Wanna build a ss 3.2?
 

If your 3.0 needs a rebuild, consider this:

http://forums.pelicanparts.com/porsche-911-technical-forum/336713-3-2-short-stroke-observations-building-starting.html

If you have a '78-'79, it'll be less costly because you already have the bigger intake and the heads don't need to be ported.

An extra 50 horses, even with CIS, is pretty good.

This engine wants to rev. :D

Here is another option.

3.2 SS twin plug MFI. 320 hp on street gas

10.5:1 JE
DC62 cams
Knife edged crank
ARP rod bolts
Supertec head studs
40 mm intake ports
40 x 41.5 throttle housings
41.5 x 52 stacks
PMO air filters
Supertec distributor (BurnBros parts)
Kennedy high torque clutch
Supertec enrichment device
Supertec valve springs
Aasco titanium retainers
930 turbo oil pump
Supertec sump cover
Supertec fuel lines
and on and on and on
http://forums.pelicanparts.com/uploa...1177866684.jpg http://forums.pelicanparts.com/uploa...1177866709.jpg

Very, very nice but..........
My poor-man"s ss 3.2 keeping CIS, 964 cams, was about $8000 DIY.
That's close to what a normal 3.0 rebuild would cost.
It's just a suggestion for people that face a rebuild and consider cost.

Now, with the beautiful Schmidt-Rocket, we are probably closer to $20,000.- for this engine?

Henry, just a question about the build of the 3.2SS MFI...you spec'd a knife edged crankshaft. I have read and agree with your opinion that boattailing doesn't do anything meaningful so I was surprised to see that you had done the knife edging, which to me would be an even smaller benefit on a street engine...

Is knife edging a crank a worthwhile thing to do? Is there a material horsepower benefit and if so is it on the order of what boattailing does or is there something else?

Dennis

There is no real benefit in knife edging a crank on a low RPM street engine.
The benefit from knife edging the crank is not less rotating resistance as engine builders of American V8s can quantify.
The benefit in this type of engine is simply a reduction in rotating mass. Simply put, knife edging lightened the crank which reduces crank twist at higher RPMs and assists in acceleration.
It is easier to accelerate a lighter rotating mass similar to the benefits of a lightened flywheel.

We are working on new flywheels and front pulleys that will also help to reduce crank twist and acceleration.

Note the small diameter on the second pulley. This is an attempt to slow the fan and reduce the horse power loss from rotating the fan at a higher RPM than necessary for proper cooling.
These are small changes but we have seen horse power and reliability increases.

http://forums.pelicanparts.com/uploa...1177897844.jpg
http://forums.pelicanparts.com/uploa...1177897923.jpg http://forums.pelicanparts.com/uploa...1177897941.jpg http://forums.pelicanparts.com/uploa...1177898011.jpg

Re: Wanna build a ss 3.2?
 

So do you think you have around 230hp???

Re: Re: Wanna build a ss 3.2?
 

For sure.
But only with 98mm P/C's 9.8 : 1 CR, 964-cams, SSI's, Flow-thru muffler and the early CIS with larger intakes.

Building the classic ss 3.2 makes only sense if a 3.0 needs rebuilding anyway or, if one feels doing it just as a challenge.

Keeping an eye on cost is a factor. :) If you want to spend more than $8k, you have many, many options but, if you are happy with 220-230 HP, and need a rebuild anyway, consider it.

I can tell you that the 964-cam comes in strong at 4000 RPM; it feels like an after-burner kicking in.

It is a pleasant surprise. :D

Do you think you would get the same or more horse if you ran carbs instead of running the 3.2ss. Essentially having a 9.8:1, 3.0, 's' cam, SSI's, and a set of 40 pmo carbs?

I am going to do a top end rebuild soon on a '81 3.0, going into a pre-smog car. I bought the motor and it had broken head studs, so the top end is coming off anyways...

That sounds reasonable.
A lot depends on your P/C's.
You'll find out when you replace the studs if you have Mahle or KS?
If you find Alusil, you migh as well go with new 98mm P/C's.
It sounds like you don't want to split the case?
Just putting carbs on a used engine with unknown mileage is risky IMHO.
Unless it's a Euro '81, the intake on the heads are 34.5 mm.
Would the 40's fit on the heads without porting?

For the S-cam, you'll probably need stronger springs and grind the rocker arms?

The motor you're describing is basically very similar to a 3.0RS which put out 230 HP @ 6200 RPM according to factory specs. You'd be using carbs instead of MFI though.

You would have to change your pistons though because you can't use CIS pistons with S cams.

The motor would be different in charachter to the 3.2 CIS motor. The 3.2 CIS would be more street/autocross friendly compared to the S cam 3.0. The S cam 3.0, on the other hand, would be a bit more track friendly. (Of course, if you have racing in mind, the class you choose will be your determining factor)

Basically the 3.2 CIS will have more low end torque and the 3.0 S cam will have better upper range torque.

The 3.2 CIS will have better cold/warm-up manners and should also give you better gas mileage. Ease of maintenence will be a big plus as well.

