Flywheel and Clutch - Original Spec

[HILLY]

Hi Gents,
To anyone how may be able to assist, I need to acquire an original / original design flywheel and Borg & Beck 7.25” triple plate clutch arrangement to suit a 289 / ZF-0 assembly utilizing a standard Mk1 bell housing and original specification starter motor. I believe that the tooth count on the flywheel is a either 115 or 117 ? and 28oz balance but that is about the extent of my knowledge. Quite some time ago there was an original flywheel going on ebay from a seller that went be the name of galtsgulch but the asking price at the time was a bit more than the budget allowed. Regardless if anyone can assist with any information, direction or if you have a couple laying in the corner that you would consider selling I would be happy to hear from you.

 

[JimmyMac]

G'day Peter,
I sent you an email with some information.
All the best,

 

[Mike Drew]

I know of two sources for GT40 clutch bits, and suspect a third:

1) Gelscoe, in the UK
2) Safir, in the USA
3) Jay Cushman, in the USA (although he doesn't list these parts on his website--he may produce them, or may source them from someplace else? Jay?)

Safir has cast up an original-style bellhousing (I don't know if it's "original-original" or a later design, but it is visibly different from the Gelscoe offering), but uses a super-modern (and expensive) multi-disc clutch from McLeod.

Here are some photos of the Safir setup:

Meanwhile, here's a photo of the Gelscoe bellhousing. Compare it to the Safir unit above; the Safir bellhousing seems to have an integral cooling air scoop or something on the bottom of it? If it hangs down low, I suspect it would become a skidplate before long. The Gelscoe bellhousing has vents on the top and bottom:

Both units seem to be sized (and drilled) for the more common Dash-2 ZF gearbox. The Dash 1 and Dash 0 use only four bolts instead of six (plus two lateral bolts), and the opening is physically smaller.

Anyway, that's a start.

JimmyMac, how about you share what you know with the rest of us? Inquiring minds want to know.

 

[Trevor Booth]

The scoop you refer to is actually at the top, the two lugs at the bottom with silentbloc bush bolt to the bottom of the horse collar. Very early housings did not have the lower mounts. There were no lateral bolts in any of them. I have more info on most variations if you need

 

[Jim Rosenthal]

Safir cars all had the later ZF transaxles with the six bolts. (M1 BMW version) The McLeod clutch is probably an improvement over the AP multidisc clutch in the Safir cars originally, which was good for racing and didn't last long in street use. The setup pictured here (both of them) uses a smaller flywheel and bellhousing than a standard Ford 10.5" clutch and flywheel, giving more room for the shift linkage to pass the bellhousing.

This is somewhat off-topic, but is there something inherent to multi-disc clutches that makes them less suitable for street use and more for racing? Just curious- I went to a lot of trouble to use a single-plate clutch in my car.

 

[Jim Rosenthal]

The vent at the bottom is so you can tell when your old style Ford rear main seal is leaking. Ask me how I know.

 

[Mike Drew]

The scoop you refer to is actually at the top, the two lugs at the bottom with silentbloc bush bolt to the bottom of the horse collar. Very early housings did not have the lower mounts. There were no lateral bolts in any of them. I have more info on most variations if you need

Ah, very good! I was confused between Mangusta bellhousings (which have two silentbloc bushings at the top) and the GT40, which has the same style at the bottom.

With respect to the 'lateral bolts', we might simply have a semantic problem (mine). The GT40, Mangusta, and Panteras with a Dash-1 gearbox all used a pair of (for lack of a better word) lateral bolts (splayed at about a 45-degree angle) between the extended sideplates, and the bellhousing. The bellhousings pictured above have the cast bosses for the holes for the bolts, but don't have the holes machined in them.

Here's the factory diagram that shows the bellhousing:

The angled bolt is #43; you can see where it passes through the boss cast into the side of the bellhousing, and is affixed with the nut #31.

Here's the drawing of the side of the gearbox:

You can see where the bolt goes, into the angled hole in the leading edge of the sideplate, #918.

These drawings would lead one to believe that the nut is on the back side of that angled hole. Yet in the Pantera (and Mangusta?) application that hole is threaded, and the bolt threads directly into the cast sideplate? So that begs the question--why does the GT40 parts diagram show a nut on the back side of the bolt?

