Explain why this makes a difference when #1 can be anywhere and the base determines timing? Is it the clocking to the reluctor?

Jebby

 

Agreed I believe you are one tooth off. Your centrifugal weight plate is pointing in a sligtlty different direction in the two pics. Assuming you had the engine at TDC, had the distrib out, did not move the engine, etc. It's very common for it to go back in one tooth off. You have to coax it back to where it should be by nudging the oil pump shaft slightly. You can do it with your fingers on the centrifugal weight plate as you insert it part way.You can feel the teeth engage and slide it up and one over if you are gentle enough..

 

A lot of good suggestions. At least no one mentioned using the bfh to pound it in.

 

I thought it was off after replacing it and looking at it's position. So I attempted to "walk it" at Lars suggests but could only get it to drop to full depth about 4 places in the full 360 degrees of rotation. After 3 attempts to walk it around and ending up with the same orientation I gave up and figured I was being too OCD and that it was where it needed to be. My question at this point-I do fully intend to work the distributor more and attempt to correct its position, ideally when I am working on that area again, however at this time does it pose any risk or adverse effects to the engine with where it sits currently or is it just an instance where it wasn't installed as intended? From my limited understanding it shouldn't but I am very limited in my knowledge about distributors. As always grateful for any helpful insights or suggestions.

 

Ok, if you can get it to drop all the way at any spot, get engine at tdc, get dist pointer where you want it and keep tweaking oil pump shaft with long screwdriver. It will drop. Put slot slightly ahead of blade on distributor so it lines up as it turns when gear teeth mesh.

 

 

It won't affect timing, but it will affect phasing. Watch the video above. If the dot is not aligned with the rotor, the rotor will not be in sync with the towers.

 

If the gear is off, you will get a miss that is hard to find.

I use a clear distributor cap to demonstrate this to guys.

 

In 2020, it's "shave the hair around it" LOL.

 

That don't make a bit of sense to me,....all need do is rotate the dizzy as to set timing per usual, the rotor tip has a wide blade on it for a reason...not a sharp tip This entire discussion makes NO sense to me.....

wether it's points or HEI, we have the 'sender' actuated by the dizzy shaft, witch is obviously driven fixed synch with the cam.....so we rotate outside case/frame of dizzy to fine tune the timing, other than affecting the position of the dizzy frame, there can be no affect to overall performance.....

 

Good pic....but I was actually speaking of the bottom of the distributor gear itself......the chamfer on the I.D. for the bottom of the gear. I have see older aftermarket stuff have very little chamfer...or none at all.....this makes it extremely difficult to get in.......one thing I did do once was install the distributor with the engine upside down on the stand so the oil shaft could just "hang"......




Jebby

 

Just to be crystal clear. YES This must be correct. If you are not 100% positive it is correct, pull the distrib and double check it.

The clocking the two gears is a different issue and secondary to this.

 

It makes no difference at all for timing and performance. It does affect the final visual "installed clocking" orientation of the distributor once the timing has been set. On many applications, such as the L79 with the tall rear manifold runner and the distributor shielding installed, there is very little rotational "range" to set the timing. If the drive gear is installed 180 off, the distributor will often hit the manifold or the shielding before the timing can be correctly set:

Normally, if you don't like the installed clocking, you pull the distributor up and shift it over "one tooth" to get it right. Since the distributor has 13 teeth, each "one-tooth" shift will rotate the resulting installed clocking of the distributor roughly 28 degrees in the block. The L79, and several other applications, don't have 28 degrees worth of range for setting the timing without the housing (vacuum advance) hitting something. By installing the gear correctly, it allows the installed clocking to be correct within 1/2 tooth, or 13 degrees.

On the HEI units, it's nice to have the distributor installed so that the square top-mounted coil ends up being "square" in the engine compartment once the timing has been set. If the gear is installed 180 out, the distributor will usually end up "cocked" in the engine compartment, which just doesn't look right. With HEI engines, it's a cosmetic thing for **** people like me who like things to look nice...

HEI with the gear installed correctly with the dot pointing same direction as the rotor. Once timed, the distributor is "square" and clean in the engine compartment. If the gear is rotated 180 degrees, the same timing spec will result in the distributor being rotated 13 degrees from this position. No effect on performance or ability to set timing - just won't "look right":



Ah - good point. Yeah, a small, or missing, gear chamfer would certainly make it tough...

Lars

 

Gene, the dizzy gear has an odd number of teeth. If the gear is 180* out, the rotor tip and the base plate where the points/sensor is will be out of sync.by 14*.
When it fires, the rotor tip will not align properly with the towers. Kinda like the first part of the video.
When installed correctly, it will act like the second video., where the rotor is properly "dancing" around the posts as it advances.

 

This is what I thought....and I learned something today about that 14 degree difference on the gear.......thanks for the great explanation....
I knew it couldn't affect timing because once the distributor is in the hole and the housing is tightened down, it is what it is regardless of the gear.
It is ironic because I am assisting installing a Sniper EFI on a ex-TBI 89' K5 Blazer 350.....and we are using a large cap HEI to fire it....but all of the guts have to be rewired and mechanically locked out....the most important being the Vac advance as it moves the reluctor and I had to buy this thing to set up initial reluctor phase relative to #1 on the cap......I am phasing the reluctor with this:

Jebby

 

I did not realize it was possible to spot the phase shift from above.
If you look at the two rotor position pictures that the OP posted, the rotor position appears to be 14 degrees off not 28 degrees off.
Leading me to conclude the gear is pinned-on 180 degrees out

 

No, not true. The gear has nothing to do with rotor phasing. The rotor and points cam/reluctor are both driven by the distributor shaft so rotating the gear 180* can't affect the angle between the rotor and points/reluctor. Turning the gear only affects the final resting position of the distributor once installed and timed, as already posted.

From what you are describing with the rotor 14 distributor degrees off from the post, the timing would be off by 28 crank degrees. So, turn the base of the distributor 14* and both the timing and rotor phasing would come back to where they should be.

 

That's correct.

 

Going back to the original posters initial question.

I believe the first answer from gjohnson answers the question concerning the distributor not dropping all the way down.

good luck!

 

If I have mixed up an experience with another brand x unit, my apologies.
I run into crap all the time that screws things up. Sometimes I lose cause and affect.
Case in point, a GM vs a "Brand X" shaft.
The difference can mess up your "Now why the hell..........??




Since retiring and spending more time with my spouse, sometimes I feel aliens are sucking my brain dry.