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Harmonic Balancer

kart_racer

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So I have been chasing engine vibrations and a miss for a while now.

After converting to a manual, a drive showed vibration in the engine. Looking under the bonnet I could see the harmonic balancer & bolt moving noticably at idle. I thought that it would be extremely unlikely for the balancer to go bad at exactly the same time we did the conversion, and assumed that it was a bad or misaligned dual mass flywheel.

The time came to replace the DMF with a solid flywheel and Mal Wood mentioned that vibrations could be caused by an incorrect balancer which, in his experience, didn't show up until the cars were converted to manuals. After putting the new flywheel on, the engine seems different, but some vibraton and misfiring is still there.

Mal Wood told us to get a VR balancer as they were the best ones...My question is, has anyone else heard of this? It seems counterintuitive to me to fit a buick engine balancer to an ecotec?Also, could a bad/incorrect balancer cause the timing to be out and be causing my miss and lack of low down power?

Thanks,

Dave
 
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fitz_vt

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the engine seems different, but some vibraton and misfiring is still there.

Mal Wood told us to get a VR balancer as they were the best ones...My question is, has anyone else heard of this? It seems counterintuitive to me to fit a buick engine balancer to an ecotec?Also, could a bad/incorrect balancer cause the timing to be out and be causing my miss and lack of low down power?

Thanks,

Dave
was the vibration there before the solid flywheel?
The VR balancer is the same, i went to get a flywheel it was VR, VS, VT, VX, VY just like the engine mounts.
 

kart_racer

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Yeah, the vibration has been there since we took the auto out. The solid has just changed it a bit.
 

fitz_vt

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i would check the harmonic balancer, it could be leading to really bad fuel economy, larger strain on the engine and all of the problems you have described. its either that or your cars ECU is not setup for a manual transmission. i assume you did a manual to auto conversion?.

Also on the note of the larger strain and having to put your foot down more i would check the compression and also when was its last oil change?
 

kart_racer

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Well the fuel economy is lower than I would have expected, but I put that down to the miss (only seems to happen at idle but engine just seems a little 'off' at higher rpm).

The thing is, we did the auto-manual conversion last July. I would have thought if the harmonic balancer was on its way out then, that it would have exploded by now?

Oil change was 9000km ago, I've got the oil and filter for the next one which will be tomorrow or early next week. I'm fairly sure there's been two oil changes since the conversion with no change in the behaviour of the engine.

Cheers for your opinion & advice, I'll be changing the harmonic balancer pretty soon.

Does anyone know if Mal Wood is right in saying the VR balancer fits/suits an ecotec?
 

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I think your vibration might be from the dual mass to solid flywheel and the motor originally being an auto, i believe the dual mass flywheels act as a dampner in themselves and absorbs vibrations to an extent,

if the flywheel is not put on in the right way to keep balance your motor could be out of balance, some say the auto and manual motors have a different balance ? i don't know, as the auto crank only has the 8 bolt holes and the manual one has extras for the dowell pins and to align the flywheel to retain original balance. could well be your harmonic balancer, im sure mal wood knows far more than me , buts its just my way of thinking,

Im not far off doing the same thing and converting a vx ecotec auto to manual to use in a hilux conversion, i think i will be using a flywheel that bolts to the original flexplate, the flywheel has a neutral balance so fingers crossed i dont get any vibrations and the original balance of the motor is still retained in the flywheel. marks adapters do them and a few other companies manufacture them.
 

kart_racer

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Done much research down that route and didn't really get a definitive answer, however there is only one part number for the crank, so I can't see there being a different balance, and neither can Mal Wood.

Many other people have done the conversion using factory flywheels on auto engines and never had a vibration.

The vibration was always there with the DMF...in fact if anything it was worse!

The thing is..the engine just sounds 'off'. There's no massive vibration entering the cabin or anything like that.

The miss seems to be at idle and just above, but there doesn't seem to be a misfire through the rev range, just the engine not sounding right. It's been out to 4500-5000 rpm a few times without blowing apart. If the flywheel was misbalanced I would have expected it to start moving at those rpm.

The harmonic balancer & bolt is definitely wobbling around so I'm going to chuck a new one on anyway. The belt is moving on a couple of pulleys and making a squeak. The water pump pulley is wobbling too, so I'd say the harmonic balancer is gone or out of alignment.
 

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So it wasn't the harmonic balancer, swapped it for a new one today, couldn't see anything wrong with the old one and the engine behaviour is exactly the same.

I'm now thinking that the miss at idle is semi staying through the range, making the engine sound like its out of balance. I've experienced having a cylinder down before and this seems different. It's really confusing. Checked all the resistances of the leads and they are well within spec, coils are within spec, one injector is slightly out compared to the rest but seems to be working.

Not sure where to go now, might just have to open the wallet and get a mechanic to give his opinion...

Edit:

I might just add a few symptoms in case anyone can pinpoint what the problem might be.

-Intermittent, but frequent missing at idle
-Weak power until 2500rpm
-General feeling of the engine not being smooth, slight vibration
-Replaced O2 sensors with no change (I don't think they are even read at idle (closed loop)?
-Feels worst when moving from a stop, letting the clutch out, just feels like a tractor...

On another note, with the crank/balancer wobble at idle, the water pump pulley seems to wobble a fair bit too and there's a bit of play in it. I assumed the balancer wobble was pulling the water pump pulley with it...but could it possibly be the other way around?

Cheers for any ideas...
 
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fitz_vt

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So it wasn't the harmonic balancer, swapped it for a new one today, couldn't see anything wrong with the old one and the engine behaviour is exactly the same.

I'm now thinking that the miss at idle is semi staying through the range, making the engine sound like its out of balance. I've experienced having a cylinder down before and this seems different. It's really confusing. Checked all the resistances of the leads and they are well within spec, coils are within spec, one injector is slightly out compared to the rest but seems to be working.

Not sure where to go now, might just have to open the wallet and get a mechanic to give his opinion...

Edit:

I might just add a few symptoms in case anyone can pinpoint what the problem might be.

-Intermittent, but frequent missing at idle
-Weak power until 2500rpm
-General feeling of the engine not being smooth, slight vibration
-Replaced O2 sensors with no change (I don't think they are even read at idle (closed loop)?
-Feels worst when moving from a stop, letting the clutch out, just feels like a tractor...

On another note, with the crank/balancer wobble at idle, the water pump pulley seems to wobble a fair bit too and there's a bit of play in it. I assumed the balancer wobble was pulling the water pump pulley with it...but could it possibly be the other way around?

Cheers for any ideas...


sagging engine mounts, and a sagging transmission mountings, but it could be many things really, i had this problem it wouldn't do anything until 2,500 revs, and then good old Mr. Connecting Rod bearing noise, and End Bearing Noise. but if you haven't experience low oil pressure. i think it might be time to open the wallet to a mechanic, but its really got me stumped i mean i'm no mechanic but i have experienced nearly everything in car car.... a harmonic balancer going, end bearing noise, con rod brearing noise..... this has got me stumped.
 

kart_racer

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Nope not engine mounts, replaced them too thinking they might be causing a jerkiness i was having, they were stuffed but they weren't the problem!

Its weird...its like a cylinder could be down but the power is ok for the most part. I don't get it.
 
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