C2 Distributor Position

[Dave K.]

Re: Take a look at this thread

Duke,

My wires are indexed properly. I thought that Brian McHale said that he rotated his 180 from the dimple to get it set properly?

Dave K.

[Dave K.]

Re: Take a look at this thread

Duke,

My wires are indexed properly. I thought that Brian McHale said that he rotated his 180 from the dimple to get it set properly?

Dave K.

[Duke W.]

Re: Take a look at this thread

Maybe Brian's wires are improperly indexed. I've seen distributors butted up against the manifold when the dimple was indexed correctly, but the wires were not.

Be wary of unsubstantiated anecdotal evidence.

The engineeering drawings say to index the dimple in the same direction as the rotor tip. The service manuals describe how to index the wires on the cap.

That's "by the book".

Just do it!

Duke

[Duke W.]

Re: Take a look at this thread

Maybe Brian's wires are improperly indexed. I've seen distributors butted up against the manifold when the dimple was indexed correctly, but the wires were not.

Be wary of unsubstantiated anecdotal evidence.

The engineeering drawings say to index the dimple in the same direction as the rotor tip. The service manuals describe how to index the wires on the cap.

That's "by the book".

Just do it!

Duke

[John D.]

Re: Take a look at this thread

Dave, In the early 90's there was an NCRS national in Warren, MI I believe. There was also a tour of the Flint engine plant. After the event Dr. Mike McCagh invited an employee of the plant to his farm. This fellow put on a demonstration and talked about how the distributors were installed on the assembly line. The distr was complete with cap and dangling wires he said. All they had to do was line up the notch on the bottom gear with the seam on the distributor case and then install it in the engine. Trick was, the man said, was to use a lite rubber hammer and smack the vacuum advance on the pass side so as to get that one tooth lined up if you know what I mean. That's all there was to it he said. That's why you see so many original vac advances with a dent in it. If the distr cap was off and you did what Duke said(and the GM employee) you would see that the rotor was pointed toward #1. Get Barry to help you if you have a problem. Also make sure that someone has not put the bottom gear on backwards-I have seen this happen. I assume that Barry put your distributor on his Sun machine? See you at the banquet. John

[John D.]

Re: Take a look at this thread

Dave, In the early 90's there was an NCRS national in Warren, MI I believe. There was also a tour of the Flint engine plant. After the event Dr. Mike McCagh invited an employee of the plant to his farm. This fellow put on a demonstration and talked about how the distributors were installed on the assembly line. The distr was complete with cap and dangling wires he said. All they had to do was line up the notch on the bottom gear with the seam on the distributor case and then install it in the engine. Trick was, the man said, was to use a lite rubber hammer and smack the vacuum advance on the pass side so as to get that one tooth lined up if you know what I mean. That's all there was to it he said. That's why you see so many original vac advances with a dent in it. If the distr cap was off and you did what Duke said(and the GM employee) you would see that the rotor was pointed toward #1. Get Barry to help you if you have a problem. Also make sure that someone has not put the bottom gear on backwards-I have seen this happen. I assume that Barry put your distributor on his Sun machine? See you at the banquet. John

[Dave K.]

Re: Take a look at this thread

John,

Yes to all of the above.

Dave K.

[Dave K.]

Re: Take a look at this thread

John,

Yes to all of the above.

Dave K.

[John H.]

Re: Take a look at this thread

John -

The only wire dangling from the distributor at the engine plant was the black primary wire that was later connected to the coil (-) terminal; the plug wires were installed at St. Louis.

Each hot-test stand had its own "slave" ignition harness with all eight plug wires, coil, and the distributor end of the "slave" plug wires and the high-tension coil wire were captured in a circular adapter plate that "plugged" into the towers in the top of the distributor. The spark plug ends of the slave harness had the connectors on each side "ganged" together in another adapter, spaced apart the same as the spark plugs, so all four connections to the plugs were made at the same time (rather than individually). The hot-test complex was a wild scene at 300 engines per hour; each engine ran for less than 30 seconds - just long enough to verify oil pressure, set the timing, and check for leaks or strange noises.

[John H.]

Re: Take a look at this thread

John -

The only wire dangling from the distributor at the engine plant was the black primary wire that was later connected to the coil (-) terminal; the plug wires were installed at St. Louis.

