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Distributor Rotor Explosion

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Michael Oritt

Michael Oritt

Yoda
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Yesterday on the way back from Akron the 3000 developed an intermittent mild miss, as if one cylinder was misfiring. This morning I removed the distributor cap and saw that the nut securing the contact set was a bit loose--I tightened the nut, replaced the cap and went for a test run. I got about 1/4 mile and the car died. I again removed the distributor cap and the rotor was missing.

I found one piece of bakelite and the brass arm on top of the distributor plate. Upon disassembling the distributor I found the arm rivet, the springplate that goes inside the rotor and another coil spring about 3/4" long laying in the body of the distributor --this was not an advance spring nor the spring under the cap contact--those were all intact. I can't find any springs in the distributor--any thoughts here? It is definitely larger than either of the above.

There was a fine shower of brass filings throughout the distributor--should I be concerned with the shaft bearing surface? Also the advance diaphragm was inoperative--who sells these parts? The distributor has the following numbers stamped into the body:

DM6A406620
PEG 560
 
[ QUOTE ]
removed the distributor cap and the rotor was missing.

I found one piece of bakelite and the brass arm on top of the distributor plate. Upon disassembling the distributor I found the arm rivet, the springplate that goes inside the rotor and another coil spring about 3/4" long laying in the body of the distributor --this was not an advance spring nor the spring under the cap contact--those were all intact. I can't find any springs in the distributor--any thoughts here? It is definitely larger than either of the above.

There was a fine shower of brass filings throughout the distributor--should I be concerned with the shaft bearing surface? Also the advance diaphragm was inoperative--who sells these parts? The distributor has the following numbers stamped into the body:

DM6A406620
PEG 560

[/ QUOTE ]
Can't say for sure. It's likely that the rotor was not fully seated down on it's shaft & contacted the terminals on the underside of the cap. Or possibly the arm rivet failed & let the brass part of the rotor lift up & contact the cap terminals.

There is a remote possibility that the breaker cam hold down screw, under the felt has become loose which would allow the cam & rotor to lift enough to contact the cap terminals.

The central (coil) terminal has a spring loaded cylindrical carbon contact inside the cap which bears on the center of the rotor. If the rotor comes apart, this carbon contact & it's spring could fall out.

I doubt if anything else was damaged. Remove the breaker plate & clean out any other bits that may remain, replace the cap & rotor, you know about the Lucas rotor reputation. I have been using a very old US made rotor for years without problems. It doesn't have the rivet. Another possibility is to remove the rivet from a new Lucas rotor & glue the brass contact arm to the rotor with JB Weld. This has also worked well for me as a spare rotor.

You didn't ask, but if using a Pertronix slip over rotor sleeve, the sleeve can sometimes hold the rotor high enough to contact the distributor cap terminals. This can be corrected by trimming a bit off the bottom of the rotor so that it sits down lower.

I don't know where to find a vacuum advance. Some of your usual sources should have one, though you might have to search. Moss has a vacuum unit for the BJ7, BJ8, but not the earlier cars.
D
 
Here's a photo of the loose parts that I found inside. Notice how little of the bakelite rotor body is present--does this stuff spontaneously combust?
 

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HI Michael, I can't imagine where that extra spring came from.Regarding the Vac/Advance unit there is someone here in the US rebuilding them for about $100.00 I looked in my file but could not locate who or where they are. Maybe some of the usual suspects know who is doing them.---Fwiw---Keoke
 
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HI Michael, I can't imagine where that extra spring came from.Keoke

[/ QUOTE ]

Someone has suggested that it goes under the lube knob.
 
Michael - You may want to contact a shop here in PA (about 30 miles west of Phila.) - they come recommended but I have not used them:
Pat Mason
Mason Racing Ignitions
1015 Second Avenue
Schwenksville, PA 19473
near Springmount, PA
610 287 1511

They are supposed to be doing great work - Good Luck
jim /ubbthreads/images/graemlins/driving.gif
 
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