Camshaft recommendations for 2.7 high compression w/ carbs

tornik550 · 02-01-2015, 07:45 AM

Question- I currently have E cams, would any other camshaft make a significant enough power and reliability improvement to justify the cost of purchasing new cams?

Background- I am building a 2.7l. Purpose of the engine is simply for fun. I do not plan on racing. I am interested in a nice balance of power and reliability. I have 2.7 crank, rods and cylinders. I have 90mm JE 9.5:1 Pistons. 2.7l s heads. I will also be using carbs. I currently have E camshafts however I am willing to purchase new cams if needed- however I would prefer to spend the money elsewhere.

cgarr · cgarr's Garage

DC 40 cams work well with that setup, exact same motor we have for both road and track. You can tweak the overlap depending if you want more low end or if your running higher rpm's

burtm5 · 02-01-2015, 08:39 AM

I had same pile of parts, with ssi early muff and kept the E cam and am very satisfied. thought about solex cam but not worth the money IMHO. best Henry

cmcfaul · cmcfaul's Garage

Your E cams can be re ground to a DC 30 (Solex) profile for not that much money. E cams with more lift and overlap. Works great with higher compression build. Power really comes on at 5k RPM's all the way past 7300 if you let it.

Chris

Lapkritis · Lapkritis's Garage

I have webcam 464/465 on that setup (2.8L) and it's happy.

burtm5 · 02-04-2015, 08:16 AM

Can anybody post horsepower gains on the 2.7 when going from lowly T cams up to S or bigger. I know you lose some bottom torque to get higher hp on top but have never seen real world gains. thanks Henry

E Sully · E Sully's Garage

This is what I found.
The base 1974 911 according to Porsche was 150 hp with 8.0-1 compression, 5700 rpm.
The 1974 S engine was 175 hp with the CIS S cams and 8.5-1 compression, 5800 rpm.

911pcars · 02-06-2015, 12:25 PM

CIS engines/cams were designed for stricter emissions compliance at the time, not for power.

The typically recommended cams for a 2.7 with any compression and Webers or MFI is an S cam. Aftermarket equivalents or slightly better are viable options. 2.7 displacement is large enough to not suffer a lack of low/medium speed torque with higher lift, long duration cam timing. RS-spec engines (w/MFI and 8.5:1 CR) were factory rated at 210 HP. In general, with one point better CR, expect at least that much with either induction type.

Sherwood

faverymi · 02-06-2015, 02:09 PM

As a driver and not a builder i can say that wilder cams are better on track dedicated cars.

My street 2.7 finally settled with DC-30 cams. I really enjoy the drivability with plenty of power on the mid to high range.

What are you using your 2.7 for? Track or street?

Neffets · 02-09-2015, 07:21 AM

Same here, 2.7 with 9,5:1 and dc-30 cams very happy with them

911pcars · 02-09-2015, 10:57 AM

Have owned both 2.7 RS-spec engines. One with E (DC30) cams, the other with S cams. Cubic inches (or ccs) provide enough low and mid-range torque to justify using S cams. Engine characteristics are different on lower displacement engines. Higher compression is also an equalizer. S cams are probably too mild for 3.4 and larger engines.

MHO,
Sherwood