The 3.0 S cam, however, will sound like a mechanical symphony when it hits 6000 RPM.

Apples and oranges. Both tasty treats.

I figured out what SS means... Short Stroke.

What if I was shooting for max torque on my stock 3.2?

I am reading Bruce Anderson's performance handbook. I have a stock 3.2 Carrera 1985. Thinking about 98mm P&Cs with a GE40 cam to get 3.4 for street use and AX. BA descibes this as a bolt on. If I opened the motor to change cams and P&C, would I have to change springs, rod bolts etc? Would that be a humongous can of worms?

Also, with motronic, what are my options for larger throttle bodies? Am I even asking the right questions?

I start out with 207HP? Cat bypass, free flow exhaust, Steve Wong chip, and now I may be at 220? How do I get to 270?

Thanks for your thoughts.. I am willing to read every thread on the forum from start to finish to educate myself. I have read BA from cover-to-cover three times.

Reeeeeeallly! :)

EVERY time the factory rod bolts are loosened, they must be replaced. For a 3,2, rod bolts are a recommended upgrade to ARP.

You can replace pistons and cams without opening the case, but if your motor has alot of miles on it, the rods will need to be re-sized.

In wayne's rebuild book there is a 3.7 cis motor that has 280-300hp, with CIS and 10:1 compression. It uses a 3.2 crank, 104mm pistons and twin plug heads.

You can get alot more horse by ditching the CIS...

Jeffrey,
98mm P&Cs & a corresponding head chamfer will give you a nice 3.4. If you want to keep Motronic, I would recommend the 20/21 cams. You can't use hotter (such as GE40) cams with Motronic; this would necessitate a conversion to carbs or individual throttle body FI.

Anytime you take apart stock factory bolts, you need to replace them. On a 3.2, it's a very good idea to use ARP rod bolts. I never use factory 9mm rod bolts in a 3.2.

Motronic with the stock throttle body works quite well on 3.2's and 3.4's. You could bore out the throttle body to a larger size, though. As far as exhaust, you may need to investigate smog regulations where you live, but the best exhaust is a header-type "equal length" setup w/o a cat. On a 3.4, a "free-flow exhaust" would be something like 1-5/8" headers or 993 heat exchangers. Another thing to think about is twin-plugging the heads.

All-in-all, to go from an old 3.2 to a fresh 3.4 twin-plug with exhaust, cams, Steve W chip and high compression (~10:1), it's probably right in the ballpark of $10k. Twin-plugging is about $1500 extra over single-plug (highly recommended when doing a 98mm and larger bore), and 98mm P&C are around $2,000. This motor can pretty easily push 270+ hp, using Motronic which is easy to live with. A hot 3.4 with carbs and a gnarly cam, for example, might make about ~330+ hp.

If he has a good bottom end, is it neccesary to open up the case?

Is there anyway to check if your rods are stretched w/o opening the case?

Great stuff but...................

You are leading this post in a different direction.

My intent in posting details on a classic ss 3.2 was to help someone who is facing a rebuild on a 3.0 with CIS and is considering an extra 50 horses without spending a fortune.

I think you should start a different thread to deal with upgrading a Motronic 3.2.

It's a different animal.

Friendly greetings. :)

Although a great number of engine builders (some good) will replace rod bearings without splitting the case, I will not.
I always want to spin the rod all the way around a crank after I install it.
It just makes me feel better to know that what I have assembled feels good. I can't count the number of times I have install a rod on a crank and had a tight spot half way around. It is very common for a rod journal to measure out of round in a good running engine.

The cost to split the case is so little by the time you have the rods off that measuring and polishing the crank seems like a no brainer.

Gunter:

This looks like exactly what I want to do with my 3.0. I have a 1979 SC with head stud problems. Given that I likely have Alusial Cylinders, this seemed like a no brainer to me - replace the P&C with a 98mm set to bump displacement. Isn't this very similar to the period Works 1 / Max Moritz bump that some owners did right out of the factory?

Did you run into any issues with fuel delivery? The builders I have spoken to all want to replace the CIS with PMOs. When I suggest staying with the CIS they are concerned that the result will be starved for fuel. What changes made this a non-issue?

Thanks,

Ed

Control is an illusion.
Posts have their own life and go in the direction of least resistance.
Resistance is futile.:)

We appreciate your intention but I would question your assertion that the engine you describe actually makes 50 additional horse power. Perhaps a dyno sheet is in the future?

Gunter, a 3.2 can just be another starting point. Maybe it's not a 3.2 Short Stroke, but who cares? Your point was about adding "98mm P/C's 9.8 : 1 CR, 964-cams, SSI's, Flow-thru muffler" which are all retrofittable to a 3.2. I've rebuilt 3.0s and 3.2s. Guess what, they both cost virtually the same amount of money to rebuild. Different animal, maybe, but still relevant. Did you twin-plug your heads when you built your 3.2SS? I would be a bit worried about 9.8:1 on single plugs w/ 98mm pistons.....sounds like a recipe for detonation.

Cheers SmileWavy

Scott