2.7 with carbs, E or 964? Options

[scotty b]

I am gathering parts for MY car (for a change) which I hope to start on next year. I will be building a 2.7 maybe (probably) with Je pistons. Weber carbs but not sure what cams to go with. E and 964 cams seem to be the most popular, but which is better? I would like real world opinions please. Is one better with stock pistons and one better for JE's (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif) Thanks for the help (IMG:http://www.914world.com/bbs2/html/emoticons/mueba.gif)

[ArtechnikA]

you really should get a copy of Anderson's "911 Performance Handbook" and read the section on performance upgrades and cam selection. he's got lift and duration specifications for many popular cams, including these...

the 964 cam is a popular performance upgrade for CIS cars; that should tell you something: it's still a fairly mild, low-overlap cam. the E cam is IMO an excellent choice. i've had them in two cars and liked them.

piston manufacturer doesn't really have much to do with it, but i gather you're looking at the 9,5:1 CR choices. watch the piston-valve clearance but you should be okay.

[xitspd]

What compression ratio JE pistons are you going to use? Are you going to port the heads and intake manifolds? Are you going to run headers in place of the stock heater boxes? This information will help with your cam selection. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[Dr Evil]

I have a 2.7 with everything stock, including the CIS, and was told by everyone that the SC cams are best for giving you a nice flat tourque curve. Even better than the 964. I'll let you know.

[scotty b]

Yep 9.5 ratio, Match porting intakes and exhaust ports, may open up the valves. I'm just in the planning/gathering stage right now. I haven't done a whole lot of performance work on 911's , and what little I have had been on the early 2.0 and 2.2 cars so this is a little uncharted territory for me. Done a lot of VW and 356 performance stuff though so I do know the basics of what to watch out for just unclear on the specifics. I do have Andersons book but I have to finish my adult learning classes first before I can sit down and try to cifer the werds!! (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) You down with ADD? Yeah you know.........what was I saying?

[scotty b]

QUOTE (Dr Evil @ Apr 2 2005, 07:54 AM)

I have a 2.7 with everything stock, including the CIS, and was told by everyone that the SC cams are best for giving you a nice flat tourque curve. Even better than the 964. I'll let you know.

COOOOL So you said a few days ago your movin east huh? You bringing a 914? When ya movin?

[ArtechnikA]

QUOTE (Dr Evil @ Apr 2 2005, 10:54 AM)

... told by everyone that the SC cams are best for giving you a nice flat tourque curve. Even better than the 964....

remind me when Porsche went to the 4-bearing camshafts?
can you run a 3-bearing cam in a 4-bearing tower - or vice versa?

i've always been fuzzy on this detail...

E cams are definitely 3-bearings, and 964's definitely 4 - but other than that i'm less sure...

[xitspd]

QUOTE (Dr Evil @ Apr 2 2005, 07:54 AM)

I have a 2.7 with everything stock, including the CIS, and was told by everyone that the SC cams are best for giving you a nice flat tourque curve. Even better than the 964. I'll let you know.

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) The Doctor is right! SC cams also work well with a 3.3 CIS Turbo engine!

[seanery]

Is this a CIS engine, or has it been swapped to carbs?

If it's a carb'd street engine, the E cams should be a great choice.
If it's a track only, there are other options for more higher end power.

[IronHillRestorations]

For a carb'd engine, you definately DO NOT want 964 cams.

E or Solex cams are popular, as they "come on" earlier, and make better torque in the lower RPM range.

I'm a S cam kinda guy myself. I prefer that "hit 4500rpm and ZOWIE ALL THE WAY TO REDLINE!!!" feel. If you aren't used to driving a engine that needs to be spooled out, and aren't comfortable doing that, then go with a cam that isn't as peaky. There is a reason the factory made these hotter cams though, and it's for more power in the upper RPM's, which makes for lotsa fun!

[TimT]

You have a couple of choices! Web Cams 158R or 20/21 cam, Jerry Woods GE 20/40/60, The Solex cam,906, or E,or S cams..

I have the 158r cam in my 2.2 and its got a nice flat torque curve, that starts at about 3500rpm, and starts to drop at about 6500rpm

I have the 20/21 in my 3.2 and is quite a screamer..

