The Stovebolt Site Forums Project Journals Project Journals 1958 Chevy Apache 1/2 Ton Panel Truck

Yes, talking with people around me. Its split 50 50 whether or not to swap.
Pretty sure not a head gasket. Oil is fine. No coolant loss. I`d like to get at least 4 and 5 cyl up to the rest in compression
and see how it does.

It would be nice to know if the "good" cylinders are really as low as reported, 75 psi is pretty low.

With the Compression readings that low you really suspect some cylinder wear and/or bad rings. The leak down should tell you the state of the valves.

Head gaskets don't just leak into the water jacket. It could be losing compression into the exhaust manifold. You also might have burned exhaust valves or broken valve springs causing low compression.

Thanks!! I`m pricing leak down testers and their quality. Renting too.
Would my spark plugs give me a clue?

Thats what I fear.

If they were fouled maybe. They may show signs of burning oil, or corrosion from water or antifreeze.

No corrosion. All were uniformed in a light black color. They looked OK. Clean
Ill try and get together a plan to get in line to have the motor gone thru, then
try and find some help at the last point of removal. Get the engine out.

You may want to check the valve lash before you pull it. If the plugs looked uniform and not oily the rings may be okay. It doesn't take much valve opening to prevent compression from being up where it should be. Setting the lash on the large end of the range would provide some insight without the effort required to remove/rebuild.

thanks. I`ll look into that for certain

Can my numbers on the side of the engine help me determine if they are mechanical or hydraulic lifters?
Its a 1957 I`m told. But lash adjustments are different for mech and hydr.

Yes sir. Post a picture and we'll help with decoding.

I can find these.

The 1st picture is just the sand casting core ID numbers for the head when it was cast as far as I know. The 2nd is the head casting number which indicates its a 1956-62 235 head. For overall engine ID, need the numbers stamped into the machined serial number flat on the block, passenger side just behind the distributor. It wouldn't hurt to have the block casting number, which will be on lower side of the block on the passenger side and the block casting date codes sligtly forward and above the starter. Those are needed if your serial number pad is blank, which could indicate it's a service replacement engine.

couple different angles

That's your engine block casting code. 3837004 decodes as a 1955-57 235 used in both trucks and passenger cars. Still need the block casting date codes and the stamped engine serial number to further ID your engine.

Below is a sample pic marked to show where all 3 codes can be found.

can you read this?

I can see the "CON 4" but the remaining is too blurry to read. The "CON 4" indicates the assembly plant conveyor number the engine was assembled on. The other would be a single letter (that corresponds to the month of build), followed by 2 or 3 numbers which indicates the day of the month and year built.

Of more importance is the stamped serial number that you should find on the flat machined pad directly behind the distributor mounting into the block.* That set of letters/numbers will give details on the engine model year and original vehicle it was installed in. That's where you will have the best info for confirming if the engine was originally equipped with mechanical or hydraulic lifters.

* If there is not a stamped engine serial number, it's probable the engine is a service replacement.

thats the best pictures I can take. all I have is a nikon camera to take pics.
I`d have to pull the engine to get any others. No, I`ve don`t and never owned a cell phone.

Does this look close to original? Two springs for the throttle and one pulling from the oil pan
for the clutch? Clutch spring in particular.

These #`s I scraped away. One should be 57 the other 58

Ist pictured engine serial# decodes as F = Flint assembly plant / 8 = August (month of assembly) / 5 = 5th day of August / Z = 1957 or 1958 Passenger car regular engine with standards 3 speed or 3 speed OD transmission. Per the 1957 GM Heritage Center archive data (and the 1958 data), that 235 came standard with hydraulic cam/lifters. It could have since had a replacement mechanical cam installed, so further checking of the lifters is needed to verify which. Since Chevrolet used the same engine serial number sequence/codes for both years, to confirm if 1957 or 1958, need to know the block casting date code.

2nd pictured engine serial# decodes as 0247780 = 246,780th engine built / F = Flint assembly plant / 55 = 1955 model year / Z = 1955 Passenger car 235 regular engine. Per the 1955 GM Heritage Center archive data, this engine would have come with a mechanical cam/lifters as it was not originally built as a "Powerglide" equipped engine. Those got hydraulic cam/lifters as standard when coupled to the automatic transmission.

Hope this is helpful.

