clutch drives me nuts - what is wrong here?

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Melchior
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clutch drives me nuts - what is wrong here?

Post by Melchior » Fri May 24, 2019 4:22 pm

hello,

I have read all clutch related entries here but cannot find the clou - situation is like this:

1) removed worn clutch disc
2) sent clutch pressure plate "Fichtl & Sachs" Type HB 225 to ZF for reman job - came back perfectly done (see picure)
3) bought clutch disc from ZF - Art. Nr. 1878 634 058
4) bought new fly wheel from Ferrari Classiche - original spare part

Now the problem started: the new clutch disc with 8 springs looked exactly like the one I dissambled from the 250 GTE II (see picture below), but it is clear that the springs will grind on the screws of the fly wheel once the disc will show only little wear.

o.k., bought second new cutch disc directly from Ferrari, but bad surprise, they sent me exactly the same disc (8springs), just 400 EUR more expensive.

What is wrong here? Is there another clutch disc? I have seen discs with only 6 springs at superperformance (see picture) - would these fit?

regards,

Martin
Attachments
6 spring disc.jpg
clutch disc.jpg
pressure plate.jpg

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tyang
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Re: clutch drives me nuts - what is wrong here?

Post by tyang » Fri May 24, 2019 4:56 pm

Hi Martin,

Normally, clearance issues occur when too much material has been removed from the flywheel but you said you have a new unit. The flywheel bolts are a little thinner than regular bolts, so how thick are the ones you're using?

Tom
'63 330 America #5053

afwrench
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Location: upstate new york

Re: clutch drives me nuts - what is wrong here?

Post by afwrench » Sat May 25, 2019 7:45 am

Not being able to see both sides is it possible the disc should be flipped? Mike
72,365gtc4,14681,2007 599 GTB

Timo
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Re: clutch drives me nuts - what is wrong here?

Post by Timo » Sat May 25, 2019 10:14 am

I concur with Toms comment about the flywheel bolt head thickness, but would also add that if new, thicker lock washers are being used, they too can bring bolt heads closer to disc center.
Also, while not exactly same setup nor am I sure if it’s a common issue on earlier cars with “F & S”, but new replacement friction discs produced for 365 GTB/4s in past +/-15 years appear to come thinner than OEM wear limits require.
Timo

Melchior
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Joined: Thu May 03, 2018 11:44 am

Re: clutch drives me nuts - what is wrong here?

Post by Melchior » Tue May 28, 2019 10:57 am

Hi all,

the fly wheel is brand new, original thickness. The lock washers have the same thickness as the ones I removed - I cannot imagine that these could be any thinner than this. The fly wheel bolts are the right ones but their heads protrude the fly wheel surface (when using the washers) for approximately the same as the lock washers are thick.

Anyhow the manual from Tom´s library says that this may happen - the bolts might protrude even when the fly wheel is new and shall be grinded in this case.

I rather think it might be better to machine the fly wheel and deepen the center area for these approx. 0,8mm. Did anyone of you do this? What do you think, would the fly wheel be too thin then in the center area?

coming to the disc: it definately cannot be flipped right away as the other side needs to be placed towards the gear box as the center area protrudes the clutch facing (see picture of other side). We well thought about opening the rivets of the disc, flip it and re-rivet it. This would bring approx. 2.5mm more distance between the springs of the disc and the fly wheel. I finally refused this idea as I am afraid that handcrafting the rivets might bring problems - what if one falls appart? What if the disc is not centered 100% after re-riveting and flipping?

May I ask a second question: did anyone of you face the problem that the springs touched the fly wheel after the clutch facing has been worn? or in other wrds, did anyone have any kind of problems using this clutch disc with the Sachs parts number 1878 634 058?
Attachments
disc back side.jpg

Melchior
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Re: clutch drives me nuts - what is wrong here?

Post by Melchior » Tue May 28, 2019 11:02 am

sorry, this is the other side of the disc.
Attachments
disc other side.jpg

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tyang
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Re: clutch drives me nuts - what is wrong here?

Post by tyang » Wed May 29, 2019 10:20 pm

I have not had the springs touch when the clutch wore.

Tom
'63 330 America #5053

enoz05
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Re: clutch drives me nuts - what is wrong here?

Post by enoz05 » Thu May 30, 2019 4:19 am

Melchior wrote:
Tue May 28, 2019 11:02 am
sorry, this is the other side of the disc.
Martin, are you still searching for a Talbot mirror?

mechaniker
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Joined: Tue Dec 18, 2012 8:18 am

Re: clutch drives me nuts - what is wrong here?

Post by mechaniker » Wed Jun 05, 2019 4:54 am

Here are brand new factory screws for the flywheel.

They are bought for an SWB, but should be the same.
Attachments
IMG_2286.jpg
IMG_2285.jpg
IMG_2284.jpg
IMG_2283.jpg
IMG_2282.jpg
IMG_2281.jpg

mechaniker
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Re: clutch drives me nuts - what is wrong here?

Post by mechaniker » Wed Jun 05, 2019 4:54 am

more pics
Attachments
IMG_2290.jpg
IMG_2289.jpg
IMG_2288.jpg
IMG_2287.jpg

Melchior
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Re: clutch drives me nuts - what is wrong here?

Post by Melchior » Thu Jun 06, 2019 6:50 am

Thank you very much for the information about the screws - this is it. I purchased my bólts from a cheaper supplier and received wrong dimensions - the head is 5mm high instead of only 4mm. I ordered the right bolts now and everything fits together.

Lession learned: when it seems cheaper it finally most of the time turns out to be more expensive...

Anyhow, thank you all for your great support!

regards,

Martin

BobA
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Re: clutch drives me nuts - what is wrong here?

Post by BobA » Thu Jun 06, 2019 12:37 pm

I have been following this forum from the start and have one question. How thick were the heads on the original bolts?

mechaniker
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Re: clutch drives me nuts - what is wrong here?

Post by mechaniker » Fri Jun 07, 2019 2:45 am

My factory supplyed screws have a little over 3.5 mm thick heads.

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tyang
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Re: clutch drives me nuts - what is wrong here?

Post by tyang » Sat Jun 08, 2019 6:41 am

Melchior wrote:
Thu Jun 06, 2019 6:50 am
Thank you very much for the information about the screws - this is it. I purchased my bólts from a cheaper supplier and received wrong dimensions - the head is 5mm high instead of only 4mm. I ordered the right bolts now and everything fits together.

Lession learned: when it seems cheaper it finally most of the time turns out to be more expensive...

Anyhow, thank you all for your great support!

regards,

Martin
Hi Martin,

I see this all the time. Every supplier will tell you they "have the right stuff," but who would tell you they "might have the right stuff?!" Check your sources, and stay away from the suppliers that don't know what they're selling. Paying a little extra for the right parts will save you money in the long run, and reward the suppliers for their diligence for sourcing the better parts and service. I don't believe in paying "Ferrari Tax" for parts simply because they have a horse on the package, but I do believe in paying for quality!

I'm glad you solved the problem.

Tom
'63 330 America #5053

BobA
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Re: clutch drives me nuts - what is wrong here?

Post by BobA » Mon Jun 10, 2019 12:49 pm

I was relooking at the photos abd the first one shown with 6 springs only has 6 splines as well. The other disks have 10 splines. Where did the 6 spline disk come from? Bob GTE 2693

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