1975 911s engine # and vin

vonmec · 01-29-2025, 12:57 PM

First off I am a late model porsche enthusiast so forgive me, but I picked up this 1975 to learn about air-cooled cars. It is a california car - EGR light on the dash - it is a 911s coupe vin # is 9115202267. Before I went looking for the engine number I asked Chatgtp where I could find it and what the sequence should be: answer was side of fan shroud and 645xxxx. more resch said 6 was engine cyl, then 4 was 911s/carrera, then the yr and then 4 digit sequential serial # or production. Then I got my # 551769 and that made no sense to me - I look to see if the 6 was worn off but not likely. More research told me it could read. 5=year, 51=engine type 2.7 california and then 3 digits of production.

What am I missing?

is it suppose to be a 6 or 7 digit number. could it be: 5 is the year, then the next 5 is the engine type 911S california, and then 1769 is the production run.

Can anyone weigh in on this - I need help!

Henry Schmidt · Henry Schmidt's Garage

Quote:

Originally Posted by vonmec

First off I am a late model porsche enthusiast so forgive me, but I picked up this 1975 to learn about air-cooled cars. It is a california car - EGR light on the dash - it is a 911s coupe vin # is 9115202267. Before I went looking for the engine number I asked Chatgtp where I could find it and what the sequence should be: answer was side of fan shroud and 645xxxx. more resch said 6 was engine cyl, then 4 was 911s/carrera, then the yr and then 4 digit sequential serial # or production. Then I got my # 551769 and that made no sense to me - I look to see if the 6 was worn off but not likely. More research told me it could read. 5=year, 51=engine type 2.7 california and then 3 digits of production.

What am I missing?

is it suppose to be a 6 or 7 digit number. could it be: 5 is the year, then the next 5 is the engine type 911S california, and then 1769 is the production run.

Can anyone weigh in on this - I need help!

Take a picture, post it here and some "expert" will tell you if the number is legitimate.

75 911s · 75 911s's Garage

"Expert" here :-D

It's supposed to be a 7 digit number. Can you snap a pic? Also helpful to get the TYPE which is stamped horizontally on the case, just below and to the right of that serial number.

Should be 6551769 6 cylinder, 1975, 5 = 911S California and 1769 production run. This is likely the #s matching motor.

Type should be 911/44

If you need any help on the 75, I'm happy to help. I have it's older sister, 0604. I believe yours would be after the break so a very late 75. Difference would be in the half shafts, you have the later 8mm 6 bolt setup, while the earlier 75s have 4 10mm bolts in the half shafts and two pins.

Did someone swap the exhaust out yet? First year of the Thermal reactors! (ooohhhh ahhhh)

vonmec · 01-31-2025, 12:38 PM

Mine is kind of a junker - rough paint - worn out seats - etc. It is a California car that for at least the last 37 years has lived in Florida; the tires are from 1999. Remember I'm newbie! The heat exchangers have been removed and it has a "Horsepower Engineering exhaust system - no heat but has the VW A/C system with the Saeko FD508 compressor. About to change the plugs, wires filters and oil to see how (maybe if) she runs. It has some rust in the front tub - especially the battery tray. I want to do shocks brakes and some bushings to see if I can get it back on the road. I was really hoping it to be a rescued (survivor) driver car. BTW I am a motorcycle - powersports & marine dealer in Seneca, SC

vonmec · 01-31-2025, 12:46 PM

Another aircooled newbie question - how desirable is a 1975 911S. And how do you upload pictures to this site.

75 911s · 75 911s's Garage

Funny thing, with all Porsches, it just depends on a few things. Sadly, yours (and mine) are not Euro MFI 75 Carreras or they would be highly desirable. I mean I love my car, but many will tell you to stay away from the midyears (74-77) because they had emissions equipment that melted the engines (the magnesium engine blocks are fine if your car is a 73 for some reason)

I've never heard of your exhaust system. The pics are a bit a of hassle, you have to hit "go advanced" then hit click here to upload photos, then either drag some into the box (you may have to shrink them down first using Paint or some other program) and then you can probably figure it out from there.

what color is it?

jonesb930 · jonesb930's Garage

BEFORE YOU TRY TO RUN READ....

First, welcome to the community, you will find many people willing to help you learn and understand these cars from deep knowledge of origional configuarations to how to modify and improve them.

If the car sat for that long, check carefully under the fan shroud for any mice/rat nests. You can use a flexible bore scope (I think even Home Depot sells them now) with a camera to look around under there without disassembling through the fan. It is very common to have them build on top of the cyliners and block airflow. My experiance with a 77 turbo sitting for only 4 years also had me chasing issues in the fuel injection system, and ultimately changing the injectors. The fuel system is not overly complicated, but a proper guage set to test pressures is a good investment once you get to the point its turning over and you have spark.

zztot · 02-02-2025, 06:15 AM

Last response re: critters building nests.
Very common so don’t dismiss. Bought a barn find 914-6 conversion that fortunately had an engine issue. Turned out it was only a tensioner ( missed by mechanic on teardown) but once the shroud was removed huge nest built on top of engine mounted oil cooler.
It most likely would have been terminal so wrenches mistake actually saved my butt.

vonmec · 02-03-2025, 01:45 PM

So it is a black car with black leather and black carpet. Sunroof and A/C. I found another tag on the exhaust so it is a Bursch - the tag line was Horsepower Engineering - its been on there a long time - like the tires they are 1999s. I'm guessing the exhaust is much older. I hesitate to write the over used youtube description of wanting a authentic raw analog visceral experience (I love watching MGideons videos making fun of porsche people) but I have a 2018 Carrera T and a 1998 built 996 so I thought a 993 would be too similar to the 996, a 964 was too expensive, and years ago I had a 3.2. And I wanted a bit of a junker - but with potential. Whether the miles are accurate on not - it is showing 61K. Ok if there is a rodent nest - how do you retrieve it?

vonmec · 02-03-2025, 01:58 PM

https://share.icloud.com/photos/0fcY3C6B4LGmhh-ukKXKdR0Xw

vonmec · 02-03-2025, 02:09 PM

vonmec · 02-03-2025, 02:12 PM

vonmec · 02-03-2025, 02:16 PM

I took out the original seats, front and rear plus the visors and am having Bucket Stitch of Greeville redo them. I bought a temporary pair off of ebay to use while working on the car. Later on Bucket Stitch with replace the headliner for me. I don't know if I should replace the carpet of clean it and leave the original in there - don't suppose the carpet matters.