Crown wheel Rotation

[Leon]

Hi Guys,........ I have a quiery about crown wheel and Pinion rotation when inverting the likes of ZF transaxles to use in application's where the axle shafts need to be leveled. I see most GT40's using ZFs do run them upside down. If you do this then You need to flip the diff to the other side to get it to drive in the right direction (am I correct in this assumtion) if this is the case and you dont change the Ring and pinion then is it not then driving in what would be reverse, and there fore be creating a lot more side thrust. In the case of "P"car trans where you simply flip it end for end to achieve the result you still drive the Ring and Pinion the same direction. My main question is, Does this pos a problem in the ZF or other transaxles that need to run upside down to get the right Engine to trans and axle shaft relationship height. cheers Leonmac

 

[Russ Noble]

Leon, the teeth are still driving in the same direction but because the ring is on the other side of the pinion it rotates the other way. Anyway the ZF was originally like that, it's the Pantera that's upside down!

 

[Jac Mac]

ZF & P.930 have pinion & crownwheel at same center heights so assuming you still have normal engine rotation then drive sides of tooth remain same regardless of which side crownwheel is installed. These can oviously be installed crankshaft above or below axle heights.

G50, & ZFQ use hypoid crown wheel/pinion ( Offset pinion & CW heights ) and cannot be swapped from side to side without making a special CW & P set to suit the application, thats why G50 is installed in low/upside down position for GT40.

Im not sure if they have made the other CW/P set yet for ZFQ in Pantera applications.

IIRC the P930 & ZF crank shaft/axle center height dimension is around 3.25" while the Hypoid helps reduce this on ZFQ & G50.

 

[Leon]

OK......I'm just trying to get a clear picture in my head, I know that flipping the "P"box end over for mid engine application is good because the Drive force between Ring and Pinion doesn't change. I understand that if the pinion and axle centre's are the same, then you can flip the diff to the other side when inverting a trans to get the right drive direction, so with the ZF ie Pantera Box are the teeth the same pitch both side's so it matters not which side of the tooth your forward drive is ???? the reason I'm asking is when I look at the teeth on the R&P from a Nissan the teeth are square to the drive side so there is little or no side thrust and if you drive in reverse the teeth are at an angle to the drive force creating high side thrust. If the teeth angles are equal then the side thrust will be the same in either direction?????

 

[Jac Mac]

ZF..ie Pantera is same as P 930... Spiral bevel, nothing has changed.... drive is still being applied to same side of tooth, crankshaft is still turning in same direction.

The nissan will be hypoid..ie pinion C/L below Crown Wheel C/L. Cannot be flipped like above Spiral Bevel.

 

[Leon]

Thanks Jac Mac, ........I just went and had a look at Russ's build log where the pictures of his trans are and I can see the difference in the teeth profile compared to the Nissan. this helps explain a few things I was wondering about with a Trans axle build. Cheers Leonmac.