On the same topic, I have a 1969 motor with 85mm pistons, 9.5:1 c.r
and twin plugs. The motor runs very well at the moment with a top end rebuild aprox 2000 miles ago. I have no idea if the bottom end has ever
had any work done to it. I am considering replacing the crank and rods
with 2.4 ones in order to bump up the displacement and take advantage
of the twin plug setup. But - from reading the above posts it seems that I
would then have to as a matter of course have the case trued which is an expense that I had not considered. Any advice?

Robert

Hi John. Here in Australia there is no-one resizing cases by milling the gasket surfaces. I checked and was advised the best thing to do was send the case out and have it align bored. It cost me $946.90 AUS for the align bore and all bearings, and I was told by the Porsche mechanic that recommended Porsche Centre Melbourne that this was a really good price as he's had to pay over $1000 just for bearings. Anyway for us Aussies it's the only show in town. If you do hear of anyone resizing cases here let me know. I'd have much rather had this done than the align bore.

Yes, all magnesium cases have the potential to need extensive machine work. The earlier cases less so, because they were exposed to less stress. Typical cost to have everything done is about $1500 at Competition Engineering (although they are so backed up right now). Check out the machine shop costs table in the Engine Rebuild Book.

-Wayne

Thanks Wayne - that is what I was afraid of. Probably makes sense to leave the motor as is for the time being and only do what I am proposing
when the engine needs a rebuild - if I manage to put enough mileage on it. Maybe swop the pistons for 10.5:1 c.r for the meantime. Any thoughts
on whether the gains would be worth the expense?

Robert

Well fellow Pelicans,

I took my case to a well respected machine shop in my home town of Toowoomba and had the the case checked for alignment and bore size... It failed :( badly :( :(

As PaulM notes, there is no one in Oz currently machining the cases as per Wayne and Christian's recommendations. I too will be align boring my case to oversize and using larger backed bearings which are not cheap. At last count my 6k to 7k estimate rebuild is now officially in to 5 digits. I hope my wife doesn't ask too many more questions!

Thanks to all of you who offered help or suggestions, I'll let you all know how it goes.

i heard a rumour that the oversize bearings are more available now, and cheaper than before. in the $200 range. that's probably cost, but i'll have to look into it.

Hi Fishcop,
You could try Stan Adler at Performance9,www.performance9.com.au, or you could ring him and ask about the oversized bearings. He's very helpful. Try your local Porsche Center as well, they have revised a lot of their prices for the older air cooled cars, and say that they are willing to go the extra set to retain your business. I have had some good quotes for parts from them. Believe me your doing the right thing. You'll feel a lot better once you get that engine back in the car knowing that your rebuild didn't cut any corners. Good luck.

This link worked for me:

www.performance9.com

However, all I get is a home page with his contact info. No add'l pages?

Sherwood

The link is www.perfoemance9.com.au the one above has a comma in it

Sorry www.performance9.com.au

Thanks guys, I will do the ring around Australia for quotes and then probably the US to compare.... Watch out for a late night phone call from Oz John Walker ;)

I just bought a set of oversize bearings through Ted Robinson at German Precision. He got them at the local dealer (Carlson) and with his small markup they were just over 400 dollars.

Have done some homework. Looks like around $700 (Australian) for align bore and bearings (not including #8). I will pay a little extra not to have the #8 done as I have just bought a brand new standard #8. It is not a problem, just more time-consuming to leave #8 standard.