2.7 carrera engine numbers

mattia · 06-24-2011, 04:13 AM

Dear All,
let me introduce to you: I'm an Italian owner of 2.7 Carrera 1974 and ask your help.
During engine reparation I've taken some pics of engine numbers here attached. Now I've the doubt the numbers were redone in a later time and the engine block is not genuine 911/83.

An non original 911/83 block makes lose the car value? Do you suggest me to find out a genuine 911/83 block?

Thanks you very much for the attention you will pay.
regards
mattia

Steve@Rennsport · 06-24-2011, 08:42 AM

Mattia,

The core value of those cars lies with that special 911/83 engine so if yours has something else, I'd recommend sourcing the correct motor for the car.

Flieger · Flieger's Garage

Looks real to my amateur eye. What makes you doubt it?

mattia · 06-25-2011, 11:49 PM

It looks real but the doubt I have is on the numbers punched on the block, particularly the 911/83(maybe used a magnesium block from standart 2.7 150CV). Someone can give me his opinion? the genuine numbers characters seems to be different.....
The other engine parts (MFI, heads, cylinder...) are from carrera.

thanks again for your kind support

bavaria911 · bavaria911's Garage

Mattia,
At first look the stamped numbers seem to look different than the factory type set. I would question the 9 and 3 for the 911/83 stamp.

tom1394racing · 06-27-2011, 01:30 AM

Mattia

Looks funny to me

Here are some original factory stampings for comparison

mattia · 06-27-2011, 02:08 AM

tom,
looks "funny"...with displeasure... also for me: I cannot understand what's done in the engine!
6640308 numbers looks real, but 911/83 is a fake for sure!

Opinion of a friend of mine is in the past original 911/83 was replaced with another 7R magnesium block (maybe 911/93 or /92 from non carrera 2.7) and made new self-made stamping.
Are 911/93 911/92 block exactly same of 911/83?
Finding original 911/83 is feasible? it worth? and parts into actual engine (crankshaft, rods...) can be re-used in the new block?
thanks and regards

tom1394racing · 06-27-2011, 04:08 AM

The S/N also does not match anything in my cross reference list

A 73 RS motor should have a S/N starting with 663.

mattia · 06-27-2011, 05:12 AM

Tom,
car is european MFI 2.7 carrera from 1974 and S/N starts with 664...
it's not a 73 RS!
mattia

tom1394racing · 06-27-2011, 09:31 AM

A '74 Euro Carrera should have an engine serial number starting with 665.

356RS · 356RS's Garage

Normally the third digit states the year of the engine. Is the 74 Carrera different? I would think the s/n 664XXXX is a 74 build year.

tom1394racing · 06-28-2011, 07:21 AM

It could be that my engine spec sheet has an error.

RatBox · 06-28-2011, 08:30 AM

The type number has definately been messed with , whether an original mistake then rectified/restamped right after the original (mistake ?) was done...no one can ever say. But then combine it with the serial # stamping. Then the chances get compounded HARD towards the negative.

The serial number... funny 2nd 6 , the numeral 4 is definately not the normal one used. And besides there being no 2nd star (I have seen them go all the way into the corner partially on the vertical to get it in) , there seems to be something under the 8 (strangely , looks like possibly a star to me).

If you look at this in person with a magnifying glass you might be able to tell more.

mattia · 07-01-2011, 01:01 AM

Dear All,
something is going to be clear: the engine block maybe belong to a 2.4S re-bored to 90mm with original engine number 911/53. Someone may suggest how understanding the machined work for re-boring?
Look at the three pics: 911/83 (my fake), 911/83 (original), 911/53 (original) you may understand there are different fonts. My engine number is a mix of them!

Ciao

RatBox · 06:54 PM

mattia ,

Stampings interest me , so I have been looking at your thread to see if I can tell you anything I might notice (of which yesterday , I was looking at your unit number stamp again and it perplexes me. But we can get into that later.

First off , you (I/anyone viewing) need to know what we are comparing specifically (apple to apples ..etc.) .

