Another hot rod

[Flunder]

Research failed to yield a definitive answer regarding the factory-correct fire bottle for installation in a 2,3L car.

Neither of the Race Department folders for 2,3L or 2,5L Competition Spares provides a listing of any such part. Similarly, the Sports Purpose manual remains moot on the topic, indicating that the factory did not include a fire bottle in the standard specs of the ST, perhaps for reasons of potential liability or maybe the conflicting requirements of various sanctioning bodies at race venues in Europe, the U.S. and elsewhere.

We were able to pick up very few data points regarding this topic but they nevertheless may be of interest to the more detail oriented readers of this thread. Here is what we learned regarding matters relating to fire bottles used during the brief era of the ST:

“my late 69 car had a Bavaria, so did the 68 TR - both original and un-restored cars”

“ ...have the bracket that you see in the picture but no extinguisher was with the car. There is no evidence that there ever was an onboard system plumbed through the car so maybe it was a large hand held bottle. I just don't know.”

“…there was no bottle with the car when it was found so no idea.”

“factory used sometimes Gloria' or 'Vulkan' in 356, then 'Baveria' hand held extinguishers for 60's / 70's cars, and then later Heinzmann plumbed in (RSR ' 935 etc). Other teams may well have used anything they felt would do the job, but these are the makes which were commonly fitted in period.”

We did find one pic of a TR interior showing a Bavaria mounted on the upright of the rollbar just behind the co-driver seat.

From what little we were able to learn, it seemed the Bavaria would be the best choice for the sake of originality and duplicating a period look in a 2,3L ST cockpit.

However, we thought if would be safer to mount the Bavaria we found to the front “X” bar of the co-driver seat on the theory that it would be better to get hit in the foot than the head in the event of an incident.

The Bavaria bottle boasts a full cylindrical shape boldly detailed with a contrasting handle, big label with the firm’s address etc. Unlike many middle market firms that supplied Porsche during the 70s, Bavaria remains a going concern.

Let’s take a look:

[Mr9146]

I just wanted to pile on and say how truly impressive this project is in both the attention to detail as well as in the acquistion/use of original parts.

For all intents and purposes this car has become what has set out to imitate - please forgive my use of the term, as it's not meant to be derogatory but, rather, complimentary in that imitation is the highest form of flattery. Through the use of factory-original parts and methods it has become as "real" an ST as is currently possible given the 40-year lapse of time since when these cars were actually built and raced.

After having read ALL 65 pages and poring over the photos and doucment scans I am left with only one burning question: what were the specs of the cams that came out of Andial 129? There was speculation that it was something like a RSR Sprint Cam but there was never any resolution as far as I could find.

On a separate note, do you have any photos of the Minilites after restoration but prior to installation? Did you have them machined for the ball-seat Porsche lugs or are you running shoulder bolts. Minilite wheels are lug-centric while the majority of 911s are hub-centric ... did you machine the center hole to be hub-centric?

This is a fantastic project and I applaud your resolve in adhering to the factory tech specs. The bar has been raised again...

[Flunder]

Hi Marco,

Thank you for your post and also for the good questions relating to the original cams and the minilites.

906 Cams
The Cam Doctor specs for the original cams equated to 906 so these were probably the original cams installed by Porsche when the engine was new. The Andial paperwork indicates that they were specially ground by Porsche for the engine but if so the grind seems indistinguishable from 906. The 906 cams were OK to use but we decided to update to the RSR cams that were already on hand.

minilite 9x15

As far as I know, all of the early minilite 9x15 inch rims sold for the Group 4 STs were machined for for ball-seat Porsche lugs (same goes for the Group 4 eight inch version). I think many of these nine inch rims, machined for the ball-seat lugs, were delivered on the factory built STs until around April 1971 when the Fuchs 9x15 wheels got into the pipeline (the earliest Fuchs 9x15 casting dates are 1-71 according to Harvey).

I am told there are two versions of the early Group 4 magnesium minilites machined for ball-seat lugs. I have heard them referred to as big and small hole respectively, in reference to the diameter of the center hole. You can look through the pics of 2,3L STs and see the difference.

The magnesium nines we have for the project car are the small hole version and we left the center holes untouched.

You are correct, the minilites are lug centric, but then so are the early factory spacers (referred to as "distance washers" in the Spare Parts list) as well as early Fuchs like the 7Rs. Later factory spacers, like the 21mm turbo spacer, are hub centric.

Again, the early nine inch (and eights too) magnesium minilite Group 4 wheels did not require machining for the ball-seat lugs. That is the way the Group 4 versions were machined when new.

Many other minilites cast for the Porsche 911 used shoulder bolts and washers - it does seems like a better solution for a race application. I think that the shoulder bolt versions typically have the centers of the spider around the bolt circle milled out. For example, all of the Porsche ten inch magnesium minilites that I have seen have milled out spiders and use shoulder bolts. But, I have only seen three such pairs of the tens so other versions with different details may well exist.

Last minute glitch

As luck would have it, one of the 9x15 minilites for the project car had balancing issues and right now they are both sitting in Harvey's shop.

Thanks again for your post Marco; it is always a pleasure hear from a kindred spirit who likes to get into the weeds on this stuff!

I hope that Harvey will jump in here to correct this post or make additions as required.

[John Straub]

Interesting, my early 7 X15 "Mag" minilites also have a ball-seat. I never really thought about it before this post. Thanks guys.

John

[Mr9146]

Hi Marco,

Thank you for your post and also for the good questions relating to the original cams and the minilites.

