Wobbling crank?!

[kart_racer]

Some of you will have read my previous posts on flywheels and my poorly running VT Ecotec.

I successfully completed a manual conversion 12 months ago, but have had problems since.

At the moment, it comes down to the crank seeming to wobble. At idle the crank bolt & harmonic balancer are visually wobbling slightly. This visually continues at revs until around 2500 and possibly higher (but is spinning too fast to see anything).

Also, at the lights, if i press the clutch in slightly i can feel pulsing through the pedal which makes me think the flywheel is experiencing the same wobble.

I have replaced the clutch/pressure plate (with new HD solid flywheel), as well as the harmonic balancer with barely any change. The solid flywheel seemed to change the feeling of the vibration in the engine (had an aged dual mass before), but it seems much the same.

The engine idles quite roughly and also sounds quite horrid through the rev range.

I've ruled out a cylinder down as removing each ignition lead or injector makes a difference at idle.

It appears that the timing might be out, and if the crank is moving, so is the harmonic balancer and therefore the interruptors for the crank sensor. I wonder if this is causing the miss.

The power up to 2500-3000 rpm is also quite 'stepped'.

I have also: changed O2 sensors, cleaned throttle body & plenum, tested resistances of all leads and the coils, readjusted the water pump pulley which was spinning off centre slightly, tried running the engine without the belt (issues all remain).

Anyone have any ideas? The engine really feels terrible, like an old truck, and I really hate driving the car like this. The power is poor at low rpm, so i have to rev it to take off or accelerate, the sound of the engine is painful to my ears, and the clutch action is very difficult, as if the flywheel & clutch plate aren't meeting properly because of the moving crank.

Could this be a valve issue or something? I would have thought if the crank bearings were gone the engine would have stopped long ago or atleast had some sort of knocking in the bottom end.

[Not_An_Abba_Fan]

When you did the conversion, did you put the spiggot bush in the crank to take the input shaft of the gearbox?

[kart_racer]

Sure did, and also replaced it with a new one when doing the solid flywheel.

[Not_An_Abba_Fan]

And this has only happened since the conversion?

[kart_racer]

Didn't notice it beforehand, there may have been a slight miss at idle but nothing like it is now.

Do you think the input shaft of the gearbox might be moving the crank somehow?

[Not_An_Abba_Fan]

It wouldn't make the crank move, but would explain the pulsating clutch pedal.

[Simonn]

iv got a solid flywheel and hd clutch kit in my vx eveythingf was installed properly and I have minor vibrating/pulsating pedal. I just put this down to the solid flywheel not being able to dampen vibrations like the old dm one did.

[kart_racer]

Hmm well the pulsating pedal is the least of my problems, just one of the symptoms.

Anything else I should be looking at to diagnose what is happening?

[Simonn]

wouldent it mean that your crank bearing are stuffed if your crank is wobbling?

[kart_racer]

I would have thought they would have kicked the can by now if they've been stuffed that long.

Another symptom is shuddering on gear changes, or more specifically when releasing the clutch after a gear change.

Weird thing is the power seems quite good on a cold night and the fuel economy was pretty good on a run down to the snow not long ago. But around town it's worse than it should be, probably the extra right pedal to get it to move like it should.

The shocks seem to have failed after only 18 months so the car is a right dog to drive at the moment.

[delcowizzid]

did you fit a manual memcal when you did the conversion obviously.ide say its a balancing issue can the flywheel co on 2 ways

[Swordsy]

Another thing to look at, is the harmonic ballencer stuffed? I'd check that out.

[kart_racer]

did you fit a manual memcal when you did the conversion obviously.ide say its a balancing issue can the flywheel co on 2 ways

Yes, manual memcal fitted. I have tried refitting the auto memcal to test the tune and all the symptoms remain the same.

As for balancing, the Mal Wood flywheel comes with alignment holes for the auto crank. He has done many conversions on these cars without issue.

Another thing to look at, is the harmonic ballencer stuffed? I'd check that out.

Replaced the harmonic balancer with a new one, no change.

[Not_An_Abba_Fan]

I guess the next step to eliminate a bent crank is to get hold of a dial gauge and check it. Also check to see if you have any run out in the flywheel.

[VSteve]

Does the crank have any end float? How many km has the engine done? Sounds like worn bearings to me. Manual engines seem to wear them quicker, especially ones with heavy duty clutches.