2024-04-17 Rattling Clutch
The old Helix clutch & this new Blueprint clutch have always had this annoying, loud loose rattle whenever idling in neutral & warmed up.
I removed the gearbox to check if it's caused by the clutch disc or the input shaft bearing
Drain plug has minimal debris which is good
The input shaft has no lateral or axial play at all, spins smoothly with no gritty noise and doesn't whine when driving, which suggests the input shaft bearing is fine so I won't open it.
Removing the clutch
Flywheel & pressure plate surfaces has the usual minor grooves
Both sides of the Blueprint clutch discs are now bedded in with full contact
Comparing my old & new clutch.
The old Helix disc uses a single-stage torsion damper
(splined center piece joins the outer friction plate through a single set of 6 heavy torsion springs)
The spline slots abit too loose onto the input shaft (which might've caused it to rattle),
Whereas the Blueprint disc for a Primera 2L diesel uses a 2-stage torsion damper
(splined center goes through a weak inner spring and then the heavier outer springs before reaching the outer friction plate).
The spline fits much tighter on the input shaft but has a lot of play on the torsion damper itself.
A closer look at the 2-sets of torsion springs on the Blueprint clutch.
That's where I noticed the splined spindle in the middle is very loose within it's casing, I can wiggle it around by 0.5mm and the inner spring is soo light I can rotate the spindle upto 5-10deg by hand (this may make it clunk when goin on/off throttle, feeling like a worn engine mount or gearbox backlash).
This amount of movement might be causing the irregular rattling
Helix disc in comparison has a solid splined center piece so it doesn't rattle around
Opening the Helix organic clutch for a closer look inside
Here's the solid internal splined center piece which sits the 6 torsion springs
On one side is a beville compression ring to keep the splined piece secure & prevent rattling
The other side has a stack of preloading washers
So I think this Blueprint clutch disc is either missing this beville preloading spring (to help stop the spindle rattling freely)
or it's damaged inside.
In an attempt to reduce tighten the spindle without cutting it open, I tried to pinch the outer casing tighter to the middle spindle with a punch/chisel
& added some thicker grease on the input shaft to reduce some play on the spline
Reinstalled the box
Filled with fresh oil
& ready to test
When the engine & gearbox is cold/thick, the clutch is all quiet but after afew mins of driving/warming up, the rattle is still there but less often.
The rattle depends on where it sits on the flywheel/PP and may seem random.
If i release the clutch in neutral too fast, biting the clutch disc too suddenly, it rattles.
If i release the clutch slowly in neutral, allowing the disc/flywheel/input shaft to line up, it doesn't rattle most of the time.
Maybe next time I'll cut open this clutch, eliminate the weak inner torsion-damper, weld the spline spindle directly to the torsion-plate making it a single-stage damper like on Helix, weld the rivets back together.