Finally getting around to doing the engine part of a 6 conversion (with my son) on my '71 914 I've had since new. I put on all OEM 6 suspension components and brakes back in the mid '70's. Did a side shifter conversion in the late '70's.

We found a 2.4T engine a couple years ago that needed a total rebuild- have gotten most of the "parts" back from Ollies and have a beautiful oil tank from ben here on the world. Going to use the OEM style bulkhead engine mount.

Don't want or need bigger than 2.2 or 2.4 as I don't want to deal with a front cooler if I can get away with it.

Just want a nice tractable engine with decent lower end torque- this will be a weekend toy to enjoy the "kids" and grandkids...

Fire away...

Which parts do you have already?and what about induction? Carbs or do you still have the mfi? Here is what Waynes book says about nice proven engines

E cams and Webbers. I had a 2.2 with that combo. It ran very good.

Already have the Webers- they just need to be rebuilt.

Agree that E cams would probably be a good choice. Just don't know which brand of jugs and pistons are considered good choices these days. It was a long time since I had my real 6 which I'm still kicking myself for selling...

Basically two choices for street:
Mahle which are the gold standard but pricey
JE which are less and generally a good choice as well

Why not S cam?

Don’t forget about Nickies if you can spare the coin.

I would suggest taking your heads and boring intakes to 36MM and exhaust to 35. Do not listen to the "you need small ports to make torque" I would not go with E cams, You can do better with a more modern grind. I would look at MOD Solex or Mod S. If you want to use stock parts then 2.4 S piston and Cylinders are the way to go for most compression (still low) on 2.4. I would suggest finding a set of worn Biral cylinders from a 2.2 to 2.4 and having them bored to 85MM and getting pistons from JE or CP to match.
The dyno chart below is from two 2.4 engines with E cams I have had in my -6 conversion. The Green is 2.4, S pistons, E cam, Stock 2.4 T heads with stock port size with 2.4T MFI. Red is similar engine that used T cast iron cylinders with JE pistons 9.5 to 1, E cams, heads were 2.4 CIS heads (about the worst made stock) bored to 36mm intake 35mm exhaust with Zenith carbs 30MM venturi and bigger main jets. You can see the larger ports did not hurt torque at any location.

Click to view attachment

My current engine is 2.5 (86 x 70.4) with same heads as red engine but with 9.8 JE pistons in 86mm Alusil cylinders and Mod S cams with Zenith carbs, 32mm ventui, bigger main and idle jets. I have not dynoed this engine yet but plan to in the next couple weeks. I can say it pulls harder than the E cam engines.

john

SKL1, mine is pretty close to what your doing. Purchased a 2.2 E long block with S pistons and E heads. Added Mod-Solex (DC -30) cams, PMO's, Ben's header and sport muffler. 9.8 to 1 comp, MSD ign, and then short gears 3.4.5. Just a blast to drive, 5 to 7,000 rpm engine is sweet. Mine is the fifth down on Wayne's book. Only did not have S heads.With out porting S cams are not recommended so went with the Mod-Solex.Best, Mark Click to view attachment

In the past I've run a 2.4 with 2.2E p/c's, solex cams, & weber 40's. That was a sweet motor. Ran fine in the 914 street or track use. A buddy of mine had a 2.4 built with 2.2S p/c's, with S cams for his 72 911. That motor was also great but was not ideal for street use. Now it ran to 7500 all day long at the track and would out run 911's with larger engines. When you add 2.2 p/c's to a 2.4 what you get is a bump in compression.
The 2.2 had more of a dome to their pistons vs the 2.4 versions. Same bore just higher compression little more power. We are talking back in the day when Mahle was pretty much the only p/c's to get. Now a days with JE you can do pretty much whatever you'd like. I have a 2.7 built with 9.8.1 JE pistons, and mod solex cams. I haven't run that engine as I'm going with a 3.4 for my 6.

If you have someone nearby that has a similar engine combo see if you could go for a drive. Nothing like real world test results.

mlindner's and the book setups are good. Also check into Henry Schmidt's 2.45 combos, those are cool. Check in and ask the same questions on the 911 engine rebuild forum on the bird board.

Uses a 2.4/2.7 crank and 86mm p/c set. AA pistons has a cost effective biral/JE set that would work. Typically uses a mod S cam (DC40), but if you don't want to go hog-wild on head work you can do the mod solex cams (DC30) listed above.

Good thing is you can use the biral cylinders on the 2.4-2.45 setup where I had a 2.7 base and needed to go $$ for a good p/c set.

Seems like Solex cams would be the preferred cams for carbed motors up to 2.7? What is the difference between E cams and Solex cams? Where is the peak power and torque rpm wise between the two?

Mod Solex (DC30) is basically a middle ground between the E and S..moves the powerband up a bit in the RPM w/o going as wild as the S.

The grind is same duration and lift as a stock solex cam with the lobe angle of an E, so it makes a nice middle ground between the two of lift at the overlap. It would make a great hot street cam for a 2.4/2.45 setup.

86mm S pistons solex cams and you have the perfect combo. That setup works great on my car

I have a 2.4 JE 9.5, ported heads to 36/35 and Mod Solex cams with 40 webbers.

Big fan of the Mod Solex (DC30) cams. Carburetes clean and torquey off the bottom and really comes alive at about 4500 and pulls strong to 7000 rpm.

If you talk with Henry Schmidt or Dougherty they will tell you it is all about where you are willing to rev to to get power. I think the progression is E, Solex, Mod Solex, Mod S, S commensurate with the power bands around 3500 to 6000 for E and working up to 5000 -7500 for an S. Higher power bands yielding ultimately higher HP.

Look at the Porsche published HP figures for 1972 and you get the idea.

Same with cylinders - the T got cast iron, the E and S got Biral. Add to that the more recent availability of Alumisil and now Nickasil with commensurate increase in quality and price. If I was doing it again I would seriously consider finding Birals and have them bored and nikasiled to size and JE, to desired compression (generally thought to be 9.5 max on pump premium single plug). I got really great service from EBS and they can do it all - bored and plated pistons with JE,s to match

Love my 2.4 Mod Solex in a narrow car. Very sporty entertainment on the street car with a sublime pull to 7200 when the mood strikes.