What can I do that the zf can handle 850nm ?
Quife also not fit in a pantera.
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You need to speak with Butfoy. I'm not sure that you can increase power handling of the unit.
He's the one that said it isn't the HP but the torque handling is the limiting factor.
He was saying he used 550 ft-lbs as the guideline.
There are others here that have not blown the things up with a lot more power documented on dynos then that.
I suppose you just run it until you hear and feel the gaboom? Then you just dial down the power?
He's the one that said it isn't the HP but the torque handling is the limiting factor.
He was saying he used 550 ft-lbs as the guideline.
There are others here that have not blown the things up with a lot more power documented on dynos then that.
I suppose you just run it until you hear and feel the gaboom? Then you just dial down the power?
From what I know the ZF's are very strong , the German's have always a high security level from 100%.
Only see them destroyed when you jump on full trottle , the wheels comes lose from the road are spinning and when you come back on the road
give's a lot of stress for the gearbox.
Simon
Only see them destroyed when you jump on full trottle , the wheels comes lose from the road are spinning and when you come back on the road
give's a lot of stress for the gearbox.
Simon
Les Gray has a great story about Jim Click's GT-40 ZF getting destroyed with that exact maneuver. The rear wheels came up under full throttle, and when they came back down - BANG!
There's a lot more to the story that I will leave for someone else to tell....
Rocky
There's a lot more to the story that I will leave for someone else to tell....
Rocky
The ZF and stock half shafts are pretty darn tough as long as you don't abuse them.
Racing is hard on any gearbox I have 250HP and destroyed 3 gear sets my last race weekend, fortunately mine can be replaced in 45 minutes!
Julian
Racing is hard on any gearbox I have 250HP and destroyed 3 gear sets my last race weekend, fortunately mine can be replaced in 45 minutes!
Julian
The limits are around 500 rear wheel horse power, the instillation of big blocks is not being done anymore by aftermarket vendors, due to high TORQUE that was twisting off the Z.F output shaft among other problems. 600 H.P. at the flywheel.
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Question; what can done to improve reliability under racing conditions?
quote:Originally posted by pantera chris:
The limits are around 500 rear wheel horse power, the instillation of big blocks is not being done anymore by aftermarket vendors, due to high TORQUE that was twisting off the Z.F output shaft among other problems. 600 H.P. at the flywheel.
That's my understanding as well but there are a bunch of people running big cubes here. If they are breaking the ZF then they are keeping it secret?
This isn't a new concept though since 427 Fords were being installed in the Pantera since way back in the '70s.
The answer is no one knows for sure but if you break it, then there is a big "I told you so" that goes with it.
quote:Originally posted by Push1267:
Question; what can done to improve reliability under racing conditions?
I recall an article years ago in PI. There was a guy racing one with over 800 hp. He stated that he was going through ZF's until he put a cooler in. With being careful on launches and using a cooler he had not damaged the ZF since.
Cryogenic treating the components ( GT-40 program), the "Candy" racer runs a oil cooler driven off the right output with a pulley ahead of the half shaft turning the pump.
The cars prepared for the 1966 Le Mans win were the American developed MK11’s which were fitted with the 427 cu ins FE motor and Ford built T44 transaxle. Holman / Moody are making the original GT-40 from the original parts NOS or re fabricated the transaxle, Kar Kraft T-44 style 4 speed with magnesium case castings, ratios are changeable. This is the correct and original transmission for these cars.
The cars prepared for the 1966 Le Mans win were the American developed MK11’s which were fitted with the 427 cu ins FE motor and Ford built T44 transaxle. Holman / Moody are making the original GT-40 from the original parts NOS or re fabricated the transaxle, Kar Kraft T-44 style 4 speed with magnesium case castings, ratios are changeable. This is the correct and original transmission for these cars.
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quote:Originally posted by pantera chris:
Cryogenic treating the components ( GT-40 program), the "Candy" racer runs a oil cooler driven off the right output with a pulley ahead of the half shaft turning the pump.
The cars prepared for the 1966 Le Mans win were the American developed MK11’s which were fitted with the 427 cu ins FE motor and Ford built T44 transaxle. Holman / Moody are making the original GT-40 from the original parts NOS or re fabricated the transaxle, Kar Kraft T-44 style 4 speed with magnesium case castings, ratios are changeable. This is the correct and original transmission for these cars.
I wouldn't count too much on the t44 as being an alternative to most of us.
