I am attempting to install a Langdon HEI in a 1954 235. After dropping the unit into the block, I notice a 1/4 inch gap between the shoulder of the dist shaft and the block. I am sure I am engaged in the oil pump drive. I am worried that when I tighten the clamp I will be binding the shaft in the block. Anyone else have this problem? Also, the o-ring sits in the notched groove in the block, but nothing is holding it down. I don't want to proceed if something is wrong.
The hei is about 1/8 inch longer than the old dis, measured from the shoulder of the dist to the bottom of the drive gear. The main difference is old dist floats in the block. The retaining bolt just keeps it from rotating. The clamp and bolt on the hei unit actually pushes the dist down into the block which I believe will bind the shaft.
The one I have fit just fine. Please be certain you have the oil pump drive engaged. Hate to ask this but you do know the shaft turns as you install it, yes? So the slot and the tab can look like they will align, but by the time that the pump is inserted it will have rotated. The o-ring? I recall a thin rubber washer but not an o-ring. Is this what you mean?
I am sure I am in the slot. The shaft rotates 5 to 10 degrees C.C.. If I'm not in the slot the gap is about 1/2 inch. I also measure 4 7/8", but it is not the tip that is hitting. The bottom of my dist drive gear, (which is 3 1/4" from the dist base) is hitting the machined flange down in the block,(which is only 3" deep). This is the reason for the 1/4" gap. This might be ok if the dist floated, but the bolt and clamp from the hei push the dist down in the block and I would think cause it to bind.
It will bind. I was going to ask if the driven gear is mounted correctly, but that's a wasted question. If it was upside down, I think it would make a difference of about 1 inch. I just stepped out and measured a block which is here and 3 inches to that flange is correct. Have you measured from the bottom of the gear to the mounting flange? Can you let us know what that measurement is?
Here are a couple of measurements from a stock distributor which may help. From the tip of the oil pump tab to the lower toothed surface of the driven gear is 1 11/16" and the stock gear is 1 1/16 wide (in total).