Question for those who are familiar with the European GTS

Geroge,

There are no spacer on the front of my 79 between wheel and hub.

Ron

thank you Ron

I ask for 4 reasons

(1) The 15x8 wheels had 19mm off-set, whereas the 15x7 wheels had only 6mm off-set. Installing the 15x8 wheels "as-is" reduced the front track width by 1 inch. To get a car to stick better in corners you normally increase the track width, it doesn't make sense for the factory to reduce it. For instance, the rear 15x10 wheels increase rear track width by a whopping 2 inches.

(2) I've known (and currently know) Pantera owners who have installed 225/50R15 tires on their Panteras, using the 15x7 wheels, without any rubbing issues. Moving the tires inward wasn't necessary due to fitment issues.

(3) I've seen 1970s era pictures of the factory GTS in which the front tires appeared to be moved outwardly further than in other pictures.

(4) Then there's this factory parts diagram which we've all seen a hundred times (below) clearly indicating a spacer for the front. Perhaps the spacer was optional equipment?

1. My car has 15x8 rims .. I dont see any indication of long studs to accept spacers ... also less factory GTS Flairs ... my car being a later version in 1979 ... they didn't build my car with handling in mind .. it was more cost effective less spacers and flairs.
2. Tire size in the front is 225/50 with no rubbing issues ..even in hard cornering.
3. I think your right and when they moved them outboard that would explain the GTS Flairs.
4. I see the diagram ... i think the tell tail would be longer studs in the front.
5. The rear of my car has 305 /50 which also fit very nice ... i never looked or compared it but at times i thought the car had a wider look at the 1/4 panels

Heres a good picture in a hard corner ...

Very interesting discussion.

I couldn't help but notice that there are components in this illustration that are probably intended for racing, such as the roll cage and the vented rear rotors?

I'd take a guess that the front spacer is probably suggested for competition...of some sort?

I'd also make an educated guess that the spacer there is a 1/2" thick. Looking at my car, I'd expect some kind of interference with that as is (without flares). Probably 1/4" thick would work though?

My thought is that I'm not sure that you need to increase the front track for a handling improvement? Since I don't race and haven't tried every combination, that is just speculation though.

Still a fun thought to consider.

I'm with Ron on the longer studs thought. I would expect those to be shown in the diagram as well as different front calipers to go with the thicker rotors? No calipers shown?

The Gp3 used big ugly non-stock iron Girlings. There are aluminum calipers eventually offered but apparently the aluminum Girling 18-4 and 16-4 units don't appear for the Pantera until sometime AFTER the factory raced the Gp4 cars in 72-73 although they seem to be on everything else but the Pantera?

They are on a couple of the Gp4 cars but might be "aftermarket" additions. That is still unclear at this point.

Example. The GT40 was called the Gulf in the '68 season. It was run with the Aluminum Girlings, and a Boss 302 also. Lola T70 used them. Porsche as well.

Are there more illustrations that go with that one George?

George,

It seems to me, the items shown in the diagram are GT3 parts not GTS. The clue is the roll cage. GT3's had wheel spacers on the front, not to increase the track width, so the reinforcing ribs on the inside of the 15x8 Campi wheels would clear the GT3's big brake calipers. Without the spacers, the front wheels won't turn. I know one GT3 owner who found that out the hard way!

There are what appear to be inaccuracies in the illustration to begin with.

The wheel shown for the front has got gussets on the outside like the 10 inch wheels do. Exactly what illustration are we looking at?

A Group 3 car wouldn't have 10s in the front. A group 4 would, but not those.

quote:

Originally posted by accobra:

Heres a good picture in a hard corner ...

That's some big rubber on the back of your GTS Ron! I'm amazed it doesn't rub the outer fender. Since the 15x10 wheel has negative 6mm offset, the sidewall of that tire actually extends outward 3mm more than a 335mm tire mounted on a 17x11 Campy clone.

quote:

Originally posted by PanteraDoug:

... My thought though is that I'm not sure that you need to increase the front track ...

... I'm with Ron on the longer studs thought though ...

... Are there more illustrations that go with that one George?

