Points Distributor governor springs (FSM conundrum)

[Chickenman]

Found some interesting Part number information for L-series distributors at a site that I frequent. Site is usually very accurate historically: ( www.datsun1200.com)

Note: Degrees and RPM's are as measured at Distributor. Double figures for Crank degrees and Crank RPM. Vacuum advance not shown.

Quote

 L-series

510
TRI-CURVE
* 0 @ 600 rpm, 6 @ 1175, 9 @ 1465, 12.5 @ 1800
22100-A5502 D412-64 ISO 0870- 510 USA EXHAUST & EVAPO [Dual points]
22108-A5500 SHAFT ASSY SET [L-series type]
22109-A5500 GOVERNOR WEIGHT
22110-A5501 GOVERNOR SPRING SET 0870-0871

240Z 1970-1971
22100-E4601 D612-52 0@500, 12@1415 240Z USA -0871
22108-A3500 ASSY SHAFT
22109-71300 WEIGHT GOVERNOR
22110-E4600 SPRING GOVERNOR
22132-E4600 ASSY CAM

240Z 1972 MT
22100-E4603 240Z USA 0971-0672 MT
22108-A5500 SHAFT SET <> 22108-A5500
22109-A5500 WEIGHT GOVERNOR -0773
22110-E4602 SPRING GOVERNOR -0672
22132-E4600 CAM SET -0672

240Z 1973 MT D611-54 Single-point 7BTDC
* 0@500, 11@1400
22100-N3300 240Z USA 0772-0773 MT
22108-A5500 SHAFT SET <> 22108-A5500
22109-A5500 WEIGHT GOVERNOR -0773
22110-N3300 SPRING GOVERNOR 0772-0773
22132-N3300 CAM SET 0772-0773

240Z 1972-1972 AT
22100-E8000 D614-52 0@700, 9.25@1000, 14@1400 240Z USA 0870-0672 AT
22108-A5500 SHAFT SET <> 22108-A5500
22109-A5500 WEIGHT GOVERNOR -0773
22110-E8005 SPRING GOVERNOR -0672
22132-E8000 CAM SET -0672

240Z 1973 AT D612-54 Dual Point
* 0@500, 12@1480
22100-N3305 240Z USA 0772-0773 AT
22108-A5500 SHAFT SET <> 22108-A5500
22109-A5500 WEIGHT GOVERNOR -0773
22110-N3305 SPRING GOVERNOR 0772-0773
22132-N3305 CAM SET 0772-0773

1972 240Z L24 single & dual carbs
D606-52
* 0@450, 6@1000
* MT:17/650 L24T, 17/550 L24S
* AT:14/700 L24T, 17/560 S24S

1972 240Z L20
D609-56
* 0@550, 9@1200
* MT:10/550, AT:10/650

 

 

 

 

Edited March 12, 2016 by Chickenman

[Careless]

paging @Chickenman's brain for distributor wisdom.

So since I don't have a distributor machine, and my attempts to find someone with one locally didn't fare too well (found someone on Kijiji who was looking for them doohickeys, which was the closest i got... must look further)... I decided to take apart the distributor taking care to not damage the finishes. I will attempt to contact some other people to see if they know anyone with a distributor machine. Would love to buy one myself- been purchasing inexpensive vintage tools- but the Sun machines are a good 2500 for a properly functioning unit from some guy in Detroit who specializes in restoration of said machines with various "future-proofing" and accuracy upgrades- so that's off the "must buy" list for now.

 

And below are my findings & photos of the internal parts. Coles notes conclusion as of this post:

• both governor weights are equally heavy: both read @ 25-26g (52g combined) [see photo Fig. 1.1 + 1.2, & 1.3]
• both springs have the same tension: rudimentary test [see photo Fig 2.1]
• spring/weight cam unit has different upper and lower slots [see photo Fig 3.1]
• spring/weight cam unit has "12" marking: D612 = 12* Max Centrifugal Advance, D606 & D609 have 6* and 9* respectively [see photo Fig 3.1 as well as full assembly in Fig 3.2]

 

Fig 1.1

 

Fig 1.2

 

Fig 1.3

 

Fig 2.1

 

 

Fig 3.1

 

Fig 3.2

 

 

Not sure if I should just slap it together with the points and just get on with it. On pace to get the motor started by end of next month. Just gotta get some items i've been putting off the ordering of so I can save on shipping mulitple items with those ones that are needed for engine stuffs (though there's not much!)

I'm still new at this points stuff. But I value the learning experience- even though I probably won't be doing this to too many distributors. Still fun, though!

Edited June 12, 2016 by Careless

[Careless]

Gonna assemble it as is, and see how she goes! This car probably will be dyno'd at some point to have the performance figures as documentation to go with the completed resto. In the mean time, I'm going to see if I can find someone with a distributor machine who will tune the advance curve or at least give me a readout.

The photos below were borrowed from Ratsun, they depict another datsun distributor that has identical governer springs. Not that it matters a whole lot, but I will assemble it as is. Those springs even look exactly the same- though it is a different distributor.

 

 

#6 (601) on this chart uploaded by Chickenman shows that #6 is there twice, and only has one part number. The difference being that in comparison to the other diagram posted, it is NOT listed as a "set". It's listed as a "spring" and is a QTY of 1. So it's possible that they are available in singles for these units.

 

In any case, I'm assembling it as is and moving on until I find someone with a distributor machine.

This discussion has been insightful and informative, and i think the photos and diagrams posted could help someone in the future. Hopefully I can get this advance curve plotted and post that up here too. That'd be a good conclusion to this mystery.

Edited June 13, 2016 by Careless

[Chickenman]

You can get by without a Distributor machine. Just use a Dial Back Timing light to check Static advance ( 6 to 8 degrees ) , when the advance starts ( around 1,200 ) and full Mechanical advance. 30 to 32 degrees should be OK for California fuel, if you go with Chevron or whatever the best fuel is in California these days.

The 12 on the Cam plate is 12 Distributor degrees which equals 24 Crankshaft degrees. Add in 6 to 8 degrees to give your total of 30 to 32.total mechanical.

Vacuum advance disconnected while setting timing of course.