Engine movement????

[zishan03]

Hello Everybody,

I have a quick question, sorry if it has been asked before.

When a car (namely mine, 2002 C200 Coupe) is in Neutral with the handbrake on and the engine is revved, is it normal for:
a) me to feel the car shake when sitting inside it?
b) with the bonnet open, to see the engine actually move quite a bit?

Thank You

Zishan

 

[stwat]

Some movement is quite normal, but if its moveing quite a lot, it could be one of the engine mounts that need replaceing.

Stu

 

[Dieselman]

You shouldn't feel the engine shake but the torque of the engine will cause it to heel over as it is revved.
Try this in a torquey diesel and the whole car heels over.

 

[zishan03]

You shouldn't feel the engine shake but the torque of the engine will cause it to heel over as it is revved.
Try this in a torquey diesel and the whole car heels over.

Sorry if this is a dumb but could you please educate me as to what 'heel over' means please.

Thank You

 

[tim.100]

Sorry if this is a dumb but could you please educate me as to what 'heel over' means please.

Thank You

It's Newton's law - every force generates an equal and opposite reaction. So when the mass of the engine (in a longitudinal installation) accelerates, the car rolls in the opposite direction. The 'heeling over' is the same as if you pushed on the side of the car when it is parked.

The effect may be more significant in diesels due to the higher rotational mass - e.g. heavier crankshaft and flywheel.

My Land Rover Tdi used to roll a little whenever you started the engine.

Hope this helps,

Tim

 

[DrNick]

Some high powered piston engined fighter planes used to try and roll over if a lot of torque was applied at low airspeeds (so I've been told) so much so it could be uncorrectable - especially when it occurs near the ground.

Doesn't really apply in this case though....

 

[tim.100]

Yes - but this was propellor-related torque action. RR Merlin-powered planes, among others, use propellor pitch control to reduce this.