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I am getting ready soon to have it all balanced and just wanted to know if I should have the clutch and pressure plate done with it?
or just stop at the flywheel?
 

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It's all a matter of personal preferance. I like to have the rotating assembly balanced separate from the flywheel and clutch. I figure that those items get swapped to different brands, burned up or what not and if they are part of the equation the motor needs to be tore down and balanced again with the new items. Those items can be balanced separately. I think that balanced with all rotating parts is probably a better job, but I would rather have the flexability.
 

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I had all of my pieces balanced separately, then checked all together. If I ever have to replace the clutch, I just have to bring the flywheel with it to mount to.
 

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URQ said:
my2000apb said:
yes do it all
The reason I ask is when I change out the clutch the next time down the line it will throw it out of balancing that was done correct?
The clutch has very little to do with engine balance.
Audi 5 cylinder engines are externally balanced, if you want to do it right
bring the pistons, pins, clips, rods, bearings, crank, flywheel and pressure plate.
 

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quattro87 said:
It's all a matter of personal preferance. I like to have the rotating assembly balanced separate from the flywheel and clutch. I figure that those items get swapped to different brands, burned up or what not and if they are part of the equation the motor needs to be tore down and balanced again with the new items. Those items can be balanced separately. I think that balanced with all rotating parts is probably a better job, but I would rather have the flexability.
This method makes sense with a internally balanced motor, not so much with external.
 

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Repaair said:
quattro87 said:
It's all a matter of personal preferance. I like to have the rotating assembly balanced separate from the flywheel and clutch. I figure that those items get swapped to different brands, burned up or what not and if they are part of the equation the motor needs to be tore down and balanced again with the new items. Those items can be balanced separately. I think that balanced with all rotating parts is probably a better job, but I would rather have the flexability.
This method makes sense with a internally balanced motor, not so much with external.
True, but it works and to 8500 rpms all day long.. With the science project I have in the garage it would have been game over a long time ago if I did an external balance. Maybe that's why some of these project cars never hit the road, they are too busy having to pull the motor and re-balance. :p
 

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Repaair said:
quattro87 said:
It's all a matter of personal preferance. I like to have the rotating assembly balanced separate from the flywheel and clutch. I figure that those items get swapped to different brands, burned up or what not and if they are part of the equation the motor needs to be tore down and balanced again with the new items. Those items can be balanced separately. I think that balanced with all rotating parts is probably a better job, but I would rather have the flexability.
This method makes sense with a internally balanced motor, not so much with external.
So make it an internal balanced motor then. Isn't that what's being done if the internal rotating assembly is being balanced and the external componants are being zero balanced? Quite often engines are externally balanced because of real estate constraints inside......counter weights would have to be to large to offset the big bore pistons and won't fit. When we build an I5 it is usually with forged light weight aftermarket pistons and rods which makes the internal balancing easier because weight isn't having to be added but drilled out and lightened. The motor that Hank is routinely running to 8.5k wasn't even rebalanced after exploding pistons in his last motor. Instead he just matched blue printed piston weights to what expoded and went with it. When I asked him how the new motor ran he, like Jim Green, said if anything the motor was smoother all the way up to 8.5k. It works, again like Jim, well enough to toast a couple of trannys!! Maybe Hank will describe how we decided to balance the new pistons to the old weight....it's interesting.
 

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All VAG engines are internally balanced. That's why you can zero balance everything and it's fine.

Brendan
 

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URQ said:
my2000apb said:
yes do it all
The reason I ask is when I change out the clutch the next time down the line it will throw it out of balancing that was done correct?
Yes that is correct.

Audi engines are internally balanced, so you need to have the internals balanced only.
 

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Lord_Verminaard said:
All VAG engines are internally balanced. That's why you can zero balance everything and it's fine.

Brendan
Anybody have some pictures of the front of balancer and the back of the flywheel?
Its easy to tell that the engine is externally balanced.
 

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Repaair said:
Anybody have some pictures of the front of balancer and the back of the flywheel?
Its easy to tell that the engine is externally balanced.
No. No it's not.

