Stumped and EXTREEMLY Frustrated.
Recently rebuilt the distributor on my 71 after installing a Pertronics Ignition system and discovering that the Tach Gear on the distributor shaft was destroyed. I replaced the upper and lower bushings as well as the shaft itself.
Here's the facts:
1. Distributor will not go all the way home. Remains about 1/2" from proper vertical housed position.
2. Removal of distributor prior to rebuild was difficult/tight.
3. Found significant scoring on lower portion of old shaft and ovaling of old distributor lower bushing. Probably from destroyed tach gear particles.
4. Attempted to jogg the engine MANY times with appropriate cam gear engagement to home the distributor. No progress.
5. Measured lower distributer casting collars. Lowest collar is 1.245". One just above was 1.247". Worked them with 220 sand paper as we think that is the bind entering the distributor bore in the block. Even tried to file a small bevel in the upper collar as the measurements and height point to that one being the binding culprit.
6. I have done in depth engine work before and NEVER had this problem.
7. Had an even more experienced 71, LT-1 Owner over who has an ME degree, works as an ME and has rebuilt the LT-1 engine from the short block. Both of us "Still could not get it"!!!!!!!.

What's wrong here?????

 

It won't go all the way in because it's hitting the oil pump drive shaft. Put it in where it's supposed to go then slowly turn the engine over and it'll go PLUNK (drop the rest of the way in once the tang of the distributor shaft aligns with the slot in the oil pump drive shaft).

 

Or, you can take a 14" long flat head screwdriver, take a look down the distributer hole in the intake manifold, and turn the oil pump shaft that way.

 

I never had a dizzy all the way apart so I have some questions for you. You take a drift-pin out to remove the shaft from the housing & swap the bushings correct?
The upper & lower bushings, can they only be installed one way? If they were up-side-down what would happen to the the alignment as far as the distance the shaft is in the block / intake hole?
Or the wrong bushings perhaps, forcing the shaft too far down in its housing,
so the dizzy housing is 1/2" up from the intake.
What about the pump driveshaft: What type of collar is on it, steel or plastic? Did the driveshaft pull itself out of the oilpump shaft alignment collar?
IDK

 

Position the oil pump slot at 11 o'clock/5 o'clock (looking from front of engine). Point the vacuum advance at the #6 cylinder. Point the rotor button at the 2nd intake bolt from the rear (on drivers side). The dizzy will drop in and be meshed with the oil pump and the rotor will be pointing at #1.


Oh yeah, put the engine at #1 tdc before doing any of the above.

 

If the gear is on upside down(believe me it will go on that way) you will have this problem.

 

That is absolutely true. Don’t ask me how I know.

 

Who knew???






bass ackwards



https://www.corvetteforum.com/forums...of-junk-3.html

 

I admit, I did this once too. At least I realized it before fitting it in the engine, cuz it just didn't look right.

Lotza good ideas here. Hope you get it solved hadams.

Steve

 

There is also a dimple on the gear. It needs to face the same way as the rotor tip, or the rotor will be out 1/2 a tooth out of phase.

 

BINGO!!!!!!

I am so ashamed!

Thanks,
Howard

 

Don't feel bad, I was in a hurry, doing a distributor clean up and recurve when I did it. I had been through several of them, just had a brain fart that day!

 

You're not alone. I did the exact same thing.

 

Thanks to everyone for the prompt and helpful responses.

I corrected the cam gear this AM and had it up and running with an hour.

Thanks again.

Howard

 

It's always good when it's an easy fix!

 

Glad you got it figured out.
BTW, post #5 above - I believe if you set the engine to #1 tdc, cylinder #6 is firing. That's why so many fire a new motor and find it to "180 off". At #1 tdc it is just beginning the intake stroke, not firing.

 

You have to look at the valves. You get TDC on each cylinder twice for one rotation of the distributor. the exhaust valve opening after tdc is where you want the distributor pointing. I did thisbackwards so many times