906 Cams
The Cam Doctor specs for the original cams equated to 906 so these were probably the original cams installed by Porsche when the engine was new. The Andial paperwork indicates that they were specially ground by Porsche for the engine but if so the grind seems indistinguishable from 906. The 906 cams were OK to use but we decided to update to the RSR cams that were already on hand.

minilite 9x15

As far as I know, all of the early minilite 9x15 inch rims sold for the Group 4 STs were machined for for ball-seat Porsche lugs (same goes for the Group 4 eight inch version). I think many of these nine inch rims, machined for the ball-seat lugs, were delivered on the factory built STs until around April 1971 when the Fuchs 9x15 wheels got into the pipeline (the earliest Fuchs 9x15 casting dates are 1-71 according to Harvey).

I am told there are two versions of the early Group 4 magnesium minilites machined for ball-seat lugs. I have heard them referred to as big and small hole respectively, in reference to the diameter of the center hole. You can look through the pics of 2,3L STs and see the difference.

The magnesium nines we have for the project car are the small hole version and we left the center holes untouched.

You are correct, the minilites are lug centric, but then so are the early factory spacers (referred to as "distance washers" in the Spare Parts list) as well as early Fuchs like the 7Rs. Later factory spacers, like the 21mm turbo spacer, are hub centric.

Again, the early nine inch (and eights too) magnesium minilite Group 4 wheels did not require machining the for ball-seat lugs. That is the way the Group 4 versions were machined when new.

Many other minilites cast for the Porsche 911 used shoulder bolts and washers - it does seems like a better solution for a race application. I think that the shoulder bolt versions typically have the centers of the spider around the bolt circle milled out. For example, all of the Porsche ten inch magnesium minilites that I have seen have milled out spiders and use shoulder bolts. But, I have only seen three such pairs of the tens so other versions with different details may well exist.

Last minute glitch

As luck would have it, one of the 9x15 minilites for the project car had balancing issues and right now they are both sitting in Harvey's shop.

Thanks again for your post Marco; it is always a pleasure hear from a kindred spirit who likes to get into the weeds on this stuff!

I hope that Harvey will jump in here to correct this post or make additions as required.

You're welcome. You and the car deserve all of the accolades you're receiving. I hope I get to see this car in person some day and really get a chance to appreciate the build ... pictures do not do something like this the justice that it deserves.

Regarding the cams: When I first read the spec sheet from Andial that you posted earlier it said cam timing was set at 6.2. Having just timed my 906 cams prior to reading the post I was naturally very curious as the spec sheet on 906 cam timing puts them at 6.8. I'm not aware - of a lot of things - but I'm not aware of any factory cams that time to 6.2. If the cams in Andial 129 were, in fact, 906 parts then I wonder if the slightly retarded cam timing was something that was reached through testing on the dyno. I do know that adjusting the injection pump timing can yield substantial gains in HP as well as altering the drivability of a car; it naturally follows that altering cam timing would produce similar results but, due to the headaches involved in testing/tuning cam timing, it's something that is/was rarely done. As we know, Porsche has been using VarioCam technology for quite some time to increase bottom-end torqe while retaining the car's top-end HP. Perhaps this 6.2 906 cam timing was Andial's compromise; their way of delivering the most HP and torque for the given engine configuration and its intended use. Maybe I should set mine to 6.2 ...

Regarding the Minilites: Due to your attention to detail and adherence to period-correctness on the rest of the car I should have realized you were using the early style hubs, but the reason I asked about the Minilites and ball-seats relates to a car that we recently built for a customer on which we used 9X15 magnesium front and 10.5X15 magnesium rear Minilite wheels; both sets (front and rear) were small-hole and used the shoulder bolts and washers. Because we used later hubs on our build we ended up machining the back side of the center hole to fit over the "step" of the hub-centric hubs, however we retained the small hole in the front for the proper look. These wheels found their way to us with a bunch of other ST parts and were found in a barn in the midwest that belonged to a mechanic/driver/owner who raced a privateer ST back in the day.

[Brad Davis]

Hi Tom,

I noticed this picture posted by matt911. It is from the 69' Monte winner driven by Waldegaard. I assume this is a fire extinguisher, or maybe a thermos for brandy.

http://www.early911sregistry.org/for...911r+Larrousse

[smedley]

Tom,

Back in one of your original posts regarding ST bodies produced by Zuffenhausen to FIA Grp 4 spec....you mentioned the tubs were "nothing special....911T tubs pulled from the Karmann line as they were thinner metal".

What was your source on that fact?? General knowledge was that TRs, ST, and later, early RSHs and RSRs were specifically fabricated with thinner metal "for sports purposes," and 911Ts were homologated lighter simply due to lighter equipment ( carbs vs injection, no oil lines, etc).

Urban mythology always had the '69 911T as the best hotrod candidate due to it's weight and longer wheelbase...but because of equipment.

Thinner metal on Ts? Not challanging this point just curious from a histroical point.

[Flunder]

Hi Tom,

I noticed this picture posted by matt911. It is from the 69' Monte winner driven by Waldegaard. I assume this is a fire extinguisher...

http://www.early911sregistry.org/for...911r+Larrousse

Brad;

Thank you for posting the pic of Waldegaard's '69 Monte winner. I don't recall having seen it before. Does anyone recognize the bottle?

The rear hump between the seats seems to have been a favored spot for mounting a fire bottle.

The attached pic illustrates use of the same mounting location, in this instance a 2,5L car, but with a different bracket and the bottle missing.

[dlp72t]

Hi Tom

I saw the car outside yesterday. It was running and getting ready for the Dyno. Looked fantastic. It is truely a piece of automotive perfection. So are you bringing it to N.H. In May?

Regards
Dana

[Cornpanzer]

Seems like we are past due for an update... =)