Converting a 911 2.2L engine from T to E

[Fishindl]

I have purchased brand new in the box E style Mahle pistons/cylinders for my T 2.2L 911 engine. I would like to know if I need to change the cams from the T style to the E style and if I need to re-jet my Zenith 40 TIN carbs. Any input/guidance would be greatly appreciated. Thanks in advance for your time and advice.

David Leader

[Rusty]

David, it you want all the performance from the E pistons, then yes on Cam grind, distributor advance curve and you may have to play with the Zeniths a bit. They may be the pain to get right. Or you could just run the E pistons and not spend the extra money.
Good luck with what you decide to do.

[Fishindl]

Rusty,

Grinding the cams will be nominal when compared to the cost of the cylinder/pistons and the total cost of the engine rebuild. Getting the Zenith carbs right will be a challenge but with the right mechanic (who has a dyno), it should be doable. Thanks for your inputs.

[diegok]

I'm thinking of starting the same process on my '69 T, but trying to figure out if it is worth the amount of $ and work it takes to get there. Don't want to hack this post, but would love to hear how it results for you, and other people's opinion on this.

[crummasel]

David,
do the cam mod also to E spec or Solex.
The distributor curve works quite well.
The Zeniths should be opened with 32mm Venturies. If you cant get hold of any you can carefully open up the ones you have to 30mm on a lathe (watch the inner contour!), put in 52 to 55 idle jets, 130 to 140 main jets (depends on your Venturies) and 180 air correctors. Just as a starting point. But be aware: you should comprehensively understand the carburettors to get the job done! Also take care of proper float level.
All in all no rocket science.
A dealer for carburettor parts in ebay is alfa1750 or carbs_and_parts.

[Fishindl]

crummasel

This is exactly what I was looking for. Thank you. Did you personally made these modifications (piston, cam, distributor, and carb changes) to your 911 2.2L and if so, was there a notable performance difference? Also, how were you able to determine these changes to the carb? Thanks.

[crummasel]

double post

[crummasel]

Yes i did. Several in that range.

You will notice a different engine.

Carb changes made on uncountable applications. But its a starting point.
Finetuning will still require your own brains. So for best results and longterm maintenance educate yourself on Zenith carbs.

[frankc]

I have a similar question about configuring Zeniths when installing 2.4S pistons in a 2.4TV. For a cam, I plan to use either an 'E' or Solex profile since this will be a street car and I prefer more torque at the bottom end.

The current Zenith configuration is as follows, and is standard for a '73 2.4TV per the Tech Spec booklet:

Venturis: 28.5mm
Main Jets: 120
Idle Jets: 47.5
Air Correction Jets: 210

I know I can order larger venturis from Alfa on eBay - should I also order larger sizes of Main and Idle jets, and smaller Air Correction jets? What would be a good starting point?

Thanks,
Frank

[cmcfaul]

I have a 2.4 crank from an 73 E. Straight, polished and ready to go. Needs +1 over sized bearings.

PM me if interested.

Chris