Pulled an idiot move installing my motor today. Tried installing motor & tranny but 7 quart Milodon pan wouldn’t clear crossmember so I changed course and removed tranny. I forgot I had removed distributor when I started turning motor over to access torque converter bolts.
How do I go about reinstalling distributor in proper orientation? I still see the marks on the distributor shaft and block from the engine builder. Do I need to get the motor in TDC and then drop the distributor in while lining up the marks?

 

Yes.

Move your #1 cylinder to TDC of the compression stroke. Then you install the distributor so the rotor is pointing toward the #1 cylinder. If you install it and it doesn't spit, cough and try to start then you can move your spark plug wires one position advanced or retarded instead of restabbing the distributor. Usually if the distributor is stabbed wrong it's only 1 tooth.

 

Thanks Olds64. Should motor be exactly at TDC or the initial timing before TDC? If motor should be at initial timing what is a good starting point (ie 10 deg, 12 deg, etc)? I know we ended up at 32 total when motor was tuned but I didn’t make a note of initial timing.

 

When stabbing the distributor it should be AT TDC on the compression stroke as Olds64 said. Remember you want the distributor in the correct position before setting the timing. Also to make sure you are on the compression stroke put your thumb over #1 spark plug hole while cranking. When air pushes your thumb off of the hole, you are on the compression stroke.

 

You can static time the engine by rotating the engine number one cylinder to the timing mark at the desired initial timing setting (on the compression stroke). Drop in the distributor with the rotor pointing at the number one cylinder. With the ignition powered, you can make sure it’s timed right by turning the distributor body, you should get spark on the number one plug wire. If that’s all good, remove the cap again, slowly rotate the distributor until the points just open, then tighten it down. Once the engine is running, you can use a timing light and see it’s within a degree or 2 of where you wanted the base timing to be.

 

Matt that’s what I’m trying to figure out. First, I have an MSD Pro Billet Ready-to-Run distributor, so no points. If I stab distributor at TDC, how do I get to initial timing from there? In my mind it seems easier to put #1 at the initial timing (not TDC). Will motor run well enough at TDC to get me started on setting the timing? If I set #1 at initial timing what is a good number for a 455?
In my case the distributor is all dialed in from the tuner so I think I just have to get it running so I can get total timing back to 32 and everything else should be good. Appreciate all the input.

 

Also, note that TDC should be on compression stroke, else your car will backfire and possibly collapse a muffler. If it does backfire, rotate distributor shaft 180 degrees, resinstall and it shoud be good to go. You can check the compression stroke by observing the rocker arms on #1 cylinder. The rockers should be sorta loose, that means both valves are closed and the lifters are riding on base circle.

 

With distributor removed... the easiest way is to put your finger over the #1 spark plug hole & have someone lightly bump the starter. When you start to feel pressure build, rotate the engine clockwise with a breaker bar (should be approx 1/4 turn) until the timing mark is approx 10 deg before TDC.

Put the distributor in the engine with the rotor pointing at #1, aligning the teeth on the pickup in the distributor. This should allow it fire right up.

 

Oldsmobile distributors turn CCW, so once you establish #1 wire the firing order from there.

 

This is good advice. Pay attention. You’ll need a buddy present, but it is spot on correct.