Aluminum or Magnesium

MarKoBrow · 08-20-2007, 07:01 AM

Does anyone know when Porsche started using Magnesium cases? Was it with the 2.7 or before?

Evans, Marv · 08-20-2007, 07:14 AM

With the 2 liter engines in '69.

ttweed · ttweed's Garage

Quote:

Originally Posted by Evans, Marv

With the 2 liter engines in '69.

Actually, the change from sand-cast aluminum came in the 1968 model year.

TT

MarKoBrow · 08-20-2007, 08:01 AM

Thanks for responding, I am concerned after hearing many stories about studs pulling out at high RPMs I plan on using this car for an occasional track day. any suggestions?

ljowdy · 08-20-2007, 08:28 AM

Case savers or Timeserts ( http://www.timesert.com/ ) can be installed. These devices reinforce the case and have threads on the inside to accomodate the stud.

Steve@Rennsport · 08-20-2007, 08:31 AM

Mark:

If you some specifics about what you want to do, I'd bet that you will receive some useful suggestions,.......

EarlyPorsche · 08-20-2007, 08:34 AM

Some people have reported that magnesium cases can get so porous that they can actually just leak oil out of the castings. True or false?

MarKoBrow · 08-20-2007, 08:38 AM

Hey Steve,

I am trying to decide what I want to do, I am not sure I want a dedicated track car or something I can drive to the track and have fun with and return home. I will get there soon, I just wanted to start with and engine that won't grenade under stress

tcar · 08-20-2007, 01:54 PM

markobrow, should we assume that you have a 2.7? You don't say...

klaucke · 08-20-2007, 02:07 PM

Quote:

Originally Posted by MarKoBrow

I am concerned after hearing many stories about studs pulling out at high RPMs I plan on using this car for an occasional track day. any suggestions?

There have been many, many nice motors built off Mag cases. Many w/ high HP and built to be run at high RPM. In my opinion, the mag cases are bashed by a lot unnecessarily. A lot of 2.7's may have pulled studs, but I suspect many of those were due to thermal reactors, 5 blade fans, hot weather and people running the AC. The upside is that these 2.7 mag cases, the 7R, are the strongest and best candidate for hotrod motors.

No one ever complains about a 2.7RS motor, and those are built on a mag case!

Steve, perhaps you can chime in on your opinion of properly prepped mag case motors? Does the mag case pose any problems?

MarKoBrow · 08-20-2007, 02:09 PM

I have a 72 with a 2.4L I would like to keep the displacement the same if that's possible

Steve@Rennsport · 08-20-2007, 02:25 PM

The real key to success with any mag-cased motor are maintaining strict control of oil temps. Keep the oil temperature below 200 degrees F and these are very durable.

Beyond that, case prep is mission-critical and all of them should get case savers and the oil bypass mods. Engines that will see over 7K RPM should be shuffle-pinned.

2.7's and 2.8's should be held to below 7500 to help prevent case cracking.