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Posted by: Catorse Oct 2 2016, 03:16 PM

So here's the deal:

- built 2.7 with Webers. All the tricks possible on this motor
- rebuilt trans
- new flywheel (not resurfaced!)
- new 914 clutch
- New TOB
- new clutch cable

Cable is adjusted so that engagement point is as close to the floor as possible. When I go above 4000 RPM, I get some serious clutch slip. So bad I can't really climb higher, although the car has a 7K limit.

I'm thinking the stock 914 clutch can't hold it, even though it is a brand new clutch. Any ideas here?

I do not believe it is making enough power to overwhelm the stock clutch, unless the stock clutch is super weak.

Posted by: Steve Oct 2 2016, 03:21 PM

I ran a 2.7 with webers, headers,etc. and had no problems with the 215mm 2.0 flywheel and 2.0 clutch. Maybe you got some bad parts or got oil on the disk. I put over 100k on that clutch, up and down hills, drag racing other porsches, etc.

Posted by: Catorse Oct 2 2016, 03:26 PM

That's what I needed to hear, Steve. I wonder if there is oil or something on it. I seem to recall a slight fluid spill on the bottom of the bellhousing. Wonder if it slung it all over the place.

Posted by: wndsnd Oct 2 2016, 03:30 PM

Or the clutch is fine and you are spinning the wheels!

Posted by: Catorse Oct 2 2016, 03:40 PM

Naw, got super stick Nitto Nt01, also new. No way they are spinning.

Posted by: r_towle Oct 2 2016, 04:21 PM

Is the pressure plate new?
Has the flywheel ever been resurfaced?

You can get pressure plates with more force if required, racing applications.

Posted by: Catorse Oct 2 2016, 04:27 PM

Brand new flywheel, brand new pressure plate. I am starting to lean towards the oil on clutch theory. I recall spilling some swepco by the bell housing, not sure how much it takes to contaminate the disc but I am guessing not much.

Posted by: rgalla9146 Oct 2 2016, 05:33 PM

"The clutch is adjusted so engagement point is as close to the floor as possible"
Correct clutch adjustment has nothing to do with "from the floor"
Free pedal movement from the pedal top stop to resistance is the conventional measure
of clutch adjustment.

Posted by: Steve Oct 2 2016, 05:42 PM

I always did the infamous 1/2" free play, pulling the clutch pedal to you versus where it rests.
I never heard of the push to the floor method. There needs to be around 1/2" free play in the cable.

Posted by: r_towle Oct 2 2016, 05:48 PM

Could be a bad pressure plate too, unless you poured lots of oil on the dick

Posted by: db9146 Oct 2 2016, 08:02 PM

Kennedy Engineering has a 228mm set-up that they recommend for a warmed over 2.7 mated to a 901. I just went through this getting ready for my swap this fall.

Posted by: SirAndy Oct 2 2016, 09:13 PM

Get the Kennedy Stage II and never look back. It'll be perfect for your 2.7L ...

Posted by: shoguneagle Oct 2 2016, 09:16 PM

I have a Stage 1 228mm clutch plate and pressure plate holding behind a 3.2 conversion. The clutch is doing very well holding all the power to a 901 transmission. Not having any trouble with the clutch whether cable or a recently installed hydraulic one.

I would work from the theory of the clutch and the pressure plate and what is needed to hold your engine's power.

Posted by: Catorse Oct 2 2016, 09:38 PM

In any case looks like the trans is coming off to have a look inside. Has to be something...this thing makes MAYBE 230hp. I doubt that would totally overwhelm a stock 914 clutch

Posted by: cali914 Oct 2 2016, 09:41 PM

ditto

Posted by: Catorse Oct 2 2016, 10:03 PM

So to all you guys recommending the Kennedy, do you really think I have too much motor for my clutch?

Posted by: Steve Oct 2 2016, 11:34 PM

I didn't need it. My motor was a fresh 911s 2.7 with webers and headers.
I would make sure you have 1/2" free play first before pulling it apart.

Posted by: sixnotfour Oct 3 2016, 02:24 AM

adjust your clutch

Posted by: Mark Henry Oct 3 2016, 08:42 AM

I know it's not a /6, but my type 4 in a bug is 180hp with 20,000km, I can feel a hair of slip if really honk on it. I also undercut my PP by .010" to give a bit more pressure.

I'd say that 180hp is about the threshold of the 215mm PP.

Posted by: bdstone914 Oct 3 2016, 09:58 AM

Ahhh.... I think you meant DISK not DICK right?

Posted by: Catorse Oct 3 2016, 09:58 AM

OK, so basically this means 1" of pedal travel before the clutch engages? Is that what we are talking about here, because that is what it is set at currently.

Posted by: Mark Henry Oct 3 2016, 10:12 AM

More like 3/4" but at 1" it shouldn't make a difference. Unless it's somehow getting hung up I don't think that's your issue.

Posted by: sixnotfour Oct 3 2016, 11:30 AM

Slits says,

Posted by: Catorse Oct 3 2016, 12:34 PM

Sweet, thanks for that. Will double check.

Posted by: flyer86d Oct 3 2016, 03:47 PM

Reread Rory's response. His is the correct explaination of free play...

Charlie

Posted by: brant Oct 3 2016, 03:49 PM

Yes the free play is loose pedal from the top (when the pedal is at rest). Not from the floor/bottom

Posted by: rgalla9146 Oct 3 2016, 09:08 PM

Start your diagnosis with a proper clutch adjustment.
You may have a problem with parts or something else but you can't know until the clutch is adjusted.

Posted by: porschetub Oct 4 2016, 12:35 AM

Wouldn't want your dick stuck in all that motion .
You should be fine with your set up,have you replaced all the consumable parts that go with the install,new release bearing slider pieces,clutch release arm ball cup for examples.
Just got my car running recently and driving today ,replaced all parts in the clutch system and it all works great all 215 mm parts new pressure plate and clutch disk and excellent used flywheel from 914ltd.
A leaking RMS will not get to your clutch so you need to look further,honestly something else is wrong,good luck.

Posted by: The Cabinetmaker Oct 4 2016, 02:49 PM

Don't want to read you wrong. Are you asking if the clutch should engage 1" from when you push on the pedal?

Posted by: SirAndy Oct 4 2016, 03:24 PM

I'm no clutch expert, but wouldn't that be the clutch dis-engaging?

Posted by: Steve Oct 4 2016, 03:27 PM

It's also obvious by moving the clutch fork at the tranny. You should be able to move it back and forth a bit, before it makes the throw out bearing engage the pressure plate. If there is no free play, it could exhibit the symptom you are running into. Like I said I ran the same configuration from 1986 to 1999 and never changed the clutch out. This includes multiple double dates with 4 people in the car going up and down mountain roads including hwy 17 and hwy 9 as well as hills in San Francisco. Never had a problem of slippage. At 1999 I upgraded the motor to a 3.2.

Posted by: The Cabinetmaker Oct 4 2016, 03:29 PM

Well, i think you are correct Andy. Thanks.

By the way, I'm pretty sure you are an expert!