Distributor mystery

[Stumpi]

http://www.da7c.co.uk/technical_torque_a...butors.htm     this may be useful reading.I restricted advance by crimping a piece of copper onto tag instead of blue connector.[mine fell off].
It seems odd that some 009s have two springs and others one on the weights?.
Andy

[Nick Mayne]

Well Pigsty have answered and also they emailed me that they use a fixed timing on all their engines. This does not concur with Hedd Jones post above as the Pigsty timing is fixed. I guess they welded together my weights when they tuned the engine although the main aim was to reduce excessive fuel consumption. This does go against the grain with me with all my previous knowledge (or lack of!) but I guess the dynamometer experiments must be right. Too late as I have fitted a new DK4A and Power spark have told me that their DK4A distributor starts advancing at 300rpm then rises steeply to 8 degrees at 600rpm then has a max advance of 10 degrees at 2000rpm. Seems to start (no kick back on handle) and run well now but some of that is due to the new CW&P which is more or less as per the original in 'The Source Book' ie more turns of the engine.
So this revelation from Pigsty confounds a lot of the online articles and maybe we will hear more! After all they build successful racing cars.

[Reckless Rat]

Thing is, with a racing engine it only does one thing, and that is flat out. You're either going at it full on or you're emergency braking. What the engine does on tick-over or mid range is immaterial because all you want it to do is go "Banzai" and give max power at max revs. I can see why they use fixed timing. However everything is different with a road car because very rarely do you ever need to use max revs. You need a progressive power delivery and good mid range torque, and usually the ignition advance provides that for you, either manually, centrifugally or electronically.

Stick a full race engine in a road car and it's virtually undriveable.

You could of course use the welded up Bosch with a manual advance, like they did with the DJ dizzy. Retard for starting and then move to full advance. However my personal view is what's the point in buying a dog and then barking yourself?

Just my 2p worth.

[Ian Williams]

My Dyno findings and race experience are somewhat at odds with Pigsty, and for Alex to say that retarded timing produces maximum power is a total red herring.
Reckless is pretty on the money, but good mid range torque will actually make for quicker lap time's than peak power in an A7 race car. This is all of little consequence to a road car and I would advise the OP to use a non auto advance distributor and make adjustments as required with the hand controls. You will have much less long term trouble that way.

[Hedd_Jones]

Well Pigsty have answered and also they emailed me that they use a fixed timing on all their engines. This does not concur with Hedd Jones post above as the Pigsty timing is fixed. I guess they welded together my weights when they tuned the engine although the main aim was to reduce excessive fuel consumption. This does go against the grain with me with all my previous knowledge (or lack of!) but I guess the dynamometer experiments must be right. Too late as I have fitted a new DK4A and Power spark have told me that their DK4A distributor starts advancing at 300rpm then rises steeply to 8 degrees at 600rpm then has a max advance of 10 degrees at 2000rpm. Seems to start (no kick back on handle) and run well now but some of that is due to the new CW&P which is more or less as per the original in 'The Source Book' ie more turns of the engine.
So this revelation from Pigsty confounds a lot of the online articles and maybe we will hear more! After all they build successful racing cars.

No my post agrees with Alex. Following the period Austin manual advice means the timing would be fixed for driving round - at full advance, which is a lot less than an auto Bosch would give you. 

The advice is that it should be started set fully retarded. As Alex notes, so it won't kick you on the handle. 

I used to forget occasionally, particularly in traffic when the swine stopped and I had to get out to swing the handle, and I instantly knew I'd forgotten

Anyone know what RPM a 7 idles at?. Sounds to me the powerspark is starting to advance as soon as the engine is running. Even 600rpm isnt a lot.

[Alex Myall]

Ian, I didn't say we set them retarded! 
When setting the ignition timing I hold the engine at full power at 3000 rpm and turn the distributor until peak torque is produced. I have found that peak power is produced a couple of degrees retarded from that setting. Many of our engines are trials engines and we test these engines down to 600rpm at full power.
When testing and setting up engines they are set to perform best for their intended use road, race or trials.

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Nick, The new distributor you have fitted will (when driving) perform exactly the same as the Bosch (with fixed timing), 2deg advance from 800rpm to 2000 rpm won't make any noticeable difference from fixed timing. The advance that is under idling speed is there to stop it from kicking on start up.

[Hedd_Jones]

its also worth noting that a 1932 car would have been fitted with a distributor without auto advance. So the welded up bosch would have been a direct replacement. 
I had never driven a car with the original manual advance set up untill I put the chummy on the road. Contrary to what my father told me (that they were a pain in the arse) I found it a revelation. Easy to use. No flat spots.

I never wired the car up, so always started it on the handle. ignition timing was sey by ear/feel. I started it fully retarded in the availible adjustment by the lever, then as soon as running the lever went to the fully advanced position like the manual said to do. And thats where it stayed. 

It ran nice with no flat spots at all. Fiddling with the lever showed it didnt go as well fully retarded (nonsurprise there), and on some fuels it could be retarded a smidge at full chat which didnt seem to effect progress but tue rear main rumbled a little less.

In comparison to the auto equiped cars which always seem to have a very small hesitation coming off idle, which I assume is probably the bob weights opening up. 

What I am probably saying that the practice of fitting auto dizzys to cars that were manually controled as built is a fix for a problem that never existed. 

I liked it so much that I'm in the process of puting a fixed dizzy on my current chummy. The stop on the job is the inner stator tube is stuck!

[Ian Williams]

Your comments now make a bit more sense Alex, your previous post was very easily misinterpreted.

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I really like manual advance cars, and would always revert an auto conversion back to this.