Distributor install issue

[Geek]

Hi I have new rebuild engine when I try to install the distributor can't get it to line up. Allways 5mm before or after the 6 marking the engine is in TDC I have checked 4 times. But still I can't get spot on the mark... I have the fixed gm distributor. All marking on the cam and balance shaft is good in TDC.

[TBLBill]

Decide which direction you need the cap to turn, and about how much. Take the distributor out, and look down into where the bottom of the shaft touches. There's a notched piece that only allows the distributor to fit in two ways, otherwise it won't go down all the way. Get a long screwdriver into the center of this piece and turn it the little bit you need, then reinstall the distributor.

[Devonian]

That could be the simple solution, although my new distributor ended up like that when fully seated as it was not manufactured exactly right.

To correct, some just elongate the hole in the clamp.

However, the distributor in the picture appears to be ~11° out.

This is about half a tooth on the cog and because there are thirteen, rotating it 180° on the shaft will move it 6½ teeth.

360° / 13 / 2 = 13.845°per half tooth.
This is a bit more than 11 but if you can move it slightly farther out at the moment it should be just right when refitted.

So - knock out the pin holding the cog and rotate 180°.
Mark the shaft and cog first so you don't forget where it was.

[sixsix]

... So - knock out the pin holding the cog and rotate 180°.
Mark the shaft and cog first so you don't forget where it was.

I was going to take a break from posting a bit - but I could not let this go.

Are you seriously thinking of turning the Cam-driven gear at the bottom of the Distr. around to close the angle that was showed earlier?
I have not heard of this before - but I have not heard of "everything" yet... so.
I am all ears, subscribed, blah, blah.

Does your rotor and the #1 cap position point to the #1 cylinder - physically?
A "big engine owner" pointed this out to me one day when I was brain-addled...

[dcsleeper]

the gear is attached to the oil pump
the cam gear is solitary
the distributor ties the oil pump to the cam, that is done THROUGH the dizzy.

IOW, s'ok

[Devonian]

The oil pump is irrelevant. It just rotates with the shaft when it fits into the pump slot.

Are you seriously thinking of turning the Cam-driven gear at the bottom of the Distr. around to close the angle that was showed earlier?

Well, assuming it is the same as mine, then -
yes, it is only a cog that slides onto the shaft held by a pin.

I am of the opinion that it was manufactured 180° out.

Does your rotor and the #1 cap position point to the #1 cylinder - physically?

If you mean lines up as it should to the 6 marking without having to rotate the distributor, then yes it does now.
Before, it was like yours. Half a tooth to one side or the other.

[MechBob]

What Devonian has said.Sometimes spinning the gear works.Also, gm(and some aftermarket) ones were just poorly made.They will run,usually OK,but these are the van owners that "eat" distributor caps.That is why drilling out the hole to turn the dist. came about.

[AstroWill]

This is about half a tooth on the cog and because there are thirteen, rotating it 180° on the shaft will move it 6½ teeth.

360° / 13 / 2 = 13.845°per half tooth.
This is a bit more than 11 but if you can move it slightly farther out at the moment it should be just right when refitted.

So - knock out the pin holding the cog and rotate 180°.
Mark the shaft and cog first so you don't forget where it was.

Great post!
With poor quality control, I could definitely see it being assembled wrong even if the parts are correct.

[Devonian]

[sixsix]

The oil pump is irrelevant. It just rotates with the shaft when it fits into the pump slot.

Are you seriously thinking of turning the Cam-driven gear at the bottom of the Distr. around to close the angle that was showed earlier?

Well, assuming it is the same as mine, then -
yes, it is only a cog that slides onto the shaft held by a pin.

100_2207.JPG

I am of the opinion that it was manufactured 180° out.

Does your rotor and the #1 cap position point to the #1 cylinder - physically?

If you mean lines up as it should to the 6 marking without having to rotate the distributor, then yes it does now.
Before, it was like yours. Half a tooth to one side or the other.

Not sure who you're talking to here - I was simply asking questions, not doubting anything you came up with.
Had never heard of it before & not surprising...
The OP never came back...
Mine / Ours was not out 1/2 tooth...

[Devonian]

Sorry, I suppose I must have thought you were the OP.