Camshaft Specs

motley911 · 08-14-2009, 06:35 PM

Hi Guys, does anyone have the specs on the Porsche cams with the following part numbers:
993 105 246 70
993 105 247 70

I am looking for the normal information including the settings were they should be dialed in.

Thanks,
Richard.

Steve@Rennsport · 08-14-2009, 08:04 PM

Those numbers are not in PET and I'd guess the last two numbers got inverted.

The 07 cam are the standard 993 hydraulic ones. One needs either the factory tools and fixtures or use a solid rocker and manual adjuster on #1 & #4 to set timing. You can use the 964 spec if you use the latter method.

motley911 · 08-15-2009, 06:30 AM

You are right Steve - I re-checked the part numbers and I had mixed up the last two digits. Correct numbers are:
993 105 246 07
993 105 247 07

I should have also explained, I am planning on installing these in a 930 engine with solid rockers.
Thanks,
Richard

motley911 · 08-15-2009, 07:22 AM

Also - as I haven't been able to find any specs, I measured the lobe profile in the engine with a degree wheel. Listed are the results:
Total lift (zero clearance) = Intake 0.485" / Exhaust 0.446"
Duration @ 0.05" = Intake 242^ / Exhaust 225^
Lobe Centerline = Intake 114^ / Exhaust 110^
Intake valve timing (zero lash) @ 0.05" = Opens 7^ BTDC / Closes 55^ ABDC
Exhaust valve timing (zero lash) @ 0.05" = Opens 42^ BBDC / Closes 3^ ATDC

To get the "Intake Valve Stroke in Overlapping TDC with 0.1.. clearance" I then checked the WebCam and Dougherty sites for cams cams with similar specs and found the following:
964 = 1.26mm (as Steve suggested)
WebCam 20/21 = 2.1mm
Dougherty DC19 = 1.9mm

I could not find the actual lift / duration / centerline information for the 964 cams, so I do not have a good comparison to know if they should be set at the lower end (1.26mm) or if I should dial them in at the higher end (~2 mm)?

Richard

camgrinder · 08-18-2009, 10:58 AM

I have the 993 247-07 listed as a 1995 993 hyd rocker cam.
Your specs look closer to the 3.8 super cup cam, number 993 247-70
I have ground a few 993 cams to the super cup profile.

motley911 · 08-18-2009, 08:34 PM

I just checked the actual part number stamped into the front of the cams and they definitely end in "70" and not "07". This answers a lot of my questions as I really wanted to know where to dial these in. I checked your website and the recommendation is 2.0mm.

I need to get a set of rocker arms rebuilt - I will contact you separately to arrange.

Thanks,
Richard.

camgrinder · 08-18-2009, 10:01 PM

Quote:

Originally Posted by motley911

I just checked the actual part number stamped into the front of the cams and they definitely end in "70" and not "07". This answers a lot of my questions as I really wanted to know where to dial these in. I checked your website and the recommendation is 2.0mm.

I need to get a set of rocker arms rebuilt - I will contact you separately to arrange.

Thanks,
Richard.

I believe the factory setting is 1.5mm for these cams. This puts them in the engine on a 114 intake centerline, or 2 degrees retarded from straight up. The 2.0mm setting puts the camshaft straight up on a 112 intake centerline.