Here's a photo of a Pantera Dash-1 ZF and bellhousing; the bolt (and spacer between the bellhousing and sideplate) can be clearly seen (even though it's an extremely low-res photo, dating from the early days of digital cameras--the filesize is only 28 kb!)

When Lloyd Butfoy rebuilt my Dash-2 in GT40 configuration, I asked about getting a set of Dash-1 sideplates so I could utilize the original GT40 mounting scheme (since I intend to use a small, original-ish bellhousing/clutch setup, i.e. Safir or Gelscoe), and he told me not to bother. He said that since the Dash-2 has one more mounting stud on the bellhousing (five versus four), plus two bolts in the bottom, it was way more secure and didn't need the additional angled bolts.

Still, in retrospect, I wish I had insisted, just for aesthetic reasons if nothing else. I may yet change them over, since I'm still years (and $100+ K) away from actually having a GT40 to put my ZF in!

 

[Trevor Booth]

I did not make the connection between the angled bolts and "lateral"

my recollection is that these were added at some later time by ZF to counter breakage and discontinued on -2 models

I also do not think that they were initially used on pre production cars (P XXX ) when they changed over from Colotti transaxle to ZF.

I am not in a position to check this right now


If you look closely at the photograph and compare with ZF parts sheet the side plates are different in this area. You may find that the side plate used in the pantera was specific to the pantera and that the one used by ford was the ZF "standard" part.
Pantera parts list may provide a clue

 

[Mike Drew]

I did not make the connection between the angled bolts and "lateral"

Yes, that was entirely my fault. We Americans never stop mangling your language! :laugh:

my recollection is that these were added at some later time by ZF to counter breakage and discontinued on -2 models

It's true the Dash-2 didn't have them. I don't know if the very first Dash-0 gearboxes had them from new, but I suspect they did.

I also do not think that they were initially used on pre production cars (P XXX ) when they changed over from Colotti transaxle to ZF. I am not in a position to check this right now

Maybe so, I have no way of knowing myself, unfortunately.

If you look closely at the photograph and compare with ZF parts sheet the side plates are different in this area. You may find that the side plate used in the pantera was specific to the pantera and that the one used by ford was the ZF "standard" part.
Pantera parts list may provide a clue

The one in the photo above, and the drawing above, is the same actually--at least, I think so. It's a bit illusory, because the drawing shows a left-side side plate, while the photo shows a right-side plate, but since the gearbox is inverted, it appears on the left. But the pieces are the same, with one notable difference:

The first-generation Dash-0 side plates were made of cast aluminum, but they proved to be fragile, and prone to breakage, so they were then made of cast iron. I've held them in my hands side-by-side and while the weight difference is substantial, they are the same in all other regards.

At least, that's my recollection--this was many years ago, and it's possible I failed to pick up on subtle differences between them. I'll be happy to be proven wrong!

 

[Trevor Booth]

ZF #908 appears to be a thru bolt and when box inverted it would be in the position of the photo which is a threaded connection
ZF # 918 appears to be threaded

a mystery

someone will know and I am not sure that the info that I have is definitive in this area

 

[Mike Drew]

ZF #908 appears to be a thru bolt and when box inverted it would be in the position of the photo which is a threaded connection
ZF # 918 appears to be threaded

a mystery

someone will know and I am not sure that the info that I have is definitive in this area

Ah, I failed to notice #908 in the drawing when I posted it--stupid of me! But it doesn't show a through bolt--the boss has no hole on the back side, indicating that it's a...what do you call it, a blind hole? A hole that doesn't pass fully through the component.

Waiting for further input from people who really know for sure. BTW both drawings I posted above come from the GT40 parts book--neither is a De Tomaso drawing.

 

[Trevor Booth]

look at the proportions and shape of the lug on # 908 and compare with the pantera photo and the parts sheet - totally different. I would also suggest that the absence of the hole in the parts sheet is just that and not an indication that it is a blind hole

 

[HILLY]

Hi all and thakns Jimmy and Mike,
The thread wandered a bit but was interesting none the less so I have waited until the dialog on the bell housing ceased before chiming back in.
Again back to the initial topic, any addition to the above info on the original spec flywheels and triple plate clutches would be appreciated.