C2:67 That darn distributor dimple again.

[Gerard F.]

Getting ready to put my original 67 s/b distributor back on the car. I've been through the thread about the dimple being in line with rotor tip, and made sure that it is.

I've had this replacement distributor on for about 4 years and it runs fine. In preparation to replace it, I adjusted the timing to spec, 6 deg BTDC (327/300), then marked the position of the vacuum can to the engine, and the position rotor tip to the distributor housing.

Then I pulled the replacement distributor. Lo and behold, the dimple on the replacement is on the opposite side from the rotor tip.

Now I'm scratching my head, should I put the original back in the same position as the replacement? Or is there a correction which should be made, and which way? Or should I just reverse the gear in the original to make it exactly like the replacement.

I'd hate to try trial and error, and then have to figure out the position of the rotor on a disturbed engine. So it's near the end of the day, maybe I'll get some advice tonight to pick up on it tomorrow.

Help!

Jerry Fuccillo
#42179

[Mike McKown]

My suggestion would be this:

"IF" your distributor vacuum can fits inside the shielding cutout and "IF" your tach cable came straight in on the distributor connection without excess bending, I'd re-install it just the way it came out.

If you don't have the ignition shielding, be sure and take a look at your tach cable connection. If it's in a bind, you'll lose your cable.

The problem is, if everything is to design intent, you won't meet this criteria. If you do, there is "something there" that is not to factory print.

I currently own one engine where you can't time it properly with the dimple lined up with the rotor and got rid of another one a few years ago. I have also heard of one other case of this. Aftermarket parts may have been involved. I don't know.

[Terry R.]

Re: C2:67 That darn distributor dimple again.

Is #1 plug wire installed in the factory position ? Sounds like they were put in 180 degrees out to solve the dist. not being installed on top dead center. Good Luck. Terry

[Mike McKown]

Re: C2:67 That darn distributor dimple again.

Indexing the wires 180 out won't do anything except confuse the next guy that works on it. The distributor position wouldn't change relative to the same timing.

[Terry R.]

Re: C2:67 That darn distributor dimple again.

If I'm understanding Jerry correctly the dist. is facing correctly but the roter doesn't.

[Duke W.]

Re: C2:67 That darn distributor dimple again.

1. Set the crankshaft at the normal initial timing value BTDC #1. For your engine, 6-8 degrees.

2. Orient the dimple to point the same direction as the rotor tip.

3. Verify that the #1 plug wire is indexed on the tower closest to the RH (passenger) side of the window and all the rest are in the proper firing order from there, 1-8-4-3-6-5-7-2. (See your CSM.)

4. Drop the dist. into the engine beginning with the rotor tip about 45 degees to the right of centerline. "Adjust" the oil pump drive slot with a long screwdriver if necessary to obtain engagement of the oil pump drive. As the dist. drops in the rotor tip will turn CCW to end up about 25 deg. right of CL when the housing is seated.

5. Rotate the dist housing until the points just open, then back a hair. In this position the cap window plane should be near pependicular to engine centerline.

6. Snug hold down bolt just enough to allow the dist. to be turned by hand.

7. Start engine and set initial timing with a timing light at no more than 500 RPM.

8. Torque hold down bolt and install the vacuum advance signal line. Adjust idle speed to normal setting.

Duke

[Duke W.]

Re: C2:67 That darn distributor dimple again.

The rotor has one round and one square index pin, so it only goes on in one orientation unless bubba filed the square index pin round. Im sure that's been done.

Duke

[Joe R.]

Re: C2:67 That darn distributor dimple again.

Hi Gerry:

My 67 300 HP had the gear on incorrectly when I bought the car, and it was still possible to time the engine correctly. However, when I rebuilt the distributor I turned the gear around to align it with the rotor. In this position everything seemed to line up better for the tach cable and the shielding.

So, while it is possible (at least for my engine) for the distributor to work with the gear in either position, I think things fit better with the dimple and rotor aligned.

If you want to avoid going through the process that Duke described (engine on TDC, etc.), all you need to know is which direction (clockwise or counterclockwise) the rotor should move as a result of changing the gear to the correct position. As long as the engine is still in the position you left it, you just reinstall the (corrected) distributor so that the rotor ends up rotated slightly in the desired direction.

