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Stock 944 Cam specs

Does anyone know the stock 2.5L NA Cam specs, I cant find any info on the stock cam

Im looking for
Valve lift, Duration in degrees, and Duration @ .050 in degrees


Only thing I have been able to find is valve lift and the info is inacurate, I get everything for .474 to .480 to .545 So Im not sure and I need the info to do some number crunching and to compare it to other cams


Thanx guys
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1986 951, Stock for now.
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Old 03-27-2005, 07:24 PM
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I've got diagrams of that on my 951 RacerX website. I got the figures right out of a Porsche spec. book, so they're accurate. The duration is actually at the European standard of 1mm lift (0.040") instead of the American 0.050" clearance.

General rule of thumb is that maximum useable lift is 25% of the valve-diameter. The stock cam is pretty darn close to that. Improvements can be made in reducing the harmonics in the valve-train at various RPMs. This reduces friction and allows for faster valve-openings, even with the stock hydraulic adjusters...
Old 03-27-2005, 10:07 PM
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Thanx Danno, I have been looking at both JM cams and WEB cams,
The specs of WEB cam is
.480 valve lift, 254 duration and Duration at .050 is 234, I dont know what it is at .040

Im still waiting fot the JM specs

What do you think about changing the cam???? If the JM one shows better then I will use them with turbo valve springs and some titanum retainers is the idea. JM's base cam S3-14 claims 12-18bhp over stock with best power band is 3600-6500rpm, the next one up PH277-14 claims 14-20bhp over stock and power band is at 4,000-6600rpm, eather one will work with my setup, Im thinking the higher rpm power band will be better because My intake and exhaust is free flowing and better for high RPMs, Im just not sure what to do yet. Any adivce would be great
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1986 951, Stock for now.
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Last edited by fast924S; 03-28-2005 at 01:09 PM..
Old 03-28-2005, 01:05 PM
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You're not gonna get any specs out of JM. I have access to 5-6 cam profiles and use the same cam-grinder as JM. When you get closer to finishing, send me a note with all your mods and I'll recommend a couple of profiles.

Vitally important is an adjustable cam-gear because it lets you fine-tune your powerband (move it up & down RPM-range). I've got one that doesn't require milling the back of the distributor housing like the other one on the market.. cleaner design & looks nicer too....
Old 03-28-2005, 10:01 PM
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Perhaps this is a hijack but very related to the topic - I am building a DE/Club Race motor (not to hot) and have been wondering if the turbo values springs are stiffer than the N/A valve springs? Any data on this? Also looking at cams.
Old 03-29-2005, 04:59 AM
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Yes I believe they are stiffer.

Danno, I would be very intrested in that cam gear you have, Also JM did send me specs, here they are

S3 - Valve lift = .475", 235 degrees @ .050, 268 seat to seat, area @ .050 = 37.3
277 - Valve lift = .478, 236 degrees @ .050, 275 seat to seat , area @ .050 = 38

Im not sure witch is better, Email me danno we need to talk
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Old 03-29-2005, 01:18 PM
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Is there any differance between early 944 and late 944 cams. I thought I read some where there was a little differance. Is it true?
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Old 03-29-2005, 02:00 PM
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i'm following fast924s delve into the world of aftermarket cams with great interest. methinks i'll let him do all the research, and testing, then reap the benefits of all his work!! keep up the good work!!
regards, bob.
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Old 03-29-2005, 02:32 PM
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Verruckt, I dont think there is any difference, You may have seen some where that some 951 guys are swapping some NA cams in to help with spool up on the turbo's.

Bigyagi- I see how it is, Im like the point man in veitnam, I get to learn it all the hard way. LOL
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Old 03-29-2005, 02:45 PM
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there is certainly a difference between early & late cams.

just read the info provided in Danno's link
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Old 03-29-2005, 04:30 PM
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The early and late turbo cams are the same spec. The pre 1985 1/2 NA cam is the same as the turbo cam. The 1985 1/2 and up NA cam is a single pattern cam using the early turbo intake lobe on both intake and exhausts.
A popular upgrade is using the later NA cam in the turbo engine.
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Old 03-29-2005, 05:04 PM
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what's an 'early' turbo?
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Early '85 944
Old 03-30-2005, 04:12 AM
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probably '86
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Looking for a nice 944S for a daily driver.
Old 03-30-2005, 05:14 AM
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I can't get the racerx site to open. So is it worth it to upgrade my 924S to a late model cam since I have one sitting in the garage? Then should I sell my early cam to a 951 guy looking for an upgrade?
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Old 03-30-2005, 01:34 PM
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Some people think there is an early and a late turbo cam. They are both the same specs. Its the early and late NA cam that are different.
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Old 03-30-2005, 01:45 PM
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Different enough to switch to the late cam?
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Old 03-30-2005, 02:24 PM
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Worth 1 maybe 2 HP. If you have the cam tower off for something else then go ahead and do it but not really worth doing just for the sake of swapping them.
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'83 Callaway 944 2.5L turbo - Soon to be daily driver
'83 Porsche 944 NA - sold
'78 Porsche 924 NA- RIP
'89 Porsche 944 S2 - Parted

Looking for a nice 944S for a daily driver.
Old 03-30-2005, 03:42 PM
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2 HP! That would make the only HP increase I have in the car! That has just got to be worth it.... Thanks for the info.
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The crashes people remember, but drivers remember the near misses. Mario Andretti

1991 944S2 Rally #951 Rally-America.com
Old 03-30-2005, 04:42 PM
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