choosing between 3.0 w/ 3.2 p/c or 3.2 carrera

nikramos · 06-06-2002, 03:44 PM

I have a 69 turbo look that is now in a shop in Orange County, So. Cal. needing a new engine. I am given a choice of 3.0 w/ 3.2 p/c , S cams and webers or a 3.2 carrera stock w/ webers. I have the ssi and the sport mufflers already. the price is about the same. He will rebuild both of them. I am leaning on the carrera engine. I have read the previous post but I am still in need of all your expert advise...thanks for any replies

Superman · 06-06-2002, 03:54 PM

As much as I would like to try an SC engine (3.0) with the 3.2 P&Cs, I suspect the Carrera engine might be a slightly better choise (maybe), assuming that the wimpy rod bolt issue can be addressed in the rebuild. Personally, I would consider the smaller, weaker rod bolts on the 3.2 engines to be the main reason for hesitation on the 3.2. They also had some poor valve guides, but those would surely be replaced in a rebuild. I would assume. I would insist.

speeder · speeder's Garage

Funny, but I was just thinking about 3.2's myself today. Can't the rod bolts just be replaced w/ race-quality bolts and that's the end of it? Also does the 3.2 snap head studs like the 3.0? Valve guide issue does not scare me since I would assume that I would be going through any 100+k miles motor that I bought anyways.

Other than those questions, the 3.2 is clearly a better motor; it has all of the other 3.0 strong points, ie. same case, most internals, with motec vs. CSI and all of other upgrades that happened in those years. BTW, any pros out there can you give any first-hand accounts of 3.2 rod bolts failing in street-use? TIA.

CamB · CamB's Garage

I disagree - I think the short stroke 3.2 will be more fun and probably make slightly more power. It should sound better and have better throttle response, and be revvier.

It will also use a lot more fuel. And it would need to have a bunch of stuff optimised to work together (eg matching carbs to cams to ports to distributor timing...)

What use will you generally have the car for?? Which 3.2 pistons and cylinders for the SC?

emcon5 · emcon5's Garage

For me, this is a no brainer.

Quoting Bruce Anderson:

"For even more horsepower fun, the Max Moritz pistons can be combined with a carburation change, exhaust system backdating, and a mild cam, like a GE40 or a 911 S cam, for a truly wonderfull power increase"

Tom

Rich L · 06-06-2002, 06:20 PM

Without the CIS, I like the short stroke 3.2 as well. The combo of GE40 or GE80 cams with Weber 46IDAs makes a very quick car. And then you could twin plug...

nikramos · 06-06-2002, 06:22 PM

thanks for recent replies, the car will just be street driven. I will ask my mechanic what type of p/c he is going to install. The fun to drive factor is definitely what I wanted to hear.....

emcon5 · emcon5's Garage

Also, for me "69" and "Turbo look" just don't add up.

Dump the Turbo tail, stick a standard lid on it and call it a 911ST , or a ducktail and call it a RSR

Tom

CamB · CamB's Garage

Just so you know why I asked - Mahle P&C are generally viewed as better. JE are viewed as ok (with bored and sleeved cylinders, I think). Others are not so well regarded.

And the compression ratio and shape of pistons is important. There are pistons which have a deeper valve pocket and can take cams up to RSR (see www.andial.com for more details). These are better...

Lastly, check compression ratio.

Wayne 962 · Wayne 962's Garage

JE and Mahle are both good quality choices on pistons. I don't distinguish a quality difference between them...

So you have a short stroke 3.2 versus a stock 3.2 with carbs. Without rebuilding, I would take the short stroke 3.2. Why? Because the 'S' cams will give you much, much better response with the carbs than the Motronic cams. Just placing Webers on a 3.2 without any other modifications will yield a decrease in performance - the Motronic is a really, really good system for that engine.

Now, on the other hand, if you're rebuilding the 3.2, then you can have the cams reground to 'S' spec. Of course, then you will have to replace the pistons, as the Motronic pistons will not work (will not physically fit) with those cams.

So, all things equal, I would go with the short stroke 3.2 (higher reving quick engine) over the stock 3.2 with Webers. However, if you're tearing them apart, I would go with the 3.2 and JE pistons and a GE or 'S' cam.

As for the statement that the 3.2 is much better than the 3.0, that's a bit of hogwash, as these engines are very, very similar. For all practical purposes, there isn't any real differences between the two...

-Wayne

nikramos · 06-06-2002, 07:40 PM

Tom, that is my next project, I like the ST look. I actually saw a 72 that has a wider front pre-impact bumpers but has the turbo flares w/ the tail at the back, like the picture of the P.O.C. ad in Excellence(gt3 no. 21) sans the gt3 tail though. I'll stop by at A.I.R. when I go down to So. cal next week.

Chuck Moreland · 06-06-2002, 07:44 PM

What about the heads? My understanding is the '78, '79 heads are better than the later SC heads. And that the Carrera heads are the best of all.

CamB · CamB's Garage

Oooops, I didn't read carefully that the Carrera engine would have carbs. Ignore my comment about fuel usage (they will both be crap). Definitely go for the short stroke 3.0/3.2 unless, as Wayne says, you can use new pistons in the Carrera and it can also have S cams.

On that note, the Carrera with suitable 98mm P&C could be a 3.4... (the increase in capacity from SC to Carrera was due to a longer stroke).

Wayne, my comment on JE vs Mahle is based specifically on being told (by someone who has used both) that JEs expand more when hot, so need a greater cold clearance (and are therefore noisier than Mahle when the engine is cold). I don't really know if there are actual quality issues (rather than refinement).

Superman · 06-06-2002, 08:29 PM

John Walker told a story of combining the early SC heads and intake with larger intake ports and different fuel distributor, etc., with later SC pistons (9.3:1 CR) for a 3-liter that made enough power to impress John. I'll bet it is a healthy engine. Combine the early heads with the Max Moritz 98mm P&Cs and carbs, and You'd have your hands full.

And yes, race-quality rod bolts would solve the problem on 3.2 engines. I guess the 3.2 heads are different, and better according to Wayne. The 3.2 crank is a longer stroke. As loyal as I am to the 3-liter, I don't think a 3.2 upgraded to 3.4 with S-cams would be a lesser engine than the 3-liter, even upgraded to 3.2. Am I missing something?

CamB · CamB's Garage

The 3.4 was me spending extra money for nikramos. I don't think it is on offer

RLJ · RLJ's Garage

Here are some basic thoughs on 3.2 motors, Carrera or short stroke. The long stroke 3.2 Carrera motor set up with the same cams, induction and exhaust as a short stroke motor will make more torque, the short stroke motor will rev much quicker.

I like the short stoke configuration with Carreara heads, good rod bolts, a light weight flywheel, short gears, light weight early car sounds like an R Gruppe ad!

Randy Jones
1971 911

Don Wohlfarth · 06-07-2002, 05:44 AM

Something doesn't sound right.
A 3.0 w/3.2 p & c versus a 3.2 motor, both motors rebuilt and running carbs, and the price is close to the same.
I recently purchased the Moritz 98mm p & c from Andial for $3600 to rebuild my 3.0 to a 3.2 short stroke. The main difference between the the 2 motors is the 3.2 Carrera has a longer stroke.
Putting the 98's on the 3.2 Carrera motor would give you a 3.4.
The labor to rebuild either motor should be the same with the only price difference being the cams in the Carrera motor and the difference between the 2 core motors.
Since this is basically a street motor and is not being built to fit a specific class I would go for the 3.4.