because of the hidden bolts. I finially had everything removed, spending time off and on after a week or so. The only problem was the lifters were rusted in. I had the machine shop remove them because they would not budge.
My .02 cents is that if the oil in the cylinders does not work in about a week or two or coke idea (not really sure about that), just tear it down and start from scratch. I would not want to possibly create more damage to the block. If its stuck that bad it may need to be bored out. Just hot tank and magna flux it, if its ok then spend the money to have the crank checked and polished and cylinders checked and bored out if necessary, then go from there on your build.
Good luck with it.
"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my sweet ride." -Amen 56 Chevy 3100 | | |
| |