Should I do a 2.0 -> 2.2 upgrade.....or a 2.0 -> 2.4 upgrade?

[M Sværke]

Hello guys

I am about to do a total rebuild of my non matching numbers 1969 2.0T engine (110 HP).

The dependencies of my engine rebuild

• I will be reusing the existing 40 Webers (I have read that this will result in less HP than if I used MFI?)

• I already have a set of 2.2S pistons and cylinders waiting to be installed

• It will not be twin-plugged

• I will be using 95 and/or 98 octane pump gas

I have studied the specs. of the different early engines models, 'How to Rebuild and Modify Porsche 911 Engines', 'Porsche 911 Performance Handbook' and last but not least this great forum where especially the 2.0 -> 2.2 update has been discussed several times.

I am considering the following 2 options

• 2.0 -> 2.2 upgrade: Using the 2.2S pistons and cylinders, E-cams and changing the heads to 2.2/2.4 heads. That should result in approx. 160 HP, do You agree?

• 2.0 -> 2.4 upgrade: The same application as above but adding a 70,4 mm crankshaft and rods. That should result in approx. 170 HP, do You agree?

However, I still think it's very difficult to estimate the number of HP......there is several aspects to consider: Displacement, compression, cams and finally the fact that it will run Webers.

Further questions

• What will work best? Heads from a 911T/E or a 911S? As far as I can tell only difference is port size (T/E have I32 & E32 where the S has I36 &E35). I am afraid that to big intake ports could hurt low RPM power so maybe I should go for the T/E heads?

• Would I be better of with the Solex cams?

• What upgrade would You recommend? Is it really worth going the extra mile putting in the 70,4 mm crankshaft and rods?

Regarding the old case I am using, I would like to hear if all of the following mods are neccasary:
- line boring
- oil squirters for the pistons
- TimeCerts/Case savers
- oil bypass
- modern oil pump (maybe from a 3.0)

Any other aspects that I need to consider?

I was hoping that you guys could help me elaborate on this subject.

[burtm5]

I followed anderson's book 30 years ago with a 2.2 t. went to 40 webbers, L cam, 2.7 8.5 rs p/c, ssi. shipped case to CA for upgrades. ran good (175 hp?)until I missed a shift 14 months ago. now that you can get JEs for 9.5 or so comp. I would go that route. only problem with 2.2 is non counterbalance crank and about 8.0 cr.

[M Sværke]

So You would use 2.7 P/C's (90,0 mm), making it a 2.5 liter engine?

Just a note: The 2.2S pistons that I already have, should have a 9.8 compression, not 8.0.

Yes, the crankshaft of the 2.0/2.2 T-engines (66mm crankshaft) is not counterbalanced.

[burtm5]

I should have read your full post better concerning the 2.2 s pistons. so my experience was going to 2.7 8.5 cr pistons because that was all that was available in the early 80s. the 66 crank with the 90 pistons gives you 2515 cc with about 8.0 cr. I now have a 2.7 with 8.5 cr I will put L/E cam, webbers, ssi/exhaust from my blown 2.5 expect 200 hp. I'm going to keep all my 2.5 bored case in the event I don't like the 2.7. the best imo is 2.0 s/e countercrank, 9.5 je 2.7 piston. that would rev well and make 220? If you'r sticking with the 2.2 higher cr pistons I wouldn't try to use the 2.4 crank its only 110 cc bigger and you have expense and maybe have issues with the really high lift from the bigger throw crank. also realize that the 2.0, 2.2. 2.4 and 74 2.7s all have 32mm heads where as the early S and 75 and later S have 35 to 36 heads. So if you want to really spin up for power you need counter crank and 35 or bigger heads. If you use the 2.2 S pistons on 70mm crank you will have good cr but I think you'll need better heads to take advantage, solex cams are pretty radical (almost to the S level) so if your mainly street I'd get E/L. read anderson's book as he discusses all the options S and solex cams and says the 2.7 with webbers makes almost exact numbers as mfi