can't get dist rotor to line back up

[yeehoo]

I am replacing the distributor in my 93 chevy 4.3 tbi. I marked the base location and the rotor location against the firewall using a straight edge. When trying to install the new dist i can get the rotor just before my mark or just after it without problem. However, I can not get it to line up on the mark. I have adjusted the oil pump slot here there and everywhere but everytime i drop the dist in and it rotates down its either just before or just after my mark. I do offset the rotor some counter clockwise to compensate for the rotation down. Is there a trick to get it to line up? Any suggestions would be greatly appreciated.

 

[PlayingWithTBI]

Just drop it down as close as you can get it then loosen the distributor adjustment bolt and turn the whole dizzy to line up the marks. Then set your timing with a light and the EST wire disconnected.

 

[Turbo4whl]

The new distributor most likely has the drive gear installed 180 degrees from how your original is installed. Knock the pin out, spin the gear 1/2 turn and install the pin.

The pin mounting hole on the gear matches a gear tooth on one side, a tooth valley on the other side.

 

[yeehoo]

I will compare the two distributors both are new. The one that came out was making all kinds of noise it has side to side play. thanks for the replies. I might just crank it around to tdc and go that route if I cant get it.

 

[thinger2]

I always set the dist to tdc before I pull it.
And verify that the piston is actually at TDC before you rely on the timing mark.
That way you know that you dont have a bad balancer.
Looks like you know about the oil pump drive spinning out of sync when you pull the dist.
I have a big monster standard screwdriver that fits into the hole and doesnt bind and I can eyeball how far I need to turn the oil pump in order to get it to drop right in.
Everyone has a favorite method for stabbing a chevy.
I look at it this way,
Setting TDC involves leaning over the fender and leaning over the radiator.
Stuffing the distributor involves pulling the throttle body studs so you dont impale yourself and crawling over the whole thing while hating the world.
All kinds of things can go sideways while stabbing a chevy
Especially if you are using an aftermarket dist.
Pull all of the plugs.
This is so you can turn the crank by the snout bolt without breaking it.
Set it at TDC and verify it before you pull it.
Make sure the piston is actually at TDC and not that the timing marks are off.
Pull it, turn the oil pump drive back a bit and stick it back in.
If it doesnt line up at TDC turn the pump a bit more.
It will only be off by one tooth.
Stab it.
Pull the coil wire and unplug both injectors.
Roll it over a few times
See if you can turn it back to TDC without turning it backwards at all and see if all of the timing marks and the roter line back up at TDC
That will tell you if you have timing chain slop.
If it does all line up again.
Probably good.
Now, again with all the plugs pulled,
You can rock it back and forth with a breaker bar on the crank bolt and kind of get a feel for how much slop is in the timing chain by looking at the rotor and how far you need to turn the crank before the rotor turns.
Keep in mind that when you turn the crank bolt counterclockwise that can loosen the bolt.
That is why you need to pull all of the plugs.

 

[yeehoo]

I'll be damned turbo4whl sure enough the pins were different one was on a valley the other was on a tooth and they were 180 off when comparing the two dist. I put it back in as close as I can get it then measured the distance it was off from the original mark and adjusted the base the same distance from the original mark. So it should fire right up? Thanks for the responses.