Datsun Roadster Forum-311s.org

I should note here that at this time I have complete sets so will think about if I have a future need. I was able to get some stuff from local members.

Makes sense to use them, as long as you don't mix SAE and Metric keyed/forklift sprockets, you will be fine. The SAE cam will never know the difference.

Curtis, You were instrumental in helping with the WIKI so I will send you a free set of sprockets for your troubles.

D-

Datsunparts.comInc wrote: ↑Fri Jun 10, 2022 1:02 pm Curtis, You were instrumental in helping with the WIKI so I will send you a free set of sprockets for your troubles.

D-

Score!!! Thanks. This is what initial confusion and ignorance can do for you. More for my hoarding.

WOW ...Dean...! ! ...Impressive vendor support !

23yrRebuild wrote: ↑Sat Jun 11, 2022 4:09 pm WOW ...Dean...! ! ...Impressive vendor support !

+1

What I don’t understand is if the cam profile is the same ( as you can see in the other discussion) SAE and Metric, why still want to have two different sprockets, SAE or metric.
When you replace always replace both sprockets, it is stupid if you don’t.
So if there is such a big timing difference between them, SAE and Metric, I would choose the one that gives me the best engine performance and won’t use the other type anymore.

Hi Richard, probably the only issue is the fit of the crank sprocket on the crank. If you can live with the less than perfect fit
of the metric crank sprocket on the SAE crank nose, you are correct, all that is needed is a pair of metric sprockets and you are set.

We have a few new SAE sprockets around which is why we supported both types. Your point is well taken as usual.

Bravo Dean!

From my point of view there is no difference between the timing SAE or METRIC as long as both sprockets are used from the same metric or same SAE engine.
As you can see the distance between the keyway and the timing mark is the same on both sprockets.
The only thing which changes is the position of the chain on the sprockets, but as far as I can see this has no influence on the timing as I showed on the pictures below.
The sprocket bore and keyway dimensions are the only different things I found, but that can not be reproduced both in one single set.

Let me know if I missed something.









METRIC SETUP:


TDC seen at top picture




SAE SETUP:


TDC seen at top picture




FSM timing set up:

Spot on Richard, Thank you, Dave(and Stan) and Curtis for all your help with this project!

I'm finishing another stroker (metric) build now, so I'm glad this is all sorted.

As with all R,H,U engines you can see the timing marks and the centers of the crank and cam are in a straight line at TDC. If you have a mis-match or are off one tooth, that won't be the case. One or both marks will be out of position.

Pretty sure lots of engines have been dorked up with mismatched or incorrect sprockets! (it stung me many years ago....)

Yes Richard correct. The company that made our sprockets started with blanks for both sprockets. Then both keyways on the sprockets early and late SAE and metric were cut respective to the original SAE and Metric sprocket dimensions. This saved time and money to make the sprockets.
Bore diameters are honed for SAE and Metric. As our customers provide the year of their cars they receive what they need.
Since some people may have a new SAE crank or new SAE Cam sprocket or have just one good sprocket and will want to replace the other these will be sold as separate sku's to be used only with these engines.

https://datsunparts.com/collections/eng ... t-sprocket

My experience is that people usually opt for replacing both sprockets and be done with it. There is a instruction sheet that comes with the sets.

D-

23yrRebuild wrote: ↑Sat Jun 11, 2022 4:09 pm WOW ...Dean...! ! ...Impressive vendor support !

Thanks. I think people need to be supported for their efforts. I knew Curtis had an early car so I felt it appropriate.

D-

I hadn't posted about the gears I received. Very pleased with what I see. Going to put them in my 1800 stroker. One of the local guys already used his set.

As to the cam specs and profile being the same, I posted links to these spec sheets in another thread. Advance is not the same. Metric shows retarded timing on the sheet. Timing difference total is 1.9 degrees.

https://kendo-usa.org/datsun/r16_sae_fa ... m_spec.pdf

https://kendo-usa.org/datsun/r16_metric ... m_spec.pdf

Curtis, you may want to be careful how you interpret the sheets above.


These data sheets are much more correct:

http://www.kendo-usa.org/datsun/datashe ... metric.pdf

http://www.kendo-usa.org/datsun/datashe ... 55_sae.pdf