| Author | Message | ||
| anthony s (Ants2au)
New member Username: Ants2au Post Number: 7 Registered: 2-2003 |
So what does it take to break one of these shafts on a 512TR/M? I have heard they are weak, but how much do you have to abuse it before it actually breaks? Will doing 0 to 200Kph drags (not actual tyre burnouts) do the trick, or is it more the driving on the track that eventually will break it? is it something that will fail after repeated racing or just fail due to a shock load? | ||
| William H (Countachxx)
Intermediate Member Username: Countachxx Post Number: 2219 Registered: 2-2001 |
5{12TR, & 512M boxes are all similair. Miller Motors told me they asked Ferrari Spa who told them that a 512M box Will fit on a 512TR. I would imagine that a BBLM box would also work. Thanks for all the help guys, I have some calls to make  | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1638 Registered: 1-2001 |
William -- Makes sense that the lower left shaft would fail (either by itself or if something downstream goes wrong) since it has the greatest slenderness (length/cross-section). Does the 512TR gearbox/diff have a fairly similar internal layout to the TR? (I would've guessed F would have beefed it up some already knowing the TR issues.) | ||
| James Glickenhaus (Napolis)
Member Username: Napolis Post Number: 941 Registered: 10-2002 |
JRV What about a box from a 512BBLM? Were they strong? Best Jim | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 1252 Registered: 11-2002 |
William, from the TR Box failures I've seen and other simular type tranny failures...the boxes experience two problems...Flexing & Heat...the first mod I'd look into is Billet Diff Side Plates like we put on the Comp Daytona Boxes...and possibly some spray bars...and an Oil Cooler, as well as the Flexing Shaft issue. imo...Flexing is the biggest problem you can find someone to help you address. with all these .02 cents thrown in you can almost make the down payment on the fix...LOL | ||
| James Glickenhaus (Napolis)
Member Username: Napolis Post Number: 940 Registered: 10-2002 |
William Gordon at Akien/Hutson Historics could fit one of those boxes. Best Jim | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 484 Registered: 11-2002 |
BTW, I mean reasonable cost for what you want to accomplish. You may be looking at some $$$, but it will give you the reliability you require. Spend cheap, get cheap. IMO, don't bother reinventing the wheel, call someone who's gone down this road. "Speed costs money...how fast do you want to go?" - anon | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 483 Registered: 11-2002 |
William, Here's your solution: Frank Capo Modena Engineering 13 Patrick Court Seaford, Vic 3198 Australia +61 (39) 782.4420 Fax +61 (39) 782.4260 Awesome stuff. I converted the internals of our 308 GT car to Modena Engineering's dog drive straight cut set up. Reasonable cost, great reliability. They can build one for your car, and probably have already done so for a Kiwi in Interserie where allot of Ferrari's run. They can also retain the helical gears if you want less noise. Call 'em. 16 hours ahead of Eastern Time Zone in US. Let us know what comes of it. Rob | ||
| Craig Dewey (Craigfl)
Member Username: Craigfl Post Number: 564 Registered: 1-2001 |
First, I would take it to an engineer who specializes in failure analysis. They should be able to tell you where they think the failure began and why it happened -- if it's a fatigue failure, defect or a strength problem. If you're breaking main shafts, it's probably happening at a diameter change. There are several things that can be done including using a different material, shotpeening, changing the radius of the transition, etc. depending on what will fit. These may be modifications to existing shafts or may require machining a new shaft. Of course, then, you might just be chasing the failure around the rest of the gearbox for the next weakest link but this would be a good place to start. You may be in a situation that requires a shaft replacement for every race weekend... | ||
| William H (Countachxx)
Intermediate Member Username: Countachxx Post Number: 2213 Registered: 2-2001 |
I bought a Jericho NASCAR road race trans for my 68 Vette roadster I am restoring. Would Jericho or Hewlet build me a trans if I send them the case ? Is that how it works ? IF they have to build the case its gonna be Huge $ Steve, from your drawing I'm guessing its in the Lower left corner where the trans picks up the power from the engine. | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1637 Registered: 1-2001 |
