R-16 Cam Sprocket Caution

[JT68]

Just a caution for those rebuilding R and H motors..be sure not to mix "Metric" (late) and "English"/USS 3/8 thread (Early) cams and sprockets as that will result in a VERY poor running engine. If you do, your cam timing will be off by ~1/2 tooth (technically 6 crank degrees) with will result in pretty pathetic performance. If you have an early cam, you must run a early sprocket. Late cam needs a late sprocket.

Thought you would want to know.. PM or email if you are not sure what you have//

j

[S Allen]

I ended up using a metric cam with a metric sprocket on my early SAE stroker motor build due to the difficulty of obtaining an early SAE cam sprocket and this very issue. I also opted to use a known good Japanese aftermarket timing chain instead of the Motor Power chain as it was an unknown brand and did not pass muster with Dave P with consultation from JT. I heard that early SAE sprockets may not be an issue going forward.

Steve

[mraitch]

I have already forgotten the details of your post, HOWEVER, I know that if ever I am doing something in that area, that there is a warning post about something about it.

Thank you for taking the time.

[C.Costine]

A big thanks to Jim for posting this warning. I had very recently assembled the motor to my '67 using the cam, lifters and pushrods from a 68 that I have. I could not remember for sure which sprocket I had used, but I got in contact with Jim for some help. Instead of installing the motor today I removed the timing cover and the sprocket was the metric one so I swapped it. This of course saved me from doing it in the car, and even worse what I would have gone through later to figure it out if Jim had not just out of the blue posted about it. A big thanks to Jim!