Cam timing questions and tips

[osidak]

I will be timing my cams today. I have a Haynes manual and also BA performance handbook.

When you install your cams the dot or the 930 stamp should be point straight up is this correct?

Should the lobes on the cam be contacting any of the rockers on a stock 78 sc cam?

When I had my head studs replaced 2 years ago the wrench that did the job dropped one of the cams (drivers side) and broke it. Now I have a old style cam (large 46mm nut) and a newer style (19mm bolt). The newer style cam when having the dot at the 12 o’clock is engaging the number 2 intake valve (I think) and the other cam is not engaging any valve.

Are my above assumptions correct?

Any advise or tips from the people in the know would be appreciated

Osidak

[GIBSON]

Here's what I would do, get the advice of others more experienced and see how it compares to mine.
1.I alway start with just the #1 and #4 rockers in place, adjust both of those cylinders for proper valve clearance. (If all rockers are installed, check for proper adjustment of all valves). Yes, the dot points up and I believe the 930 mark points up. Seems like one of the books (Anderson?) has a profile drawing of the cam lobe orientation at top dead center.
2. When setting the left cam, starting at top dead center for #1, the #4 rockers will be tight while the #1 rockers, of couse, will have not be activated. Put your dial gauge on, rotate the engine to the overlap or
cam timing point (360 degree rotation) and measure the lift of the left cam. Adjust as necessary and recheck. When you are satisfied, repeat for the right cam, starting at top dead for #4.
See if this helps and compare with the comments of others.

Bruce Herrmann

[BK911]

Do a search for "Cam timing" Lots of hits. If I remember correctly (50/50 shot) the keys go up. Or is it down? I think it is up. Do the search here and on Rennlist.

Good luck!

[stormcrow]

To time your cams properly, you need a dial indicator. Set #1 piston to tdc. Set your dial indicator on #1 piston intake rocker arm. Rotate the drive shaft 360 degrees and check your readings.

If they are not within spec, then you need to loosen the nut on the cam shaft, remove the pin and rotate the cam ever so slightly to the left or right.

Insert the pin, washers and nut - tighten. Start over and do the same until you get the cam within specs. Do the same with #4 cylinder for the other cam.

Steve