The Very First S-Caliper?, an interesting look at one of DaveP's calipers Options

[davep]

Those calipers look gawd awful. Send them up, and I'll pretty them up for you.

BTW, the fellow (Gerhard (Gary) Hirsh) I got the race caliper from did indeed own 9140430033 for a short time, however the last time I saw the car it had the proper 908 calipers on it. I suspect the race caliper came on some other, earlier, race car however I don't recall all the cars he drove.

[Eric_Shea]

Is he around?

[davep]

Somewhere near Toronto I understand.

[Eric_Shea]

We should try to look him up (unless you still owe him money) (IMG:style_emoticons/default/biggrin.gif) It would be nice to see if he has any recollection of the caliper. It may help us find it's mate.

I'm fairly certain we've narrowed this down to a 908 caliper. I would say it's a fairly rare 908 caliper as well. All of the logo markings are in the exact locations for 908 and the shaved top says 908 as well. The only thing that doesn't is that 910 style pin and "most" of the 910 calipers I've seen now don't even have an endurance pin.

908 being the predecessor to the production S-Caliper (virtually one in the same), I think this is one of the first from this casting but... that is PURE speculation based upon the pin vs. the spring loaded pad mechanism.

Thoughts?

[davep]

here is an interesting thread I came across in my research:
http://forums.pelicanparts.com/showthread.php?t=169568
I have a few emails out to the fellows involved trying to learn more.

It would appear that the caliper evolved from the 910 style with the round back cover to the more familiar S caliper.
Varieties of the caliper were made to suit particular applications.
The most familiar 908 variety with the bottom pins and plate was an endurance caliper with thicker pads. However the single pin for pad release seems to stick out quite a bit, and may not be suitable for rims less than 15" diameter. My caliper is shaved down and would fit smaller rims better. Therefore I think we need to look at cars that used the smaller rims.

[Jeff Hail]

here is an interesting thread I came across in my research:
http://forums.pelicanparts.com/showthread.php?t=169568
I have a few emails out to the fellows involved trying to learn more.

It would appear that the caliper evolved from the 910 style with the round back cover to the more familiar S caliper.
Varieties of the caliper were made to suit particular applications.
The most familiar 908 variety with the bottom pins and plate was an endurance caliper with thicker pads. However the single pin for pad release seems to stick out quite a bit, and may not be suitable for rims less than 15" diameter. My caliper is shaved down and would fit smaller rims better. Therefore I think we need to look at cars that used the smaller rims.

Going back to my original post.........Hans Metzger of Porsche typed model 906/2000 which was known as the Ollon-Spyder. This model first appeared at the Swiss Ollon-Villars hillclimb event. Metzger took inspiration from the Elva-Porsche. This model used exclusivly 13 inch front wheels. Porsche at the time did not make 13 inch wheels and had them produced from an outside source along with revamped uprights. The original wheels were steel would have had a barrel thickness of approx 1/4 an inch. This would have meant shaving any parts including calipers to clear the new wheels. The steel wheels used a reinforced center section extending into the barrel shell requiring even more clearance. The calipers at the time would have to have been experimental or cast and machined for the smaller wheels. As well as the prototypes class (called group 6) aimed at the big manufacturers they also defined a class for competition sports cars (class 4) where a minimum production number of 50 cars was permitted. Piech saw an opportunity in the new ruling, but was convinced that Porsche would need a completely new chassis and car. He decided to use the Ollons-Villar spaceframe chassis (not the 904) as a starting point.

The 906 (or Carrera 6) used both steel wheels and magnesium. Applications included 13 inch wheels for up to 2.0 liter versions. The Daytona running 910 also used 13 inch wheels and would have had to use the early shaved calipers. The long tails had brake cooling issues and were than updated with 4 piston calipers and ducts to alleviate cooling problems at the high speed course's. In late 1968 some calipers were updated again to magnesium bodies from the previous aluminum versions for weight savings. Porsche returned to aluminum calipers as the magnesium versions had problems associated with high heat. Even later updates on the 908 and then 907's all wheels were updated to 15 inch. This allowed the use of larger calipers and ventilated brakes to be utilized. The 908 with updated wheels and calipers stopped better than any other previous racing Porsche.

Based on the factory documentation and Erics' information the timeline is narrowed even more on Dave's caliper. Based on the inspection marks I honestly believe he has a real Mccoy 908 racing caliper and not one that appeared on a 914 GT as off the shelf racing parts. Adding Porsche has always used the 20% safety margin (or over-build) on it's racing parts unless unavoidable. I cannot see a logical reason for the factory to shave calipers unless it was for smaller diameter wheels. The factory never skimped on brakes. The 907 units used entirely different calipers and then that eventually evolved into the 917 model.

[Eric_Shea]

910 - 1967
907 - 1967-1968
908 - 1968-1969
S-Caliper - 1969

I'm not sure about the shaved thing Jeff. I agree totally however, all of the 908 calipers I've seen have the shaved top. (IMG:style_emoticons/default/confused24.gif)

I'm going to call this one of the very first 908 calipers. As the 910 caliper (and it's endurance pin mechanism) evolved, the 908 caliper came to be. I'm going on a limb and saying; this 908 caliper, as one of the very first, received the 910 pin assembly. Subsequent 908 calipers had the single pull pin spring.