Each hot-test stand had its own "slave" ignition harness with all eight plug wires, coil, and the distributor end of the "slave" plug wires and the high-tension coil wire were captured in a circular adapter plate that "plugged" into the towers in the top of the distributor. The spark plug ends of the slave harness had the connectors on each side "ganged" together in another adapter, spaced apart the same as the spark plugs, so all four connections to the plugs were made at the same time (rather than individually). The hot-test complex was a wild scene at 300 engines per hour; each engine ran for less than 30 seconds - just long enough to verify oil pressure, set the timing, and check for leaks or strange noises.

[Gerard F.]

Re: Take a look at this thread

Dave,

To add to the confusion, the first picture in the referenced thread is for a 67 base engine with a 30* centrigal factory distributor, 6* BTDC initial timing and with the dimple lined up with the rotor. At this setting, the vacuum can is about 1/8" off the coil for my car. I could probably retard it to 5* BTDC with the can up tight against the coil.

Your 66 might be different in the distributor, or even the internal drive gear.

If you had a 24* centrigal distributor with an initial timing of 12* BTDC, I think the vacuum can would be more centered between the coil and the manifold.
The difference between the dimple reversed to the rotor position is about 14*. One tooth is about 28*

I think in your case, once you check the dimple orientation and revise it to line up with the rotor (if necessary), you might want to go through the engine disturbed procedure to reinstall the distributor, verify #1 TDC, and that all the indexing is correct as Duke suggests.

Let us know what the final orientation looks like.

Jerry Fuccillo
#42179

[Gerard F.]

Re: Take a look at this thread

Dave,

To add to the confusion, the first picture in the referenced thread is for a 67 base engine with a 30* centrigal factory distributor, 6* BTDC initial timing and with the dimple lined up with the rotor. At this setting, the vacuum can is about 1/8" off the coil for my car. I could probably retard it to 5* BTDC with the can up tight against the coil.

Your 66 might be different in the distributor, or even the internal drive gear.

If you had a 24* centrigal distributor with an initial timing of 12* BTDC, I think the vacuum can would be more centered between the coil and the manifold.
The difference between the dimple reversed to the rotor position is about 14*. One tooth is about 28*

I think in your case, once you check the dimple orientation and revise it to line up with the rotor (if necessary), you might want to go through the engine disturbed procedure to reinstall the distributor, verify #1 TDC, and that all the indexing is correct as Duke suggests.

Let us know what the final orientation looks like.

Jerry Fuccillo
#42179

[Brian M.]

Re: Take a look at this thread

My wires are correctly indexed and it took putting the dimple 180 out to get the can centered, and timed to specs.

[Brian M.]

Re: Take a look at this thread

My wires are correctly indexed and it took putting the dimple 180 out to get the can centered, and timed to specs.

[Duke W.]

Re: Take a look at this thread

While we're at it let's review the static timing procedure for the umpteenth time.

Rather than setting the engine at TDC, which is the advice you hear 99 percent of the time, set the balancer notch at the target initial timlng mark BTDC #1, and make damned sure it's #1 and not #6 by verifying compression or pulling the valve cover to watch the #1 inlet valve close if you have even the slightest doubt.

Install the dist. and rotate the housing until the points just open. If you use an ohmmeter you should be within one degree of your proper initial timing point and the distributor orientation should be as discussed in my previous post with no interference.

If this is not the case, something is screwed up - GUARANTEED!!! Pull the dist. and reinstall it a tooth ahead or back as required, and if this doesn't do it, go back and check the dimple and wire indexing on the cap along with verifying that you are at the initial timing point BTDC #1, not #6.

IIRC the oil pump drive slot should be oriented at about 10-4 o'clock and a paint mixing stick is a good "tool" if you have to reorient it to get the dist. to seat.

If you static time with an ohmmeter you should be within one degree or your target. I can get it within two or less by just visually watching when the points just begin to open, then back a hair.

One degree rotation of the dist. housing is 2 degrees timing at the crank, so the difference between 6 and 12 BTDC is just 3 degrees of housing rotation or less than 1/100 of a complete revolution.

K-19 AIR cars has specified initial timing of 4 ATDC, which would require the dist. to be rotated 5 deg. CCW relative to 6 BTDC, and it's possible that the dimple needs to be indexed "backwards" to achieve that, but unless I inspect one or see the drawings for those AIR distributors, I'm don't know for sure.

Duke