They wanted $995,000, for a "continuation" MarkIV, two years ago when I was at SAAC 39 at VIR.
How much is a transmission for it? Don't bother.
The only way you can get one is to buy the car and take it out. They wouldn't even talk to me about selling me parts.
Of course if your name is Shelby, Foyt, Andretti or Penske I'm sure something could be arranged?
The only discussion they would have about parts was that there were 7,000 pop rivets in a MarkII
"continuation" car.
Easy, precise shifting and no ham-handed abuse or showy 'getting-air' allows higher torque without breakage. Jr Wilson shifted slow & easy in his SS racer and had quite a run of successes with a 900-bhp big-block racer. In the past, Lloyd has made up critical ZF gears of even higher-grade steels than Ford specified back in 1970, for racers who routinely abuse their cars. Note that these upgraded parts are still 'real ZF gears' as supplied from RBT. And a ZF cooler may be of some value in real 1-hr-or-more races.
Bwahahahahaha. . . .
The real answer?
When I had my ring & pinion changed I asked Lloyd what power level the ZF could handle. Lloyd's answer? "I know people that can break an anvil in a sand box . . . " Basically he said if you drive like you want to break it, you will. Smokey burnouts and donuts are a no-no at any power level.
Drive it like you stole it, but carry a spare ZF!
The real answer?
When I had my ring & pinion changed I asked Lloyd what power level the ZF could handle. Lloyd's answer? "I know people that can break an anvil in a sand box . . . " Basically he said if you drive like you want to break it, you will. Smokey burnouts and donuts are a no-no at any power level.
Drive it like you stole it, but carry a spare ZF!
this got me thinking!
Given the ZF is the weak link, is there a way to limit possible damage. my first thought was torque limiting slip clutches, BUT then I though with modern engine controls, why not stutter the motor when torque exceeds the ZF's capability.
the most obvious condition would be a situtation where at full throttle the tires loose contact, then regain grip. a similair situaton was a very big concern to electrical generators, as the power produced by the driver far exceeds the iniertia of the generator when the electrical load is suddenly lost. their engine managent controls had a circuit called Power/Load unbalance, that would sense the sudden loss and stutter the engine immediately.
Surprisingly a google search came back with the necessary components to make such protection for axle drives is available from "automotive" speciilty companies. So I wonder if some auto my already have such control. Maybe it is an advance feature in traction control that is being offered now
Given the ZF is the weak link, is there a way to limit possible damage. my first thought was torque limiting slip clutches, BUT then I though with modern engine controls, why not stutter the motor when torque exceeds the ZF's capability.
the most obvious condition would be a situtation where at full throttle the tires loose contact, then regain grip. a similair situaton was a very big concern to electrical generators, as the power produced by the driver far exceeds the iniertia of the generator when the electrical load is suddenly lost. their engine managent controls had a circuit called Power/Load unbalance, that would sense the sudden loss and stutter the engine immediately.
Surprisingly a google search came back with the necessary components to make such protection for axle drives is available from "automotive" speciilty companies. So I wonder if some auto my already have such control. Maybe it is an advance feature in traction control that is being offered now
The zf was tailored to the 1970-ish version of the 351c.
Ford tinkered with the ratios such as the 2.41 vs. the 2.20:1 first gears, in order to reduce the likeliness of waranty replacements of the ZF.
There is documentation somewhere that Ford thought it likely that 1 out of 4 ZF's would fail under waranty and as a result recommended that Pantera dealers consider stocking them in the replacement parts department.
I saw quite a few NOS still in crates being "wholesaled out" in the late '70s.
I do not think that the waranty "concern" ever quite developed as Ford expected it to?
Having said all of that, the unit is designed for an engine that produces a max of around 550ft-lbs and horsepower of about the same.
I think that obviously they can and are run with much larger capacities but I think the key with that is you need to "pussy-foot" them.
If you stay with a 5.7 liter naturally aspirated engine and somewhere around 500 hp, you are in the ball park of GOOD longevity of the unit.
Things like safety wiring and messing around with better lubes are just going to help you out.
In fact, the cable shifter adds durability to it and certainly will help with the chronic second gear synchro issue.
Other then that probably go with a T44 if you can afford one and figure out how to put it into the Pantera chassis?
I would take a guess on the cost of one at around $35,000, considering you would HAVE to get one through Holman.
The only current users that can accurately comment on the longevity would be current racers. I haven't seen any bitchin' about breaking them but they may just break so much in race situations they don't even mention the ZF's breaking.
