FS: 911 ST Preschona Oil Pressure Relief Valve

Price: $3,500

• 1971 PORSCHE 911 ST EARLY RACING PART
• Porsche Part Number: 901.107.285.20
• Fully Adjustable Opening Pressure (unlike the later 911 RSR Valve)
• Indispensable Component of an Endurance Porsche Vintage Racing Car
• Central to a Racing External Oil Cooling Dry-Sump Lubrication System
• Limited production, not many made. More pictures here

A perfect reproduction of the OEM Preschona Oil Pressure Relief Valve, many years in the making.
This is a 'first generation' exacting copy of my "NOS" original Preschona Valve and not 'a-copy-from-a-copy' produced by anyone else.
In order for me to reproduce this rare oil pressure relief valve, my "NOS" and "OEM" valve was used.
Even its internal spring was made in three attempts, until it was duplicated correctly matching the 'specs' of the original coil. This valve is perfect in every way.

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Link to thread where these photos were borrowed...

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Feel free to contact me with any questions. Thank you.

Here is a book photo of a 911R engine bay (R4).

Difficult to see, but there is a Preschona Oil Pressure Relief valve behind some of the oil line components at the right side of the photo...

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And the period blueprint drawing

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What’s the book???

Please!!!

Quote:

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Originally Posted by StephenAcworth

What’s the book???

Please!!!

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Hello Stephen, you will have to contact Ernie Wilberg. While attending the 2018 LAX Hilton Literature/Memorabilia Show, I snapped these photos of the books Ernie displayed at his table. I'm not clear if he has plans to offer his 911R books for sale in the future.

In the meantime...

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A borrowed photo from Ernie's 911R pBase site, but we still can't clearly see the 'Preschona' valve in "R4" behind the oil lines.

Curious... Can anyone provide a better photo? :cool:

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Failed to also upload a few pics of the steel cap.

The cap alone took hours to fabricate, hand-made on a lathe from a solid chunk of steel, no CNC used here...

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The material tolerance held here, from top to bottom was approximately between .016 and .017

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Very cool piece also, if I may say so... :rolleyes:

Hallo Armando
Compliment for the job: it’s PERFECT! Bravo!!!

Here you are another “real” photo.
A Nos preshona valve mounted on my 2.5 St engine.
In this “exposed” configuration It’s mandatory the special oil filler with the correct attachment.

Ciao
Andrea70

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And this is a photo of the “hidden” version taken from the excellent and superb Ernie Wilberg’s site:

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In this picture you can see the second version of preshona valve.

Thank you Andrea, I'm very satisfied with the results.

Here you go, the 'special' racing oil filler neck you mentioned as shown in your photo.

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The tag attached to his piece was labeled "IROC" when I purchased it.

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I have not confirmed that...

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...and I'm thinking "Early 911 ST"

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Armando

It’s not an IROC part , but a 911R part

Here you are my nos filler with the correct Porsche code (typewrited as pre-1970 tags)

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