# Biggest Cam for CIS



## Shrttrackr (Oct 13, 2004)

What can CIS Basic handle for a Cam?
I have a cylinder head with oversize valves that i need to put a smaller base-circle cam in.

i have a Web Camshaft that i would like to run.

here is the card info:

Part #:
00-342

Grind:
211
--------------------------------------------------------------------------------
Intake
Exhaust

Valve Lash (Inch):
.010
.016

Valve Lift (Inch):
0.480
0.480

Valve Lift (mm):
12.19
12.19

Advertised Duration:
288°
288°

Duration @ 0.050":
261°
261°

Lobe Center:
102°
102°
--------------------------------------------------------------------------------

Intake Opens 28.5°
Before TDC
Exhaust Opens 52.5°
Before BDC

--------------------------------------------------------------------------------

Intake Closes 52.5°
After BDC
Exhaust Closes
28.5° After TDC

--------------------------------------------------------------------------------

Valve Timing Is Checked With Zero Valve Lash
@ 0.050 Inches Of Valve Lift.


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## WaterWheels (Aug 14, 2005)

CIS is really no different then carburetors. It can "handle" that camshaft but you are not going to have what most people would like for an idle. All the fitting requirements a side, I would guess the idle will need to be in the 1500RPM range with a lot of initial ignition timing, maybe as low as 1200RPM but I doubt it.


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## Shrttrackr (Oct 13, 2004)

Thanks, idle quality is not an issue as this is for a race car. I guess i should have put that in the original post. 

this is for my side project car. the main race car has a cam that makes my teeth rattle... 

Ignition timing: i have this setup with non-vac advance distributor set anywhere between 32-34deg.


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## ToddA1 (Apr 22, 2002)

On basic, I've run a Schrick 280* asymmetric with a silky smooth idle @ around 900 rpm. The same cam in a Lamda car needed to idle around 1200 rpm. TT's 280* is a Schrick clone. I have a TT 288* that I haven't run yet.

Collin @ TT told me a friend of his ran a Schrick 316* on basic, but it obviously didn't idle well.

I was under the impression that carbed cars handle larger cams better.... it's the sensor plate bouncing around that screws the idle up.

-Todd


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## WaterWheels (Aug 14, 2005)

ToddA1 said:


> I was under the impression that carbed cars handle larger cams better.... it's the sensor plate bouncing around that screws the idle up.


My not be 100% the same, but the carburetor relies on engine vacuum (low pressure in the intake system) to draw fuel from the bowl of the carburetor. So fluxing pressures also upset the mixture in them also. Cure is to raise the idle to smooth the pulses out and get an idle you can live with, same as with CIS. But yes, they can stand maybe a bit taller cam than the CIS can.


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