7A Distributor play end float

[Pearl White Rob]

Afternoon.

Halfway through swapping my drive gear, as it was making a hell of a grundy noise. Obviously I assumed it was the gear all mashed up a bit a ruined. However, after its removal the gear is near perfect in condition visually, identical to the brass replacement I have. So Im starting to think "oh god here we go".

End float seems to be another contributor to noise, and.... there seems to be a huge amount of end float or play in the shaft, more than 030 thou or 0.76mm (my largest feeler gauge!). I'm assuming this is wrong, so does anyone know what the correct tolerance is for the end float.

Car is a CQ 20v.

Many thanks,
Rob

[Martin62]

20v.org states 2 to 5 thou in the section covering nylon gear replacement.

Martin

[mcandmar]

You want to dial out as much of the end float as you can as it causes ignition scatter. The shims needed are an unusual size having a large ID vs OD diameter, i found RC model shops tend to have a plentiful stock of stainless shims the right size.

If your engine is high mileage it may be worth replacing the timing chain too as any slack due to wear causes an oscillation between the cams at low rpms which makes the dizzy rattle like crazy. I.e. if you have a loud noise from the dizzy ~1500rpms, that's what the problem is.

[UrS4boy]

Thoughts on the cam chain, cam installation and alignment

If your engine is high mileage it may be worth replacing the timing chain too as any slack due to wear causes an oscillation between the cams at low rpms which makes the dizzy rattle like crazy. I.e. if you have a loud noise from the dizzy ~1500rpms, that's what the problem is.

Agree. Rob: Read this thread not just my post:

Thoughts on the cam chain, cam installation and alignment:

http://forums.quattroworld.com/s4s6/msgs/322571.phtml

Item 18:

[Pearl White Rob]

Cheers

Thanks guys really appreciate it,

Yes, the noise was across the rev range but unfortunately mostly from idle to 2500 i'd say, so timing chain is probably slack. Is there a lot involved in changing it?

Thanks for the clearance info, I had seen that elsewhere so good to confirm. I have now rebuilt the distributor by making up some shims, although it did seem pretty big compared to what was on there originally, and now there is good clearance. Looking forward to refitting tomorrow morning!

Fingers crossed it was all worth it.

Rob