I'm putting in 3.2 Chain tensioners what else should I do while my engines out?????

[matty74]

I'm putting in 3.2 Chain tensioners what else should I do while my engines out?????

2.7L stock with CIS strock exhaust, may upgrade exhaust not sure.

I want to get more power, studs and cases savers alraedy done.

Ad a new camshaft???? but don't want to change from CIS this is quite reliable but I do want more grunt..

any suggestions? money not tight but I don't want a race engine either, I want a hot street motor.

[2.7RACER]

As you probably know already, the CIS found on the 2.7 does not respond well to hot cams. Your current cam runs 224 intake degrees. It is possible to go with a SC grind which would add 10 degrees to the intake cycle without too much impact. The 964 grind offers more intake timing, but I'm not sure if it is the best choice. The other issue is your 2.7 cams are three bearing cams. The SC, Carrera and 964 cams are four bearing cams so aren't usable in your motor unless you replace the cam towers.
John Dougherty is the cam expert on this site. His advice is solid.
You may need to be concerned about emissions, which also limits what you may do with your motor.
Ultimately the CIS was a early response to tightening emission regulations around the world and as such is difficult to hot rod.
I replaced my CIS with Webers last year which allowed me to use Solex cams. The solex cams offer more intake timing while maintaining street drivability. Along with 9.5:1 JE pistons I have gained about 25HP.
Emissions are not an issue in the county where I live.
Bottom line, to get to 3.0 or 3.2 type performance with your 2.7 motor will require you to replace the CIS.

[dd74]

Matty - your signature states you have a Euro spec 911S 2.7. If so, you already have 175 hp engine. That's five hp shy of a 3.0, and probably performs on par if not better than a slower-winding 3.0.

If you have a '74, then you have the good exhaust on your engine, so I wouldn't mess with that.

What 2.7 Racer says is true: the best you can do from this point is tear apart the engine, install higher comp. pistons, hotter cams and Webers.

You should near 220 hp with those modifications - but it's gonna' cost ya...

[matty74]

Thanks Guys, very helpful. I'm also looking at changing my gearbox.

I have a 4 speed but want to go to a 915 box, there are some close ratio gears you can put in these boxes, what the story with that?

I hear that this moification can give the perception of 30% more power?

[Porsche84]

I would recommend replacing the O ring on the thermostat as well as replacing the oil pressure switch (the small one for about 10 bucks). These will avoid messy oil leaks which are very difficult to fix with the engine in the car.

I have a file with many 915 gear set options and some misc gear data I have gathered for 915 transmissions. Send your e-mail address and I'll send you the file (it is EXCEL format).

[matty74]

That would be great

matt@sourcee.com.au

[Porsche84]

sent you the file

[matty74]

Thanks dude thats awsome

[Henry Schmidt]

Originally posted by matty74
..........I'm also looking at changing my gearbox.
I have a 4 speed but want to go to a 915 box, there are some close ratio gears you can put in these boxes, what the story with that?............

For about $1,600 we can rebuild your box and change it to a 5 speed.
Email me and we'll talk.

[aigel]

RSR seals on the rocker arm shafts comes to mind! That won't make it any faster, but will help prevent future leaks.

George

[Henry Schmidt]

Proper installation of rocker shafts and cam towers without damage and RSR shaft seals are not ever necessary.
We have never used them in a street engine and we guarantee our engines won't leak.

Inspect the cam towers and polish the shafts. Position the shafts properly and torque to spec. No leaks. .

[aigel]

RSR seals are a belt and suspenders thing. It's only a few bucks and 3 ounces of weight! Wayne is a big fan of them. Must be because he sells them eh?

Along the same lines, you can limit travel of the carrera tensioners. Here is a link to the procedure:

Shops that don't recommend Carrera Tensioner Update?

I have written a more extended tech article about the procedure and submitted it to PP but nobody got around to posting it yet.

George