Later style cam - timing?

[kstylianos]

I've been playing around trying to time my sc330 cams to the upper end of the range (2.0mm). I've set the left side to 1.97mm and I'm currently trying to match the right side.....the closest I've gotten the right side is within .10mm. I know I have room for improvement here.

I know I have the pin in the correct cam sprocket hole as it gets me closest to my needed value....the other 2 adjacent holes put me ~.25mm off of either side. Since I can't physically hold the later style cams (like the early cams) to tweak them within this very small range of the cam sprocket hole, how does one get these cams sopt on......is it just trial and error?

Thanks for any help....I'm back in the garage tonight

[ChrisBennet]

The good news is, you can hold them to get the fine adjustment. I know 've done it.
The bad news is, I can't remember how. I don't think it involved anything special.
-Chris

[john walker's workshop]

the pin will allow the sprocket to move a bit without changing it's hole. rotate the engine until the cam is where you want it, remove bolt and washer, pull the pin, and turn the crank forward or backward to the Z1 mark. (the cam will stay put). install the pin in whatever hole accepts it, snug the bolt, and recheck.

[kstylianos]

Chris....that helps man

JW....One thing I forgot to mention....the pressure of the rocker on the cam lobe will spin the cam once the pin is removed. So, at least I found the correct hole in the cam sprocket....just need to fine tune now. I've been wrestling w/ the idea of using the cam bolt w/o the washer, but once its fine tuned, how to get it off w/o disturbing the cam? May need to use the procedure for high lift cams (>2.0mm lift).

Off to the garage....thanks guys

[ChrisBennet]

I remember now. It is trial and error.
I put the pin in, rotate things until the sprocket isn't loaded (pin can move easily).
Then I move the sprocket a little with the 9191 (big 3 pin cam wrench) and give the center bolt a little "burp" with the impact wrench to hold it.
Then I check the timing.
Rinse and repeat until I get the figure I'm looking for.
-Chris

[john walker's workshop]

if you only have the #1 and #4 rockers adjusted and all the others loose or not installed, the cam can indeed move when you pull the pin. makes it a PITA. if they're all installed, and in approximate adjustment, the cam stays put. i never do the one rocker method for that reason. the cam bolt just needs to be snug enough to hold the sprockets together, not fully tightened. that way, you don't disturb the cam much, if at all, when it's loosened again for the fine tuning.

[kstylianos]

Thanks JW and Chris....


I put the exhaust rocker in 4 and both rockers in 5 and the cam held still.

Found that there is really no way to hold the cam still during torquing. It really is trial and error with the later cams. If you hold the sprocket still with the tool, the pin will want to migrate all the way to one side of the hole during torquing....at least this gave consistant/repeatable figures, but they were about .01 off each time. What I had to do was not try and hold the sprocket still, but move it int he same direction while torquing to try and get the pin off the one side of the hole.......finally nailed it.

Left bank ~.078"
Right bank ~.077"

[Wayne 962]

Looks good to me - that's why there are two slightly different methods for high lift and low lift cams...

-Wayne