R16 Timing Components and Cam-SAE vs. Metric

[Curtis]

Mystery was solved, just hadn't checked all MY gears carefully enough.

[Curtis]

Dave suggested I post up some photos from yesterday. I used a deep socket that fit the gears. I took some key stock and ground it down so it would lock the two gears together in the key way. This is different from the way I did it before and gives better results.

Here you can really see the difference of the teeth. SAE gear is in front.

IMG_3149.JPG

IMG_3151.JPG

[notoptoy]

Great comparison, thanks Curtis.

[Gregs672000]

Oh no, THAT won't cause any cam timing issues...

[richard]

SAE cam sprocket with metric cam. Crank gears are the same.

All I can tell you is it was a major PITA to chase down when you don't know.

Are you sure all crank gears are the same?

[Curtis]

SAE cam sprocket with metric cam. Crank gears are the same.

All I can tell you is it was a major PITA to chase down when you don't know.

Are you sure all crank gears are the same?

Dean thinks so.
https://www.datsunparts.com/2290

And lower timing chain is the same for 1500/1600/2000.

[richard]

Working on a 3 main right now and I have a 6 degree difference on the crank gear.

[Curtis]

Working on a 3 main right now and I have a 6 degree difference on the crank gear.

According to JT 6 degrees is about what the wrong cam gear will give you.

[richard]

Working on a 3 main right now and I have a 6 degree difference on the crank gear.

According to JT 6 degrees is about what the wrong cam gear will give you.

Plus 6 on the crank.

[Curtis]

Better check the cam and gear.

[Curtis]

Here's the key stock modified to check them.

IMG_3170.JPG

[JT68]

To clarify, the SAE vs. Metric cam sprocket difference is about 1/3tooth, each tooth is 9degress on the cam, so 1/3 tooth is 3 cam degrees.
That equals 6 degrees at the crank (since the crank rotates twice as fast/far as the cam gear does)

I checked crank sprockets tonight and there does appear to be a significant difference, so I believe Richard is exactly correct. There was an early part number SAE crank gear 13021-32200 and late Metric 13021-73601

The -32200 has one tooth indexed perfectly with the woodruff key center.

The -73601 is indexed over to the left side of the keyway.

See photos. Since those are crank degrees, it is a mile of difference. (each tooth is 18 degrees) (there is some parallax in the photos, the blades show the correct angles)

The bottom line is never mix up the early sprockets with the late, always use a metric cam with the late sprocket set. and an early cam with the early sprockets.

[Curtis]

Well damn, another wrench in the works.

[Curtis]

I just checked my crank gears and found the same tooth difference. If you look at the bigger photo of the gear on Dean's site it looks to me to be the later metric number gear. The H20 gear I have is the metric one.

[Curtis]

Can someone who knows how to do this set it up with a degree wheel? Be nice to know exactly what the different setups are.