web cam question

[drumbraker]

just took a set of 149/149 Web Cam out of engine. Wondering how they might work in 2.0 vintage race engine? looks like they are pretty much S cams?

[stownsen914]

Just looked at the Webcam site, and that is indeed the 911S grind. It's a nice sporty cam for a 2.0, though probably wouldn't give max power for all out racing.

Scott

[Steve@Rennsport]

Originally Posted by drumbraker

just took a set of 149/149 Web Cam out of engine. Wondering how they might work in 2.0 vintage race engine? looks like they are pretty much S cams?

Its an "OK" choice for a race engine; better for rally cars.

Depending on your gearing, the 120/104 is a better option, but you'll need to work harder and engine configuration must be spot on.

[drumbraker]

Steve,
Thanks for response. I am tearing down an engine that was built some years ago, had not REAL knowledge. Better safe than sorry.
So Far:
Cosworth Pistons (pictured), these 149 cams. Weber 40's. Bottom end not apart yet, but I can tell it has 2.2 rods, counter balanced crank. It is a 3R case, but does have piston squirts, and I can see plug from oil Mod. More info when totally apart. Heads were also fresh, but small port (T/E type).

I'm looking to salvage best of parts and add to, to make "PRETTY GOOD" 2 liter. I'm not trying to build ticking time bomb, but do want 200+ HP.

All directions/suggestions welcome!

Scott

[Walt Fricke]

200 hp out of a 2.0 is not easy to do. What did Porsche claim for its race motors - 220. 10.3 to 1, twin plug, 38mm ports, and Weber 46s (or you can go slide valve MFI - good luck on that) with the 906 cam.

[stownsen914]

As a point of reference, the '67 2.0L 911S on Webers made 160 hp DIN, which is ~180 hp using the SAE standard that is more common today. To get to 200+, you may want to consider cylinder head work and twin plugs.

Scott

[Steve@Rennsport]

To make 200+ HP from a 2.0, you need:

1) CNC'ed heads a MUST.

2) 149/171 cams or equivalent. There are many good choices as well as several bad ones.

3) 11.2:1 or more & Twin-ignition.

4) 46mm Weber or PMO's on tall manifolds.

5) Headers are very critical and there are tradeoffs. Long-tube 1.5" one with a proper dual-in/dual-out race muffler is a MUST.

The crank MUST be cross-drilled and you will need Carrillo or Pauter rods. Porsche rods are too heavy (2.2 rods are the worst ones to use). SC or Carrera oil pump is fine.

There are some other details, but this is a good start toward a strong & reliable race engine.

[drumbraker]

Would love to hear more about good and not good cam profiles for application.

[stownsen914]

In my 2.7L race motor, I have an Elgin 310-296, which is almost like a GE80. It's an 8000 RPM cam in my engine, so maybe a bit much for a 2.0L unless you're going to rev to at least 8500. Maybe a GE60 or similar?

[racing97]

I don't believe you would need to spend $10,000 on a set of heads to make 200 just emulate the 2.0 Carrera 6. Unfortunately as you take small displacement motors up in the RPM range the torque will be reduced in the lower RPM ranges.

regards

[Walt Fricke]

My 2.7 race motor has Elgin 315 cams. They are most notable for a lash setting of 0.008", for reasons I don't understand. Great cam, very flexible. But not an 8,000 rpm cam for my motor. I used to shift at or above 8,000, but after breaking valve springs and a trip to the chassis dyno, found that peak HP was more like 7,200, and optimum upshifts were at 7,600. The chassis dyno showed 220 hp, which generously might equal 250 at the flywheel. I was kind of hoping for something closer to 270, which indicates the difficulty of achieving high numbers by just assembling parts. If the torque curve could have been moved up the RPM axis maybe 500 rpm, the horsepower would have risen.

[stownsen914]

Originally Posted by Walt Fricke

My 2.7 race motor has Elgin 315 cams. They are most notable for a lash setting of 0.008", for reasons I don't understand. Great cam, very flexible. But not an 8,000 rpm cam for my motor. I used to shift at or above 8,000, but after breaking valve springs and a trip to the chassis dyno, found that peak HP was more like 7,200, and optimum upshifts were at 7,600.

Interesting. Hotter than my 310. I never put that engine on a dyno, so maybe I overestimate the top end? I always limited my revs to more like 7500 and assumed I was leaving some power on the table, but maybe not. With the 310, I had really no power until 5500. What was your experience with the 315? Granted, many other factors - just wondering. Thanks.

[larrym]

you have a parallel thread going here -

http://forums.pelicanparts.com/porsche-914-914-6-technical-forum/944446-2-0-build-opinions.html