The flywheels are zero balanced, as in, balanced to themselves, not to the engine.

Front pulley is that way too.

So is the crank.

If the engine were externally balanced, the front pulley and/or flywheel would not be zero balanced.

Brendan
 

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quattro87 said:
Repaair said:
quattro87 said:
It's all a matter of personal preferance. I like to have the rotating assembly balanced separate from the flywheel and clutch. I figure that those items get swapped to different brands, burned up or what not and if they are part of the equation the motor needs to be tore down and balanced again with the new items. Those items can be balanced separately. I think that balanced with all rotating parts is probably a better job, but I would rather have the flexability.
This method makes sense with a internally balanced motor, not so much with external.
So make it an internal balanced motor then. Isn't that what's being done if the internal rotating assembly is being balanced and the external componants are being zero balanced? Quite often engines are externally balanced because of real estate constraints inside......counter weights would have to be to large to offset the big bore pistons and won't fit. When we build an I5 it is usually with forged light weight aftermarket pistons and rods which makes the internal balancing easier because weight isn't having to be added but drilled out and lightened. The motor that Hank is routinely running to 8.5k wasn't even rebalanced after exploding pistons in his last motor. Instead he just matched blue printed piston weights to what expoded and went with it. When I asked him how the new motor ran he, like Jim Green, said if anything the motor was smoother all the way up to 8.5k. It works, again like Jim, well enough to toast a couple of trannys!! Maybe Hank will describe how we decided to balance the new pistons to the old weight....it's interesting.
Changing a motor from external to internal balance is a expensive and a pain in the ass. You have
to machine off the imbalance weight off of the balancer and flywheel. Then you usually have to add
weight to the crank by drilling large holes and plugging them with mallory. It can be $50-$200 just to add weight. This is in addition to the cost of balancing.

Audi engines come from the factory with a decent balance, so it doesn't suprise me that you guys can rev the heck out of these things. External balance is good!
 

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Changing a motor from external to internal balance is a expensive and a pain in the ass. You have
to machine off the imbalance weight off of the balancer and flywheel. Then you usually have to add
weight to the crank by drilling large holes and plugging them with mallory. It can be $50-$200 just to add weight. This is in addition to the cost of balancing.

Audi engines come from the factory with a decent balance, so it doesn't suprise me that you guys can rev the heck out of these things. External balance is good!
Internal balance is better!! You don't have the offset weight on the ends of the crank trying to twist and bend the crank or at least not at the magnitude that the weight at the ends of the crank will do.

If you start with an internal balanced motor, which I still think is the case with an audi I5, to rebalance to new pistons and rods is not that expensive. If on the other hand the I5 is in fact an external balanced engine, the flywheel in our cases are aftermarket zero balanced items and the front damper/pulley would be the only item in question. In all the I5 motors that I have built, not one of them have had to have weight added to the crank. It has always been drilling weight out, and that is including my stroker motor which took quite a bit of drilling to balance. I suspect it was because of being out of an industrial application that probably had diesel like heavy pistons, but I'm not certain. With todays balancing machines that can isolate which throws/counterweights are out of balance and pinpoint where in the crank the imbalance lies, why would you want to externally balance? Not only is the balance better, but being able to change out flywheel/clutch etc is a plus. Ideally, the best balance would probably be to zero balance the external components, and then include them with the internal balancing spin.

Don't get me wrong in that I'm not saying external balancing doesn't have it's place, but it's usually because of engine space/design, or time/money that internal balancing would cost on the production line. I suspect that you could eventually get your crank forgings balanced and consistant enough to go without rebalancing, but just cranking out a bunch of rotating assemblies and taking the average balance of the bunch to determine what external weight to use would in the end be cheaper and easier.

Lastly what do you suppose the drill holes in the audi I5 damper/pulley are there for if not to offset the locking tool chunk of metal in the hub? I find it interesting that with these two examples that it's easy to see that the holes aren't even drilled into the same spots which makes one think balancing. I think they are zero balanced.

 
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