replacing distributor-- spline doesn't align

Question

I'm working on my 63 impala (283 motor) and the previous owner had put a beat up Delco HEI distributor on the car, but it's so large that you can't really time it correctly-- the cap hits the firewall and you can't rotate it. So I got an original style distributor to replace it with.

The problem is that the spline on the bottom of the new (old style) distributor doesn't line up the same as the spline on the HEI. The HEI spline is exactly aligned with the rotor-- if the rotor is at 12 o clock, the spline is too.

On the new one, the spline is at maybe 2 o clock when the rotor is at 12. So when I drop the new one in, I can't get the rotor to align to the proper mark I made showing where the rotor from the old cap was pointing.

I hope this is clear!

I'm not sure how to proceed. It seems like the safest thing to do is to move the engine to TDC and then drop the distributor in and make sure the rotor is pointing at the contact for cylinder 1.

However, I kinda think it'd also be ok to use the position that the motor is in right now, and just try to turn the oil pump with a screwdriver down the distributor shaft hole until it lets the distributor drop where it's supposed to be.

Any tips on how to deal with this?

Answer 1

If I understand you problem correctly you can't get the distributor to drop all the way down and line up. Older V-8 Chevys drove (spun) the oil pump with the distributor. The way it works is the crankshaft is connected to the camshaft by the timing chain. At the end of the cam shaft a gear meshes with the distributor drive gear. The bottom of the distributor has screwdriver shaped end that fits into a slot in the oil pump. You can try to rotate the oil pump shaft with a long screwdriver to align everything. Or insert the distributor so the rotor looks like it is aligned slightly ahead of the correct plug wire contact. While pressing down on the distributor have an assistant bump the ignition switch until the distributor aligns with the oil pump and drops in. If the timming still looks off, gently raise the distributor until the gears just begin to unmesh. Rotate the distributor until you feel the teeth of the gears mesh, then repeat the bumping process. This can be frustrating if you have never done it before. You may have rotate the motor several times to get to the right start point which is #1 cyinder at (TDC) top dead center ready to fire (both valves closed). You may be able to remove all the plugs and turn the motor by manually turning the crank pulley. It will be more accurate then using the starter motor.

Answer 2

Mike's answer is spot on. Using the long screwdriver is by far the best method for straightening this out. It can be frustrating, though.

There is another way you can alleviate the condition if you just cannot get things aligned. You can move the spark plug wires one position (forward or rear) on the cap, which will straighten things out. You are keeping the same firing order (obviously), but by moving the wires, you are allowing the cap terminal to align at the proper time with the rotor. When doing this, it is important to only have two wires off of the cap at a time, as it can become confusing very quickly.