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Posted by: vintage914racer Sep 17 2019, 09:32 PM

This past weekend I took my 914-6 vintage racer to the Elkhart Lake Vintage Festival at Road America. My car ran great up to the final feature race on Sunday. Long story short, I was running up front in fourth behind a couple high-budget, blazing fast 911s when my clutch pedal went to the floor while downshifting in a heavy braking zone. I was able to pull it back and regain normal operation for a lap or two when it happened again and sidelined me for the rest of the race.



Well, tonight I pulled the tranny to assess the damage and the problem is clear -- a blown clutch. It now sits on my bench in three pieces.



I have a few questions for the wrenches wiser than me on these forums:

1) Should I be concerned about some underlying issue causing the failure?
2) Is it worth upgrading to a lightened flywheel and racing clutch kit? My understanding is these early flywheels are pretty light to begin with. For reference, the car is running a 2.5l six putting out somewhere around 250hp.
3) Given the state of the clutch and what was spinning around on the flywheel, is it reasonable to think the current can be resurfaced, or am I destined for a new flywheel?

Any and all input would be appreciated.

Posted by: Mikey914 Sep 17 2019, 10:34 PM

Yep, that would do it

Posted by: Superhawk996 Sep 18 2019, 06:14 AM

Resurface (assuming material is there to do so within factory spec) and move on.

This looks to be a 914 flywheel on a six? Likewise a 4 spring clutch disc. Are you running the 901 transmission?

If so that clutch / trans was never intended to take 250 HP if that is what you have. Clutch should be viewed as a fuse if this is indeed the case.

Posted by: wndsrfr Sep 18 2019, 06:18 AM

Just had the same thing happen to me.... look at my post in the Paddock section. Call Kennedy... get a proper racing puck clutch with 901 splines and the spring hub. They shipped one to me last week via priority mail... had it here across the country at noon of second day.

Posted by: johnhora Sep 18 2019, 07:38 AM

Nice racer 914...show us some more pics.
Looks like a stock disc and pressure plate...how many hours on those?
Need something a little stronger or change stock ones often.
Kennedy and Center-force work well for track use.
As mentioned check flywheel for in spec measurements...if in should be fine..they are tough.
As for a lighter flywheel...there was a GT ones...here are pics.

Posted by: brant Sep 18 2019, 10:30 AM

more flywheel options that work well on race 901's
the aluminum 5.5 has proven much more robust than the steel 5.5 which I broke

the 901's become NOT cost effective at 200hp on the track
the annual rebuilds... Cooling my 901 has so far doubled the life expectancy for high RPM use.




Attached image(s)

Posted by: vintage914racer Sep 18 2019, 11:31 AM

I will investigate. Does Kennedy provide the pressure plate as well, or just the clutch?



I hear you. The lesser built engines I used to run over the years played nicer with the trans. I just added cooling this season after I found I was cooking the fluid. Have to get the stack rebuilt again this winter...

Who makes the setup you have, Brant?

I’ve had my eye on the JB Racing setup. Seems to have a good reputation.

Looks like there’s been a few failures with the Patrick lightweight flywheel kit

Posted by: sixnotfour Sep 18 2019, 11:37 AM

Ive got 3 of them from different owners , bad starter ring gear,
the whole flywheel seems soft

Posted by: brant Sep 18 2019, 11:44 AM

My flywheel came from beck. But I think pms sells the same one
It’s held up for over 5 years and beck used to run the same without problems

He also had good reliability to n arguably one of the fastest 2.5 914/6 cars ever built

Around 1600 lbs and around 305hp

Posted by: wndsrfr Sep 18 2019, 12:35 PM

Kennedy does have pressure plates...I'm pretty sure mine's a stock Sachs one though. The clutch disc was only about $160, not bad at all. My flywheel is AASCO aluminum with a steel starter ring gear & replaceable friction surface disc. That was $600 a couple of years ago.
FWIW if your flywheel is in spec I'd suggest just install a Kennedy clutch disc, scratch up the surface of the flywheel & pressure plate with 80 grit sandpaper & drive it...

Posted by: SirAndy Sep 18 2019, 12:47 PM

I contacted Kennedy after i burnt up my previous clutch and they made me a special version (not listed on their website) that can take the torque from the 3.6L and still work with the 901.
That included the pressure plate and clutch.

So far, so good ...

Posted by: vintage914racer Sep 18 2019, 03:21 PM

Kennedy sounds like a winner, and a relatively cheap one at that.

The general consensus seems to be that my flywheel is probably fine. I’m thinking about having it lightened RSR style at Ollie’s. Any wisdom from folks on this approach?



I’m going to reach out and see what they recommend. Glad to hear they build to suit if you will

Posted by: vintage914racer Sep 21 2019, 05:33 PM

Spoke with Kennedy about options. I'm leaning toward their race spec clutch that works with existing flywheel and PP. Toying with the idea of having Ollie's shave some weight off of the OEM flywheel. Anyone done this?

Posted by: rick 918-S Sep 22 2019, 07:10 AM

I have a clutch failure on an Isuzu Trooper we owned. I had the shop just do the disc. Got 4 blocks away and PP failed. Cost me twice. wife was not happy

Posted by: rick 918-S Sep 22 2019, 07:18 AM

Did a lightened flywheel on the 2.0 in 7 of 9. It was a noticeable difference. The guy that purchased her said the car is faster than his factory 6. The engine will rev faster. The down side on a street car it will also decel faster and sometimes stall the engine. Not an issue on a race car.