[DeTomaso] Fidanza flywheel/ARP bolts warning

[Mike Drew]

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 don’t 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:


-------------- next part --------------
A non-text attachment was scrubbed...
Name: image1.jpeg
Type: image/jpeg
Size: 115735 bytes
Desc: not available
URL: <http://server.detomasolist.com/pipermail/detomaso/attachments/20180527/b1590cea/attachment.jpeg>
-------------- next part --------------

That makes all the difference on an aluminum flywheel. 

2). He also told me that Fidanza doesn’t countersink the holes deep enough in their flywheels.  Here is the Fidanza flywheel (which has holes for both 10.5 and 11-inch clutches)

-------------- next part --------------
A non-text attachment was scrubbed...
Name: image1.jpeg
Type: image/jpeg
Size: 84523 bytes
Desc: not available
URL: <http://server.detomasolist.com/pipermail/detomaso/attachments/20180527/b1590cea/attachment-0001.jpeg>
-------------- next part --------------



Notice there is only a small chamfer. Here is the McLeod flywheel:

-------------- next part --------------
A non-text attachment was scrubbed...
Name: image2.jpeg
Type: image/jpeg
Size: 91141 bytes
Desc: not available
URL: <http://server.detomasolist.com/pipermail/detomaso/attachments/20180527/b1590cea/attachment-0002.jpeg>
-------------- next part --------------



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 doesn’t 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 weren’t 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 that’s a different story.....

Mike (coming up on 30 years of Pantera ownership and still learning things every day!)

Mike

Sent from my iPad