Some. here are some more. The unpainted should be 55. Now that 235 engine was in the 1958 panel truck originally and
I`d bet my life its the original one. I wonder why it came with a 1955 engine? Under the dirt and oil you can see the original
blue/color the engine was.
The freshly painted is the "57".

Did a leak down test on the low compression cylinders at 25. All the leak was thru the exhaust. Vent tube and exhaust pipe.
#5 had a 90% loss.
I`d like to think something is stuck there. At TDC when tested.
Can I run a mix of marvel mystery and fuel in a separate container and try to free up
anything that might be stuck? What would be the mix ratio?

Probably a chunk of carbon caught between the exhaust valve and the seat or may the valve is burned. May try to rotate the enging until the intake valve on cylinder is open and then tapping on the exhaust valve to unseat/seat it to see if you can dislodge whatever it is. What was the leak down on the other cylinders?

By "vent tube", are you referring to the road draft tube?

If air is exiting the road draft tube, that means air is getting past the piston and into the crankcase. You either have extremely worn or broken piston rings or a blown head gasket.

Air exiting the tailpipe is, of course, an exhaust valve.

thanks, hmmm. putting things together. When I pulled the spark plugs a few months ago ,# 5 plug ...the
electrode was bent down on the plug. Pretty sure I did not put it in that way. The truck cranked fine with it but
once I regapped the plugs to specs ,the engine seemed to have woken up a little more.
When I did a compression check the plugs were all fine, a little black. And when we pulled #4 #5 for the leak down ,those plugs were fine.
But would there be anything that may have broken off the piston that would have come in contact with the spark plug?

I`m gonna pull this engine out. Any tips?
My biggest question is can I pull w/o taking the bell housing off too? I put it in with the BH on.

Sure you can, as long as you add support to hold and secure the front of the transmission (if you're not removing it first) and pull the radiator to allow for maneuvering space.

Not to get the cart too far in front of the horse but when you reinstall the engine (assuming that you leave the bell housing and transmission in place) be very careful aligning the transmission input shaft with the engine, it is very easy to get things out of alignment and bend the input enough that it will bind preventing the clutch from disengaging the transmission.

Thats not a concern for me. Maybe some. I`m working alone .Lifting the engine in or out is stressful by myself.
I`ve installed way too many transmissions to make that mistake. That I can do alone. Use guide bolts.
Did you bend your input shaft?

Leave the BH on. The bolts on top would be near impossible to remove. Removing the tranny will give you the clearance you need.

Thats what I thought!! thanks. of course I`ll take out the radiator. but still it`ll have to be tilted to get it out of there.
The hood might need to be taken off. I want this truck to have the 235 in it.

this morning SM-319 removed. Floor jack and transmission plate adapter.
Guide bolts and its amazing how easy that`ll roll out. After about 500 miles or so, everything
is looking brand new still. Now just a matter of prepping the engine for removal. Thats another day.
The trany took me most of the morning. Most of that looking for the right wrench or socket.
Lowered with the floor jack. Rolled off on a piece of carpet with a cardboard box on top. Dragged out.

Engine ready to pull. Are there are recommended lifting points for having the bell housing on
and having to tilt it for removal?
I set the engine in but it was struggle alone.

I pulled the engine on my '51 with the transmission in place, but I used an engine leveler bolted to the valve cover bolts. That's not an option on your 235 however.
The 55.2 shop manual I have says remove the engine and transmission together, using eyebolts in place of two cylinder head bolts, but it doesn't specify which ones. The 47-51 Shop Manual says use the third bolt from the rear on the left side and the 4th from the rear on the right side of the head (but the picture attached shows the right side farther forward than that - like between cylinders 2 and 3). You may have to experiment with lifting points without the transmission hanging on the rear. Maybe move forward one bolt hole on each side.

Thanks Kevin, thats what I was looking for.
I would think that shop manual would be for if the fenders and radiator support were
removed.... if the trany is still attached.
I`ll keep track of how it goes.

Does anyone know the part number for the output shaft seal on a SM-319? same as 318. timken 59338ej is what I`m finding
but no parts house number. Masterpro or precision? National 415938 ??? Not sure

Try GM PN 591448 That's listed as the rear seal for a 55-57 Commercial HD 3 speed 2-3/8 ID x 3" OD x 1/2"

My best guess from looking HERE

Few more leads. thanks. I might just pop the old one out and see.
I`ll measure the shaft first