1969 2L S engine rebuild

[agbucks]

As a part of the restoration of my early 911S, we are doing an engine overhaul including a rebore.
The new pistons we have been able to source are Wossner.
Does anyone have any experience of these?
Thanks,
Andy

[Freitasporsche]

Hi there! Old thread, but i am rebuilding an 69 engine, and thinking of going this route. Wossener 81mm pistons, and reboring the original cylinders. How did it go? do you recommend it?

[agbucks]

Hi there! Old thread, but i am rebuilding an 69 engine, and thinking of going this route. Wossener 81mm pistons, and reboring the original cylinders. How did it go? do you recommend it?

Happy with the rebuild and seems to be running fine. The main challenges were the CDI unit (I have had the internals replaced with modern electronics an that seems to work fine) and setting up the MFI pump.
Good luck,
Andy

[Richy]

Thinking it was GTPorsche magazine where I read a story about England's well respected engine builder Neil Bainbridge insisting on using Wossner pistons in a 2.8 RSR engine he was building . This got my attention . I used them in my 2.2 S rebuild . I used the 84.5mm pistons . Absolutely no complaints . I would recommend the 80.5 mm size if reboring the cylinders if possible. 81 might be getting a little thin .

[Freitasporsche]

Great news guys! thanks.

I'll be going with wossner and a rebore on my biral Cylinders.

[1968DT]

Are you adding a 70.4 crank for more compression?

[Freitasporsche]

Humm... no.

:-)

I would only change the crank if I wanted to stroke it, which I don't. Besides, the shorter the crank the happier it will rev ( less piston speed ). Also, raising the compression is a problem on these early 69S engines, they have the 80P26E Pistons, and compression is already 9.9:1, which is high enough on pump gas.

Also, if i wanted to bump the compression i would go for Wossner 10,5 pistons ( even higher than 906 engine ), it would be easier and cheaper.

But all this would only make sense in this engine if i "twinspark" it, which i also don't plan on doing! That would solve the detonation problems, but that's effectively building a 906! Unfortunately Mr. Bank Manager wouldn't allow it!

So, this one is going to be an original 69S, just with 80,5 Pistons.

[beh911]

Let's see some pics and info about your car, freitasporsche...

[Freitasporsche]

By all means! Check build thread at :

http://www.early911sregistry.org/for...Freitasporsche

Project 911T/R restoration

i will be updating it with some more fotos.