The Last New 914-6 GT Project

[ajserrano]

Silver






































Penske, Mark Donohue, Cam-Am 1972 - Part 1...

[ajserrano]

Other Good Reproductions...

[ajserrano]

The Oil Pressure Relief Valve - NOS

Note the incorporated mounting tab, used so that it can be securely attached to a chassis bracket.















The valve below is from a 917K, note the larger diameter hoses connected to the thermostat



Difference between the oil pressure thermostats used in the smaller 2 liter engines and a 4.5 or 5 liter 917K twelve cylinder engine (uses 26mm ports).



The next photo shows the thermostat properly mounted via the mounting bracket in the engine bay of a factory built 914-6 GT.

Most dealer built GT cars don't have this mounting bracket installed.



A couple of photos you normally don't get to see...









Penske, Mark Donohue, Cam-Am 1972 - Part 2...

[ajserrano]

The Simple Components of a 917k Oil Thermostat

[ajserrano]

Oil Pressure Relief Valve

This is by far the rarest of ALL the 914-6 GT parts that make up its lubrication system. Recently, a lot of people are calling this valve the "Preschona Valve" since Preschona was the manufacturer of the part.

The photos below are of my NOS Oil Pressure Relief Valve. Check it out...









































Below are comments posted by Thomas Callahan as he describes the history and function of this valve. The picture references he makes in the comments below are of photos located on his thread, go to his post #229 to see them.

Tom maintains an excellent 911 S/T thread, "Another Hot Rod" located at the Early911SRegistry.
(his thread is by far one of my very favorites, you should visit, get ready to be amazed!)

Uberdruckventil

“Over pressure valve” is the literal translation of uberdruckventil. However, we would more readily recognize the appropriate terminology as “pressure relief valve.”

We are used to seeing this part fitted to RSR and 914-6 GT and many on this board are familiar with the elaborate warm-up procedures observed for race engines . A pressure relief valve was also used on some 911 ST especially those prepared by the Race Department to Special GT Group 4 specs as well as the highly specialized ST Safari.

This valve, like most others, is designed to function in two positions: open and closed.

The pressure relief valve is comprised of a piston held in the closed position by coil spring pressure, all contained in a cast housing with threaded ends on the inlet and outlet spigots cast integrally with the body of the housing.

The purpose of the pressure relief valve is to protect the remote oil coolers from sudden high pressure conditions, such as would be generated upon start-up with cold 40 weight oil, the viscosity specified by the Race Department for competition spec engines. This was especially critical in cool weather conditions such as those encountered at the Nurburgring and at pre-dawn in the African desert.

The valve was plumbed into the oiling system between the engine case and the oil tank filler neck and is designed to open at 5.0 atmospheres of pressure (approx. 80 lbs per sq inch). A high oil pressure condition (5 atm and over) moves the valve's piston to the open position thus de-pressurizing the system by diverting oil from the case directly to the dry sump tank - away from the oil coolers. Under normal operating pressures, the valve remains closed, allowing oil to flow from the case to the oil coolers.

Next, there are two images showing ST installations, one a MY 70 2,3L ST prepped for circuit racing and the other a MY 71 ST Safari. The "red top" variation shown on the MY70 2,3L ST is very rare and found only on early cars. The version shown on the Safari is the same as the first example but is missing its red can covering.

As a sidenote, the Safari oil filler neck is sporting a big Blau oil cap, rarely seen on ST but a universal fitment for RSR.

Next, there is an image of the second and most common version of the uberdruckventil, that was sourced from Germany for the hot rod. The second version of the valve came into use for some 2,5L ST and universally on MY 73 Carrera M 491 2,8L. The next image shows the installation of the second version on a 2,8L RSR.

The Spare Parts List Carrera M491 1973 2,8 ltr. competition type lists the part as:

911.107.017.00 Uberdruckventil

Finally, there is an image of a serial number tag from another type of valve produced by the same manufacturer, but one designed for a non-Porsche application. However, it is nevertheless extremely interesting.

This pressure relief valve used by the Race Department was manufactured for Porsche by the Berlin-based firm Armaturen-Apparate-Fabrik Preschona (“Preschona”). Preschona was the leader in its industry and a member of the engineering elite of Germany’s middenstand, an enviable network of privately held mid-sized manufacturing businesses, a group that of course included Porsche KG in those days. Preschona’s area of expertise lay in the realm of high pressure fluid dynamics.

Preschona’s credentials in the area of pressurized fluid control were un-rivaled, its expertise having been established at the very dawn of modern rocketry. Providing the uberdruckventil to Porsche’s specifications was by no means the most challenging job Preschona had fulfilled, having previously manufactured such exotica as the fuel distribution and fuel pressure valves for Werner von Braun’s early rocket designs.

The final image shows a well worn serial number plate from a Preschona fuel pressure valve, an artifact recovered from the crash site of a V2 rocket.

Yes indeed, rocket science for hot rods.

[ajserrano]

Oil Pressure Relief Valve Taken Apart

[ajserrano]

Testing the By-Pass Pressure

Making all the connections and getting ready to test the "Oil-Pressure Relief-Valve"



All the connections are done and we are ready to go!



