There has been a lot of discussion concerning why there are differences between the way early sprockets for the 3 main were timed as compared to the way 5 main sprockets were timed. We have made these sprockets faithfully timed to original Nissan parts for both the 3 main bearing engine and the 5 main bearing engine. Since Nissan provided differentsprockets for each engine so have we in this tidy universal set. You the customer, decide which positions you wish to use and what engine you use them in based on the following information.
Crankshaft sprocket and Camshaft sprocket have 2 key way slots cut in them. 1 slot is for use with all early SAE G-1500 3 main bearing motors and R-1600 SAE 3 main bearing motors and SAE Camshafts to R-40000 and the other is for 67 1/2 - 70 Metric 5 main bearing motors with METRIC camshafts from R-40001 and up.
NOTE: Each keyway slot is marked E and L respectively. Early engines use the E slot positions and Late engines use the L slot positions. Install and orient the sprockets into your engine accordingly. Mixing up the positions in your engine will result in incorrect timing. In other words NO E to L, L to E combinations.
E to E for 3 main bearing, L to L for 5 main bearing.
If you have a 67 1/2, 68, 69 and 70 you can also buy part 1170. They are the same sprockets and the same price without the extra slots for the early motor timing positions.
A two step process was used to make these parts. Professionals were used in the comparative analysis of the early and late sprockets.
1st: A set of early SAE sprockets and a set of late METRIC sprockets were sent to a US manufacturer. Both of these sets of sprockets were reverse engineered using an AutoCAD program that calculates the degree locations. A comparative analysis was performed with notations of the differences between these two sets.
As a sprocket and gear manufacturer they are accustomed to and specialize in replicating these type of parts. They do this day in day out and have tools and equipment oriented toward this type of work. A print and 1st articles were created.
2nd: The same set of early SAE sprockets and late METRIC sprockets were sent to our team of engineers at Gerhardt Gear, an aerospace gear and sprocket manufacturer (See Inspection Reports) for analysis on their equipment. New production 1st article parts were also included and a final inspection report was obtained 5/8/22. Both the print and the parts were examined and the conclusions were exactly the same.
All in all, 4 automotive engineers worked on this project and I completely trust their conclusions.
Sprockets are US made specifically and exclusive to Datsun Parts. No cheap, Forklift third world sprockets are ever used.