Alfa Romeo Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Evening guys,

I don't want to be waking up any sleeping dogs but I have come across some controversy in general about the aspect of flywheel (engine in general) balancing and would be in for some guidance as I don't know what to believe anymore... Were 105 nord engines (2000 specifically) internally balanced? Does that mean that the flywheels are 0 balance and just bolted on after having been balanced with the pressure plate?

This specifically interests me as I am currently revising the gearbox for my 2L '88 Spider and shifted my attention to the flywheel this weekend. I've bought a new Sachs clutch kit (disk, pressure plate and throwout bearing) as the old kit is up for replacement and even though the flywheel looks relatively good, I thought it might be a good idea to have it resurfaced and balanced with the new pressure plate. Just wondering, is this standard practice? Or is this very likely to throw off engine balance in general?
 

·
Richard Jemison
Joined
·
7,775 Posts
Were 105 nord engines (2000 specifically) internally balanced? Does that mean that the flywheels are 0 balance and just bolted on after having been balanced with the pressure plate?
The flywheels are balanced separately as are the pressure plates. Balancing the flywheel & PP as an assembly isn`t a good practice as replacing either would result in both having to be re-balanced together again. Re-surfacing is not needed normally unless there is raised "hot spots" on the friction surface. If your surfave does not havwed raised (and extremely hard) hot spots just clean the surface with an orbital sander to clean and break the "glaze" .

These overly heavy flywheels can be lightened which makes a big improvement in engine response and shifting quality.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Ok so as I understand it correctly, the flywheel isn't balanced to 0 balance (perfectly in balance) to compensate for the imbalance of the engine. Which would mean that balancing the flywheel would unbalance the engine. Does that mean that in a default scenario I could just bolt on a new pressure plate to the flywheel assuming that the new pressure plate is perfectly in balance?

If the above is true, how does one proceed with lightening the flywheel? I can imagine that it would need to be "unbalanced" upon completion to its original specification and remounted in exactly the same way it came off the crank in order to complete the engine balance. Is that correct?
 

·
Premium Member
Joined
·
922 Posts
Hey Sebastiano

Were 105 nord engines (2000 specifically) internally balanced?
Yes

Evening guys,

Does that mean that the flywheels are 0 balance and just bolted on after having been balanced with the pressure plate?
Okay I'm going to break that one up into parts

Part One
Does that mean that the flywheels are 0 balance?
Yes

Part Two
"....and just bolted on after having been balanced with the pressure plate?"

This is where you are going wrong. The pressure plate and the flywheel are normally never balanced together. The pressure plate is manufactured as a 0 balance component. The clutch disc (the one with the friction surface) is also manufactured as a 0 balance component. If the pressure plate or clutch disc need balancing it means there was an error in their manufacture.

The clutch unit consists of three pieces, the engine flywheel, the pressure plate & the clutch disc. All of these were zero balanced as part of the manufacturing process. When they are bolted together they are still at a 0 zero balance state.

Hope this helpful
Ciao
 
1 - 5 of 5 Posts
Top