Thanks for sharing, will read your thread later. What comp ratio are you running?

JE pistons CR 9.5:1, they measured exact as advertised.

I know of a few people who did the 3.4 upsize on their Carrera 3.2 and were disappointed in the power gains. Had they do it over again, they say they would have just done the 3.2 high compression Euro pistons. I think that disappointment has a lot to do with using mild cams and Mahle swirl dome pistons. Had they used more aggressive cams and JE or CP Carrillo domed pistons, maybe they'd have seen bigger gains in their 3.4

The 3.0 crank & rods is a good combination. I would stick with those and get your 3.2SS with the 98mm pistons & cylinders. CP Carrillo makes a very nice 98mm 10.5 compression piston for the SC crank & rods. It's kit part number XP5003 http://forums.pelicanparts.com/911-engine-rebuilding-forum/877614-3-2ss-mfi-twinplug-another-one.html

Regarding oil pumps, for street use and even racing use the SC pump is fine. If you could find a Carrera 3.2 pump for a nice price, that'd be better simply because it has the built in pickup tube strainer. As these cars are getting older, we're starting to see some of the SC strainers fail. With the Carrera pump, you do away with the separate strainer.

But if you're wanting for a replacement pump with more volume, a good used 964 pump is a great value. Just be sure to use the oil pressure relief spring shim/spacer shown in the parts diagrams.

looking forward to reading more about your build.

I went the 3.2ss route and here is my build thread
http://forums.pelicanparts.com/911-engine-rebuilding-forum/901641-3-2ss-78sc.html

I'm a first timer at this, but would love to answer any questions best I can if you have any!

Thanks again. The 74.4mm crank is expensive. Otherwise it's a no brainer with a 7k rpm limit I reckon. Going from 3.0 to 3.4 with all the right supporting modifications would surely offer an advantage over 3.0. That said I had advice from an engine builder yesterday saying what you have said, but in the end his comments were driven by additional cost vs benefit. I think 3.2SS will offer best bang for buck, and especially if the CIS is kept, but whether that's what I want is another matter. I'll keep an open mind about this choice.

I note your comments re the piston choices and have 10.5 in either JE or CP upper most in my mind. I'll check out your link.

All builders are advocating for a camshaft change which seems right.

None of them are mentioning an oil pump upgrade as necessary but some say they do some small modifications to them. My be taking some sharp edges off or modifying the strainer so it's more reliable? I'll look further into this.

Really appreciate your advice and input.

Ha! I've read your thread a couple of times now and will keep an eye on it. I'm interested to know how happy you end up with it once back together again, and particularly with the PMOs as yesterday the same engine builder I've mentioned above said they're horrible on the street and only like being at WOT and are hard to start, don't like being cold etc. Cheers.

The 3.0L SC crank is expensive too. So if you really wanted more displacement, I think you could sell your SC crank and rods and not have to spend a ton more money to source a good STD/STD 74.4 crank and rods. FYI the crank from a 3.2L Carrera or a 3.3L 930 is the same, as are the rods. So that widens your pool of potential cranks. Just be sure to use improved rod bolts in the 3.2/3.3 rods such as ARP, since those rods use a lower strength rod bolt than was used for the 3.0L. The 3.2/3.3 rods carry a 9mm diameter bolt and the 3.0 uses a 10mm diameter.

So going from 3.2SS to a 3.4 is simply a matter of changing your crank and rods. The pistons you buy will simply be complementary to whatever crank you have and there's no cost difference there. In other words, 98mm pistons for the Carrera are the same cost as the 98mm pistons for the SC. Just note that they must match because the wrist pin diameter and pin height in the piston are different between the Carrera and SC.

Ideally you'd like to have a set of Carrera heads for the 3.4 but they're certainly not mandatory. The '78-'79 "large port" 3.0L SC heads are fine.

Regarding the pistons, i've gathered from a few of the regular engine builders here that they find the CP pistons to be a bit better than the JE. I believe the CP come standard with a very nice forging that is similar to the more/added expensive JE piston's FSR design (FSR= Forged Side Relief). So it would appear that you get a more elegant piston from CP without the added cost.

The original oil pump is very good. Like I said the only downside I see to the SC pump is its multi-piece venturi tube and strainer. The later style pumps have a built in strainer. This is a plus because i've seen the separate strainers starting to fail with age.

Nothing wrong with opening the pump to clean up some sharp edges. It's easy to do. Just make sure upon disassembly to keep the gerotors/gears matched to how they are originally assembled, to keep the teeth meshing the same as they always have.

You definitely have to change your routine in terms of startup with carbs. There's a reason cars that were originally equipped with them have a choke system. Whereas with the PMOs you're just on your own to bring them to life when you fire up the engine cold. Takes a few pumps of the gas pedal to squirt some fuel into the ports to start the fire. Then, depending on how you've got the idle set, you have to wait a little bit to warm the engine & keep it running. Many people increase the idle speed by turning in the stop screws and therefore the engine will run on it's own right away (with no gas pedal input from you) and that obviously increases your idle rpms. That's technically not actual idling. Because when you turn in the stop screws, you're cracking open the throttle plates a little bit. Which is the same as depressing the throttle pedal a little bit to increase engine speed.

OK that's great. Everything you've said above is consistent with what I've come to believe from other conversations I'm having. The 74.4mm crank and rods is just a matter of me figuring out how much extra power I want and am prepared to pay for. I'm not sure I could sell my 3.0 bottom end as it came with the car but in reality is will just sit in a cupboard and rust if I don't...

Yes, CPs seem to be in favour and yes the JE FSR also look like a good option but I'll leave that choice with the builder as long as they can properly explain their decision to me.

Carbs is a big one. They're an unknown to me, expensive, and people seem to have quite divided opinions on their merit so far as performance gains, and practicality are concerned. On the other side of the fence there are also divided opinions on keeping the CIS and being able to adapt it enough to make the most of your new hardware.

I'm getting a ride on a freshly built 3.2SS with CIS and a cam upgrade this Sunday so it'll be interesting to see what that's like.

Cheers.

Hi I have a 1981 SC. Just getting it out of the paint shop. So I'm watching this thread and dancing around the rabbit hole. Will you please send me the same build costs and info?

I was planning to leave the CIS, because I didn't want to have to hassle with carbs and I also thought the CIS is pretty darn good. I was leaning toward 964 cam's and leaving the CIS. However the carbs look so darn good! Do you have to adjust them a lot? I'm in Colorado, so I can easily have 5,000' elevation changes in a drive.

Also where do I find Fred's build and the build comparison?

http://forums.pelicanparts.com/uploa...1474685203.jpg

A few things of note
LN cylinders are not forged or billet, they are custom high density extrusions from Alcoa.

As the LN cylinders are machined they have more rows of fins, thus they have a larger cooling surface. Mahle cylinders are spun cast.

The material used in Nickies is very close to the same expansion rates as the material used in JE pistons, thus they run tighter cold tolerances than a JE piston in a mahle cylinder.
Mahle pistons in mahle cylinders have very tight tolerances.

In my 1967 VW bug with a type 4, 914 base engine I am running 102mm LN Nickies with JE pistons and ARP headstuds.
2.6 litre, 180hp, single plug, 9.2:1 CR on pump super. My summer daily driver, about 20,000KM on the engine. Wicked fast :D
My 914 has a 1979 SC 3.0 engine and I'm using Mahle cylinders and 95mm Mahle RSR style pistons and Supertec studs. Twin plug 10:1 CR, haven't finished the car yet.