Engine Moves At High Revs

[SAM LOVERS HER TOYOTAS]

Heres one for the real experts...maybe...My 2001 1.8vvti hatch SR...

Is it normal for the whole engine to move when you revving it hard? With the bonnet open you can see the engine rock backwards when you pull on the throttle...Also sitting inside the car with the gaers in neutral and revving hard you can actually feel the engine moving...again is this normal or could it be the engine mountings? Actually how do you know/tell if the engine mountings are worn/faulty/etc??? Please help guys. Any advice very welcomed!

Sammy

[SF695]

Mine does that too. In fact the engines on all my cars have done it. The mounting of the engine allowes for some movement to absorb vibrations i guess

[Jamesbelfast]

All engines tend to move slightly under the torque but anything excessive should be treated with caution as this can cause exhaust pipes to fracture, etc.

With the bonnet open and someone watching and the handbrake firmly applied let out the clutch gently - any accessive movement should be easily noticed. Also watch and see if the gear lever dips badly. Listen for clunks or rattles.:)

[GeorgeJoseph]

Heres one for the real experts...maybe...My 2001 1.8vvti hatch SR...

Is it normal for the whole engine to move when you revving it hard? With the bonnet open you can see the engine rock backwards when you pull on the throttle...Also sitting inside the car with the gaers in neutral and revving hard you can actually feel the engine moving...again is this normal or could it be the engine mountings? Actually how do you know/tell if the engine mountings are worn/faulty/etc??? Please help guys. Any advice very welcomed!

Sammy

Hello Sammy,

I am no expert, but I am thinking by you mentioning "revving it hard" , you mean a rev range of 5500 rpm+ into the red line marker in the rev/rpm counter. I also persume you were doing it just to test the stability of the engine .

Yes , it is normal for the engine to vibrate in the redline range - while driving, if you happen to be pushing the revs to the redline you will notice that the car actually looses power - I feel this is because all inline 4 cylinder engines (the AZ,ZZ,FE engines are all 4 cylinder inline)

are a bit unbalanced , because of the asymmetry induced by the movement of the 2 pistons at the top dead center and the 2 pistons at the bottom dead center when going through their storkes - this just means that the accelerations caused by the opposing pistons are not cancelled out. The effect of revving to high redline RPMs is that this asymmetry is magnified and hence the feeling that the engine is planning to jump out. The actual movement of the engine(the engine itself and not the crank shaft) in this asymmetry would be an upwards and the then downwards push.

It also stresses the engine mounts.

On a different note, these engines are not expected to run in the redline RPM. Constant stressing in the high rev range with varying loads will cause engine wear. Over-revving from cold starts is very harmful to the engine, since the oil flow to all the components would have just started off ...

This issue does not happen on engines having V6,V8 ... configurations.

[Thermal]

Is it normal for the whole engine to move ...

Hi Sam,

Yes, that's perfectly normal for inline engines to move a little when revved up and down.

All engines are mounted to the chassis on rubber blocks, to eliminate transfer of vibrations from the block to the chassis and to compensate the torque.

If the engine would be bolted cold to the chassis, these vibrations and torque would cause the engine to be ripped from its mountings in the end, due to material fatigue.