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On the few OE items I've seen that have been machined to loose weight, the lobe on the inner surface of the harmonic balancer has been removed. This lobe provides a locking point for the crank locking tool and is an offset weight that is part of the harmonic balancing for the crank. This results in the two points I've mentioned above needing to be addressed. On the cars I know of, changes to the front pulley have been done at the same time as balancing the crank. I personally, would always address crank balancing when making any changes to any part of the crank assembly. There is no way that the affect of the lobe being removed by either machining or replacement of the pulley is insignificant. Take a look at an OE pulley, they are all drilled on the front face to fine tune the balance..
Same case on my engine. The lobe was romoved for balancing. Everything is balanced to 0! With the locking noth in place the cranck has to be balanced in another way to compensate the weight of the notch.
RS2 Black - stock 315 HP
RS2 RS blau - stock 315 HP
Sport Quattro - 1005 HP High Octane website
On the few OE items I've seen that have been machined to loose weight, the lobe on the inner surface of the harmonic balancer has been removed. This lobe provides a locking point for the crank locking tool and is an offset weight that is part of the harmonic balancing for the crank. This results in the two points I've mentioned above needing to be addressed. On the cars I know of, changes to the front pulley have been done at the same time as balancing the crank. I personally, would always address crank balancing when making any changes to any part of the crank assembly. There is no way that the affect of the lobe being removed by either machining or replacement of the pulley is insignificant. Take a look at an OE pulley, they are all drilled on the front face to fine tune the balance..
Originally posted by Jeffer
Same case on my engine. The lobe was romoved for balancing. Everything is balanced to 0! With the locking noth in place the cranck has to be balanced in another way to compensate the weight of the notch.
So if you change your crank pulley due to a failure does the crank need balancing again??? ( Not being a pedant - just asking a question?)
Cheers,
Steve
The Perfectionist
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Audi Class Concours winner Stoner Park 2014, ADI Concours D'Elegance Class Winner 2008, Runner up 2014. Winner, S2Forum Show'n'Shine Billing 2006 & 2008.
What crank locking notch???
If you mean a 'key way'....the stock pulley doesn't have one!
If you mean the part on the stock pulley that requires a special tool to tighten...you are right this one doesn't have one. It can be tightened using an impact gun.
Again, most of the vibrations are taken up by the dual mass flywheel, not the crank pulley.
The locking notch is not an offset weight either, it's just there to help tighten the main bolt with the special tool. The stock piece is cast steel, if you look closely on the stock pulley there are 3 holes on one side. They were drilled there for balancing it.
Absolutely not, you do not have to get your crank balanced if you change your crank pulley!!! These guys have been very very misinformed!
If you look at your stock pulley at this very moment, most of the rubber is probably deteriorated by now. Your stock pulley 'according to you (steve)' is then perfectly balanced even though the rubber is not functioning anymore. Again 'according to you (steve)' this means that you are doing harm to the crank as we speak.
There is a locking tab on the pully notch on the pully that the VW/Audi Crank locking tool fits into. (see pic)
Do NOT use a impact gun to do the crank bolt up. By all means use one to undo it, but to tighten it lock the crank, using the VW/Audi tool and torque it up to 450Nm, with the specified loctite locking compund. If you tighent the crank pully bolt using and impact gun, it can crack/shear the woodruff key on the crank pully(this is seperate to hte balancer), which then causing the Pistons to hit the valves, big re-build required.
If you replace crank pully you do not have to have the crank re-balanced, the crank pully is a seperate piece to the harmonic balancer. These balancers cost lots from Audi, and there is a reason, its because they are balanced.
If a non balanced pully was to be used, it would not cause the engine to fail necessarily, but puts more load on the crank, and removes a feature audi determined necessary on this engine, and I would trust them.
Not all cars have Harmonic balancers, nor do they have dual mass flywheels.
So if you change your crank pulley due to a failure does the crank need balancing again??? ( Not being a pedant - just asking a question?)
Cheers,
Steve
You do not need to rebalance the crank after replacing the pulley or vibration damper. I have had a new vibration damper on my ABY (50,000 miles ago) and have had no problems whatsoever.
The vibration damper is a common failure point on 5cyl diesel engines in LT vans etc. So much so that the design has been modified several times. Again the crank does not need rebalancing when you change them.
I have access to the workshop manuals for both petrol and diesel 5cyl engines and there is no mention of rebalancing the bottom end when renewing the vibration damper.
If someone can show me documentation stating otherwise then of course I will stand corrected.
Ben
the best intentions are fraught with disappointment - gil grissom
Hello, very intresting topic!
I had that "crack/shear the woodruff key on the crank pully" problem, I almost destroy my engine, thanks god, I didnt......
The symptoms came with a loos of power and "hall sensor" fail code, thanks god I check the crank pulley and I note the problem at time!
A question, please, ¿ Do the original crank pulley have only one position to be resambled? Cause I dont remember it? Maybe Im running debalanced? HELP!
Audi S2 94 6 speed ABY-ADU 330hp, Lancia delta EVO2 mint
Dr.Ferdinand
If you replace one OE harmonic balancer for another 2nd hand or new OE balancer you shouldn't need to re-balance anything. This is because they are already balanced during manufacture. This is as close as you will get without re-balancing the crank assembly. This is not the same as replacing the OE unit for one that is totally different, like a lightened unit. Speak to any reputable balancer that knows the Audi 5 cyl crank and they will advise you accordingly. With regard to old units with perished rubber, this will result in minor imbalance, just like wear and carbon deposits have an affect on balance (however minor) This is likely to be one of the reasons some of the keys become cracked on the pulleys or the nose of the crank gets hammered. You have to remember we are not talking perfect condition of an engine after 10,000's miles, so all these will have some affect. I would have though anyone thinking of using a lightened item would be rebuilding and/or looking for more power, this is definately the best time to strip the engine, replace bearings, etc and get the whole assembly balanced. I can't think of anyone who would want to add a lightened pulley by itself.
Remember too, there's lots of 5 cyl motors out there without a dual mass flyweel, where's the vibration being damped in them?
[QUOTE=Corey]More often than not it is due to someone trying to undo the bolt by holding it on the transmission/brakes. 450Nm on that little key = trouble[/QUOTE
Also likey to be due to grease monkeys with impact wrenches.
The locking the transmission trick to undo the 450Nm Bolt sounds like a key failure mode to me!
Cheers,
Steve.
The Perfectionist
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Audi Class Concours winner Stoner Park 2014, ADI Concours D'Elegance Class Winner 2008, Runner up 2014. Winner, S2Forum Show'n'Shine Billing 2006 & 2008.
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