When you look at the time line above and the pictures from the 910 manual... it starts to become obvious. Dave is on possion of one if the very first 908 calipers ever made. Want to bring the thread full circle? This is one of the very first S-Calipers ever made, as 908 calipers are really nothing more than an S-Caliper. Amazing history when you consider the success of the 908 Caliper and the S-Caliper.

Dave, I found the original owner of that GT as well. Good conversations all around. Thanks guys.

E.

[Eric_Shea]

Been busy cloning things...

[davep]

Very nice. They will look even better in person.

[Sleepin]

I see you finally have got my calipers done! (IMG:style_emoticons/default/lol-2.gif)

[Eric_Shea]

I see you finally have got my calipers done!

(IMG:style_emoticons/default/smoke.gif)

[grouperalley]

Intresting stuff. For what its worth, i believe the "bump" you show is the remnant of the "spru". When metal is cast the spru is central the channel the molten metal is poured into to cast multiple castings in the same mold.( imagine a tree upside down, metal is poured into the trunk and flows out the branches, finally filling the fruit). Then they break off/machine off the tree & branches leaving only the fruit. If it is a spru the variation of the bump (spru) location probably indicated a change from low production moulding/manufacturing techniques to higher volume methods. if their are casting marks, then the calipers were not made using lost wax technique, which is generally one off. So a theory is ate/porsche used wooden pattern plates for the earliest of your calipers, then went to higher pattern cost/production metal plates and possibly changed from horizontal to verticle molding equipment for the "s" calipers once they had committed to multi year application for a production car

[Eric_Shea]

I seem to have stumbled upon the missing link today. This is an amazing find. Something I never expected to see.

Another supplier was looking for a 908 caliper and sent me this to find a match:



Notice:

1. It originally had the 910 pad pin mechanism. You can see the cutout for the latching tab on the nose section of this caliper. As suspected, this would place Dave's 908 caliper as the earliest version of such caliper I've yet to see.

2. It now sports the 908 spring and pull pin. This is literally the missing link, showing the progression from Dave's 908 caliper to the more common 908 caliper.

3. It does not have the pad rests at the bottom ala later 908 calipers, it still retains the pins. This shot shows that it has the wrong pins in place (it should have the "U" pin as seen in Dave's caliper).

Wow...

[ChicagoPete]

Eric,

Although I have never chimed in as I really have nothing of value to add to this thread, I am completely fascinated and keeping a close eye on your recreations.

To be completely honest, I have been on the hunt for some sets of the early S calipers as well. A couple of sets have come up on eBay recently, went in the mid-$300's. Even a mismatched set went to that level, one early, one 2nd generation.

I think your work on these things looks awesome, and certainly want the "next" one wearing these.

Peter

[Eric_Shea]

Thanks Pete!

I just grabbed 3 pair for @ $250 over the weekend so, they're out there. Keep looking. I wouldn't pay any more than that for an S-Caliper as they're all basically "junk".

Let me qualify that statement; the pistons are almost always a throw-away item. New ones will add some coin to the bill. Most compensating lines are bent or broken or break when you attempt to remove them. The finish is usually gone. You can glass bead blast them but, that leaves them unprotected for the future, these are anodized. so... add de-anodizing, polishing and re-anodizing to the bill. If you don't anodize them they'll corrode even faster.

We've sold out of this first run with more on order. I'll keep you posted on the next build. So far there's 3 sets on backorder with 4 cores. I'd be proud to have them on anything you create. (IMG:style_emoticons/default/wink.gif)

[Eric_Shea]

Played around with the "V" (versuch) stampings. I think they came out well!

[Eric_Shea]

Oh Happy Days!

Pins and clips are done and back from plating!! (IMG:style_emoticons/default/w00t.gif)

[Eric_Shea]

Done! (that was a crazy project) (IMG:style_emoticons/default/wacko.gif)

The first pair are off to a 914-6/GT IMSA car that belongs to one of our 914World "darlings".

Enjoy!

[914Sixer]

Whoa, those are things of beauty!! Keep up the good work!

[ME733]

...........ERIC, your knowledge of brakes and systems is just great. you are obviously an expert....I found the previous post about 914 brakes, and especially the proporting valve explanation the best of any I have ever read....this post about other calapers and uses is great also.......I would like to know if you have , tracked , compiled ,information reguarding the calaper PUCK/PISTON sizes as well.....if you have it could you post it?......here,s my reason for the question and intrest....FOR going on forever - I have read, and been told by brake experts...that the IDEAL brake proportioning is ...FRONT 60%-----REAR 40%....(without a proporting valve in the mix as on stock 914,s.).....I am curious to know IF the front and rear calapers have different PUCK/PISTON sizes in the various , early A-thru----what ever information you have available-917 etal, carrera etc. etc..... This information would be very informative, especially to provide a basis of fact, and stistics relative to BRAKE BIAS.............great job. thank you Murray Mcafee.