William -- Here's a (poor quality) jpeg of the upside-down TR gearbox/diff -- can you identify the failing shaft (lower left, lower right, or upper right in the jpeg):  I'm thinking that if there was some single/few components that could be replaced to improve the TR gearbox/diff the F engineers would have issued a TSB and we'd have all done it by now. My guess is that the TR failure is more subtle -- e.g.: 1. flexure of the housing, 2. causes some internal components to interfere/bind, 3. then something in the power transmission train fails due to #2. On that TR drawing, I can envision the pinion shaft flexing the supporting web of material containing it's large tapered thrust bearing so much that the cylindrical bearing supporting the shaft below it locks up causing either the lower left or lower right shaft to fail (but the real problem was the excessive internal flexure of the housing itself). I'm not sure that the 512TR is the same, but I just wanted to say the part that explodes sometimes isn't the root cause of the problem. I still don't understand how these 1000 HP turbo TRs don't leave a trail of gearbox parts behind them... | ||
| James Glickenhaus (Napolis)
Member Username: Napolis Post Number: 939 Registered: 10-2002 |
William The strongest cheapest thing you could do esp. in your race car is to fit a "Quaiffe (sp.) or "Jerrico"(sp.) sequential race box or a Hewlet, or RBT/ZF. Even Ferrari used ZF's in some of their race cars (P3) and the internals of the 333 box are Hewlet. Ferrari/Michellotto race trans are very strong as well and Sal can help you there but they are not cheap. Best Jim | ||
| William H (Countachxx)
Intermediate Member Username: Countachxx Post Number: 2212 Registered: 2-2001 |
This is my 3rd trans rebuild. the first 2 had the main shaft break or deform, this one is probably broken & it seems it wiped out 1st gear also. My mechanics tell me that thie main shaft acts like a fuse and sacrifices itself to save the rest of the trans. So I would need to strengthen the whole trans before strengthening the main shaft or I'm really asking for trouble. Jim, I'll speak to Sal at WWOC, thanks guys | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1635 Registered: 1-2001 |
I think the most attractive advantage for the straight cut gears vs helical gears is better efficiency (less power lost to heat generation) rather than better strength (IIRC a helical gear is actually a little stronger since the effective width of each tooth is a little greater than the same width spur gear). I've got a cross-section poster of the TR gearbox/diff and if the 512TR is still similar I'd say the weak point is the structure to support the axial load of the pinion shaft from the hypoid diff gear. Are you having a single internal component fail or is the damage more extensive? | ||
| James Glickenhaus (Napolis)
Member Username: Napolis Post Number: 937 Registered: 10-2002 |
William Sal @ WWOC can help you out get in touch with him. Mention my name. Best Jim | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 1250 Registered: 11-2002 |
William, I think a very good starting place for a tranny guy would be Mr. G's mechanic that he referenced a time or two either about building the P4 tranny or maybe it was about rebuilding a 333SP tranny. We were talking in the past about some special mods those tranny's have. Send Mr. G a private em or get him to answer you on here. If that doesn't bear fruit let me know. | ||
| William H (Countachxx)
Intermediate Member Username: Countachxx Post Number: 2211 Registered: 2-2001 |
Thanks JRV, you are always a great help. Do you know any good shops that specialize in turning road trans into race trans ? Thanks again | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 1249 Registered: 11-2002 |
>>Will a race trans with straight cut gears be stronger than the regular road trans ?<< Not exactly stronger per se. The striaght cut gears change the stress loading, reducing/changing stress on the gears, shafts and the case. >>Do you just replace the regular gears with custom straight cut gears or is there more to building a race trans than that ? << Yes you "can" just change the gears, but generally there's alot more to it than that. The real answer to beefing up a gear box is to find out what is breaking and most importantly "why", and effect changes to address the weakness/durability issues with the parts or the design itself. It's important to understand/find out if the parts are to weak or were overheating or a combination of both that caused the failure and address all the issues during a rebuild modifying, adapting, changing, upgrading as necc. | ||
| William H (Countachxx)
Intermediate Member Username: Countachxx Post Number: 2210 Registered: 2-2001 |
It seems I'll need to build a race trans for my 512TR race car. Will a race trans with straight cut gears be stronger than the regular road trans ? Do you just replace the regular gears with custom straight cut gears or is there more to building a race trans than that ? Thanks |