New Guy Fundamental Question

Jack,

A ZF style trans-axle/bell housing bolts directly to the engine but has the differential (this is the part similar to the center of the rear axle assembly of a rear wheel drive car) mounted inside of the trans case forward of the gear changing cluster assembly. This is so you can attach axle drive components directly to the gearbox and have the correct wheel/tire placement to the engine location.

Some trans-axle used in front engine/rear wheel drive cars have the differential mounted directly behind the gear cluster and the entire trans-axle in mounted in the back of the car---C5 and C6 Corvette's have this style.

A standard transmission/bell housing bolts directly to the engine and the power from the engine passes through the gear changing assembly into a tail shaft and in most cases ties into a drive shaft that is connected to the rear end or differential.

Some mid engine cars have a transmission that bolts in front of the engine protruding into the cabin and uses a shaft from the trans to drive the differential mounted directly behind the engine creating the correct orientation for the axle drive components in a mid engine car layout. Lamborghini Countach and the later models use this layout.

Confused??? Don't feel bad---I wrote it and now I'm confused. (:>) Hope this helps.

Kirk

ZF

Jack,

More simply put (I like simple), most typical transmissions send the power shaft out the back. In a rear mid engine car, typically the transaxle (incorporating the TRANSmission and the rearAXLE) sends the power out the sides. The benefit of this is to reduce weight and overall length. The center of the black parts in the photo that Mark (DEVIL) posted are where the driveshafts are attached (and what rotates to drive the wheels).

Mark

The Pantera was my first encounter with 5 DS-25-x series ZFs. In recent years, as I became interested in mid engine component cars, I’ve learned more about a number of other viable alternatives but just have to say that I think -2 ZFs are a fine piece of engineering and I can’t ever see anything but the ZF residing in my Pantera. Have I ever found the need to alter the gearing to suit or wished I had a 6th gear for cruise? Occasionally yes (though I don’t do much highway cruising) but that’s no different than matching any other transmission and power train on any other non-Pantera build.

Given that the ZF is a 5-speed sync’d gear box and a limited slip differential, it is a very compact package that even with bell housing is light enough that I can pick it up from the floor and set it on my bench (maybe 175lbs or so?). The dense packaging is also why they require a fair bit of knowledge and special tools to maintain. With a few exceptions and a little common sense, they can perform very reliably with about anything that can be thrown at them with a normally aspirated sbf and this has been proven time and time again in many forms of motorsport. For the era they were developed, IMO, they are quite an impressive and venerable piece of engineering and a pretty darn nice compromise of performance and reliability.

Has an input shaft ever been snapped with high HP, slicks, and a 7krpm dump of the clutch-Yup. Do syncro’s wear out with use? Yup; but you’d have to confess the same for top-loaders and Muncies. Did they ever break under racing conditions? Yup; but what doesn’t? Did the GT40s of the 60’s squat a few of them? Yes, but the Hewlands and T44s were not exactly free from failures either. That environment humbled a lot of equipment and racers for that matter. Being able to extract high performance without breakage is another driver skill that helps keep equipment light and reliable.

On top of it all, the ZF just looks like it belongs in the PCar, and frankly, I’d say the same for GT40s. Aside from price to acquire and repair, I just can’t see why to deviate in a PCar.

Now, step out of the Pantera world, and I think similar cases can be made for G50, and perhaps ZFQ. Even though the initial results look very promising, ZFQs need to demonstrate a longer time-proven track record before they gain equal standing to ZFs in my eyes. Besides, they’re not even available in PCar configuration.
As far as Ricardo’s go, I think they’re probably in a class of their own as far as power/torque handling potential, but they’re a much larger unit than a -2 and require extensive chassis mods for Pantera use. If I built an SL-C, it would have a Ricardo.

Are there other high end boxes? Absolutely, but stratospherically priced.

By the time you’re done with the mods, I just don’t think the alternatives really saves you much money in the end for a Pantera.

The other lower cost boxes such as the Audi or Renault being used in component cars, though certainly viable, just don’t stack up in the durability category IMO.

It’s also worth noting that the new -2 boxes available from RBT IMO are actually improved versions with M1 main case and many internals.

Would I like them to be more economical; -You bet. But realistically, they are and always have been a low production volume part. I’m pleased they continue to be supported and available and even though the prices are what they are, I don’t think Lloyd or his partners are getting rich and anyone that knows them would know this to be true. I don’t begrudge them making a living.

Sometimes I think we can forget how blessed we are with the Pantera. Try having this conversation with the Lambo or Ferrari gang.

Best,
Kelly

I have a great ZF story.

A good friend who purchased his car in 72 and (still has it today) lost a transaxle after 12 thousand miles. He received a new one from Ford and was able to keep the broken box. I restored the car many years later and he gave the old box to me as part of the payment. It sat in my shop until the late 90s when it was needed for a project.

So I opened it up and found the problem---second was severely broken but everything else was in great shape. Now in the tear down I came to second on the main input shaft, started to remove it and UH-OH! Where's the bearing? Now keep in mind the transaxle was driven 12 thousand miles----yes 12,000 without a bearing in second before it let go.

Frankly I was so impressed, I called ZF which was still in Florida and complemented them on a fantastic design.

Off topic---how about this for German engineering. This copy was built up from the prints and remains of the real bat wing bomber we captured after the war was over in 1945. They say the radar signature was so small even by today standards, we never would have seen in coming---and with a top speed of around 600 MPH, we never would have caught it.

I stumbled onto the model pictured below last year in San Diego at the air museum which was very nice. Drove up the they had a SR-71 racked outside and from then on it was discovery after discovery---plus several very good simulators inside---well worth seeing. I love San Diego.

