"Thoughts"; 3.0/3.2/3.4 stuff...Wayne? Henry?
 

OK, so I might be very interested in doing a large displacement engine (3.0+). I want to use Weber 46IDA's and single-plug, and from what I can tell, 98mm Pistons are the biggest I can go on single-plug. True?

-Wayne, I see in your book that you recommend a 3.0 Turbo/6 bolt crank case for the 3.0. Is there any reason not to simply find a more available, and probably better? (because it was made later) 911SC case and crank (9bolt)?

-Comparing 3.0 to 3.2 heads...

This would be going in an early car (my 72 probably), and is currently in very hypothetical stages (can you tell I am excited???) so any suggestions welcome. I had these configs outlined:
3.0, 10:1, modified heads?(3.0 or 3.2?), RSR cams
3.2 short stroke, 98mm JE's 10.5:1, heads???, RSR cams
3.4, Elgin DC80 or RSR cams
Again, only single plug and Weber 46's!

Scott;
What sort of engine do you want to end up with?

What will be the mix of it's future use? Street? Drag? Auto-X? DE? Full-race in ??? sanctioned series?

Where do you want the rev range? For the sake of discussion pick a 3000 RPM range where you want the engine to be strong. 2K-5K? 3K-6K? 4K-7K? 5K-8K?

What sort of fuel do you want to use?

Single plug and Weber 46's are the means to an end -- where you do want to end up? You keep calling out full-race cams (GE80's, 906's, etc) but your last post suggested that this is going to be a street motor. Forget about the pieces until you figure out what the goal is.

4500-7500 redline please! Pump 91 gas...Mostly a race/track engine but some time on street.

I think you will need to stay with 9.5:1 JEs if you want single plug on 91. They seem to have lots of cam clearance though. For that RPM range I think you would be better off with a 3.2SS than a 3.4. Maybe something like GE80 cams. Not great on the street. I don't know for sure that the 9.5:1 JEs clear GE80s.

The main reason for a 3.0 Carrera/turbo case is to run a 66mm crank for very high RPM. There is of course a limit to the displacement you can get out of this type of crank vs a 70.4mm crank.

Why not something like a machine in 3.5 conversion 100mm kit for 3.0/3.2? I don't see any issue with running single plugs with a bore like a 100 or 102, as long as you have a good CDI and good plugs, say iridium.

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

You really don't think there are any issues running single plug on that big of a bore? Hmm....gets me thinking... How available are cylinders that big? Is it possible to bore out 3.2 cyls to 100/102mm?

Kobalt--I see that the euro carrera case is good for using the 66mm crank and 95mm+ P/C, but Wayne also mentions using the case with your basic 2.7 crank, and I was just wondering, since the SC crank is the same stroke, why you wouldn't want to just get a more plentiful SC set-up (that might be stronger/newer anyway)???

I dont want to say too much here becuase Im a real noob with this stuff. Guys like Wayne, Henry, John, Charles, and Andy will be able to help out a lot more than me.

Check this thread out. Henry covers a 3.5 MFI single plugged monster engine as well as some other great sounding engine configurations. Towards the end of the thread there is some more good stuff from Henry about when to use a 66mm, 6 bolt 70.4mm, or the 9 bolt 70.4mm SC crank.