The front track was reduced one whole inch by installation of the 15x8 wheels in the front. I'm curious if De Tomaso compensated for that by adding a spacer. I'm agreed about the need for longer studs. Since 225/50R15 tires can be installed on the 15x7 front wheels without rubbing, I see no reason why that spacer couldn't be 12mm thick because the 15x7 wheels have 12mm less offset than the 15x8 wheels.

That illustration is an incomplete version of an illustration scanned from Jan Norbye's Pantera book. Mr. Norbye's comment below the picture reads "what it takes to make a European spec GTS out of your standard Pantera". I assume the picture is from the "Post Ford" European Pantera parts manual; but that's only an assumption since I don't have a copy of that version of the parts manual.

quote:

Originally posted by David_Nunn:

... It seems to me, the items shown in the diagram are GT3 parts not GTS ...

When the Group 3 Pantera was conceived, it could only be equipped with the same components as the road version save for a few safety items. The standard Pantera was not "race ready" so an improved road going Pantera (the GTS) was a necessity in order to compete in the Group 3 class. The GTS and Group 3 are therefore kissing cousins. The Group 3 was based on the GTS. Or to look at it the other way around, the GTS was created so De Tomaso could go Group 3 racing. After a couple of years the Group 3 rules were relaxed, allowing for a few parts such as brakes to stray from the production items. But ... a customer could have ordered a GTS from the factory at any time, and had it equipped with every part used for the Group 3 as optional items. So ... are we looking at a Group 3 exploded view, a GTS "options" list, or both?

The original wide body road going Pantera, what we call the GT4, was also conceived as a GTS with optional wide wheels/tires and fender flares. It didn't become a model separate from the GTS until 1980, the year the GT5 was introduced. The heavy duty brakes and uprights installed on the GT5 and GT5-S Panteras were sourced from the Group 3 race car.

Anyway, I've digressed. I've never heard of a GTS having a spacer up front. I'm just being thorough, making sure I haven't overlooked anything. Seeking the facts. I'm hoping to be educated. Your comment about the Group 3 brakes has indeed educated me.

The "spirit" of Pantera International is the sharing of information. Thanks to all who've chimed-in. I hope the comments keep coming.

At the time, no one had determined that using a larger diameter wheel (16,17,18)with the same exterior tire dimensions of the 15 inch tire would give greater cornering stiffness to the tire itself.

Widening the wheel was still considered the most you could do to gain cornering grip and maximum tire wall stiffness.

Therefore, the 8 inch rim with a 225-50-15 would generate better cornering g-force than the 7". Even with the exact same tire.

As the picture Ron posted (great pic Ron) indicates, the 225-50-15 tire fits so nicely within the stock fender without interference. Why fix something that ain't broken?

Even the fact that just the iron Girlings were used on the race cars indicates the car is not even in dire need of controlling the shocking more precisely by reducing unsprung weight?



These cars are really an outstanding example of how you can drive them daily on the street and take them racing on the weekends.

Much more so than even a Cobra is. If you get a little warm in the cabin during the race, turn on the a/c. A little bored waiting around for the flagman to call your group, turn on the stereo? No need to hide under the underpass if you get caught in the "rain"? In the Cobra? I don't think so.

I personally purely by coincidence was able to do a side by side comparison of a 71 Pantera and a 427 s/c. Circa 1978.

The Pantera was by far easier to handle than the Cobra and with it's Weber equipped, high compression Boss 351, was notch per notch, as fast. The Pantera had Scheel seats in it, which for me made the cabin too confining...but it wasn't my car, so who could complain? Both were low EASY 12 SECOND 1/4 mile cars. I had to give each back unless I WANTED to get arrested AND have the cars confiscated as well.



What is the item in the illustration that looks like a Chiropractors spine display and the other rod that looks like a shift shaft component?

What is the item in the illustration that looks like a Chiropractors spine display and the other rod that looks like a shift shaft component?

Seat belts

Seat belts?

quote:

Originally posted by JTpantera:
What is the item in the illustration that looks like a Chiropractors spine display and the other rod that looks like a shift shaft component?

