The Stovebolt Site Forums The Shop Area Engine Shop 235 distributor shaft doesn't reach oil pump slot

Here's the latest in the saga of this POS engine: the distributor shaft won't reach the oil pump drive slot, even when it is pushed down so everything else is bottomed out. The shaft was measured below the drive gear and the distance is actually less than what is needs to be to reach. The plate in the inside of the housing reads part #1112403, which according to my research indicates the correct distributor for a 1956 235 like I'm working on.

Does anyone have an idea what could be wrong here? The only things I can of are something is amiss with the oil pump (it pumps oil when spun with a drill, though), or possibly the insides of the distributor got changed out with those from another engine's distributor. Any help would be much appreciated.

check to see if the vacuum advance didnt slide down the shaft a little, loosen the screw that holds it to the shaft and slide it up then try again, i have the same motor and been thru the same problem, and thats what I did to fix mine, with the same part no.

that would be your problem, what hoozat say. I saw that as a possibility when I built my engine. I put in a rebuilt distributor, and noticed that could have happened.

Compare
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With the vac advanced installed I measure approx 5 1/8 from bottom of advance to end of tang

Sometimes you have to move the pump slot with a long screwdriver the get the tang to engage.

Just remember where you are as far as timing.

Even without any vacuum advance at all on the dist. I can't get it to engage the fuel pump. Measurement-wise it seems like it should engage about 1/8", but it just won't engage. I've tried moving the shaft all the way around without being concerned about the timing just to see if it will engage at all, but still no luck. I think I'll try to move the slot in the fuel pump as you suggest and see if this helps.

What is the general consensus as to which way the rotor should point at TDC: toward the fender or toward the #1 spark plug? How does this shape up as far as the orientation of the fuel pump slot and the orientation of the rotor before the distributor goes in the hole is concerned?

See the instruction when the engine has been disturbed: http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm1229.htm

It sounds like the pump is to low. I suspect the lock bolt is not in the indent on the pump.

it doesn't matter where the rotor ends up, you just find #1 tdc, and wherever the rotor ends up will be #1. Then just go in order clockwise. If you aren't concerned about timing, get the slot close to where you think it might line up with the tang on the distributor, and turn the crankshaft one way or the other till it falls into place. Then you can find TDC on #1 and go from there. But beware that if you are pushing too hard on the distributor using this method the friction alone could cause the oil pump to rotate right along with the distributor and never get it to line up.

I was thinking the pump was too low also. Now I have to hope I can get the oil pan off without having to lift the engine up or take it out.

I know theoretically it doesn't matter which way the rotor points at TDC, but I was just wondering which way was considered "correct" on these I-6 engines, pointing it toward the fender or #1 spark plug. Or is it one of those things that everyone has their own opinion about? I've never bothered to look up in the shop manual whether it states one way or the other.

They came from the factory with #1 pointing straight at the fender. To me it looks a little odd if it is not located there.

you notice where #1 is?

In this link you can see where #5 is. Of course that is the next after #1

That's what I thought, but I had an old timer tell me to point it to #1 spark plug. He didn't say what his reasoning was though.

In various factory illustration, I have seen #1 being located from 5-7 o'clock (1954). (1956) Note the location of the grease cup, you want that in a position that will allow free movement when the distributor rotates due to vacuum advance

That's a good picture. That's the way I had it, then I took the truck to an old timer for help and he changed it all around.

Got it figured out! The O-ring on the distributor shaft was too thick and was keeping the distributor from going all the way in the hole. I don't know why the O-ring is even needed if the tolerances are that close.

is there a factory O-ring there??

Bill

The reman you get from napa comes with an o-ring

I had the same problem, once I removed the o- ring it dropped in. Should of mentioned that before but he said his distributor was bottomed out in his first post.
I dont believe there is suppose to be an oring

1956 235?
I double Bill's question.

You got it right by saying "I don't know why the O-ring is even needed if the tolerances are that close."

No o-ring, seal, or gasket is used.

If you did force the O-ring in it will be so tight it will lock the vacuum advance from twisting the distributor. Seen it done.

I always thought the lack of a seal there is to insure good electrical connection, the dist case needs to be ground

Bill

Put the grease cup to the rear. The Vac advance to the front with #1 at about 5 o clock. Turn the oil pump until it is clockwise to the shaft tang about 5 degrees or 1 tooth on the cam. Slide the vac advance all the way up the dizzy and try to set it in place. Wiggle the shaft if needed and you should feel it slip into the pump. If it does you are good. Now loosen the clamp on the vac advance and set the bolt into the motor with the "octane" gauge at 0 degrees. Lock the bolt down and set the points to just open at the "BB". Snug the clamp. Should start. Watch the oil press gauge. If no pressure. TURN IT OFF! Try again. Are we having fun yet? If you felt it engage the pump you should be just fine. Much worse on a hot motor in the intersection. Yes I have had it happen....:)
Steve

I would guess that a good ground should be achieved through the vacuum-advance clamp? However, oil/grease around the distributor might hamper a good ground of the distributor body/clamp. I know it is silly, but I have at times run a wire from a distributor-cap clamp-screw to the head (clutching a straws in dealing with high-rev misses).

A good timely topic.
This is what I'll try next.
My dist's original position had the grease cap at the 6 oclock positon (pointing straight at the fender) and with a now functional vaccum advance, with the grease cup at 6 oclock it hits the vaccum can when it advances and I don't think I'm getting max adv. It just don't seem right to my uneducated eye (and I could be wrong).
I believe I'll have to reposition the plug wires clockwise but no problem if Steve's recommendation will get the rotor lined up w/#1 plug wire.

I must have had the dist in/out 5 times last night playing with mine and altho it's a 216, the dist didn't have an O ring.
Dave

....vrooom....
...vroooom...

Yeah to all of that, there is no O'ring used on those distributors.
DG

Thanks DADS50,

I repositioned the dist w/the grease cap turned all the way back and moved the plug wires CCW 1 position and the vaccum adv is working nearly as good as in your vid.
One thing I discovered is I need to keep the idle down between 450 & 500 rpm as the ported vaccum to the dist starts pulling (advancing) the dist above 500.

And as been stated, this 216 really likes to be advanced past the BB at idle.

450-500 is the idle specification for the 1956 235 truck engine.

Good work, figuring this out.

DADS50 Has again provided the best picture of what I tried to say. Nice vid.

I wonder why that extra slot is cut into the shaft if there isn't supposed to be anything (like a seal) in there.