Cam durations for all S38/M88's?

[M5BB]

Behind again.

Yes, I am running both B36 cams.
My whole mission was to build my S38 into a M88 or better.
B36 cams are very similar to M88 cams as far as lift and dwell.

Soon to run much better if I ever get the time to finish putting it back together.

[2wheelsoff]

Are we talking exhaust side here and if we are why would anyone want the exhaust center at 90degrees?

Paul

Like I said, lots of confusion about the meaning of retard vs advance when you talk to people about this. I'll just post my measurements of the sprockets. Based on these measurements, the stock (unmarked) b35 sprockets are both about 105 lobe center.



In this CAD drawing I've shown the location of the dowel relative to the nearest sprocket tooth. The drawing is a view looking at the front of the engine. All measurements were made on a rotary table and should be accurate to about 0.1 degrees. The markings (A, E, A100, etc) are just as they appear on the sprockets. Note that I'm showing 5 different sprockets on the drawing.

The sprockets have 36 teeth so every tooth represents 10 cam degrees or 20 crank degrees. This is important when discussing cam timing because duration numbers and event timings are typically specified in crank degrees, but lobe center spacing is specified in cam degrees.

The S38b38 sprockets are marked E108 and A108 but I've never measured them.

According to the above measurements by Devinder; swapping the E and A gears from an S38B35 - would that effectively be the same as having 110 gears? A to E110 is right on and E to A110 is extremely close. I was having my gears slotted by the machinist, but truthfully was intending on setting them at the 110 spec for my build. This would save time and $ as my dead motor had a fresh stock gear set. Build is S38B35 with custom 11:1 + B36 cams and crank.

[Randomg]

The intake has a raised center compared to the exhaust sprocket to account for the ignition rotor mount. If you switch them, you'll additionally push the rotor forward. I imagine this doesn't affect the spark voltage much, but something to think about. If you put the more shallow exhaust sprocket on the intake, look out for the bolts contacting the cam carrier, you might have to use some thicker or additional flat washers.