I'll bet they all have at least one spare.
Ford tinkered with the ratios such as the 2.41 vs. the 2.20:1 first gears, in order to reduce the likeliness of waranty replacements of the ZF.
There is documentation somewhere that Ford thought it likely that 1 out of 4 ZF's would fail under waranty and as a result recommended that Pantera dealers consider stocking them in the replacement parts department.
I saw quite a few NOS still in crates being "wholesaled out" in the late '70s.
I do not think that the waranty "concern" ever quite developed as Ford expected it to?
Having said all of that, the unit is designed for an engine that produces a max of around 550ft-lbs and horsepower of about the same.
I think that obviously they can and are run with much larger capacities but I think the key with that is you need to "pussy-foot" them.
If you stay with a 5.7 liter naturally aspirated engine and somewhere around 500 hp, you are in the ball park of GOOD longevity of the unit.
Things like safety wiring and messing around with better lubes are just going to help you out.
In fact, the cable shifter adds durability to it and certainly will help with the chronic second gear synchro issue.
Other then that probably go with a T44 if you can afford one and figure out how to put it into the Pantera chassis?
I would take a guess on the cost of one at around $35,000, considering you would HAVE to get one through Holman.
The only current users that can accurately comment on the longevity would be current racers. I haven't seen any bitchin' about breaking them but they may just break so much in race situations they don't even mention the ZF's breaking.
I'll bet they all have at least one spare.
Hi Peter -
There are a couple of the POCA Newsletters you might want to check out.
The Sept. 2015 issue has an article titled "Little Known ZF Facts", and has lots of good information. This article has some pictures of the BMW M-1 setup, with an oil cooler.
The Oct. 2015 issue has an article titled "How Many ZFs Were Made". This discusses the ZF generally, but has some interesting information on some other options that were tried , such as a Hall Pantera 3-Speed automatic transaxle, using Ford C-6 innards.
There is a bit of discussion of the rare Ford T-44 2 Speed crash box built for GT-40s by KarKraft. There is also a box from a Renault integrated into a Pantera at Steve Wilkenson's shop pictured in the magazine.
Unfortunately, none of the automatic options attempted, and discussed in this issue, provided robust performance with powerful engines, but it is interesting to see some of the design solutions.
Note that in this issue, you will find out own Simon joined the club in Oct. 2015.
There are a couple of the POCA Newsletters you might want to check out.
The Sept. 2015 issue has an article titled "Little Known ZF Facts", and has lots of good information. This article has some pictures of the BMW M-1 setup, with an oil cooler.
The Oct. 2015 issue has an article titled "How Many ZFs Were Made". This discusses the ZF generally, but has some interesting information on some other options that were tried , such as a Hall Pantera 3-Speed automatic transaxle, using Ford C-6 innards.
There is a bit of discussion of the rare Ford T-44 2 Speed crash box built for GT-40s by KarKraft. There is also a box from a Renault integrated into a Pantera at Steve Wilkenson's shop pictured in the magazine.
Unfortunately, none of the automatic options attempted, and discussed in this issue, provided robust performance with powerful engines, but it is interesting to see some of the design solutions.
Note that in this issue, you will find out own Simon joined the club in Oct. 2015.
Peter,
Having followed many of your requests for parts etc. what is your intended use of the car? Will you be racing it and if so what series? Many of the vintage racing outfits particularly in Europe are very strict in using original as raced in the day parts and configuration.
If it's not racing and you are just building a high HP street machine, how often will you use it in real anger? Yes there are other transaxle options available; Albins, Mendeola, Ricardo etc. but all cost $$ and will require some modifications to fit.
Julian
Having followed many of your requests for parts etc. what is your intended use of the car? Will you be racing it and if so what series? Many of the vintage racing outfits particularly in Europe are very strict in using original as raced in the day parts and configuration.
If it's not racing and you are just building a high HP street machine, how often will you use it in real anger? Yes there are other transaxle options available; Albins, Mendeola, Ricardo etc. but all cost $$ and will require some modifications to fit.
Julian
Hi GT4, can you translate you 880nm's to lbs of torque?
650 ft-lb.
Not to beat a dying horse, that is going to stress the Z.F. that has not had special treatment and is driven with those considerations. Greg Isokoff (sp) has or had a full racer with those numbers and he told me he had to go through many hardening of parts to make his trany survive, those that are familiar with his car know it is very fast....................!