When first tested, the pressure setting was found at the lowest setting, approximately 30 psi



The pressure was set at the lowest setting, approximately 30 psi and could be adjusted up to the maximum of almost 120 psi.



Here is a better view of the Dial Pressure Gauge almost at 120 psi



Testing performed by Bernie Buschen...

[ajserrano]

Oil Pressure Relief Valve Original Drawing

[ajserrano]

Aluminum Oil Console Spacer



























...it belongs here, sandwiched between the oil console and the external oil tank...

[ajserrano]

Oil Console 'NOS', Aluminum. These consoles were also available in Magnesium...

...but those are much more difficult to find in good shape these days since the Magnesium parts tend to errode away around the large o-ring sealing area.

















BOSCH CDI Box Test Fixture...

[ajserrano]

Specialized Oil Lines used by the 914-6 GT in the Engine Bay Area



This is a good photo of my NOS set...



Below are larger photos of each individual 914-6 GT oil line...



























Using my original, Spraker created an "over the top" reproduction of this particular 914-6 GT oil line.

Aside from the obvious photo color difference, once cad plated, no one can tell them apart, period. It just doesn't get better than this...

[ajserrano]

Factory NOS 914-6 External Oil Tank - p/n 901.107.005.40













Great video, hand-picked, worth watching every minute of it!

Observations...

• At around the 1:40 timeline, pay attention to the behavior of the early mechanical tachmeter, another view opportunity at 5:30.

• Starting at 2:30, note the very rare Magnesium 908 Calipers (I have a pair of those for the front of my GT).

[ajserrano]

An Schematic Drawing of the Oil Lubrication System used by the Porsche 914-6 GT







One more, to compliment the above Redman video Like I said; Only the best!

[Dave at Pelican Parts]

Originally Posted by ajserrano

Using my original, Spraker created an "over the top" reproduction of this particular 914-6 GT oil line.

Aside from the obvious photo color difference, once cad plated, no one can tell them apart, period.

I can. The welds on the new piece are much better looking than on the original part. I think your guy does better work than the factory did.

--DD

[ajserrano]

Well, it wasn't intentional as we purposely tried to also duplicate the weld 'look-n-feel' of the factory original 'production' oil line. The welds of that factory oil line actually look pretty good, compare that to some of the other early stuff we've seem.

BTW, the very same goal and effort was applied during the reproduction of the large 914-6 GT oil filler necks. In retrospect, I wish I had asked Mark to fab 20 of those GT filler necks and not just a handful. I still get request for them. Never to be done again...

Thank you for the post Dave!

[Dave at Pelican Parts]

Yeah, I was also thinking about the 917s when I wrote that...

--DD

[ajserrano]

Hurley Haywood: The History of Rennsport

Originally Posted by ajserrano

PS: ...got word that my newly restored and powder coated old engine stand is ready for p/u...

I completly forgot to post the 'after-restoration' photos of the engine stand, used a low-key color. The stand looks funny empty, needs a motor bad...



I've had this thing for over 20 years, it needed some TLC...



















...as good as new.



Not sure which engine will be the one to end-up on the stand for most of the time; a decision I don't have to make
at the moment, but in the meantime, it's okay to dream a little in anticipation.

Here is a 2.3 liter 911 S/T carbureted motor (Edmond Harris). A piece of art, it doesn't belong in a garage, should park one in my office so I can just stare at it.



...and what I should have installed in my 914-6 GT, a new flat-eight Porsche 907. Check out this bad boy!
(C. Thompson built this entire engine from parts he had on the shelves. Note the flywheel).



A little trivia;

In the time that it takes to build a 907 engine from scratch, one can build four 917 twelve-cylinder motors.

To tear down a 907 engine and freshen up the motor, the estimated costs is approximately $40,000 (that quote was from 10 years ago).

Next, I will continue to post the rest of the 914-6 GT factory parts that handle the lubrication end of things...

[Philippe Roger]

[QUOTE=ajserrano;6585314]Specialized Oil Lines used by the 914-6 GT in the Engine Bay Area



This is a good photo of my NOS set...



Hello Armando,
Any address where I could get good repro's of those oil lines and fittings?
Thanks,
Philippe

[ajserrano]

Sorry Phillipe, those are my NOS GT oil lines. We only reproduced one oil line for a friend, but no others.

If there is someone today reproducing those exact oil lines for sale, I'm not aware. Let me know if you find any sources.


The Greatest Years of Rally (1970 - 1979) A bit long, but remarkable video footage from an era long gone...



...fast forward to 2010; The Marrakech Media Test Drives

[ajserrano]

2012 Le Mans Classic - Recent in-car video footage from Simon Bowrey and his factory built 914-6 GT. The car is being driven by Steve Winters of Jaz Historic Motorsport.




1970 Porsche 914-6 GT at Le Mans Classic, Plateau 5, Driver Geoff Turral




2012 Le mans classics, Group C Crash! advance to 2:39 to see the actual crash...



...and then we have this video. Very cool to be able to do this...

Is funny to listen to these two guys, the passenger appears to have 'Parkinson's'. He's not only a "proximity sensor", but also a "parking-brake" and "rev-limiter" all rolled into one. Probably owns the car. lol