58 283 truck engine - won't turn past 1/4

[bhap]

I'm looking at a 283 truck engine that has been sitting inside for years. History is unknown and when we try to turn it over, it will turn by hand, but no more than 1/4 turn then "thunk". Back the other way, same thing - 1/4 turn then thunk and a hard stop. While doing this we looked down the distributor hole and the slot on the shaft that drives distributor is not moving. Any guesses at what this might be? Also, is a 58 "M" code 165 hp, truck motor an ok block to rebuild? This will be going into my 62 C10. Once we pull the pan we'll see what's wrong so I'm more interested in knowing if this early block is a good starting point to build a stock-ish 283. Stamp on pad is F0404M. I don't have casting number.

[Clyde65]

Sounds like you need to either pass or dig deeper

[Mack B]

Originally Posted by bhap

I'm looking at a 283 truck engine that has been sitting inside for years. History is unknown and when we try to turn it over, it will turn by hand, but no more than 1/4 turn then "thunk". Back the other way, same thing - 1/4 turn then thunk and a hard stop. While doing this we looked down the distributor hole and the slot on the shaft that drives distributor is not moving. Any guesses at what this might be? Also, is a 58 "M" code 165 hp, truck motor an ok block to rebuild? This will be going into my 62 C10. Once we pull the pan we'll see what's wrong so I'm more interested in knowing if this early block is a good starting point to build a stock-ish 283. Stamp on pad is F0404M. I don't have casting number.

The distributor is driven off a gear on the cam, the slotted shaft you see is what the distributor drives the oil pump with, so it shouldn't move with the distributor out. Unless I'm reading you wrong and it's the actual cam that's not turning.

I had a 56 sedan that had a rebuilt 283 that came out of a 58 or 59 truck. It bored .060 over no problem, steel factory crank, and was pretty fun to drive. If what you have turns out to be rebuildable I wouldn't be afraid of it based on age.

Good luck!

[TopFuel1966]

Sounds like maybe a piston is colliding with a wide open valve. Remove the timing cover and see if the cam is turning when you turn the crankshaft. You may have a broken timing chain or a stripped drive gear. A broken camshaft is also a possibility.

The slot that you are seeing thru the dist hole is the drive slot in the end of the oil pump shaft. This shaft does not drive the distributor shaft but instead is driven by the distributor shaft via the gear that meshes with the drive gear on the camshaft.

[bhap]

Thanks guys, yes.. now that I think about it, the distributor does drive the oil pump. Mack B addressed one of my concerns about the early 283's having thin cylinder walls and overheating problems. Does anyone know when the blocks were "fixed"? With a stamp of F0404M, this block was stamped April 4th - yes?

[61K10]

that last 283"s built had thinner cyl walls late 60's. The early ones could be bored 1/8", Most anyway. we called them 301"s back in the day.

[Captainfab]

I always understood that '58 was the last year of the 283's that could be bored to 4".

[68Gold/white]

Originally Posted by 61K10

that last 283"s built had thinner cyl walls late 60's. The early ones could be bored 1/8", Most anyway. we called them 301"s back in the day.

I have a .060 67 283 that has 175,000 miles on it, it ran great never had a cooling issue, just saying. Stay at .030 or .060 at most I'd say you will be OK on any 283...

[68Gold/white]

There is likely corrosion in one cylinder, When you rotate the crank, you are likely pushing the piston below the corrosion, until it hits bottom dead center, then on way back up it hits the corrosion again, stopping its movement. Ask me how I know these things...

I would not buy it unless you could take the heads off.

[AcampoDave]

As for your thoughts about early castings being thin walled.... https://www.motortrend.com/news/smal...ugh-the-years/ looks like you may be right. At first, they were just overboring 265 blocks.

[GASoline71]

Originally Posted by Clyde65

Sounds like you need to either pass or dig deeper

Yup, either start pulling heads to check out the cylinders, or yard it out and find a different engine.

Gary