Big_Ern

Is it normal for the engine not to be able to hold the car on a slight hill if you park it with the tranny in 1st and no e-brake?

or does my motor have really bad compression?

every piston vehicle I've driven has been able to hold the vehicle in gear on some pretty steep hills, but I had to park my GSL on a slight hill at work the other day and it kept slowly rolling down. I can feel each compression 'stroke' as it lurches forwards. Ended up find a rock in a garden to put under my tire

The car still feels good and has lots of power for a stock 12a, so I'm wondering if this is normal for rotaries?

Big_Ern

nevermind. Did some more searching and found my answer. Apparently this is normal. Guess I need to get my e-brake fixed (cable broke from the axle twisting when i broke both lower suspension links at the same time...)

or maybe I'll just keep that rock in my car

64mgb

iTrader: (1)

I think the motor should still hold it, even without the parking brake. I use my parking brake all the time anyway, but I think the motor should hold it unless you're on a really steep hill.

Rich

steve84GS TII

Since the engine movement is so slow,compression is minimal since most built up pressure is going to leak by.A lot of what holds you is internal engine friction,just like during "compression braking".......which is misleading, because when the throttle plates are closed,what is there to compress?!

Since rotaries have few moving parts,there is little friction to hold the engine in place.Plus,rotaries have a naturally low compression ratio.....and your GSL has rear disc brakes,which make poor parking brakes since discs require a lot of pressure to generate friction.This is why most modern rear disc equipped cars use mechanical drum parking brakes integrated into the rotor hat.Drum brakes use leverage advantage to apply the shoes,so they require very little pressure to grab well.Plus,shoes have more surface area than pads,so they can grab and hold well,even with only a cable pulling them taught.

Kentetsu

Low engine compression will make it worse, but even a good engine will hardly hold on a good slope. Reverse seems to work a little better than 1st though...

Big_Ern

ya reverse is a hair lower gear ratio which helps to hold it, but still not enough. I'll just keep a rock handy until I get the cable fixed


Good explanation Steve, that makes a lot of sense

Rogue_Wulff

Steve is 100% correct on this.

I'm still not sure how the parking brake came to be known as the "Emergency Brake"...... Must have something to do with the Park feature in auto trans.

Big_Ern

It serves both purposes. Its original design was to be a backup emergency braking system incase your regular brakes fail. But it also works as a parking brake

Here's a quote from wikipedia:

Rogue_Wulff

I was being a smart-***. A true "Emergency" braking system will utilize all wheels, not just the rear. The hand brake's primary function is that of a parking brake. Failure to use this device during the parking section of a driving test can cause you to fail the test........

kleinke

I have always simply call it the "Hand Brake," which is the common nomenclature. Many Cars will roll when parked with gears engaged; the behaviour is entirely normal and not exclusive to a Rotary Engine Vehicle.