Seat belts

I guess I wasn't expecting to see that? why would you show stock belt configuration here? I would expect competition shoulder harness and the aircraft type release seat belt.

George,

See the attached Invoice for my car it only mentions the rear 10" wheels ?

Doug,

I can confirm the goofy female end of the seat belt with the long stiff stem extending far above the plane of the seats .. is not on my std 73 Pantera ... but equip on my 79 GTS. Also the seat belt configuration lap and cross belt is different also and not recessed in the rocker but mtd more like a mustang with a std bolt.

I am thinking that this is an example of what the asterisk means. "The manufacturer reserves the right to substitute appropriate..."

These are from the PI Motorsports 2004-5 Resource Guide.

Item 21 shows as an 8x15 wheel, interesting. My 1978 Pantera did not have spacers, the studs would not be long enough. In the same book it mentions front and rear brake assm with short and long studs.

I have a 5mm spacer, and I must have the spacers because the big Gr3 brakes, I can't put on the front rim without spacer, the rear rim have perhaps 1-1.5 mm clearance without spacer.

it is unable to put on stock spare wheel on a Gr3 Pantera with big Gr3 brakes.

There are more parts in the suspension which is unlike on stock Pantera brake and big Gr3 brakes.

The Gr3 safety belt was a Britax 4-point safety belt most likely made ​​by Sabelt in licence of Britax.

The charts is one of several performance parts, Gr3 parts was marked with * at part no. But not all Gr3 parts are in any of those two parts catalogs that I have.

The part catalogs is from ca 1975.

JTpantera Yes it seat belts but Not Gr3 seat belts.

It was possible to put on the Gr3 parts on "L", GTS, GT5, GT5S Pantera.

I have never seen the Gp3 brakes. If you have some pictures of them I'd love to see them.

quote:

Originally posted by George P:

... The standard Pantera was not "race ready" ...

what do you mean that it was not "race ready"?
what was missing to be "race ready"?

quote:

Originally posted by Anders Hellberg:

... what was missing to be "race ready" ...

All the mechanical improvements made to the GTS, as standard or optional equipment, those not found or available on the "standard Pantera, were missing. Ventilated front brake rotors, better shocks, stiffer springs, etc.

quote:

Originally posted by PanteraDoug:
I have never seen the Gp3 brakes. If you have some pictures of them I'd love to see them.

pic 2

pic 3

pic 4

pic 5

pic 6

pic 7

Wow! The Motherload! Thank you...a million!

The fronts really resemble the pictures LarryW posted of the Girling Maserati Quatroporto.

Now if we can only cross these over to aluminum.

I see the 5mm spacer and I see the face of the caliper machined down.

Hey Larry, you said you know where there are more right?

I just looked at my original brake master cylinder which I replaced. It is stamped 23mm on the inside flange.

I'm wondering if they increased the size of the bore on your car?

Anders, the adjustable proportioning valve in the last picture, is it plumbed into the front circuit or into the rear circuit?

One other question, what size front tire do you have installed, are there any clearance issues?

Thanks,

-G

quote:

is it plumbed into the front circuit or into the rear circuit?

Looks like the front.

John

I believe the GRP3 brakes are similar to the later Pantera brakes. My car has those bigger brakes and I can run 15" x 8" all round without any wheel spacers. Attached is an old photo, the calipers have all been plated with new stainless pistons and seals. These brakes were used on many other cars, Aston Martin, AC Cobra, Masarati going by the pad equivalent charts, maybe different spacer shims were used between each caliper half depending on rotor thickness.

A picture of my front calipers split, no seal between the 2 halves.

Anders, it looks like you have a thin spacer on your hubs as well, is that the case?
If you do not use the spacers, where do your wheels hit on the calipers?

Larry, it looks like those Masarati assm's could work. The steering arm you could use from your Pantera.

quote:

Originally posted by bdud:
A picture of my front calipers split, no seal between the 2 halves.

Anders, it looks like you have a thin spacer on your hubs as well, is that the case?
If you do not use the spacers, where do your wheels hit on the calipers?

