3.0 to 3.2 max moritz engine with webers

[oldtimerguru]

hi guys!

my new Project is to convert a 3.0 into an 3.2 Liter max Moritz engine.
i bought some original max Moritz Piston and cylinder.
max Moritz claimed 220 hp with the conversion using their cis.
i am planning to use Ida 40 for that and 964 cams.
anyone has a Suggestion for jetting for the beginning?

tks mike

[DCPorscheFreak]

Hmm, are you using the Webers with 964 cams b/c you have them already?

For those who want to optimize power, I've seen S cams or something hotter (GE) in 3.2 motors w/ carbs. Not that carbs and those cams wouldn't work, but I'm sure others will chime in on the best options.

The CSI w/ 964's is a great option for 2.7's or 3.0's, but with carbs, other cams are typically paired with those for better performance.

Is this for a street car? Track? More info will help.

[hasaramat]

I agree with DCPorsche, S cams or better would give some better power but I think those pistons are wedge shape with no pockets so there could be some clearance issues. I remember a 3.2 big bore motor I built a long time ago with max moritz pistons and stock CIS with SSI's in a 1980 SC. We lost a ring land at an autocross because of lean running. We just couldn't get quite enough fuel into it with the stock fuel injection.

[tom1394racing]

The Max Moritz pistons are designed to work with the CIS system. As such, you have to stick with a CIS compatible cam to avoid piston to valve interference. A better choice would be a set of JE 9.5 CR dome pistons and a more aggressive cam.

That said, the Max Moritz with carbs and 964 cams will work fine and will provide a nice improvement over the stock CIS system.

[oldtimerguru]

hi guys!
thanks for your messages.
the car will be used on the street.
it is an original max Moritz engine which was build usually in werk 1.
they used to upgrade the weak engines with a set of 3,2 Piston made from mahle and a Special cis sytem which was developed by bosch.
in the Porsche 911 Performance book by anderson it is said that it is possible to use the Piston in Connection with the 964 cams without maschining them.
this is the reason why i Chose that cams.
i will also backdate the exhaust with ssi and use a set of weber carbs.
do anyone has a Suggestion for jetting that engine?

thanks very much

mike

[Eli W]

So, carbs will work with Max Moritz but not ideally nor will the 964 cam?

I have a 3.2 that has CIS injection and is twin plug and 964 cam, so if something happened to the CIS I was planning on going PMO.

[Steve@Rennsport]

JMHO,

The MM pistons were designed and intended to provide high compression on single ignition; hence their wedge dome, instead of the swirl-inducing domes found on the CIS-equipped engines. Many CIS systems will not deliver sufficient fuel for safe operation which is why we prefer using the '78-'79 FD's or the Carrera 3.0 ones to start with.

964 and 20/21 cams can be used without piston-to-valve contact, however anything with more lift/duration requires careful measurement and piston modification to work. We have used Mod S cams with these pistons, but we had to machine them to fit.

36mm venturies with 160 MJ & 180 A/C's will get you close. 55 idles and F26 emulsion tubes work fine. You'll need to put this on a dyno to finalize WOT jetting.

[Eli W]

Steve thanks for the info, my problem is I did not do the build so I really do not know what pistons I have. Which sucks.

I guess I could remove the spark plugs and use a video camera to take a look at the top of the pistons to see what I have.

I will just add my car starts very well, turn the key once and it starts instantly, no trouble. Once warm it I have the Idle set to 950 or so, they idle does not seek or vary but it will be consistently high or lower depending on weather which is not unheard of with CIS because of the way it works. And they air fuel ratios are good, or so says my mechanic.