2.2T to 3.2 Twin Plug on Carbs
 

To the Guru of all things 911!

For my 71' 911 Lightweight

What I have:
2.2T Engine with 40mm Webers, single plug Bosch distributor, 1 5/8 headers, Pea Shooter muffler

3.2 Long Block engine complete (minus P&Cs, distributor, plastic), I have Weisco pistons made for 9.8:1 and Nikasil Cylanders stock size

What I want:
3.2ltr 10:1 compresion, twin plug, 46mm carbs, Race cams

I was going to send the carbs to Bieker Engineering to rebuild to 46mm

I was going to cut the heads to raise the compression a bit more.

My questions:

Can my 71' engine donate it's plastic, fan, manifolds and other minor tid bits I will need when I start the build?

I want to convert my Bosch distributor to twin plug or buy one, can you help with this?

I will be running Aviation 100LL fuel and want cams that will work with my engine combo and fuel, what do you suggest?

Thanks in advance for your help!

Twin plug conversion

This should square you away. :)

Have fun with your build!SmileWavy

Bump, help!

I will answer your questions, or at least try.

Yes, cut the heads to increase compression, but measure your CR first, you may not have to.

You can use your shroud, exhuast etc just fine.

Contact John at DRcamshafts (camgrinder on the board) and talk with him about your desired power band etc.....

That twin plug dizzy is still pretty expensive, I would go with a crankfire setup instead, either used (cheap) or new (still cheaper) unless you really need a dizzy with 12 leads comming out of it.

Hope this helps

Cheers

Thanks for the help. I think the ignition choice is more for the look than anything else. What about the 2.2T fan on the 3.2 block?

I *think* it will work, but a quick test fit should tell you. That is one that I can't say for sure on.

Cheers

2.2T fan, won't work for your cooling needs, specially in the tropics,best to use the small diameter 11 bladed fan,I think only in 78' was used.,cheers,Antonio.

The very best fan you can use for maximum airflow over the engine is a 245mm 930 one. The 225mm ones used on the '78-'79 SC's don't flow enough air for 911's used in hot climates.


With all due respect to "Brother Jeff", your carbureted engine will run and drive FAR better with a distributor driving a pair of MSD's. With few exceptions (Motec), the current crop of cheap crank-triggered coil pack ignitions have a tough time keeping the plugs clean when the engine idles for long and cannot support the wide plug gaps (.040+) that make more HP and better drivability.

Hey Steve, was wondering if you would "correct" me on that!! I still have not ruled out the single 12 plug distributor option either!! :)

Cheers

A couple of more details to deepen the discussion. Costa Rica's Central Valley area where I live is 70F basically all year. I am at 3000-3500 ft altitude. I am going to run a large front bumper mount oil cooler too. I was not awair there were so many different sized fans! So I guess here are the new questions:

So for sure the 2.2T fan is not going to work even with a pully change?

What are the various sizes out there?

What about 964/993 fan?

Thanks guys.

Joe:

You can use your 2.2 fan; just change pulleys. :)

The 3.6 curved bladed fans do not flow as much as air your 245mm one with 930 pulleys.

Lastly, don't use 100LL Avgas. Its octane is insufficent (car gas & Avgas octanes are rated differently), its vapor pressure will not work right with normal Weber float levels, and that highly leaded gas (compared to 100 green Avgas) makes a huge mess.

Use 100 octane unleaded race gas and you & your motor will be FAR happier in every respect... :)

I assume the pullies are a dealer item? Is there one year better than another?

On the Av-Gas issue I have three choices here that will not break the bank:

80 Oct RON (yes really) $3.30/Gal
85 Oct RON (thats the good stuff) $3.5/Gal
100LL Ave Gas $4.11/Gal

I know there is a lot of additives in 100LL to keep the fuel from freezing at altitude, keep it stable for long periods and keep out water. When burned the 100LL leaves a chalky white residue on the plugs. But given the alternative I think it is the best choice. By the way I am running this car on the street and at weekend fun days at the track. Also the regular pump fuels are extreemely dirty. I change fuel filters once a month and pre-filter with a course screen. I have found sand, water, wood chips, paint chips and heavy oil in my filters and pre-screens.

My real track car gets drums of VP 115 OCT imported for it. It ends up costing me $8/Gal by the time it gets into my fuel cell! Of course the nice part is that it is fully sponsored!

Joe,Av/Gas will leave lots of deposits inside your combustion chamber.
Steve the reason I say the smaller fan I guess that I thought it will fit better his fan housing,also it will put more air pressuse thru the engine, good for short trips in hot climate, well this is just a thought on my part.
Cheers,Antonio.

Thanks for your input Antonio. Any more input on the 100LL based on limited choices?