Here I have some personal experience on this subject.

First off, to move the caliper further inboard for more wheel clearance, you can shim it. You can machine spacers for it if you really need to move it back, then use longer bolts.

The critical factor though that controls that is the offset of the rotor. I think what is at play here, causing the variations in wheel clearance, is that there are several rotors being used in these different set ups?

Whatever location you determine the caliper should be located at, you still have to center the rotor in in. I've used hardened shims for this. Some as thin as .010" to get them right.

The rotors are all 12" (304.8mm) diameter and 1.25" (31.75mm) thick but the offsets are varying by what looks like up to 1/2" (13mm) or so.

I'd bet you a nickle, i.e., a US 5 cent piece, that the calipers are all the same, but the rotors vary? The spacers on this thickness rotor all look the same.

The simplest solution is to put the caliper where it needs to go to clear everything, then forget about finding an original application rotor that will fit. Just do what Anders did. Find a hat that comes close, or have some made to your specs. Those should last forever since you can change the rotor rings separately as need be.

Bdud. Do you have pictures of your rear brakes that you can post? Also, what is used for a gasket between the spacer and two halves on these calipers? Just silicone?

FWIW, the front and rear brake rotor assemblies are illustrated slightly differently in the early(?) Euro GTS/Gr-3 Parts Supplement, compared to the later(?) Supplement. In the early list, front & rear rotor spacers have their own part numbers, while in the late list, only the rear spacer is listed separately. On another page of the late list, the front ('anteriore') spacer is shown as part of a three-piece front rotor ass'y (rotor/hat/spacer).

Neither Parts Supplement is dated, but my early one has 11 pgs (came with the factory GR-3 brakes I installed on my partner's non-Euro pre-L in the early '80s), while Anders' later listing has 14 pgs & a few more parts. I'm assuming the first list is 'early' since pg 1 shows the famous skeltonized pushbutton Pantera with prototype multi-slat seats, while the 'later' list shows a flared-fender GTS/Gr 3 with rectangular door-pulls on pg 1.

I don't dare draw too many more conclusions based on artists' illustrations, but the later List also shows a fully baffled & trap-doored '10-liter' oil pan with rectangular pump pickup, that looks a LOT like a U.S-made Aviaid '10-qt' racing ass'y. In both Euro Parts Supplements, the GTS/GR-3 had its own front & rear upright part numbers, so the front spindles may have been a bit different from std. I know the very complete Gr-3 brake kit's rear outer stub-axles used double-row ball bearings at the inner position (to support 10" rear wheels). The '87 GT5-S used even wider straight roller bearings there (to support 13" wide rear wheels). Anders' dedicated Euro GTS/GR-3 web-site has more info and photos- (www.scuderiadetomaso.se)

quote:

Also, what is used for a gasket between the spacer and two halves on these calipers? Just silicone?

The 2 halves are connected by an external brake pipe, no O rings or silicon required.
See picture.

quote:

Do you have pictures of your rear brakes that you can post?

This is what I call bad timing. My media storage took a dump but its replacement is due tomorrow, so I am scanning my old photos at the moment.
Here is a picture of the rears also split and coated, they also have external brake pipes separating the halves.
Let me know if you want different pics. They have thinner ventilated rotors like Anders.

quote:

I don't dare draw too many more conclusions based on artists' illustrations, but the later List also shows a fully baffled & trap-doored '10-liter' oil pan with rectangular pump pickup

My car has the factory sump as you described. Here is a picture.

quote:

Originally posted by bdud:

quote:

Also, what is used for a gasket between the spacer and two halves on these calipers? Just silicone?

The 2 halves are connected by an external brake pipe, no O rings or silicon required.
See picture.

You misunderstood. The calipers have an inner and outer half that are bolted together. Between those halves, what seals them?

I understand about the transfer tubes. The left and the right fluid chambers are only connected together by the tubes.


I've got the Aviad pan and that ain't it ^


For what it is worth, Wilkinson has the GT5 calipers listed new at $1,900 each and $600 each for the rotors. These don't make any great sense at all to install at that price, IMO.