Ed Hughes

That is classic. It would make a good quote for Doug Bray's signature.

Jonny A

Ed:

I was looking something else up in my Bruce Anderson performance handbook, when I can across a chart of Mahle pistons and cylinders available for 911 engines.

At the bottom of the chart there are 102mm's that will fit and bring it up to a 3.8 lit.

Just wondering if you looked at other options other than going to 3.4?

This is a great thread, I look forward to following your great upgrade.

Thanks

Jon

Ed Hughes

Indeed. 3.4 is the largest you can go with just a bolt-on process. 100mm and up requre more machining starting with the case. I'm not planning on splitting my case again on this project.

rusnak

I think the Ruf P&S were 3.5, but they had thinner walls. Indeed, 3.6 had wider spacing. Not worth going over 3.4 and paying through the nose for Ruf stuff. And I think their compression is ....I want to say 10.5 to 1 or something. Can't recall exactly now.

Jonny A

Ed:

Would the 3.2 case be able to take the 102mm cylinders without making the webs too thin ?

When I finally find the sc/carrera, I am thinking about the engine I would like to build. Since I would be thinking about maching the case anyway, I was wondering about those 102mm cylinders.

Thanks

Jon

Ed Hughes

Ruf may've had such an offering, and I think I recall seeing that before. Mahle 3.5L (100mm) require the case 1/2's to be machined.

theiceman

That there is pure car **** ...

Ed Hughes

I don't know. There are many who think the expense to go 3.4 isn't worth the gains. You start machining the case and whatever else is needed accelerates your check-writing and gets you a lot more radical and opens up more doors for more modifications-heads, fuel (carbs or ITB), engine management, etc.

3.5 is probably the biggest that is reasonable and can exist with a Motronoc system.

But what do I know? I'm just a hobbyist who loves his Targa and has no kids to feed and no bills to pay. There are guys like Steve and Peter on here that can probably build anything one can dream up and tell you the pros and cons of each.

theiceman

well lets put it this way ... if I could choose between your 3.4 and a 99 Carrera 3.4 .... it would be an easy choice .... I would choose the porsche.

dshepp806

hehehehe...

whalebird

I think the 3.4 is a good choice. Any bigger and you would probobly run into limitations on the Motronic and the basic architecture of the intake. Even with the 3.4, you would have to go with twin plugs and thats already done. You can que Porsche on the fact that they had to make major changes to achieve a 3.6. 3.4 is it on the stock stroke I would say; without major induction changes. Too far "over-square" would yeild limitations. There is probably some keen engine builders who could offer insight, but these are my instinctual feelings. A healthy compression ratio with safe clearances, twin plugs, and sufficient port flow will create a wicked engine. Any more bore and your diminishing returns will become a compramise.

Ed Hughes

Well, I made my list of "odds and ends" needed today, and went through some of my books to get my "rebuild head" on. It's been a couple of years, and this was my only flat 6 build, but it is coming back to me.

The good news is I don't have to touch the case, but I still have a pretty good list together. My wife is happy I'm not buying a 964 or 993 now, and I probably should-or quit spending money on Ruby, but I'm still going to have to keep the total on this upgrade a secret. I keep reminding her I only spent $10k on Ruby when I bought her. She simply rolls her eyes now.

theiceman

this is going to be an excellent build thread . I have to do some oil leaks eventually and I have a couple of base gaskets leaking so the rebuild procedure will be identicle ..

Ed Hughes

Base gaskets are one of my unknowns. .25mm is "stock", but I have to be real careful on measuring deck height with the high-domed pistons. Other sizes available are .5 and 1 mm, I believe. I'll look for a deck height clearance of probably 1.25mm minimum. I think some guys go as low as 1mm, but trying eke out any higher compression probably isn't warranted for my engine. I'd prefer a bit of a safety margin.

TT Oversteer

European Car Magazine did a series of articles on building up a 3.2 similar to what Ed is doing. Check out the links on the RH side for the other articles in the series.

http://www.europeancarweb.com/projec...ork/index.html

They did a beautiful job and spent $$$. RW HP turned out to be around 243 I think. Looks like a fun build but the HP/$$ ratio favors a 3.6 964 or 993 motor conversion.