what year engine case is this??
 

I can"t find a site that has the information of how to break down engine case numbers to tell me what I have. I know its a 2.7 but don"t know the year or any specifics-

The engine number stamped onto the alternator stand is *6275299* and the raised cast in number on the side of the case is 901.101.102.7R

any info someone might have would be great, and any reccommendations regarding a book that breaks down part numbers would be appreciated.

thanks-

Third digit of 7 verifies that it is a '77 model engine case.

Engine Type Number of the form '911/xx' stamped into horizontal surface to the right of serial number will give you more info to work with ...

Thanks for the info! Early S Man- your quick

Interesting thread as I have wondered about these numbers myself. I read in "911 and Porsche World" magazine
earlier this year, an article about the evolution of the 2.7RS by Paul Davis and Russell Lewis,aparently a couple of experts. Quote"--the 2.4 litre engine ,which forms the heart of the Carrera unit,has a crankcase manufactured in pressure cast magnesium alloy,used first on 2.2 litre engines--but then modified with internal strengthening webs supporting the mains bearing saddles and identified by the casting number 901-101-101-7R.
With the introduction of the 2.7 unit,this became the '102-7R'[with additional reinforcing]and ultimately the basis of all all Porsche production engines ,until the the Carrera 3 unit appeared in 1976----"Sounds OK to me .
I have a 76S ex US. so curiosity led me to have a look at the numbers---The engine type is 911-84 S/N 6561274 which appears correct and I believe is the original engine.
I also have another engine [The on-going never ending rebuild!]
which is a 911-85 S/N 6274937 and therefore is a 77[as it was supposed to be.]
But both of these engines have casting numbers 901-101-101-7R
on one half of the crankcase and 901-101-102-7R on the other half!
It seems logical to me that the 2 case halves would be different casting numbers --but what was the 102R previously?
Triva I know,but interesting nevertheless?

Your correct Bob. 901-101-101-7R and 901-101-102-7R are the castings numbers for the left and right side of the case.

As for the arcticle from Porsche 911 World they are in error not only about the 7R cases but also about the 2.2L engines being the first mag case engines. The first mag case engines were made in 68' which were 2.0L engines. The 2.2L ones didn't come out for another 2 years.

The way the article reads it seems to suggest that 101-7R was a 2.4L case and when they went to 2.7L the case was then numbered 102-7R. In fact the castings numbers are the same for 2.4 and 2.7L 7R cases. The machining is what is different in that the 2.7 cases had larger spigots cut into them.

Thanks,Bob--I have noticed that 911 and Porsche World get a lot of info
wrong.---Guess the facts sometimes get lost in the editing.

Interesting that Porsche 911 world got the info wrong about when the first mag case appeared, I thought it was common knowledge among folks who are Porsche enthusiasts. Maybe Im assuming the staff of a company that puts out a magazine for Porsche enthusiasts would be enthusiasts as well-

here's an interesting tidbit. In Porsche parts nomenclature, odd last 3 numbers denote left side parts, even denotes right side.

101 = left

102 = right

I am looking for the same info right now. Can you tell me what type motor this is? 901.105.111.1R