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Distributor Help - Replaced Vacuum Advance And Now Won't Start

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#1 scottwkurth


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Posted 13 June 2018 - 02:59 PM

Last night I decided to finally replace the broken vacuum advance on my distributor (45D). It has had a hole in it for quite some time but I wanted to get it replaced for the road trip to MMW. Despite my careful efforts not to create a new problem while solving another, the car will no longer start.


I took photos and marked the location of the distributor relative to the pinch bolt and the rotor position before I removed it. I had to disconnect and move the coil out of the way to get at the two bolts to remove the distributor and clamp. 


Once out I removed the two screws securing the vacuum advance unit and tilted it out as the workshop manual suggested. Getting the new unit to slot onto the peg on the back of the base plate was not as easy. I had to remove the rotor and the two outer screws that secure the base plate to the distributor body. Then, after several tries and a little manhandling, I was able to get it connected. I referred to my photos on rotor position relative to the dog gear and reassembled the internals.


I set the rotor position to the right location and reinstalled it in the engine. When I went to start it, it barely cranked and didn’t even attempt to turn over. I opened it back up and it looked like the points gap had closed up from all of the pulling on the plate. I set the gap to 0.010” because that is what I found via a hasty internet search (although with a clearer mind this morning it looks like it is supposed to be between 0.014” and 0.016”). I replaced the cap and tried to crank it over again. Nothing. It at least cranks normally now but there is no firing at all. I double-checked all the leads and they are secure. I left the leads connected to plugs and the cap while working so I know that the leads are still connected in the right order.


Clearly I screwed something up in the process of what should have been an easy repair, but what? Can anyone provide some suggestions on what / where to start to track this down? 


1963 Austin Cooper Mk1, 1275, Dual HS2s


#2 nicklouse


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Posted 13 June 2018 - 03:49 PM

so have you checked the basics.




and the vac unit is exactly the same. (advance and vac figures stamped on the side)?

#3 scottwkurth


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Posted 13 June 2018 - 04:03 PM

Without an assistant to turn the key while I'm in the engine bay I wasn't able to test spark while cranking, but I was able to get a spark across the points with a tap of a screwdriver while the ignition was in the on position.


I didn't know to check for stamped figures on the vacuum unit, but this is the replacement I ordered:

https://www.minispar...|Back to search


As I haven't even connected the vacuum line yet, I didn't suspect the vacuum unit itself. Should I?

#4 scottwkurth


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Posted 15 June 2018 - 01:36 AM

Just to close this up: I went back to basics—checked static timing, rotor orientation, etc.


It turned out to be the points. When I tried to "fix" the gap after it was off from manhandling the vacuum advance slot onto the peg, I actually made it worse. I was rushing and having trouble getting a clear look at the points through my glasses and set the gap at the wrong point on the cam.  Once I reset the gap properly (and quadruple checked my work), it started right up.




#5 gazza82


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Posted 15 June 2018 - 03:29 PM

The other usual suspects are are two small wires inside the body from the points connection and then one from the body (ground?). These are ultra flimsy fine wires with canvas insulation and over time get pulled and stretched.


You don't want one to fail on you on a narrow twisty road, between two high banks, going uphill .. :X


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