4K Flywheel

[Banjo]

Stripping a 5K this weekend, & measuring & listing everything, before it's off to the engine rebuilders next week for rebore.

 

The 5k already has a 4K flywheel,but it needs attention with a couple of shallow grooves in the 180mm dia. clutch plate area.

 

This flywheel has probably been resurfaced several times in its life, as the raised 180mm section is probably only

1 mm above the flywheel surface. My question is; does anyone know what the height of this raised 180mm section is, above the flywheel surface, on a brand new flywheel ----->.

 

I have a factory K Series repair manual, I got off eBay,which covers the 4K & 5K, but it doesn't give this dimension. I've also scanned our forums and can't find this dimension elsewhere.

 

 

As I see it, this dimension is critical,as the driven plate is in contact with the raised 180mm section, but the pressure plate is mounted to the lower section of the flywheel surface. As the height of the raised section is lowered during resurfacing, without reducing the flywheel area <--------> accordingly, then the pressure on the driven plate would be reduced, resulting in possible slippage as the driven plates wears. (correct me if I'm wrong)

 

I can't see that it is any great issue, as I gather a machinist would normally remove the three clutch plate locating pins before resurfacing. I would think it would simply be a matter of resurfacing the 180mm raised area, and then machining the outer face area, until the original raised height dimension was reinstated.

 

The amount of material removed would not upset the flywheel, and as it's on the outer edge, it could only assist in making the engine a little more responsive with less flywheel inertia.

 

If anyone on here has had experience in this matter, or resurfaces flywheels for "a crust", I'd like to hear their thoughts.

 

P.S. I only raise this, as I have had flywheels resurfaced before, but only the 180mm raised section was machined. The outer lower area was never touched.

 

Many thanks.

Edited February 20, 2011 by Banjo

[basher_ke20]

mate i have had a few flywheels machined and some have had it all machined even when it had a raised section. Even if the raised section is lower you can adjust the clutch cable accordingly to give you that very small amount of more travel that you need

[altezzaclub]

You're dead right Banjo, machining that down reduces pressure plate pressure, so its like taking half a mm or whatever off the clutch plate. The nice thing is, that if you surface the face back 1mm and the carry area where the pressure plate bolts on back by 2mm, you've just increased your clamping pressure! Instant heavy-duty clutch.. :laff:

[Banjo]

OK ! I eventually got the info I wanted ! :dance: The PBR manual at my local Brake & Clutch centre lists the lip between friction area of 4K flywheel & outer area as

1 mm.

 

This is what it looks like after having had machining of both surfaces.

 

 

Cheers Banjo.

[Redwarf]

Sexy.

 

Good to see you back, Banjo. :)