Sachs pressure plate / help ID application

[typ901]

the piece is identical to a stock 2.0L pressure plate in every respect except the foot is ALU vs. cast iron.
any help appreciated.
TIA

[Jon B]

the piece is identical to a stock 2.0L pressure plate in every respect except the foot is ALU vs. cast iron.

It's probably a 69S pressure plate, although I don't have a Sachs reference to confirm that number.
The Porsche number was 901.116.009.00.
The 69S alloy pressure plate had an iron coating on its contact surface. Is the surface slightly magnetic?

Jon B
Vista, CA

[edmayo]

And how many of those do you have ????

[chris_seven]

Jon,

Do you know how the Iron coating was applied ?

Flame spraying Iron onto Aluminium based metals is notoriously difficult although I believe that Sulzer Metco did develop a Plasma technique in around 2005 but this has been mostly used for engine cylinders and for friction reduction.

I guess that in 1969 the process would be an 'Arc Spraying' type of technique that could result in the formation of brittle intermetallic films at the interface of the Iron/Aluminium layer and obtaining consistent adhesion could have been difficult.

We are looking at making Aluminium Pressure plates at the moment and have considered Plasma Spraying Tungsten Carbide but the cost is quite high so we are starting by testing some parts which we have plated with an Electroless Nickel which can then be precipitation hardened to produce good wear resistance.

The precipitation hardening process also improves the bond strength between the coating and the Aluminium and we hope that this technique will be successful.

[typ901]

It's probably a 69S pressure plate, although I don't have a Sachs reference to confirm that number.
The Porsche number was 901.116.009.00.
The 69S alloy pressure plate had an iron coating on its contact surface. Is the surface slightly magnetic?

Jon B
Vista, CA

give that man a cigar the magnet doesn't stick to any other part of the casting.

[Jon B]

Jon... Do you know how the Iron coating was applied ?

Chris, I don't recall seeing any detailed information on that, but I'll report back if I find something.
In the early 60s, Mahle supplied Porsche with iron-coated Ferral cylinders for the Super 90, Carrera 2 and 904 engines before switching over to Biral, or reverting back to Chromal for racing engines.

Jon B.
Vista, CA

[72targa]

Related reference thread...

http://www.early911sregistry.org/for...sche-equipment

[chris_seven]

It would be interesting to know if the copper plated face pre-dated the plain Iron facing or if this treatment was not applied to the later parts.

Flame spraying in the Sixties wasn't well developed and I imagine that the process used may be best described LVOF but it is possible that a 'detonation' technique may have been used.

In either case it is probable that the adhesion of the Iron wasn't very good and that the iron layer may also have been quite porous.

It is possible that the Copper plating could have been applied to help with surface defects that may have resulted in the development of surface cracks from the disrupted Iron layer.

[uai]

If someone stumbles upon a MF228 with the aluminium Pressure plate as it was used on BMW and Opel I'm a buyer.