8 replies to this topic

[Benno - SAC]

In the Hawk 7 motor thread I read following interesting quote by Jersey John:

 

Rule of thumb for best performance:

Hypoid bracket (motor is flush to chassis bottom), use angled pinion only.
Non-hypoid bracket (rear of motor angled up), use a straight pinion.

 

I don't have much experience with inlines and never heard of this. Can someone explain to me why?

[Cap Henry]

You can use either style pinion for either application with no issue.

[Jaeger Team]

no issue or best performance ?

[Alan Dodson]

Cap is right, but in the hypoid configuration I think the angled pinion breaks in quicker. Just my opinion, no hard facts. All full size cars use angled pinions mostly because they are much quieter. With plastic crown gears noise is not usually a problem. The ARP angled pinion is a quality piece that I have never had a problem with, so I just stick with them.

 

Happy Thanksgiving to all! BTW, this forum is one of the things I am thankful for!

[JerseyJohn]

I disagree. .there is a difference in efficiency and friction.

 How much? well in retro east where position is determined by hundredths or thousandths It all matters .

Sure you can use a straight pinion on a hypoid set up , but friction will be increased on the crown gears exit. 

In the hypoid st up any given pinion load is distributed over several teeth, resulting in less wear, also the motor, being lower also lowers the center of gravity.

However HYpoid gears  have a  greater degree of sliding friction between the meshing teeth and by there nature produce increased side thrust along the axle'.

Straight gears in a non hypoid arrangement has advantages of reduced side thrust, single point gear contact and less friction. 

 

​So i stand by my statement for best performance  and gear mesh use a straight pinion in non hypoid brackets and angled  pinions for hypoid. 

 

 

 

JJ

[Eddie Fleming]

As I see it John

 

The Hypoid setup you are talking about and in your illustration are not quite the same as the slot car setup. The picture with the spiral cut gears is as used in an automobile. the gears in a slotcar are not spiral cut. The slotcar pinion is just a straight pinion with a little taper to the diameter, and we use the same straight cut crown in ether application. In a slot car hypoid situation the teeth of the gears are never in true proper alignment and depend on the lash or wearing in to mesh smoothly. The angled gear is slightly more tolerant of this misalignment and tends to produce a quieter running car.

 

The angled pinion is just a fancy straight cut gear and tends to work well in inline cars of all type.

[Don Weaver]

John,

 

Completely agree with your statements.  Angled is best with hypoids.  

 

Don

[Ramcatlarry]

Noise IS friction.  Angled pinions will have a lower contact patch until the gear is fully seated.  Hypoids can be heated with a lighter and the motor running at low RPM to alter the tooth form to the undercut shape with nylon gears like Parma.

[Benno - SAC]

Thank you guys!