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Join Date: Sep 2002
Posts: 507
Early vs late E cams

I just compared 2.4 E cams to 2.0 E cams using a dial indicator and rough marks on the pulley....
They seem to be the same.
The cams are original to my 69E built in Oct,'68. It looks like there is no difference in early or late E cams.
'69 911E 2.7MFI
'71 Volvo P1800E Wife's car
'78 VW bug convertible Family car
'02 M3 Winter car
Old 07-27-2004, 08:39 AM
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jluetjen's Avatar
Join Date: Oct 2001
Location: Westford, MA USA
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Thanks for the clarification Ed. Now we know -- I'll adjust my data.

- John
'69 911E

"It's a poor craftsman who blames their tools" -- Unknown
"Any suspension -- no matter how poorly designed -- can be made to work reasonably well if you just stop it from moving." -- Colin Chapman
Old 07-27-2004, 10:36 AM
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jgparker's Avatar
Join Date: Feb 2003
Location: Melbourne FL
Posts: 427
Live and learn. There are a couple of references that have this wrong then. Thanks for the info.

-- Last Engine rebuild project, Now a coffee table.
-- New engine rebuild project, Alive and well.
-- '72 911 Martini RS, '69 911E Targa, a 2004 Cayenne S, and a Miata too... Looking for a Cayman S
Old 07-27-2004, 12:40 PM
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camgrinder's Avatar
Join Date: Feb 2004
Location: California
Posts: 921
I can always make you a "late" E cam...
John Dougherty
Dougherty Racing Cams
Old 07-27-2004, 06:37 PM
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Join Date: Jun 2004
Location: Rio Rancho, New Mexico
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When I really studied cam data from Paul Frere's book "Porsche 911 Story" and compared to Bruce Anderson's book "Porsche 911 Performance Handbook" I noticed the specs didn't always match.
Upon closer reading Frere's book he changes the criteria for cam specs at page 83. On page 81 he shows the intake cam timing for the 3.2 motor as open 27 degrees btdc/ closes at 73 degrees abdc. This is the old way of measuring cams. It is done with the normal 0.1mm valve clearance and shows the valve opening when it just begins to move.
On page 83 he shows the same cam timing with "zero clearance and when the lift has reached 1.00 mm" to reflect Porsche workshop operation. With the new spec at 1.00 mm lift the same cam becomes intake open at 4 degrees btdc/ close at 50 degrees abdc. So you can see with the two different ways of measuring the cams gives us two distinctly different sets of numbers for the same cam.
Frere, from page 83 on, shows cam timing numbers using the newer (1.0mm) numbers.
Without knowing this you would assume the older cams had much more duration than newer cams.
Notice there is about a 46 degree difference between the two sets of numbers for opening and closing. 23 open and 23 close.
I'm convinced this has caused confusion for many people trying to decipher cam specs.
I hope this proves useful.
'76 911S 2.7, webers, solex cams, JE pistons, '74 exhaust, 23 & 28 torsion bars, 930 calipers & rotors, Hoosiers on 8's & 9's.
'85 911 Carrera, stock, just painted, Orient Red
Old 07-28-2004, 08:41 PM
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