[Johannvb]

I have heard about the importance of balancing the Flywheel and pressure plate together so many times on this forum. So I decided to look for a shop that can balance my new LUK DMF Flywheel and Sachs Pressure Plate. However I am really struggling to find a shop to help me. They all claim that they need my crank as well when balancing the flywheel. Obviously there is no way I am opening up the engine to give them my crank, so I am in a bit of a bind.

I have done some research and I read on LUK's website that their DMFs are dynamically balanced before leaving the factory. I have sent an email to Sachs asking them if their pressure plates are balanced as well, but I am still waiting for an answer. My theory is that if they are both balanced any imbalance caused when screwing them together will be minor.

However if, Sachs tell me that their pressure plates are not balanced I might have a problem. Now my question is...how big is the risk that once I have the car all buttoned up that I will have vibration coming from the clutch? I have read on this forum that the DMF should absorb the vibrations, but I am worried it will fail prematurely.

In an attempt to ease my worries I also spoke to the chief mechanic at the Porsche Main Dealer and he says they never balance the two parts together. Not even on the 997 GT3RS. According to him they never have vibration issues....I am very confused and don't want to go down the wrong path.

Please help

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[banditsc]

Just had a original (30k miles) flywheel and new Sachs pressure plate on a 911SC balanced. It apparently wasn't balanced as they drilled out some metal on the side of the pressure plate. Cost me a total of $60.

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[flash]

first off, they do NOT need the crank to balance a flywheel - they only need the appropriate plate - they probably didn't want to make one

as for balancing a DMF, this is a HUGE "catch 22"

while it would be preferable to have it done, you will have a hard time doing it - by design it will want to change position - the guy i use here, who has been doing this for 40 years and will balance anything, said he wasn't sure he could actually do it - the problem was in trying to keep the two halves still - the idea we came up with was to make a fixture that connected the crank bolt pattern to the pressure plate pattern - this fixture would first have to be balanced to eliminate that as a factor - then the bolts balanced - then it could be fitted and the two halves would then be connected, thereby removing that factor

if you don't have it done, and yours is inherently out of balance, it will always be working to achieve balance, and thereby cause the dampening mechanism to fail earlier than if it were balanced

however, until it does fail, the dampening mechanism should eliminate vibrations

you could theoretically help things by first having the pressure plate balanced on a "zeroed out" single mass flywheel, and then install it on the DMF

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[xrad]

balance the fly first, then you want to balance the pp on the fly because no matter how well it is made at the factory, it may not line up on the dowels

I will be replacing the fly with an S2 unit (lighter) and a centerforce disc and PP

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[flash]

yes, but he is dealing with a DMF, so first you have to figure out how to isolate and eliminate the dampening characteristics, which throw the balance off

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[Johannvb]

Thanks for the advice guys, I am starting to think going the OEM route wasn't the best choice. I have decided to install the parts as they came without balancing. I have spoken to the Porsche Main Dealer and a Tuner here in town and both of them said that they only ever balance these things on cars that go racing and have blue printed and balanced engines. For road use they just bolt them on with no extra work needed.

I might have had less worries if I choose the RS Barn setup, since Pete offered to send me the whole lot pre balanced. But that would have cost me a lot more than I paid for OEM stuff and modifying the giude sleeve worried me. Then again, I might have no issues after buttoning the car up. If I do, I will view it as school fees to the school of hard knocks and do it differently next time.

I will let you know how things turn out

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[flash]

you probably won't feel the out of balance condition - you may or may not notice the power drop - it will be a long time before any out of balance condition shows up in issue in the engine

i think it will be fine for a street car - now, if you tracked it...........................

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[xrad]

hmmmm...get rid of the DMF

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