Joined: Aug 2017 Posts: 529 Threads: 17
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Location: Hampshire UK
Hi Nick
I can only think that someone in the past has welded up the weights so as to use it on a manually adjusted system. Nothing to do with the car's electrics.
Some rotor arms have a suppressor resistor between centre and tip. This component is sometimes encased in the insulation or under "potting compound". They should read roughly 5000 ohms. If it shows open circuit, throw it away and replace it with a good quality new one.
Joined: Aug 2017 Posts: 138 Threads: 28
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Location: New Forest
Car type: 27 Chummy
Hello Nick
This is not due to an electrical short. Someone has arc welded the weights together for some reason.
Adrian.
Joined: Jan 2018 Posts: 58 Threads: 20
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Thank you all for the information. I bought the Bosch distributor advertised as new on Ebay and have no other detailed records....a mistake maybe as I suppose it could have been welded. I think I would have disassembled it as I had to have some machining done on the body (known problem) but perhaps did not look at the bobweights. Also Pigsty looked at the mixture (made a special needle) and timing for me and I suppose they could have welded the weights without me knowing however I did not have a rod from the steering column. I might try to cut open the welds and clean up the weights and suck it and see! I had already added a small stop to limit the advance to about 3 degrees which I was told was about right as the Bosch otherwise had a much larger advance.
My engine is tuned in so far as it has a medium machined camshaft and followers and oil filter and machined oil pump from Pigsty and they also sold me a Nippy manifold. The engine also had oversize inlet high spec valves, double valve springs, an inlet manifold from John Barlow and a high compression head. John Barlow also supplied his new crankshaft, NC machined con rods and special pistons with floating gudgeon pins. I only aimed for a bit more power but got rather carried away as it is only a van hard to keep in a straight line and hard to stop!! The fuel consumption was very high and that was why I took it to Pigsty. They pointed out that the engine did not fit regular specs so they modified the SU needle in a lathe using emery paper! I find it hard to believe they welded those weights but will not ask now as it was a long time ago. Will keep you posted.
Joined: Jan 2018 Posts: 58 Threads: 20
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Got weights separated and put all together. Engine runs but advance not smooth with sudden extreme advance so I need a new distributor. The Powerspark one seems to have the electronic option and using that I would have to abandon my nicely made copper wire HT leads as the small print says they would not be suitable so why is that?
Could someone increase my knowledge and tell me why there is a high value resistor in the rotor arm?
Joined: Aug 2017 Posts: 405 Threads: 18
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Hello Nick,
I do hope you get it all sorted out but I’m left with an image of you hurtling along in your 60mph van, with no brakes.
Is this a good idea?
Joined: Sep 2017 Posts: 10 Threads: 1
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At Pigsty, we have done extensive dyno testing of many types of A7 engines and have found that the engine does not need an advance curve in the distributor. The dyno data shows that with fixed timing if the ignition is retarded slightly the peak power goes up very slightly high in the rpm range but the bottom end loses power. However, this does make the engine kick back when hand-cranked.
Joined: Aug 2017 Posts: 1,230 Threads: 33
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Location: Salop
Car type: '28 GE Cup. '28 AD Chummy '30 RL Saloon. '34 RP Saloon. Too Many toys!
That pretty follows the advice as I remember it in the handbook for the manual set up.
Retard to start, when running move the lever to the fully advanced position.
Which is what I did on my chummy with a manual advance/retard on the dizzy.