What MY (model year) case is the third photo (the 911/83 stamp with the round head 3) .... 73 , 74 , 75 , or 76 ?? I could be completely wrong , but isn't the normal small 3 digit stamp tool font for 1973 MY type stamp a flat top 3 ? Similar to the motor unit number stamp flat top 3 ...only small. Is this correct / anyone ? I will ask someone I know to post a 73.

I do not know which small 3 was used in 74 , 75 , 76 MY . If anyone has any photos of any of these , maybe they could post

And what MY case is the 2nd photo (the clean stamped 911/53).... 72 , or 73 ??

As far as your number being changed from a 911/53 to a 911/83. If that was the case...why would the 3 be restamped...as it would already be there ?

Lastly take a close/clear photo of the casting date mark and post it. It might tell us something. This is it , circled in the photo :

fryardds · fryardds's Garage

Mattia,

The correct 911/83 stamping should be like the last photo you show in your previous post. The 3 is rounded like that photo shows. I have photos from several '73 Carreras that show this style.

Unfortunately I have to agree with Ratbox. The serial number on your case was not done by the factory originally but has been restamped. The numbers are incorrect in style.

FYI the last photo shows a very rare Aluminum 7R 911/83 RS case.

fryardds · fryardds's Garage

Quote:

Originally Posted by bavaria911

Mattia,
At first look the stamped numbers seem to look different than the factory type set. I would question the 9 and 3 for the 911/83 stamp.

Actually the '911' in Mattia's case is correct, but the '83' has been restamped sorry to say.

RatBox · 07-02-2011, 03:18 PM

Thx Fryardds.

To the gallery , I have not studied small engine font per year as closely as the larger engine font for unit numbers.

Is this small font on the 911/53 case mattia provided a photo of , the norm for 1972 then ?

mattia · 07-04-2011, 02:10 AM

Ratbox
agreed that numers had been restamped

to end the issue, find a pics taken of casting date mark as for your suggestion.
It's only visible numer 50 and any idea about the meaning.
regards
mattia

RatBox · 02:37 PM

mattia , thank you.

I'm still learning about magnesium case casting dates . If i'm not mistaken, I see a digit 3 where I have pointed . So that would make it a case cast in the 50th week of 1973 :

Can anyone verify that single digit of the last year of the decade cast were at the right of the bar depression in this casting date on a 1973 / 74 vintage case ? And that in the example provided by mattia above is not just some slag that strangely looks just like a numeral 3 ?? (I would find this hard to believe but one never knows). More from this vintage would need to be examined.

I know by 1977 , this casting date layout had changed . And the last 2 digits of the decade it were cast was below the bar. And I cannot tell for certain , without having one of each physically in front of me. But on mattia's example the circle seems like raised material with the bar and numerals being depressions within the raised circle. In the example below , it seems (to me) to be the opposite.....that the circle is a depression & that the numerals & bar are raised material within the depression.

Here is an example from 1979.

Thx again mattia. Now back to your case. I would not be so quick to discount your case as being anything one way or another until you study it harder. Way too many people are quick to discount things as 'phony' just because they are differant than the norm. One does not always mean the other.

I do not know anything for certain . But a few questions go off in my mind. First , why would someone do the unit number so strangely if they were trying to fool anyone ? And if stamped over a complete other existing unit number , why does the surface not look like it has been ground ?

Lastly I have seen all the digit stamps on your unit number (664 0308) used by the factory before. Even if I said the were not the 'normal' ones used for that location / that year. I did not mean they were fonts that were never used

Again, I would break out some high powered magnifying instrument , and examine things very closely. Is that actually a star under the 8 ? Is it an 8 and not a 3 (is either ...the number that records show , was originally put in your chassis ?).

Is there any reason to think that your car was special in some way. Motors and chassis that were built away from the normal production areas sometime have strange stampings that can have font digits normally used in other model years & other stamping locations/applications.

I am not saying this is the case , just that I would study it closely before I made up my mind conclusively.