Which engine do I have?

[TwoSeatsOrLess]

I recently bought a 912 converted to a flat 6 and I'd like to know exactly what I've got. The seller told me it was a 2.0L but after talking to two other Porsche guys they seem to think it's a 2.2L. The VIN seems to be 6290134*, I'm attaching a couple photos.

My main concern is that I want to do a tune up and valve adjustment and I want to make sure I buy the correct parts, including spark plugs, etc. Thanks!

[Porchcar guy]

6290134 translates to
6 = six cyl motor = 2.0 ltr
2 = E
9 = 1969
0 = manual trans
134 = prod #
BTW...I got this info online in 5 minutes by doing a search for 911 engine numbers

[TwoSeatsOrLess]

Thanks, I did a number of searches for Porsche serial numbers and I didn't have much luck getting an answer that seemed 100% accurate.

Even on Pelican there seems to be some talk about 619x and 629x engine numbers and having them mixed up in certain engine books.

And, as I mentioned one Porsche fellow was "certain that it's a 2.2 Mag case" when looking at my car, fwiw.

[Grady Clay]

TwoSeatsOrLess,
First, WELCOME to Pelican
You will find a lot of help here.


You have a somewhat collage engine.
As noted above, it appears to have started life as a ‘69E with MFI, 143th one built.
I see Zenith carbs from a 911T (year tbd: '70-'73) and some remaining MFI parts.
Another mod are the later (‘Carrera’) chain tensioners.
Overall it is a very presentable engine.

There are another two numbers (green arrow below).
One should be either 901/08 or 901/11 (if it had been originally configured for a Sportomatic transmission).
The other is the ‘build number’.





If the internals of the engine are as original, it has 80 mm (1991 cc) 9.0:1 CR pistons, and 911E (similar from late ’66) cams and related parts – all good stuff.
When addressing ‘tuning’ we need to the details of the carburetors and the ignition advance curve.
Both are easy to determine.

First, use a timing light and record the ignition timing at every 500 rpm from idle to 6000 rpm.
This will tell what distributor advance you have.
This can be compared to the many stock advance curves.
Is there a CD ignition? If so, what brand? I see a normal Bosch blue coil, not OE Bosch ‘ignition transformer’.

The carburetors require a bit of disassembly to measure jet size, venturi size and a bit more.
This is all easy and will not change settings.



What is the ‘tune-up’ history of the engine?
How well does it run?
Have you recently measured the cranking compression and cylinder leak?
What is the cam timing and valve clearance?

We can help you through this if you are so inclined.
Our Porsches were built by mortals and mortals can work on them.

What year 912?

Again, welcome.

Best,
Grady

[Porchcar guy]

When in doubt..Ask Grady Clay, he is the resident guru :=)
I was typing this as Grady's post was coming in...Serendipity

[TwoSeatsOrLess]

Thanks guys and Grady, really appreciate the great response!

I will try to provide as much info as possible.

The car is a '69 912. I bought it two weeks ago, I didn't do any compression tests, etc. It happened to be the exact type of "hotrod" I like, it ran well and was priced right so I had no choice

I've put about 1,000 miles on it in the last two weeks. The car starts well, it puffs a bit of smoke initially then clears up right away. It does not seem to burn/use any oil although it does leak a healthy amount. I consider it to run pretty well, although the fuel mileage is poor and the valves are on the more noisy side (which I know can effect MPG) - hence the reason I want to do a tune up; also no clue when the last tune up was.

The previous owner installed a MSD 6A ignition system and yes, you're correct that it has the upgraded tensioners. I will have access to a timing light and a compression tester later this week, and a friends shop as soon as the valve gasket kit comes in later this week. I haven't ordered new plugs because I'm not certain what to get, although I assume its best to start with replacing what's in there now. Was also thinking about at least taking the carbs off and apart and cleaning them.

Any thoughts are appreciated!

Thanks again
Ryan

[pwd72s]

Ryan, don't expect great mileage from an early 911 engine. 16-18 is what I averaged with a 2.4 liter S in stock trim.

[Grady Clay]

Ryan,

Go under your ’69 911/912 and report the transmission numbers.
(These are stamped on the longitudinal rib under the differential area and forward.)
The ’69-only’ 912 had a 6-tooth pinion in some (most?) applications.
This has very limited life with a 911 engine. (Even 2.0.)


Where are you located?
You will find local PCA and Pelican members available to help you.
Some ‘Porsche-talk’ with a bit of lager and pizza goes a long way.


Please report about the oil leaks.
Some are way-too-common but only objectionable.
Others can be harbingers of impending problems (slipping rocker arm shafts & other).

The MSD ignition is great.
Figuring out your best ignition timing will be an ‘art’.

Critical to this exercise will be to measure your cam timing.
This will confirm (or refute) your 911E cams and not something other.
Is there a cam extension from the front of the left cam? (Look between the left heat exchanger and engine.)

You will find sparkplug ‘heat’ very driving dependent.
Most will recommend you use NGK BP7ES to start with and BP6ES for normal ‘street’ driving.
The BP8ES are useful for ‘sporting’ driving in warm weather.
Having multiple sets is vary useful.
Gas/oil fowled plugs are easily cleaned for re-use.


What is your DIY inclination?
You will find many here to help.

Best,
Grady

[TwoSeatsOrLess]

Thanks!

I am located in San Francisco, planning to head to a local meet up on Saturday where I hear a lot of early cars show up. I did live in Vail for a short while, which is pretty close to you in CO; great area.

From what I can tell the car leaks the oil from a couple spots from the case. I am hoping to get it on a lift this weekend and check out exactly what's going on.

I will check for the cam extension and the gearbox number. The gears are very short, which I assume is not stock. 70mph in 5th gear is 4,000rpm.

Also, I tried calling MSD to see if they had any input on plugs/timing/etc but they seemed to care less and just told me to set everything to 'stock.'

My DIY abilities are decent. I haven't worked on cars much the past few years but I've gotten back into it over the past 6 months or so helping a friend with his 911 Turbo and working on some LeMons racecars.