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This spring when I do my annual tune up/oil change and such, I am also planning on dropping the oil pan and changing the gasket to try to stem some of the oil leak there. My question is, is there anything else I should do when I have the pan off? The engine runs fine and the oil pressure is good (I have no filter), but I do not think anything has ever been done to the engine interior since it was built. I don’t want to open up any worms, but I would also not like to miss the chance to improve things, or check things. I might also pull the side panel, and I read in an earlier post about cleaning out a oil line while it is accessible; I have not looked in there before, is the line removable with just the side panel off, or would I need to also pull the head? At present I have no plans to do that, compressions are descent, so I think my valves are okay.
My mechanical skills are adequate, but I have never been inside an engine (other than changing an oil pump on a previous old vehicle), and I don’t have too many of the special tools I have seen used when rebuilding an engine.

Thanks for the input, Lee.

Since you didn't identify what engine you're working on, I'm going to assume it's the 56 235 in your sig line. That one has replaceable rod bearings. You could drop some rod caps off and inspect the bearings, and replace them if they're showing wear. Be sure to measure the crankshaft diameter with a micrometer and get the right size replacement bearings if you choose to change them, and use a torque wrench to tighten the rod nuts to the specified torque values.
Jerry

Thank you Jerry, yes it is the 56 235, and when I checked the numbers on the engine it matches the truck so I am pretty sure it is the original engine. I will check the bearings as you suggested.

Lee.

The line behind the side cover is an easy and very doable project. The line is tapped into the rear cam bearing and bleeds some oil pressure from the galley and feeds it to the head, where it is then fed to the rocker assembly. Very very common for this line to get clogged up over the years.

To remove, first remove any rings on your fingers and disconnect the battery. Why, because one of the bolts is near the solenoid and it is very easy to short out a tool onto the solenoid and your hand or rings and you can get burned really badly. How do I know this, a couple of years ago I was in a rush and forgot to do both and darn near burned my finger off. Three operations and skin grafts. I have the photos to prove it. 40 some years of always removing jewelry and disconnecting the battery and wham.

Next, remove the bolts holding the side plate. A couple of them can be a speck challenging but you can get them. Depending on how your distributor is mounted, you should be able to remove the side plate without removing the distributor.

Next, disconnect the steel line, and clean it out really well. if you have a little compressed air, blow a little air in the upper fitting on the head. If you hear air in the valve cover, the passage is clear. Reinstall the line. Wipe the block mating surface nice and clean. Take a look at the side plate, any dimples where the bolts go, or any dents, straighten them out. Install a new gasket, cork or the orange rubber version that is available. I usually like to use just a little rtv or permetex No. 3. Tighten the bolts evenly, no gorilla work here. Otherwise you will split the gasket or push it out or otherwise cause a leak. Firm and secure but not tightened to death.

You are done!

Lee,

Can you expand on your matching numbers comment for us...what do you mean "the engine it matches the truck"?

Thanks,

Mike B

If I have read the numbers correctly:
SN: 273564 F56X; assembled in Flint in 1956 and regular production.
Date code: B256 (I cannot recall how the B and the 2 are translated, but the 56 is pretty clear)
I have the block and head codes also, but I do not know how they are translated.
I guess I should say that the dates match the truck year model, and the person I bought it from though was not the original owner, he purchased it in 1967 and had not changed the engine or done any major work on it during his ownership. In my 2 years of ownership, I have not seen anything yet to suggest anybody has done much work on the truck before me; the generator and starter seem original as well as the distributor. So though I cannot be sure, I would bet that the engine is the original one.

Lee.

1956 Chevrolet Trucks serial number decoding
Engine Serial Number info is on second page.

Thanks for the link Tim, I have decoded the engine and VIN serial numbers, but not the transmission yet. None of the numbers I have down for the transmission match what shows on the page, so maybe I have something written down wrong, or the transmission is not original to the truck. I have looked all over the differential and have not been able to find any numbers on it. Maybe they were on a tag that is now gone, I do not know.
I looked at the shop manual and it looks like I have the newer style main bearings, so that should be easier to change them out this spring.
Thanks Mike for the detailed info on removing the oil line behind the side cover; I’ll try to remember to disconnect the battery! I don’t think it would have occurred to me to do that, not thinking about the fact that the cable to the starter is right there and hot.

Lee.

Post you transmission codes, here, Lee

Members will try to help with identification.

Lee, your 56 motor has the updated rod and main bearings (55 was still using the older style pinned and/or adjustable shimmed bearings), and as an added bonus, 56 was the first year for the neoprene rear main seal. Truth be told, if this motor is not making any rod or main bearing noises, I would not my self be inclined to take the rod or main caps off. Sometimes its just better not to open a potential Pandora's box. I would be more inclined to remove the oil pump, lines and pickup, and clean out the lines and the pickup then mess with the bearings.

B = February (Month)
2 = Day


I agree and thanks for clearing up the numbers question for me. At first it sounded to me like the engine and chassis numbers were exactly the same and that would be of interest. It's always nice to find a vehicle that's never been molested with all of it's original equipment still in place...makes it rare and special!

Mike B

Sorry, but I am not able to edit the earlier post?

F 56 X
Truck code
F Flint
56 1956
X 3100/3200 truck engine (mechanical lifters)

Thanks Tim, I’ll post the transmission numbers on the driveline section and see what I can learn.

Lee.

If I do need to replace the main bearings, what would be a good source for quality? The same for the oil pump? Or is it possible/desirable to overhaul the pump? I had an electric fuel pump on my S-10 fail and I replaced it with a generic one from a FLAPS that failed after just 2 years of use. The next one was from the dealer and it lasted much longer, so I do not wish to repeat the experience.

Thanks, Lee.

Any of the NORS (New Old Replacement Stock) bearings available on Ebay from manufacturers like Federal-Mogul, TRW, Clevite, Vandervell, original equipment GM, etc. would be my first choice. Just make sure the size is correct and the shaft is round and not scored. Once the upper bearing half is rolled out, some careful measuring with a dial caliper can check for out of round and taper of the main bearing journals. It's not quite as accurate as a micrometer, but there's no room to use a mike with the crankshaft still in the block, and no practical way to lower the crank enough to do so. There are several Melling M-45 oil pumps listed on Ebay most of the time, and those pumps are also "best quality" choices. In 60+ years of engine building, I've only seen two actual oil pump failures and both of those involved a piece of metallic debris jamming the pump so tightly it sheared off the drive. I have seen badly scored pumps from ingesting metal too small to actually lock up the works, but those pumps still moved oil well enough to keep the engine lubricated.

If there's any way to avoid using an electric fuel pump, I'd choose an original mechanical pump. The only reason I'd consider an electric would be if the pump lobe on the camshaft was worn or damaged.
Jerry

Thanks for the info Jerry, I appreciate it. As far as the fuel pump is concerned, I have no plans to replace my mechanical one for an electric. My story was just indicating how I want to be careful to buy with quality in mind and not price. It was not easy getting to that fuel pump in my S-10 and want to avoid doing things twice!

Lee.