79 911SC - 3.2ss or 3.4ls?

[craig.wilson1]

I'm considering an engine upgrade and was hoping to get some feedback and costs on the 3.2 vs. 3.4 upgrade. It is a stock engine with the trombone oil cooler. I use the car for street only and would like to keep the CIS. Based on what I've read so far, I'll need the following:

3.2ss:
Upgraded oil cooler
SSI HX's/Dansk 2/1 muffler
98mm p&c
Any machine shop work?

3.4ls:
Above plus
3.2 crank and connecting rods

Options:
upsize valves
twin plugs

Any advice would be appreciated.

[Roger 911]

I'm assuming you are familiar with the costs associated with rebuilding a 911 motor. Have you considered swapping the motor for a 3.2, or even a 3.6?

Just a thought.

Roger

[spsfiend]

From what I have read, SSIs are not really good for a 3.2 ltr and up application as the diameter are too small and restrict power above something like 5500RPM.

Headers with 1 5/8" diameter I believe would be what you should look into for a 3.2 - 3.4 ltr application.

[craig.wilson1]

Again, from what I've seen from other posts, the 3.6l swap looks like it would be in the $15K range where a 3.4lss conversion might be <$10K and 3.2ss <$5K?. Are these figures close?

[Roger 911]

Originally Posted by craig.wilson1

Again, from what I've seen from other posts, the 3.6l swap looks like it would be in the $15K range where a 3.4lss conversion might be <$10K and 3.2ss <$5K?. Are these figures close?

The big question is how much of the work can you do yourself? Either way, a swap will still probably wind up being cheaper, assuming you sell the 3.0. You should be able to pick up a nice 3.6 for $7-8K. You can probably sell the 3.0 for $3-4K (depending on mileage and condition). So you're talking net cost around $3-4K.

If you rebuild, the P&Cs alone will probably run $3K. Then you still have to do some machining and other basic prep. I would guess that you are talking $6K, if you assemble it yourself. $10-12K if you pay someone else. The upside is that you have a new motor. But it won't be as fast, or tractable as a 3.6 Motronic.

I just did a 3.2 conversion in my '72 for about $2.5K net. I love it. It made the car better in every area of performance, including drive-ability and fuel economy.

Roger

[craig.wilson1]

So, not sure if I'm going to go the 3.4l conversion or 3.6 swap route. Regardless of which way I go, I assume I'll need to upgrade the existing trombone oil cooler. Does the "late Carrera" front fender mounted oil cooler have enough cooling capacity for either option?

[otto in norway]

Yes it has. The oil cooler in front only gets used when the engine oil reaches about 85 C. It is mostly needed for track days and really hot days.

Take a look at my garage. I did the 3.4 Conversion using a 3.2 engine for a base. But it does not come cheap. I did all mechanical tear down and assembly myself. (Of course, I could have stayed Clear of the PMO and hot cam, but once I started that path, i thought I'd get the most of it...

It's probably cheaper to buy a 3.6.
You should talk to steve weiner. He knows a thing or two about this, and is familiar the costs for the different tasks and parts. He made my P/C set for my 3.4 engine.

[TibetanT]

Craig:

First and foremost, I am no expert on this but I too am considering some tweaking to an early 911SC 78 motor.

My plan, currently since I have a 1978 911SC 3.0L engine available is to use the crank, rods, and heads from the 78 MY. Then, add a set of 9.3/1 CR pistons from the 83MY with my current cam reground to the 964 profile.

Apparently this can be a cheaper route to go, for me, but thought I would throw it out since you have the same type of 3.0L engine. Of course, my plan doesn't come near the capacity you are looking to obtain.

[Dave Kost]

Just bought a 1980 sc with a built up motor. Documents say, it has 98mm Mahles with JE pistons, 964 cams B&B heat exchangers and B&B 2 in and one out muffler. Kept the 1980 small port heads and CIS. IT IS A BLAST TO DRIVE! Its peppier that my stock 89 Carrera.

Nice thing about this is the you can later go with bigger heads and carbs or EFI etc , that should jut bolt right up.

Just my $.02......

[Number1_dog]

I am running on my 1979 911SC with CIS: 98mm P&C 9.3 compression, light weight flywheel,964 cam grind, SSI, M&K 2in 2 out with Harley Davidson 2 inch Drag pipe baffles. It is a torque monster, in auto cross I shift to 2nd and it is always pulling.
I built the engine my self, and got the P&C from here for $1,500. It probably makes at the crank 200hp up from the 180 that was stock.