I may not be remembering this correctly, but I *think* that looking down on the rotor, you want it to move counter-clockwise from the position it was in when you removed it. I think there are 13 teeth on the gear, and reversing the gear rotates it 1/2 tooth, or about 14 degrees. So, with the engine in the same position it was when you removed the distributor, you want the rotor's new position to be about 14 degrees counter-clockwise from where it was when you removed the distributor. You will need to use a large screwdriver to move the oil pump shaft back the same amount.

Now, having said all this, it is possible that I have remembered this backward and that the rotor should actually move 14 degrees clockwise. Hopefully someone will correct me if I have this backward.

[Duke W.]

Re: C2:67 That darn distributor dimple again.

I one follows my instructions and verifies the geometric relationships I referenced, it will be correct. No guessing required.

If the gear is on backwards, one may be able to achieve the initial timing on engines with single digit intial timing specs, but not with double digit specs that are typical of SHP engines.

As you stated, the tach drive will not line up properly with the gear backwards even if you can get a single digit timing spec dialed in.

One other geometric reference: With the timing set at the proper initial setting, which varies from 4 to 14 degrees depending on engine option, the vacuum can should be about half way between the interference points at the coil bracket and manifold in addition to the plane of the window being approximately perpendicular to engine centerline.

If the above is not observed, the gear is probably on backwards or the dist. gear is not indexed properly on the cam gear.

It's that simple!

Duke

[Gerard F.]

Re: C2:67 That darn distributor dimple again.

Joe, Duke,

I've determined that my plug wires are in the correct positions in the cap. The #1 wire is in the first tower position clockwise of the adjustment window, and the other wires are in the right firing order clockwise around the cap.

When I took the replacement off after correctly timing it, the rotor tip was pointing to the #7 plug wire in the cap in a seated position. So I think it makes sense to put the the original back so that the rotor tip is pointing to the same #7 plug wire regardless of the overall position of the distributor.

I think this will move the position of the distributor clockwise(looking from the top), and more to Duke's described orientation and with less bend in the tach cable. Also, I noticed that when I took the replacement out, the rotor tip moved CCW of its seated position. This means to me, that I'll need to move the rotor CCW the final position upon installation.

We'll I'm going to try the above in the morning. Do you see any fatal flaws in the above procedure?

Thanks for the advice. This is probably worth a little picture story.

Jerry Fuccillo
#42179

[Duke W.]

Re: C2:67 That darn distributor dimple again.

Rule #1: Always remove the dist. with #1 at the initial timing mark.

Since you apparently didn't follow this rule, my suggestion is to remove the #1 spark plug, place the gearbox in top gear (I hope you don't have PG.) and bump push the car until until you can feel compression on #1, then a little more until the notch on the balancer is at 6-8 degrees on the timing tab.

Then install the dist. per my previous instructions.

Now, you may be able to short cut the above basic, no-brainer, way to get it right, and you may get it right, or you may tie yourself in a knot. Your choice.

When you are faced with possible previous bubbaeering, the best choice is usually to go back to fundamental, basic, no-brainer, read-and-follow-the-instructions methodology.

I've given all the advice I have to give.

Duke

[Richard S.]

Re: C2:67 That darn distributor dimple again.

Duke,

Youy experience and advice is very much appreciated. I'm sure many people will copy and save your post on correct distributor removal and installation and it will save many of us...and probably some automotive mechanics....a lot of trouble. Thanks for taking the time to respond and for helping all of us.

[Jack J.]

Re: C2:67 That darn distributor dimple again.

AMEN!

[Clem Z.]

anytime you remove a distributor.

from a engine always bump the engine around till the rotor tip is pointing to exactly 12:00 o'clock and that way when you put it back in there is no guessing if it is installed correctly.

[Howard M.]

Re: C2:67 That darn distributor dimple again.

Duke:
Is the distributor on a 1960 283 set up the same way? The car runs O.K. and the timing can be properly adjusted but it looks like the coil bracket has been bent backwards to provide room for the vac advance. The window is pointing slightly towards the right bank. I'm wondering if the "mechanic" who installed the dist in 1975 for the previous owner got one tooth off and just bent the bracket to provide room. Will indexing the dist one tooth ccw be the proper thing to do?
Thanks