diffs in T &,E,S cranks and heads

[356robo]

In my parts book for my 70 911, I noticed that the cranks and heads have different part numbers for T's and E's & S's. Valves are all the same. What are the differences?

Robo

[YTNUKLR]

MFI injectors in E, S

Ports 29-32-36mm, T-E-S ...MFI system built to suit the ports

Compression and cams, increasing T->E->S

forged pistons in the S

[deathpunk dan]

yep, and as far as cranks go, the 2.2T had a non-counterweighted crank.

Not a major issue for street driven cars.

[356robo]

Are the exhaust ports in T, E, and S heads all the same size?

If so, then I'm going to assume that the paperwork on my rebuild referring to "2 mm porting" means that the intake ports of my T heads were enlarged by 2mm, making them nearly the size of E heads.

Are Weber manifolds made in different sizes to fit T, E, and S heads?


Robo

[Flieger]

Ports are different, valve diameters are the same.

[356robo]

Max,

Are the exhaust ports in a T, E, and S head all the same size in a 2.2?

Robo

[Flieger]

yes

[Flieger]

Sorry, I was mistaken.

1970-1971:

---------intake port diameter------exhaust port diameter

911T------32mm----------------------32mm-----Euro version, Zenith carburetors

911E------32mm----------------------32mm-----Mechanical Injection

911S------36mm----------------------35mm-----Mechanical Injection

The valve diameters for all the above models were 46mm intake, 40mm exhaust.

This is for factory-spec street cars according to Bruce Anderson's 911 Performance Handbook.

Race cars had bigger valves, bigger ports, some had carbs, some had injection, you know the factory's way of working...

[PCA7GGR]

OK, so what's a "911.104.306R" head for? Thanks

[Flieger]

Sorry,

My reference (Wayne's Engine Rebuild Book) only lists part numbers 1974-->

The cylinder heads he lists are 901.105...

The R suffix is a factory replacement part, I think.

[Flieger]

I think it is an early 911S (Mechanical Fuel Injection) replacement cylider head.

I am going by the 901.104 coming before the 1974 901.105 CIS heads.

901.104.306R I think is 911S because of the "3". My 911 VIN is 91113... (911= typ#911, 1= model year 1971, 3= S specification)

[PCA7GGR]

Here's a pic of one of the "911.104.306R" heads on my 2.8. I was wondering what they were since they were not shown nor listed in either of Anderson's Performance books. Thanks

[deathpunk dan]

Originally Posted by Flieger

1970-1971:

---------intake port diameter------exhaust port diameter

911T------32mm----------------------32mm-----Euro version, Zenith carburetors

911E------32mm----------------------32mm-----Mechanical Injection

Thanks Max. This is good news for me as it means no port work need be done to suit E or solex cams (when the heads get rebuilt).

[Flieger]

I think 901.104.306.0R is different from 901.104.306R. The 0R is like a 7R case number. The .306R I think means replacement part. Are all the heads the same number?

[PCA7GGR]

As the pic shows, the 910.104.306.0R head is also stamped "1-70".

[PCA7GGR]

Flieger,

Yes, all the heads are the same.