cam timing

OK, I haven't been able to get a definitive answer on this one. I just got a stage 6 block w/ 1" lifters and standard cam and location. Crane says to advance the cam acouple degrees and go. Do the manufacturers grind them specifically for 1" lifters? From where I see it, it should cause more duration and slightly different timing. What have you run into with this? I have see most others bush the lifter bores back to standard.I dont want to do that unless there is no option.Thanks

 

Crane makes a different cam for standard lifter and 1" lifter. If you map out your cam you shoud be able to split the difference.

 

see what I mean? Mike I agree the center is the center, but when I degree the cam it is a couple degrees earlier and closes later.

 

If a 1" lifter has a bigger roller then that would mean as the lobe starts to push on it, it would start moving sooner and it would close later. It would seem to me that a standard cam with 1" lifters would have slightly more duration. But it is probably so minute that it might be redundant. I don't really know.

 

what gear drive are you using?

 

What roller diameter do your lifters have?

 

I dont have access to the lifters right now, but they are from a fuel car if that helps

 

1.00 lifter =.920 wheel
.904 lifter =.820 wheel
total difference is aprox 4deg split will work
engine will start and run but will not run properly,as cam profile will change
best solution is to bush lifters
or purchace cam ground for .920 wheel
hope this helps
mk

 

thank you Mike. that's what I was hoping to hear. How much do you get to do the bushings?

 

BUSH LIFTERS IS 280.00
1-860-345-3004

 

Actually it changes the duration 1 ¾ degrees @ .50
Not as much @ seat timing
If you advance the cam 1 ½ degrees to close the intake at the right time you should be fine
This from someone knowing cams better than most anyone here

 

John348
I have .920 rollers and cam ground for this size roller but am using a cam checking tool with radius for the .820 roller. Would the opposite be true. When setting the int. valve opening @.o50
and 34 degrees what would the actual setting need to be to compensate for the smaller radius?

 

Weighing in a little late, but are we splitting hairs while missing the boat here?

I set my cam by placing the intake centerline where I want it to achieve the desired results. I do not use the mfg's .050 lift at X degrees BTDC, or the split overlap method. "IF" I want the intake c/l at X degrees ATDC, I set it there. "IF" I need to make adjustments at the track, the gear drive makes such easy. Well relatively easy considering all the plumbing and blower drive belts, etc, on the motor.

This method has worked on motors from Ford flatheads w/ either flat tapped Howard M14's or Isky's 404 w/ the pinned, radius tappets, to todays aluminum hemi fuel motors...

So for me, I set the centerline of the intake lobe to where I want it, and the dia of the cam follower is basically a moot point from there on...

 

I used to set ctr. line of cam with a straight edge across the lifters and then go from there but don't think if you want to follow cam manuf. or card settings that method is aaccurate any more.

 

I took a slug of steel, turned the o.d. to fit the clearance hole in the block just above the lifter, drilled a press fit hole in the center of one end and pushed in a 3" piece cut off the end of a push rod. Set the cam with the lifers in place.
The weight of the steel slug keeps the lifter following the cam.
There is a million ways to skin a cat.

With the amount of pushrod deflection we get, I wonder what things really look like at rpm.

[ January 09, 2005, 11:06 AM: Message edited by: T.Howell ]

 

Intake cl is absoutly the best way to install a cam however,the roler dia. will affect the 4 events as i explained before this is why split will work and engine may even run well depending on how the shaft was ground that is why we check the 4 events @.050

 

Does any one check the deg at the valve
and not at the cam with all of the deflection
in the valve train why check it at the cam
just a ?