Datsun Roadster Forum-311s.org

GeoffM wrote:My starter issues ended up actually being a defective starter. Armature was dragging and causing high amp draw.

Was the "replaced" starter a gear reduction type? By dragging, do you mean shorted/bridge commutator sections?

Hi Garth,
As you know, my foundation of the physical world is deeply rooted in physics and not this voodoo electrical mumbojumbo so Ill assume something mechanical was causing the armature not to turn....perhaps a misaligned bushing or the rotor rubbing the stator.
It is a gear reduction starter from Wilson and I wasn't there when they put it on the test bench but the diagnosis when they called me was that it was "dragging" so I assume that means so much torque to cause the rotor to stall. Funny thing is that the amp meter didn't show Locked rotor amps when the solenoid would switch over. I put in the warranty replacement tonight and it works just fine. Would have been interesting to find out the mode of failure of the old starter. If you were around I'm sure you would have been able to diagnose it in no time.

GeoffM wrote: Funny thing is that the amp meter didn't show Locked rotor amps when the solenoid would switch over....

Current through the solenoid and starter does not flow through the ammeter circuit. That's a good thing on many levels!

garth wrote:

GeoffM wrote: Funny thing is that the amp meter didn't show Locked rotor amps when the solenoid would switch over....

Current through the solenoid and starter does not flow through the ammeter circuit. That's a good thing on many levels!

Interesting because as my first starter was failing, when the solenoid would switchover, the ammeter would hit -30 amps.

GeoffM wrote:

garth wrote:

GeoffM wrote: Funny thing is that the amp meter didn't show Locked rotor amps when the solenoid would switch over....

Current through the solenoid and starter does not flow through the ammeter circuit. That's a good thing on many levels!

Interesting because as my first starter was failing, when the solenoid would switchover, the ammeter would hit -30 amps.

That's because the solenoid does go through the ammeter via the ignition switch. The starter motor does not. This is why I have been adding a starter relay to the new harnesses I make, takes that initial high current flow out of your expensive ignition switch.

Thanks for the memory support Curtis! Of course the ammeter reads the solenoid current and it can be as high a 60 amps for a few seconds.

garth wrote:Thanks for the memory support Curtis! Of course the ammeter reads the solenoid current and it can be as high a 60 amps for a few seconds.

Easy to forget, I had to think about it for a moment and even went to my layout drawing first before posting. Good thing for the 67.5 and up there are some cheaper alternatives for the switch.

This made me think about how to build in a connection for the solenoid on the starter harness to use a test button.

Re Clutch Adjusting:

The tech wiki says...

"With a flat tip screw driver holding the adjustment rod back off the locking nut. Now tighten the adjusting nut so it takes the slack out of the clutch fork sticking out of the tranny. Back off one quarter turn and tighten up the locking nut. Put the spring back on and go for a spin."

What does the adjustment rod feel like when the spring is disconnected? Does it wiggle around a bit? because mine does.

Yes Ralph because it just sits in the cup of the slave piston and the boot kinda holds it in place without the spring tension sandwiching it between the shift fork and the piston.

Got it. Thanks

I know this info in on this site but I don't have time to search it out........

3/4 vs 7/8 brake masters. I have a couple of each but only have hard lines for the one that is mounted in the car which is a 3/4.

Are the fitting for the two hard lines coming out the bottom the same for each size brake master? Near as I can tell they are but I need confirmation.

thanks!

Which octane to use?
The car has 94 in it now for initial start-up & testing but once it is being used (hopefully) daily, which octane should I use for the U20? Any additives needed? Anything to be sure to stay away from? (we have 94, 91, 89, & 87)

tjp wrote:I know this info in on this site but I don't have time to search it out........

3/4 vs 7/8 brake masters. I have a couple of each but only have hard lines for the one that is mounted in the car which is a 3/4.

Are the fitting for the two hard lines coming out the bottom the same for each size brake master? Near as I can tell they are but I need confirmation.

thanks!

If I remember right, the 7/8" Z/510 master had the different line sizes than the 3/4 Roadster part so you needed to swap fittings.

Ralph wrote:Which octane to use?
The car has 94 in it now for initial start-up & testing but once it is being used (hopefully) daily, which octane should I use for the U20? Any additives needed? Anything to be sure to stay away from? (we have 94, 91, 89, & 87)

Probably the 91, but it depends on your engine, compression ratio, ignition timing and the weather (cooler the better). Octane is the ability of the fuel to resist exploding before you want it to and has nothing to do with the quality or power capacity of the fuel (actually the higher the Octane the less explosive it is). Run the engine on what it needs in order to not ping. I run my high compression engine on 92 pump gas, needing to add a real Octane Booster only in hotter weather or in CA which has only 91. Listen to your engine!

Ok, thanks Greg