My son Jack has just bought an old distributor tester.
This is a real eye opener as it has allowed me to test & in most case rectify the problems of my assorted car distributors.
My Bradford dizzy was 12 degrees out between cylinders! No wonder it ran rough.
By fixing weights & springs, it improved dramatically.
The crazy part is that the new points supplied by the club were absolute crap, cleaning up 70 year old points brought the dizzy into speck.
The new points kept the car 6 degrees out of synchronisation.
Jack tested both sets of points & found the new points had a tension higher than his spring tester could measure.
This may be ok for racing, but would certainly shorten the points life significantly.
Last problem, does anyone know the correct dwell for a Bradford? Any listing he can find is 90 degrees & this seems way too high.
Distributor machine
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David Kemp
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- Joined: Sun Mar 09, 2008 1:18 pm
- Location: Brisbane ,Australia
Distributor machine
Good memories of Bradfords.
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Re: Distributor machine
What does the dizzie tester do to test the springs?
The dwell governs the energy put into the spark. It may be different for 6v and 12v and for 2 and 4 cylinder. Dwell is always a compromise on fixed dwell distributors. Mapped ones allow optimum dwell across the rev range.
https://www.denso-technic.com/bg/everyt ... -charge-up
Low compression engines would need more energy in the spark to ignite the mixture.
Most dizzies are extremely worn so a full recon is advised.
Please advise JCS of your concern on the part supplied.
The strong spring on the points may have made the wear look worse by following the cam more closely. A weak spring allows the points to bounce, increasing pitting and causing misfire, especially at higher revs.
The dwell governs the energy put into the spark. It may be different for 6v and 12v and for 2 and 4 cylinder. Dwell is always a compromise on fixed dwell distributors. Mapped ones allow optimum dwell across the rev range.
https://www.denso-technic.com/bg/everyt ... -charge-up
Low compression engines would need more energy in the spark to ignite the mixture.
Most dizzies are extremely worn so a full recon is advised.
Please advise JCS of your concern on the part supplied.
The strong spring on the points may have made the wear look worse by following the cam more closely. A weak spring allows the points to bounce, increasing pitting and causing misfire, especially at higher revs.
-
David Kemp
- Posts: 628
- Joined: Sun Mar 09, 2008 1:18 pm
- Location: Brisbane ,Australia
Re: Distributor machine
Thank you, to clear up my post the parts were bought off JC S Australia & appear to be Ferguson tractor points.
I have spoken to Jim about them ,he was surprised they were so strong.
Further investigation of this distributor, shows it is just worn out.
All the new parts I have added,springs, weights & Bush's can't make up for the 75 years of wear.
My current actions are to try & find a better dizzie to rebuild.
To get my baby running I have ordered an electronic distributor that I will modify by grinding two reluctor points off .
My son will then remap the curve to suit the Bradford, either by changing springs & grinding weights, or by using a programmable timing control box.
I have spoken to Jim about them ,he was surprised they were so strong.
Further investigation of this distributor, shows it is just worn out.
All the new parts I have added,springs, weights & Bush's can't make up for the 75 years of wear.
My current actions are to try & find a better dizzie to rebuild.
To get my baby running I have ordered an electronic distributor that I will modify by grinding two reluctor points off .
My son will then remap the curve to suit the Bradford, either by changing springs & grinding weights, or by using a programmable timing control box.
Good memories of Bradfords.