What exactly does it take to install 964 cams into a 3.2
 

I know this is a popular mod and something I'd like to consider. I know better exhaust and a chip would be part of the equation. What mechanically needs to be done? New studs? Valve work? Rocker work? Injectors? Extrude hone intake runners? Enlarged throttle body?

What kind of gains could be expected? All input will be appreciated!

Thanks!

Dean

Dean:

I think the most important point is that it's rather involved to get at and replace the cams. Don't think it would make sense unless you were already having a top end overhaul performed to replace leaky valve guides (which many 3.2 carreras suffer from -- how's your oil consumption?). If you're "in there" for that, it shouldn't be too big of a deal to have your cams re-ground to 964, etc. spec. as part of the top end overhaul.

You wouldn't need to anything else to reap the benefits of the new cams, though a new chip, etc. would likely help too :)

964 cams would be an option when you are looking for a little more breathing while still being able to get it past smog. If you aren't going to smog it then you probably would want to go a bit wilder.

The ends of the cams are different on a 964 from a 3.2. It can be made to work but unless you already have the cams laying around it probably would be a better idea to get a set of 3.2 cams reground.

I really wouldn't think about going with the 964 cams (or others) unless I had changed the P&Cs to a larger displacement and/or put in an aftermarket rod to spin the thing faster. If you pump noticeably more air though the engine through increased RPM and/or increased displacement you will enter the land where a larger throttle body, extrude hone, and a higher CFM air sensor will make a difference.

The big "But" behind this...
When you start to get to this level of modifications you have to ask yourself, "How much $$$ could I have saved by going low pressure turbo?"

Greetings Dean,

Along with installing a new set of camshaft profiles into your engine, upgrading the supporting valvetrain components will greatly benefit your project. Many times factory rocker arms can be worn and will require servicing. Another sometimes forgotten upgrade are performance valve springs. Factory valve springs can weaken over time and will not retain the proper seat pressures to prevent valve float and harmful valvetrain harmonics when upgrading to a more aggressive profile. As far as other head servicing, I recommend a tear down by a reputable shop to inspect condition of valve guides, seals, and valve job.

Other performance modifications such as improved induction or exhaust will also benefit your project. However, horse power number gains can greatly vary depending on the overall health of the current engine and the type of performance parts/services performed.

What are your goals for your project? And please share more about your build.


- Julio A.

I've done 3.2 cams reground to 964 spec. At a minimum you'll want to reface and rebush the rockers so they wear in properly with the cam regrind. This is really a modification that belongs with an engine rebuild in my opinion. I did mine when upping to 3.4.

Overall you breath a little better at the top end with these cams and it smooths out the power curve around 3.5k. Don't expect some massive power gain or seat of the pants rush with this mod.

i'd do 20/21 webcams.

964 grind won't get you much - like John says - 20/21 or 993 ss cams = but then you probably won't pass smog

I had a set of 964 cams installed in my 3.2 but did it as a package with an enlarged TB, SSIs and a SW custom chip. Also the engine had to come out for a clutch anyway.
As a package I'm very happy with the results. My engine is more responsive with better power from low rpm all the way to redline.

Plus one on Webcam 20/21 grind....I also turboed it for good measure. :D

Probably a dumb question but what exactly is meant by the term "20/21 webcam"? I see it all the time and don't know what it means. When I rebuilt my 3.2 I did not change anything but maybe I should have...too late now I guess. Back then though I was too nervous to try anything that was not by the book.

Webcam camshafts, grind # 20/21.

Like mnez mentioned. It is the number dedicated to the grind WebCam offers for a specific specification.

If anyone is in need of further assistance with camshaft reprofiling services or custom camshaft design. Bisimoto is a premier Webcams dealer and have several services available on our web store with cost effective prices. :)

- Julio A.

Hello.

I am in the process of building an SC engine.
Ive installed 3.2 pistons and cylinders with 10.3 compression and carillo rods
Ive also converted the heads to twin spark
This will be fed through a set of new 46mm PMO carbs
Ive also got a nice set of 964 cams but i now see that the original engine oil cooler does not fit.
Whats the solution to this ?

Believe there is a drive gear on the end of one of the camshafts that drives a pump on the 964's. Believe you have to cut this off.

Maybe the issue?

I put a set in my 3.0 build and yes you have to cut a piece off of one of the cams but it was really simple with a cutoff tool.

Other than that just a retiming of the cams and it was ready to go.

I am still in the break-in mode so I can't say if it is really producing more power.

Any pics of how much and where should i cut the cams ?

964 cams......
 

Porsche changed the cam gear design sometime in late 1980 or 81 to the Carrera type gears with bolts. All you should need is a set of the 964 cams. You can reuse the gears and other hardware (bolts, spacers,gears, etc.) from your 3.2 cams.

You cut a single cam.

This link shows a pic of the power steering drive cut off in the first post.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/620769-3-2-top-end-overhaul-success-story.html

Do some searches, you will find info. I am certain the cutting job could also be a grinding job.

You want to know what is involved, here is what I have gone through. I'm doing just that mod.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/819269-3-2l-rebuild-quest-more-power.html

It never ceases to amaze me how one thing turns into man. I started out doing a simple install and it turned out to be a top end rebuild. I have learned so much and given the choice, would do it again but it has at times been very frustrating because of my own hang ups and work schedule getting in the way but all in all it has been a good ride. Budget as much as you can because it will not be enough. There will be times that you get into one thing and see that in order to do that one little item you have to do three other things just to make that one little item right.

Best of luck