Thanks guys. And I appreciate the support of the ZF. Being so ill-
informed on the topic of mid engine cars all the above is very
valuable to me. I was not intending at all to cast dispersion on the
ZF, so if it sounded that way I am sorry, for sure! I just could
not imagine why mechanically, a car could not be built, say using
a 1969 Mustang Engine & transmission, connected to the normal
differential, just using a universal joint and no shaft, and build the
car in a mid-engine format around such a set-up. What I am get-
ting here is it would be a LONG car. AM I ON THE MARK? Thank you.

Regarding KE's ZF NO BEARING story, that's pretty darn impressive!
As to the above air craft, a B2 Bomber ancestor I'd call it...

Jack,

No worries---early ZFs did have issues and even Ford thought the DS-2 was going to be problem which is why they purchased so many for their warranty stock in the 70s. That was good for AmeriSport ending up with 53 NOS ZFs in the 80s.

I have a copy of the original report Ford did with Detomaso in 1970 about the transaxle----very interesting their thoughts (good and bad) and how well the trans did and still does.

Sorry I went off topic with the old school WWII stuff---just love old planes.

quote:

Originally posted by AdvenDriver:
Thanks guys. And I appreciate the support of the ZF. Being so ill-informed on the topic of mid engine cars all the above is very
valuable to me.

Besides here, you might have a look over at the GT40 forum if you want more transaxle reading. The component car guys can get pretty creative.

http://www.gt40s.com/forum/

quote:

I was not intending at all to cast dispersion on the ZF, so if it sounded that way I am sorry, for sure!

I did not take it that way at all. The statements were not targeting any individual. It was just me stating my own view that transaxle swaps in Panteras are attempts at fixing something that isn't broken.

quote:

I just could not imagine why mechanically, a car could not be built, say using a 1969 Mustang Engine & transmission, connected to the normal differential, just using a universal joint and no shaft, and build the car in a mid-engine format around such a set-up. What I am get-ting here is it would be a LONG car. AM I ON THE MARK? Thank you.

Yes, in a nutshell.

quote:

Regarding KE's ZF NO BEARING story, that's pretty darn impressive!
As to the above air craft, a B2 Bomber ancestor I'd call it...

Right on with the B2 comment as well and thanks for that post on both subjects Kirk. I rest my case . Having spent my life in the defense industry, I can tell you the Germans were doing some remarkable things. We are fortunate we intervened when we did or we (yes including our EU friends) would all be goose stepping now with our right arms straight and chin stuffed into our right shoulder.

With respect to the Batwing plane, it's not nearly as large as B2 and I suspect would have a small fraction of the payload, but I bet it didn't cost $1B per copy (yes $1 Billion!) even corrected for time value of money. If 600 mph is fact it would be every bit as fast B2, but B2 is subsonic so as to have low heat signature.

Take care,

Kelly

Adven,

Nobody here gets offended when inquiries are made, no matter the kind. We all love to educate anybody who will listen about our 'Diamonds in the Rough'! We truly love Panteras and enjoy bringing others into our fold.


Thanks for the picture, Kirk! I love WWII warbirds myself.

Michael

Here is a link to the National Geographic special on the design. http://channel.nationalgeograp...erview#tab-Photos/23 There are stills on the link and the build speical on the model is airing on NGEO channel December 9th at 9PM if anyone is interested.

quote:

Originally posted by Kirk Evans:
Here is a link to the National Geographic special on the design. http://channel.nationalgeograp...erview#tab-Photos/23 There are stills on the link and the build speical on the model is airing on NGEO channel December 9th at 9PM if anyone is interested.

Now if you want a laugh, until I clicked on the link I
thought the above show was about the ZF based on
how K.E. typed out his thought.

That is funny Jack. My typing and spelling are always good for chuckles.

The intended off topic link was for the plane---but of coarse lacking the written detail one would assume it's a ZF special... Very funny when you open the link.

Made you laugh so it was well worth the error.

Sorry to all, but this post is totally off the topic of ZF's, but slips into
the above "funniness".
Here's a "funny" that happens where I work all the time; and we have to proof
read each other's reports because of this zany English grammar, which we all
"slide into". It's an aspect of the English language that shows itself often!
Imagine a police report as follows, : "Bob punched John in the face; then he
hit him with a pipe. Immediately thereafter he shot him dead." Though the
grammar "flies", we can't say for sure who's dead, nor who got hit with the
pipe. That's why in many places such reports are written with the names of
the persons involved typed over and over again. He, him, she, and all other
pronouns are FORBIDDEN. Again, a quirk of our English language. When we point
out to one another, the parts that can be understood to mean more than one thing,
it usually takes about 2 -3 seconds for "the other side" to show itself to the
original writer. Then it always results in a big grin and we get the GRACIE ALLEN
award. {If you're too young to know what made her so funny it's youtube.com time;
to view some classic clips of her with her husband George Burns} SO, please don't
feel picked on because it certainly is NOT something I've never done. It just
made me laugh when I expected to see an engineering show about transaxles and
the airplane info popped up! I said to myself, "JUST LIKE AT WORK!!!"

Kirk,

Thanks for sharing that link. I very much aprreciated it!

Michael

Just to be clear: that bat-wing is only non-operating a model, right? Is it full-scale? It looks tiny.

Yes it is a full scale replica of the original fighter/bomber. One of the 2 originals crashed from engine failure taking the test driver with it. During testing it was much faster and more maneuverable than even the ME 262 jet. There was nothing in it's day close.