Inliners International Forums General Discussion Engines Engine Identify

Looking for info on an engine that is currently in my 54 GMC Truck. It's not the original which I do have.
Having a hard time searching for the numbers, etc.
This is what's on the engine: 00II242F54X CON1 K5
on the head 6835913
Attached are the photos. Looking for year and size so when I order parts I get the correct ones. Also who is best for the engine parts for rebuilding, etc.
https://flic.kr/p/2jKaVMX
https://flic.kr/p/2jKaVyv

I haven't looked at the numbers but is a 235 or possibly a 261 Chevy engine. Check the "Casting Number" feature on the left in this window. The number you posted doesn't seem to match. Here is a good link: LINK

Based on the engine serial number that is a '54 235. The 'X' suffix decodes to a 3100 series truck application.

The specifications are online here at: The Old Car Manual Project The engine serial number decoder is at the bottom of the page.

I'm going to pull the engine when I start on the body and go thru it see what all it needs.
Any suggestions to the best way to rebuld the engine as well as best place for parts that won't take my wallet, need to have something left for the rest, LOL. Like to keep it as stock as possible.
I do have the original 54 GMC 248 engine that I'd like to put back in, just need to find all new parts and have the head/block checked out.

What's wrong with it?

So far I can turn the engine over by hand. Unsure why the truck was parked and figure I can refresh or rebuild the engine since it was sitting for the last 40 plus years. Hate to try to start it and have something break in it. Getting ready to start tearing the truck completely down, pretty much rebuild everything from the frame up.

Before you take it apart, do a compression test

What panic said!! Unless the engine has been open to the weather, you may find that it will build compression and run!! Squirt a little spray lubricant in through the spark plug holes and give it a spin!! Make sure the oil is good and look to see if it'll build oil pressure.

Ain't much more fun than getting an old engine to fire up after it's been dormant for decades!!

Bought a gallon of marvel mystery oil and will put some down cylinders from what I read. I got a tractor 6v battery and can use it, just need to find an ignition key setup and hope all the wires are good.

Be sure to check the oil level! If it still looks and feels like oil and is at proper level you can probably safely fire it.

If oil level is high there may be water in the crankcase. If it's low or doesn't look, feel, or smell like oil then you better change the oil before firing the engine. My opinion...

If you put a gallon of Marvel Mystery oil in the cylinders then you better change the oil before firing! I would expect MMO to run down the cylinders and into the crankcase. Why not just use motor oil in the cylinders if you feel that's needed?

Oil looks good, just about to the low line. Turned crank by hand and it seems to stop at 1/4 turn back and forth. Will pop the valve cover and plugs to see what may be stopping it. Need a way to turn the crank, no bolt on balancer, have to make something to insert into the "plus" part of the balancer to turn.

Remember that if it has been sitting for a long time the impurities will have settled out of the oil. If there is water it will be on the bottom and likely not show on the dipstick.

turn it by the flywheel if it has one on it.

Hi,
My two cents:
I wonder if it hydraulic locked on the Marvel Mystery Oil?
I would pull the plugs and leave them out. (cover plug holes with a rag)
Drain the oil and refill with clean.
Turn by hand, not the starter, and see if you can get the whole 360 rotation
Could also have some mouse or squirrel's stash in one of the cylinders too.

Good luck!

How much is "some" MMO?
My guess: no more than 50% of the chamber volume (never the cylinder volume). If you added the full chamber volume the CR would be infinite: breaking things.
Chamber volume = cylinder volume ÷ (static CR - 1)
For a 235 @ 8.0:1 CR
39.25" ÷ 7 = 5.6" or 92cc; add 2.8" or 46cc.

Sorry I did not mean for him to use the starter Use a flywheel tool or you can sometimes use a screw driver. Or just take the dampener off and use a crank socket and turn it over that way.

Did not use the MMO yet and everything is pretty much covered, cannot see rodents getting into the engine. Yes, I know not to use the starter but to use a screwdriver to turn. I'm going to make a tool to put on the balancer shaft end to turn, don't really want to go under and up several times.

If the engine has a generator, assume it has not been converted to 12 volts. Gotten a 6 volt battery for farm equipment. Once I know things turn freely and safely, I'll check for compression. Almost want to try to start before tearing down. Then again might change mind... Anxious to get it running, but don't want to screw it up either.

You could be dealing with a little rust on the cylinder walls from condensation. Some valves had to be at least partly one. It will likely be OK it you take it slow and easy. Thats where the MMO comes in with all the spark plugs removed. Work it back and forth and let the rings spread the oil and scrape the walls a little at a time.. There may be rust above and below the rings on the cylinder wall. If it's more than a light rusting it will need more attention.
There could be some stick valves and lifters too. If the engine is '56 or later it may be a 12v system. When they changed to 12v they also changed the flywheel and the ring gear won't work with a 6v starter. Although a 6v starter will work with 12v so when the engine was installed the old flywheel may have been used. I Can not remember when Chevy went from 4 to 6 bolts, about the time of the voltage change I think.