[DeTomaso] Fidanza flywheel/ARP bolts warning

Mon May 28 22:17:57 EDT 2018

I took a look at my flywheels and pressure plates.

My Fidanza flywheel has 3 bolt patterns.  3/8”, 5/16”, and believe it or
not, 1/4”.  All are drilled for shoulder bolts.

My original flywheel is drilled for the 5/16” pattern only.  It has more
holes, but they’re not tapped.

I’m currently running a non-Pantera Centerforce clutch/PP.  The PN is
DF700000.  It is drilled for the 3/8” pattern.

I’m using ARP bolts for a Chevy, which are 3/8".  Ford bolts are 5/16”.

The Chevy bolts are shoulder bolts, but the shoulder portion is too long.
It bottoms out in the flywheel, so I’m running 2 hard washers.  Even with
2 washers, there are threads showing on the back side of the flywheel. I
know, it’s probably better to get proper bolts, but this works fine, and
it’s easy to find Chevy PP bolts.  I thought about cutting the top couple
of threads in the flywheel to allow the bolts to seat properly, but I feel
better running 2 washers.

My original long style PP matches perfectly with the 5/16” pattern in the
Fidanza flywheel.

I also have a dual disc clutch from Mcleod that is going in the Cobra.
It’s drilled for all 3 patterns.  I will be using the 3/8” pattern.

And I thought it was going to be a boring Monday.

On 5/28/18, 4:23 AM, "DeTomaso on behalf of Thomas Törnblom"
<detomaso-bounces at server.detomasolist.com on behalf of thomas at hax.se>
wrote:

