Difference Between Helical Gears And Straight Cut

[cudvig]

So the car im am looking at has helical cut gears in the oil pump, he said it reduces oil pressure? but is quieter. Is this a good or bad thing and could someone expand on this more?

THanks
Colin

[Jed]

Are you talking about a DSM? If so, anything newer than 90 or 91 (somewhere in there?) I believe should have helical oil pump gears. The helical style does make less noise especially on those cold winter mornings when you start your car. As far as lowering oil pressure, I wouldn't think it would make that huge of a difference-at least in our cars.

[niterydr]

Unless you are having problems with excessive oil pressure, reduction in oil pressure is typically a bad thing. It usually leads to oil starvation of different parts of the motor, pending how the system is routed.
What kind of car?

[cudvig]

a 91 galant VR4

[JustROLLIN]

To give you an idea what the gear differences are, look at it this way. Helical gears are cut an angles, the gears spline into each other at an angle, not directly at each other. Like this ///
\\\

While spur gears are straight cut gears. When you back up in a manual transmission car, that noise or whine you hear, those are the spur gears singing. They meet at a straight point, versus at an angle. They tend to not be as strong as helical gears due to a single contact point.

Just more info for ya.

[cudvig]

I know! i just mean like whats the difference in an oil pump + and - i guess, sorry for posting a wrong question. and thanks for the info anyway