I wouldnt go with the SC cam its kinda mild

What is the intended use of the car? that plays a huge roll in cam selection

[don9146]

Everyone seems to have forgotten the Solex cams (except for Perry) that came on the early year 911s. Their profile is between the "E" and "S" cams from later 911s. I have one on my 2.7 liter 9146 with Weber carbs, 8.5 to 1 RS pistons, mild port and polish, and GT racing headers. It pulls from ANY RPM, making 1st gear almost (but not quite) pointless (Perry has driven it a few times as well). I would recommend that cam as the "mildest" I would use on a 2.7.
If you are going with a port and polish, match porting, and higher compression pistons, I would think that an "S" cam would be a great match with that displacement engine.
As for 964 cams, everyone else has said it laready; they are popular with the CIS crowd. Its profile seems to be the most radical that can be used with a CIS system. I would avoid it with Webers. It would probaby work OK, but there are more radical cams you can use since you are not constrained by the limitations of CIS.

[TimT]

Solex cam is good, I think its been mentioned twice before already?

[ArtechnikA]

QUOTE (don9146 @ Apr 2 2005, 05:10 PM)

Everyone seems to have forgotten the Solex cams that came on the early year 911s. Their profile is between the "E" and "S" cams from later 911s.... I would think that an "S" cam would be a great match with that displacement engine.

we haven't forgotten the Solex cams, we just realise that they're hard to find new or serviceably used. if you're going with reman cams from WebCam (for instance) it's a nice profile - but like the S profile, it's got too much lift for a stock CIS (or 911T) piston. with aftermarket pistons it's a contender.

lots of people like the early S cams in bigger engines. it had a reputation of peing peaky with 2,0-liter displacement, which it was, but a 50% displacement increase adds in bottom-end the 2,0 engines never had.

[don9146]

QUOTE (TimT @ Apr 2 2005, 05:18 PM)

Solex cam is good, I think its been mentioned twice before already?

OOOops! Missed it in TimT's listing of recommended cams (sorry).

we haven't forgotten the Solex cams, we just realise that they're hard to find new or serviceably used. if you're going with reman cams from WebCam (for instance) it's a nice profile - but like the S profile, it's got too much lift for a stock CIS (or 911T) piston. with aftermarket pistons it's a contender.

My engine was originally a 2.4 T engine. When the swap was done to 2.7 liter pistons and cylinders, the cam was left stock. Later, during a top end rebuild, the cam was re-ground to Solex specs. Should be easy to do with any cam (I think?).

lots of people like the early S cams in bigger engines. it had a reputation of being peaky with 2,0-liter displacement, which it was, but a 50% displacement increase adds in bottom-end the 2,0 engines never had.

Exactly. Bruce Anderson recommends rebuilding a 911 engine with an "S" cam after you reach 3.0 liters of displacement. With the way my 2.7 engine feels, and the modifications Scotty B is doing to his 2.7, I think an "S" cam would be a great choice.

[Qarl]

E cams are okay.
Solex cams are VERY NICE
S cams are great, but make power a little high.

You can get some cams reground or some new cams..

Elgin makes a modified S cam (what I will be using). It's a cross between a Solex and an S cam... makes power a little lower. Also similar to the GE90 cam I believe.

First choice...

Solex

Second choice

Modified S cams

Thirs choice

E cams

[don9146]

Its in the combo!*






*The phrase "its in the combo" is a registered trademark of Raby's Aircooled Technologies. The phrase cannot be used without the expressed written consent of Jake Raby or Jake Raby Enterprises, Inc. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[J P Stein]

I shied away from the S cams back when I made the choice....on the advice of *my* guru ....tuning issues with carbs on a street motor. Did Solex (one NOS & one "touched up" by Web Cams...300 bucks) and had plenty of tuning issues to keep me busy (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif). 9.7 :1 Shasta pistons, mild porting. It wurks (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) Reground (reduced base circle) can be problematical. I see Solex cam F/S fairly often.

[scotty b]

QUOTE (9146986 @ Apr 2 2005, 11:12 AM)

For a carb'd engine, you definately DO NOT want 964 cams. E or Solex cams are popular, as they "come on" earlier, and make better torque in the lower RPM range. I'm a S cam kinda guy myself. I prefer that "hit 4500rpm and ZOWIE ALL THE WAY TO REDLINE!!!" feel. If you aren't used to driving a engine that needs to be spooled out, and aren't comfortable doing that, then go with a cam that isn't as peaky. There is a reason the factory made these hotter cams though, and it's for more power in the upper RPM's, which makes for lotsa fun!

I too like the S boost. I put the 67S and the 76-77 930 as my favorite "power" Porsches. First ride in a 67S was a customers car going to lunch, my boss (and very good friend) was going on an entrance ramp and said " you're going to love this" and nailed it at around 4G.

Me go (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/w00t.gif)

Short wheelbase was also alot of fun (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)