RB gearbox conversion

[morgzc]

Having some major issues with my conversion and hoping someone can help diagnose my issue.
It’s on a S15 but that section seems dead, hence posting here.

It stripped the centre plate on my clutch last year and damaged a few splines on the input shaft so I threw an act clutch and another used box on.

It’s always had a grinding that’s most prominent on deceleration and the you can feel vibrations through the clutch pedal when resting your foot on it lightly even when in neutral.

My mechanic friend (a must have for a silvia owner) reckons it may be the box isn’t engaging with the spigot.
I’m no expert but I don’t believe they do on an SR but am unsure if it should when using a RB gear box?

[Slamz]

What conversion plate are you running? RB box input shafts are shorter than standard so don't engage fully, and the type of plate will make this worse. The input shaft needs to engage the spigot bearing (as it does do fully with an SR box) or the shaft can move around, causing gearbox and clutch issues. If yours is stripping clutches, I'd wager this being your issue

[green_rs13]

the input shaft still sits in the spigot bearing.
are you using a decent conversion plate?

[morgzc]

I thought it was a garage D item to be honest but can’t be sure as it was done before I bought the car, didn’t check when the last one came off either.
It’s all coming off at the weekend so I will check the plate.

Would I need a different spigot for the RB box or is a standard replacement ok?

Hoping you guys are right otherwise it will be onto gearbox number 5. :/

[green_rs13]

all the spigots are the same. CA RB SR...

i would fit a new one but not wack it fully into the back of the crank but instead till its just flush with the face.

if you have a proper clutch alignment tool ( the one supplied with most clutch kits) then check to see if its a tight fit in your current fitted bush first.

the box wants to line up perfectly with the engine as any misalignment will chew the spigot bearing, so maybe whip the adapter plate off and check the back of the engine isn't crusty and that your gearbox flange isn't crusty.

[morgzc]

Spigot is fine. My flywheels not flat though so that might be it.

[Slamz]

I still reckon it's not engaging far enough with the spigot/clutch plate as a slightly off-flat flywheel won't kill 5 boxes. What adaptor are you running?