What crank options do I have for a 3.0L case?

[Kevins911]

I posted this over at the engine rebuild forum but there doesn't seem to be much action there... What crank options do I have for a 3.0L case? I just want to know what my options are before I start looking for parts and building this thing

Thanks
Kevin

[SP2]

Hi!
It's in Wayne's book engine rebuild book. Something about bigger P/C's and turning it into a 3.2 short stroke. You can also put in 964 cams. I know that doesn't address the crank.

[Kevins911]

Originally Posted by SP2

Hi!
It's in Wayne's book engine rebuild book. Something about bigger P/C's and turning it into a 3.2 short stroke. You can also put in 964 cams. I know that doesn't address the crank.

Thats the plan, 98mm pistons and cylinders, twin plug crank fire ignition, PMO's or some kind of fuel injection with ITB's, S cams or worse I just don't want to short change myself on the crank, at least I can go with a 3.2 crank and get 3.4L out of it.

Kevin

[JeremyD]

with the right machining on a 3.0 case you can go up to a 3.6 crank and a gt3 oil pump with a little work anyway.

[Gunter]

Originally Posted by Kevins911

Thats the plan, 98mm pistons and cylinders, twin plug crank fire ignition, PMO's or some kind of fuel injection with ITB's, S cams or worse I just don't want to short change myself on the crank, at least I can go with a 3.2 crank and get 3.4L out of it.

Kevin

To make a SS 3.4 you would need 100 mm P/C's and a crank from a 3.2 which means serious machining to accommodate the larger cylinders.
With a SS 3.2 (98 mm P/C's) no machining required but you'll need the crank from a 3.0 (70.4 mm stroke)
I believe you cannot use the 74.4 mm crank from a 3.2 on 98 mm P/C's. ??

[andrew15]

I've got a 3.2 crank if you ned one
AM

[Grady Clay]

Guys,

Let’s be a little more specific.

If we start with a 3.0 911SC (’78-’83) case, what are the options?
What are the modifications to use the later, longer stroke crank? Is it possible? What mods? What with a Turbo 3.3 case or a Carrera 3.0 case?

Lots of unanswered questions here.

Best,
Grady

[Kevins911]

Originally Posted by Gunter

To make a SS 3.4 you would need 100 mm P/C's and a crank from a 3.2 which means serious machining to accommodate the larger cylinders.
With a SS 3.2 (98 mm P/C's) no machining required but you'll need the crank from a 3.0 (70.4 mm stroke)
I believe you cannot use the 74.4 mm crank from a 3.2 on 98 mm P/C's. ??

I believe you can get 98mm pistons for either 22mm 3.0L or 23mm 3.2L wrist pins, if not I'm sure I could get a set made up from JE. Using the 3.2 crank and 98mm pistons yields 3367 cc, basically a 3.4L. 100mm pistons would get me just a touch over 3.5L.

A 3.6L crank has a stroke of 76.4mm, with 98mm pistons that is only 3458cc (3.5L) I am not sure if I want to punch out my case and heads to accept the 100mm pistons and cylinders and make a 3.6, than I might as well find a core 3.6L. But then I start all over again....might as well go to 3.8 lol, that'll be the next build

Someone posted on this thread on the engine rebuild forum that a 3.6 crank fits with no mods, but if I am only using 98mm P/C's the displacement increase is marginal over the 3.2 crank.

The goal is to build a fun reliable engine using as many of the 3.0L parts that I already have, after some research a 3.2 crank and 98mm P/C's I think is the best setup.

Thanks
Kevin

[Kevins911]

Originally Posted by andrew15

I've got a 3.2 crank if you ned one
AM

Hi Andrew, I would be interested in the crank, is standard? Do you have the rods too?

Thanks
Kevin

[JP911]

I went with a 3.2 crank + 100mm P/Cs to get to 3.5. The engine has lots of power, but my one complaint is that it doesn't "rev" as fast as a 3.0 with carbs and headers or a 2.7 with headers. Personally, I find the rev-happy 911 engines to be alot of fun. If I were to do it all over, I would go with a high compression 3.2 short stroke (3.0 crank + 98mm P/Cs).

[Jeff Alton]

my 3.4 (build is detailed in the engine rebuild form) 98mm P/C is very rev happy. Has light weight internals and Ti retainers and mod "S" cams all running through 48mm throttles and headers...... made 285 at the wheels..... amazingly quick throttle response.

Throttle response is more a factor of the intake type than anything.

Cheers

[andrew15]

Hi Kevin - I do have the crank with the rods still on it - I was going to take the rods off and take the crank to my machine shop to make sure it measures out ok.
Regards,
Andrew M