>I have the larger standard 351C Centerforce clutch, on a Fidanza
>flywheel in  my GT5.
>
>I used to run the Pantera specific Centerforce clutch, with drilled and
>tapped holes for the smaller PP.
>
>In an attempt at resolving my vibration issues I replaced the clutch
>with the larger one, which lined up to the stock bolt holes.
>
>So at least for some, the larger CF clutch works also in a Pantera.
>
>The clutch was not the source of my vibrations issues, it was an
>incorrectly balanced crank, and the issue has now been resolved.
>
>/Thomas
>
>Den 2018-05-28 kl. 08:23, skrev Mike Drew via DeTomaso:
>>
>>> On May 27, 2018, at 17:29, Will Kooiman <will.kooiman at gmail.com> wrote:
>>>
>>> Hi Mike,
>>>
>>> I have Fidanza flywheels and Centerforce clutches in my Pantera and my
>>> Cobra.  They¹re the same PN for both the flywheel and clutch/pressure
>>> plate.
>>>>> Centerforce makes a Pantera-specific clutch. It uses a 10.4 diameter
>>>>>disc. The normal Centerforce Cleveland setup uses an 11-inch disc and
>>>>>has a different part number. If yours are both the same, you either
>>>>>have a Pantera clutch in your Cobra or a regular Ford clutch in your
>>>>>Pantera?
>>>> If I recall correctly, the Centerforce PP lined up to 3/8² bolt holes,
>>> which are stock Chevy.  I used Manley PP bolts for a Chevy, and it has
>>> worked fine.
>>>>> Interesting. I know Centerforce clutches won’t bolt up to a Ford
>>>>>flywheel, and they have to be custom drilled which can be
>>>>>problematic. From what you’re saying, apparently they just use a
>>>>>Chevy PP which might account for it.
>>>> The long style PP that was in my Pantera lined up to the 5/16² bolt
>>>>holes,
>>> so maybe that¹s what you¹re having a problem with.
>>>>> I noticed the Fidanza flywheel looked like a piece of Swiss cheese,
>>>>>it had so many holes in it. Apparently they drill their Ford
>>>>>flywheels for big and small Ford clutches as well as Centerforce
>>>>>(Chevy?) clutches. But none of the holes are properly countersunk.
>> If the pressure plate metal is very thick it might prevent the shank of
>>the bolt from bottoming out on the side of the inadequately countersunk
>>hole. But it won’t help the problem that the ARP bolts are too short.
>>>> I have the 428 apart right now, so I¹ll confirm tomorrow.  I¹m
>>>>replacing
>>> the 428 with a 427/482 - BBM block, Pond heads.
>>>>> Awesome. Yeah, take a look and see and let us know what you find?
>> Mike
>>>
>>> On 5/27/18, 6:06 PM, "DeTomaso on behalf of Mike Drew via DeTomaso"
>>> <detomaso-bounces at server.detomasolist.com on behalf of
>>> detomaso at server.detomasolist.com> wrote:
>>>
>>>> All,
>>>>
>>>> I recently installed a new Fidanza aluminum flywheel and McLeod
>>>>clutch.
>>>> The Fidanza flywheel was about $200 less than a McLeod flywheel. Along
>>>> the way I learned some stuff from Dennis Quella.
>>>>
>>>> 1). ARP males great bolts but their Ford pressure plate bolts don¹t
>>>>cut
>>>> it‹they are too short!  I had found this out myself previously. I had
>>>>a
>>>> different aluminum flywheel and McLeod clutch and when I went to
>>>>torque
>>>> the bolts, they stripped!  It turns out the hole in the aluminum
>>>>flywheel
>>>> is countersunk and the ARP bolts were only engaging about two
>>>>threads. I
>>>> chose to have the flywheel machined for larger/longer Chevy bolts and
>>>> enlarged the holes in the pressure plate instead of using helicoils.
>>>>
>>>> Then under-head length of the McLeod pressure plate bolts is about 1/4
>>>> inch longer than ARP bolts plus included washers:
>>>>
>>>>
>>>>
>>>> That makes all the difference on an aluminum flywheel.
>>>>
>>>> 2). He also told me that Fidanza doesn¹t countersink the holes deep
>>>> enough in their flywheels.  Here is the Fidanza flywheel (which has
>>>>holes
>>>> for both 10.5 and 11-inch clutches)
>>>>
>>>>
>>>>
>>>>
>>>> Notice there is only a small chamfer. Here is the McLeod flywheel:
>>>>
>>>>
>>>>
>>>>
>>>> It looks like it is threaded for two different sized bolts, but it is
>>>> not. The marks on the larger diameter are machining marks, while the
>>>> threads are below in the smaller diameter. You will need to copy this
>>>> model and enlarge the top of the holes in the Fidanza flywheel to make
>>>> sure the the chamfer of the bolts doesn¹t bottom out against the
>>>>chamfer
>>>> of the holes before they are securely clamping the pressure plate
>>>>against
>>>> the flywheel.
>>>>
>>>> A friend recently assembled a motor and after a few months two of his
>>>> pressure plate bolts had ejected and the others were loose. He had
>>>> torqued the pressure plate bolts to the proper spec, but they weren¹t
>>>> tight against the face of the pressure plate.  The tapered shank of
>>>>the
>>>> bolts had bottomed out against the inside of the flywheel holes
>>>>before
>>>> the clamping surface was tight against the pressure plate, and after
>>>> awhile they worked loose.
>>>>
>>>> Leaning this, before I installed my setup, I put the flywheel in a
>>>>drill
>>>> press and increased the diameter of the top 1/8 of an inch or so of my
>>>> Fidanza flywheel, and all was good.
>>>>
>>>> Of course after I installed everything and went for a test drive my
>>>> clutch master cylinder failed, but that¹s a different story.....
>>>>
>>>> Mike (coming up on 30 years of Pantera ownership and still learning
>>>> things every day!)
>>>>
>>>> Mike
>>>>
>>>> Sent from my iPad_______________________________________________
>>>>
>>>>
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>
>-- 
>Real life:   Thomas Törnblom             Email:    thomas at hax.se
>Snail mail:  Banvallsvägen 14            Phone:    +46 18 32 31 18
>              S - 754 40 Uppsala, Sweden  Mobile:   +46 76 209 8320
>
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