I just ordered some parts from courtesyparts.com two days ago.  (Mainfold Studs from a 300zx for my 280z engine rebuild),  first time ordering from them so we'll see how they work out.   I tried called 4 dealerships in my area.  What I discovered after looking on their website is that they show the parts available but when you call they tell you otherwise.  I guess my point is to actually calingl the dealerships will save you time.   Like I said before NissanPartsDeal has worked well for me, and I like how they show you manufacture schematics to help you ensure you have the right part.   Good luck, the hunt is part of the passion. 

"What I discovered after looking on their website is that they show the parts available but when you call they tell you otherwise. "

 

I have had good luck with the local dealer. But I have to give them the part number because their current system does not look up the part number for older cars.

Removed a D612-52 from a 4/70 and found only one spring, not too many early units fall into my hands, so I'm not clear if they were to have one spring or two at this point. I believe someone else had been in there prior to me as you can see the cam took a hit where they just slightly closed the slot prior to the weights normal max swing.

We destroyed this topic a short while ago.

 

After seeing this thread, I had to go out to the garage and check out my

D612-52 dizzy I picked up on eBay, supposedly off of a barn find parked

in 1978.  Also came with a nice set of Sumitomo plug wires dated coded

1977.

anyway, after tearing it down, it also only had the single spring, FWIW.

Dan 

6 hours ago, AZ-240z said:

it also only had the single spring, FWIW.

Dan 

Yep.. I had my 240z 1971 distributor cleaned up 20 years ago and... IT HAD ONLY ONE SPRING IN IT..  May be a modification from Nissan?  Could be that there is something in the service bulletins Nissan regularly brought out? ??   I to wondered then why only one spring but i did'nt change it in 2 springs and it ran and runs still with one spring till this day!

 My 71 had two springs when I got it. I used to remove one spring during track days to speed up timing advance. The engine will work fine with one spring or two.