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Quick question about my stock flywheel that the shop doing my
McLeod twin disk clutch install pulled out today. The debate was whether it needed to be match balanced with the new flywheel going in. From the reading I've been doing here, it's money well spent to have it done so as not to gamble on getting some bad harmonics. Anyhow, the shop sent me a pic of the old flywheel and I'm curious if some of you experts could chime in on whether it appears to have had substantial weight added or removed during GM's hot balance after assembly. Check out the pics. Thanks for any opinions!
Looks like weight was removed between 1-2 o'clock.
While I'm no expert, that's what I thought. Considering this is a VERY high end shop that services lots of exotics, I was and still am a bit worried that they were not familiar with the issue of match balancing the old with the new. At an additional charge, they agreed to have the new flywheel and I believe the new pressure plate sent out to be match balanced to the old. Question is, if they were to only match balance only the new to the old flywheel, will that accomplish the goal or must the machine shop match the flywheel and pressure plate together as a unit to the old flywheel? Also, now that the old pressure plate was removed from the old flywheel, is it possible to recreate the orientation of the old flywheel/pressure plate if they didn't mark them? They say they did, but I believe it was disassembled after the issue was brought up in some detail. Anyhow, either way, it's off at the machine shop being "match balanced". How bad could they screw things up at this point? Getting paranoid!
While I'm no expert, that's what I thought. Considering this is a VERY high end shop that services lots of exotics, I was and still am a bit worried that they were not familiar with the issue of match balancing the old with the new. At an additional charge, they agreed to have the new flywheel and I believe the new pressure plate sent out to be match balanced to the old. Question is, if they were to only match balance only the new to the old flywheel, will that accomplish the goal NO
or must the machine shop match the flywheel and pressure plate together as a unit to the old flywheel?(needs to be matched to the old flywheel AND pressure plate. Match the new COMBO to the original COMBO) YES
Also, now that the old pressure plate was removed from the old flywheel, is it possible to recreate the orientation of the old flywheel/pressure plate if they didn't mark them? The factory LS1/6 clutch used two locating dowel pins, 170° apart from each other, to locate the pressure plate to the flywheel. It should only go on in one orientation. Later designs used 3 equally spaced dowel pins, and could be orientated 3 different ways.
They say they did, but I believe it was disassembled after the issue was brought up in some detail. Anyhow, either way, it's off at the machine shop being "match balanced". How bad could they screw things up at this point? Quite a lot
Getting paranoid!
comments are in BLUE
Ask them to "pretend" that this is an externally balanced engine. If they are as high end as you say, they should then know to have the whole clutch assembly matched to your original clutch assembly, which consists of both the flywheel and pressure plate.
Quick question about my stock flywheel that the shop doing my
McLeod twin disk clutch install pulled out today. The debate was whether it needed to be match balanced with the new flywheel going in. From the reading I've been doing here, it's money well spent to have it done so as not to gamble on getting some bad harmonics. Anyhow, the shop sent me a pic of the old flywheel and I'm curious if some of you experts could chime in on whether it appears to have had substantial weight added or removed during GM's hot balance after assembly. Check out the pics. Thanks for any opinions!
Your stock flywheel has 12 through holes equally spaced around the perimeter. This is where GM would have added weights during the hot balance process if necessary. Have them look at those holes. If they can't see through them, then there is a weight stuffed in there. GM did NOT remove weight to balance during the hot balance, they ONLY added these weights. Even if you do not see any weights added, you want to match a new combo to your original combo. An infinite number of balance tolerance stackups are possible, so just because you don't see any added weights, they whole assembly could very well be "non zero" and needed to coordinate with your engine internals to avoid the bad harmonics you mentioned.
Match your new COMBO to your original COMBO.
That's the "engine side" of your OEM flywheel, correct? The other side should have two pins that are not symmetrical. The pressure plate will only go on one way on these pins.
Matching the assembly (Pressure Plate + Flywheel) is a MUST !!!! As well as matching the orientation of your original flywheel as mated to the crank.
Looks like weight was removed between 1-2 o'clock.
Those milled holes are indeed to remove weight for balancing the flywheel alone. However, they were done by LuK in order to get the flywheel in balance to within their balance spec prior to delivery to GM. They are delivered to within a certain balance tolerance, as are the pressure plates. When everything is assembled, those tolerances stackup. GM then adds weights during the hot balance to the flywheel to account for these stackups of all components.
Short answer: Those milled holes were not done by GM during the hot balance procedure.
Those milled holes are indeed to remove weight for balancing the flywheel alone. However, they were done by LuK in order to get the flywheel in balance to within their balance spec prior to delivery to GM. They are delivered to within a certain balance tolerance, as are the pressure plates. When everything is assembled, those tolerances stackup. GM then adds weights during the hot balance to the flywheel to account for these stackups of all components.
Short answer: Those milled holes were not done by GM during the hot balance procedure.
See.... he's a clutch C5 Clutch Consultant and deserves a raise !!!!
I am anxiously awaiting his guidance on using an EVA2 (portable vibration device) to fine tune my new clutch.
See.... he's a clutch C5 Clutch Consultant and deserves a raise !!!!
I am anxiously awaiting his guidance on using an EVA2 (portable vibration device) to fine tune my new clutch.
Thanks again, thblwZ !!!!
now that's funny
I'm looking for a writeup I did about a method for balancing the clutch in the car. Eric D is the true expert.
If you'd like to PM me and send me your email address, I can attach a write up that way.
Thanks for all the helpful information guys. This place is has always been an amazing knowledge base. Many of us would be flying mechanically blind without it!
Thanks for all the helpful information guys. This place is has always been an amazing knowledge base. Many of us would be flying mechanically blind without it!
have them focus on the order of operations and the hot balance steps. They should get a better understanding of what's going on.
sounds like they are open to suggestions.
BTW, it may come out that your stock combo is very near zero balanced. That's fantastic, having your new combo zeroed also will be the way to go, and it will be "matching" your original. Very well worth the money to check.
Thanks for all the helpful information guys. This place is has always been an amazing knowledge base. Many of us would be flying mechanically blind without it!
Has there ever been a list created of the C5 Tribal Elders???
Balance match the assembly. I have wasted so much time because I did not know better the fist time. Just finished a new LT1-S and it has no vibration. I had a machine shop only do the fly wheel and that did not turn out right. Do the FW and PP as an assembly, and save yourself a ton of aggravation.
Flywheel balance question
