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Discussion Starter #1
JRV: More problems with the n

JRV: More problems with the new Boxer clutch!....studs may be too short!

While assemblying the clutch onto the flywheel, on the table, I noticed that the clutch frame sits off the flywheel by about 2 mm. Those at AP Racing tell me this is normal, and that it will go down to meet the flywheel when the bolts are torqued.

The problem is that there is little thread on the studs to engage, and possibly hold the clutch housing. The stud has a threaded portion on both ends, one being longer than the other. The long end is the end removed from the flywheel. The short end was the end holding the clutch.

Facts: Hole in flywheel depth = 13.9 mm
Stud lenght = 45.2 mm
Long threaded portion of stud = 15.5 mm
Short threaded portion of stud = 12 mm

AP Racing told me they have the stud stick out, from the flywheel 33 mm.

My solution: I can get this, and it should solve the problem, but I would have to inset the short end into the flywheel, not the long end, which was originally in it. With the long end in, the useable lenght becomes only 30 mm. With the short end in the useable lenght becomes 33 mm.

The short end lenght is 12 mm deep, but the flywheel frame depth is 13.9 mm deep....it may be short, but will it be adequate?

Your opinion?

I heard that studs do not have to Locktited down....true?
 
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Discussion Starter #2
Hi Henryk,

First off let me


Hi Henryk,

First off let me say that on the Nut End (outer)you really only need full thread engagement + 1 thread sticking out. Less than full nut (thread) engagement would be risky.

Now, by reversing the studs if you get 12mm thread engagement this is actually plenty, as the general fastner rule of thumb is 100% of the cross section is minimum, and at 12mm you have 150% of the cross section (8mm) engaged.

I believe the reason they suggest no locktight is neccesary is because it's expected that the studs are bottomed and tightened very securely into the flywheel itself, and then the nut tightened with lock washer on the outer end with the PP applying constant pusing pressure against the studs insuring no amount of vibration could work them loose. It's common on PP studs to simply use lock washers as the PP then applies constant force insuring they can't come loose once properly tightened. In essence the studs are spring loaded.

So it sounds like you should reverse the studs to get the 33mm protrusion hieght, unless of course that leaves more than 1-2 threads sticking out of the nuts with lock washers. As to lock tight on the threads inserted into the flywheel, doesn't sound absolutely necc. as long as the studs are bottomed and tight, but also couldn't hurt, either way is fine.

Regards, JRV
 
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Discussion Starter #3
I will then turn the studs aro

I will then turn the studs around.....something for you to keep in mind when you do these.

FYI: Here is a picture of the nuts (bolts?) they sent with the new clutch. There are no washers.

The torque setting is 11 ft-lbs. This was comfirmed twice with AP Racing........I thought this was a little low.......they assured me it wasn't.

My next concern is whether the gap between the clutch casting and the flywheel will close with only 11 ft-lbs of torque. They told me that the clutch casting should be right against the flywheel. I initially thought of this as a "floating" design, but they assured me it wasn't.
 
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Discussion Starter #4
I will then turn the studs aro

I will then turn the studs around.....something for you to keep in mind when you do these.

FYI: Here is a picture of the nuts (bolts?) they sent with the new clutch. There are no washers.

The torque setting is 11 ft-lbs. This was comfirmed twice with AP Racing........I thought this was a little low.......they assured me it wasn't.

My next concern is whether the gap between the clutch casting and the flywheel will close with only 11 ft-lbs of torque. They told me that the clutch casting should be right against the flywheel. I initially thought of this as a "floating" design, but they assured me it wasn't.
 
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Discussion Starter #6
Henryk,

Are those the nuts


Henryk,

Are those the nuts in the photo for the new style PP?

These appear to be self aligning nuts, interesting.

Also, the 11 ftlbs should be fine as PP's 'spring load as I mentioned.

Yes I'm sure the PP will draw down as they explained as this is normal to spring load and clamp the discs.
 
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Discussion Starter #7
A note, if the PP doesn't

A note, if the PP doesn't draw down and spring load then you'll need to reverse the studs back the other way, as a failure to seat all the way down will mean the studs bottomed to soon.
 
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Discussion Starter #8
Yes they are. Six of these ar

Yes they are. Six of these are included with the new clutch.....as are 3 alignment pins (same as the old ones).

Here is a picture of the hole where the new bolts go into. Why no washers?
 
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Discussion Starter #9
Reversing the studs, I do'

Reversing the studs, I do't think is an option. This will leave less than the 33 mm required.......unless I just screw in the long end 12 mm deep, without bottoming it out on the flywheel.....is this acceptible?

My other option would be to just extend the threads on the short end with a metric die.

I thought of this possible problem earlier. I will know by getting to 11 ft-lbs, and feeling if the nut bottoms before then.
 
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Discussion Starter #10
OK Got It !

You don't r


OK Got It !

You don't reverse the studs, the 12mm lenght is supposed to go down giving the correct protrusion hieght. The special centering bolts need the long threaded end to pull the PP completely down. Neat!

They don'trequire lock washers because the PP keeps constant sring tension (load) on them. Cool Setup!

Can't wait to see and install this new design.

Regards, JRV

ps: how did the CO/HC testing go on your TR?
 
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Discussion Starter #11
The testing of the TR was put

The testing of the TR was put on hold, due to the above project. It seems to run fine, but I do agree with you.....it can use some fine tuning. I bought a spark tester, from OTC......measures the kv needed to start the plug, kv while the plug is firing, and the lenght of time of fire in ms. I need to get two vacuum gauges. I will use the spark tester, to isolate any bad plug firing, then use the new ohm meter to test ohms in the plug wires, connectors, etc. I have 12 new plugs.

I will send some more pictures when I have it assembled on the table, and also when in the car.

Thanks for your help.....it is nice to get one good response vs many varied ones......and these are from people who should know!!!!

I think I told you once, that I will retire in Texas, and work for you!!!!!!HAHA
 
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Discussion Starter #12
Sounds like you have all the r

Sounds like you have all the right tools lined up to dial the TR in.

As soon as I saw the Nuts the whole set-up made sense and the reason the short threads went into the flywheel, Trick Set-Up, and pics really help alot of the time fully understanding things.

Yea you're welcome in Texas anytime..;-). 11 months driving season down here..;-).

The flywheel Bolt Torque Mele was pretty humorous. So Ferrari made more mistakes in 5 books in series, what else is new...haha...itwouldn't surprise me if many mistakes and ommisions were on purpose to trip up the unwary.
 
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Discussion Starter #13
I took out my depth gauge and

I took out my depth gauge and did some calculations: Bottom line; the aligning nut will thread 13.44 mm onto the 33 mm stud. Since the long threaded portion is 15.5 mm, the nut will bottom, when the clutch casting meets the flywheel, and still have 2 mm of thread left.

Interesting, this would NOT work of the stud was placed into the flywheel as original.....long threaded side into the flywheel. The short side is only 12 mm long...1.5 mm too short.

They never told me to reverse the studs.....I just figured it out by myself. Apparently someone HAD to reverse the stud at AP Racing. They did state that these where the original studs.

I wanted to do the measurements above, so that I didn't have to install the 6 studs, and find out later, that this wouldn't work.

I will go over my calculations one more time......just to be sure, prior to final install....I still plan to install the clutch onto the flywheel, on the table first.....JUST in case soemthing else goes wrong.....like finding out that 11 ft-lbs isn't enough to overcome the tension.
 
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