911RS Base Circle and Lift

[HKZ Bob]

Hello Forum,
I would like to find a base way to identify if a 911s cam is stock cam by caliper measuring & a angle gauge.


My cams are not good for any reference.
Hopefully you can give me some precise data




Maybe you can help us with folloing data in metric numbers?
Measured with a caliper & a gauge.


Intake
Base Circle: mm
Base Circle & Lift: mm
Angle:

Exhaust
Base Circle: mm
Base Circle & Lift: mm
Angle:


What else can I measure.


Do I have a 1:1 projection on the valve lift on std. rocker arms?
Direct correlation of the data.

I cannot predict opening & closing but with this 3 values I may predict if the cam is orgininal?



BR
Bob

[HKZ Bob]

Hello Engine rebuilders & Cam Gurus,
I donīt want to take your job.

Somebody offered me some 911S cams and I want to kow how to check it quickly.

BR
Bob

[tom1394racing]

Bob

Here is how I do it....

DIY Cam Doctor

[HKZ Bob]

Originally Posted by tom1394racing

Bob

Here is how I do it....

DIY Cam Doctor

I know,

just image you are on a vintage swap meet and somebody offers you some s cams.

You have a caliper and a angle gauge.

What would you measure?

BR
Bob

[tom1394racing]

I don't think you could do it at a swap meet with a caliper and angle gauge

[Flieger]

If you know the profile then cut out a piece of Aluminum or something as a go-nogo gage so that you can just fit it over the pointy side of the lobe. Make sure the metal or plastic is thick enough to be reasonably dimensionally stable.

[HKZ Bob]

Originally Posted by Flieger

If you know the profile then cut out a piece of Aluminum or something as a go-nogo gage so that you can just fit it over the pointy side of the lobe. Make sure the metal or plastic is thick enough to be reasonably dimensionally stable.

Yes but I need the data first to make a profile gauge.

Forum who can help here?

BR
Bob

[Flieger]

I thought the RS used S cams, so those should be pretty easy to find.

[HKZ Bob]

Originally Posted by Flieger

I thought the RS used S cams, so those should be pretty easy to find.

Yes correct my typo.
Here I picked up some roomes.

Base circle 29,4mm and Base Circle plus lift 37,4mm

Can someone confirm this values?

BR
Bob

[gtc]

There are some specs here:
http://www.drcamshafts.com/911profiles.htm
http://www.elgincams.com/c-por2.html

[HKZ Bob]

Originally Posted by gtc

There are some specs here:
Dougherty Racing Cams Porsche 911, 930 and 964 camshaft profiles
http://www.elgincams.com/c-por2.html

Thanks Graham,
but you are not getting my point?

BR
Bob

[jariusj77]

I don't think you could do it at a swap meet with a caliper and angle gauge

[tom1394racing]

Remember ...To get the overlap, you need to measure the degree location of the peak intake lobe relative to the exhaust lobe. Solex and S cams are very close to one another and precision measurements are required to determine the differences.

[euro911sc]

It looks to me that you can get base circle and lift only with a caliper set. You will not be able to get the center to center distance or the diameter of the nose which would really define the individual lobes. If you had an angle finder you may get close to the lobe separation if that helps? If you had a radius set you could get close to the lobe diameter which may be useful in determining all the right numbers.

-Michael

[HKZ Bob]

Thank you all,

So we all know the Solex and the 911S MFI are very close to each other.
I will not find an MFI cam with an Solex profile as a original setup. So I have a seperator.

Who has an old original 911S cam at home to measure Base Circle and Lift for intake and exhaust lobes and probably measure the ramp angle as showed in post one.

BR
Bob

[HKZ Bob]

Originally Posted by tom1394racing

Remember ...To get the overlap, you need to measure the degree location of the peak intake lobe relative to the exhaust lobe. Solex and S cams are very close to one another and precision measurements are required to determine the differences.

Hello Tom,

Did you measured the lobe height from intake and exhaust?

If you have a lobe height of 37.3 mm (Intake RS) and a valve lift about 11.15mm.
Base Circle 29.4mm ( lift dia to base circle offset) 8.2mm.
8.2mm times 1.45mm makes it to 11.89mm lift.

OK I got you.
Let see

BR
bob

[HKZ Bob]

Hello Tom

I made some calculations of the S cams
Can you confrim the data.

I calculated base circle and lobe height with the data from Tom

[larrym]

check the recent DIY Cam Doctor Thread - maybe willsolve your issues

.