Distributor noise

[croker]

Hi, I have narrowed down the search for a rattley noise to (I think) the dizzy. Its a 125A. Does anyone have a similar experience or know what it could be? I will take the cap off tomorrow and investigate but if anyone can point me in the right direction it would help.
Thanks

[alh]

If you remove and gently shake distributor you should not hear any noise if everything is in order. If there is any noise, inspect the advance mechanism. If the weight axles are really worn down then that can lead to a rattley noise when the engine is running.

To remove the advance mechanism from the distributor body:
- Remove the top locking plate by removing the three screws (exchange them against stainless steel cross-head screws while you are at it), the circlip and the upper bearing using a bearing puller
- Mark the position of the bottom plate with a Sharpie for the reassembly, then remove the six screws at the bottom plate (also exchange as above)
- Pull out the advance mechanism/axle/bottom plate from below. If the assembly is stuck, gently tap the axle from the top with a rubber hammer.

Good luck,
Adrian

[croker]

Thanks Adrian.
When you say the weights worn down, are these repairable? Its very noisy while the engine is running. I havent removed anything as yet but I will have a look over the next few days. Will I notice anything by just removing the cap?

[alh]

The weights/axles can be repaired/restored but its not that easy, and usually you need a distributor testing machine to readjust the advance curve after the repair. If the axles are still ok then a recommended approach would be to drill out the axle holes in the weights and then fit a brass tube as bearing for the axles. The axles/guides are marked with yellow arrows in the image below.

S125 Axles.png (376.66 KiB) Viewed 10154 times

You won't see much by just removing the cap as the points mounting plates cover the two holes where you could see the axles below. The easiest thing would be to mark the distributor body position on the engine with a Sharpie, remove the cap and mark the position of the rotor finger, then remove the distributor and shake it to see if anything is making house.

Good luck,
Adrian

[croker]

Hi,
So I have dismantled the unit and discovered 2 main problems.
1. The nylon bush between the spindle and the weights had broken into pieces and was loose inside.Distributor Base Nylon Wear Spacer

2. One of the collars or collets or whatever you call them that sit on the weights and slide in the slots of the cam base has worn out.

So my questions are:
I see the nylon part is available from Superformance but are the collars available individually (I will call them tomorrow)?
Should there be any movement at all on the axles/guides? Mine dont seem bad at all, quite a good fit and dont rattle or move excessively. Are there any oil seals anywhere? I see on the superformance site there are seals available but not sure where they go. Any experience with the bearings they sell? As its all apart, I guess its worth changing them, but again mine arent bad.
Look forward to your valued opinions, Thanks!!

[alh]

I don't think there are any oil seals required, there should be no oil in the space in-between the distributor body and dogdrive/camshaft anyway if your engine is properly sealed.

First time i've seen such a worn down collar, i wonder if there were bearing issues before which put a higher load on the side of the collar.
Your best bet is to have a workshop replicate the collar, i am not aware that those are available as spares and you need to adapt them to the camshaft and weight axles anyway.

Take extra care not to mix up things when you disassemble the distributer, any swap of parts (even if they look identical) can change the advance curve.

[croker]

Superformance said they will sell the collars individually or as a pair, but they are out of stock for a couple of weeks. So I will try theirs and if they are no good, then get some machined. There is oil in the dog drive area so I guess the oil seal is shot in there. The bearings seem ok, perhaps it was the broken nylon collar which increased the wear on the steel collar?
So, in a couple of weeks I will up date on the rebuild.
Thanks

[croker]

Update and still not right. So I got a new nylon bush and the small collars. Fitted them and there is still play as can be seen in this video.http://youtu.be/q1h61SFp7R0
Any ideas? Are the springs wrong?

[fdus172]

The video is marked as private.... but I did notice that the plate slots seem to be rather worn... could the collets be moving (or sticking) in the plate slots...

[croker]

I have made the video public now. The collets are new but there is a tiny bit of play there. the most is between the weights and the centre nylon bush. The pins that have the springs dont sit up against the spindle outer ring. There is movement there so would that be the cause?? Wrong/worn springs? Should it be a snug fit?