K Series Starter Motor

[Videocameraman]

2006 Roadsport SV K series. Starter motor was faulty so WOSP LMS430 was supplied and fitted.

Pinion does not fully retract when engine starts and seems to stay on edge of flywheel (see polished rim in photo). Motor was fully seated and aligned. New starter faulty or any suggestions welcome?

[revilla]

Was this spacer fitted?

https://www.autoelectricsupplies.co.uk/p/caterham-spacer

[Videocameraman]

Yes it was. Sorry, should have mentioned that!

[revilla]

Well that's the obvious answer eliminated then!

I've seen a few Caterham WOSP starters and never seen that before, so I suspect there's something not right with the motor. Seems odd that it would actually touch the flywheel on its travel in and out though. Are you sure the starter is the right spec with the right gear fitted?

It may just be your photo, and it is showing a bit elongated on my phone, but something looks unusual about the flywheel too. The starter teeth are normally a separate, interference-fitted ring gear. So the bottoms of the troughs between the teeth would still be noticeably proud of the actual flywheel casting. On yours it looks almost as though the bit that has scraped is flush with the bottoms of the tooth gaps ... or is that just the picture angle?

[SLR No.77]

With the starter bolted into position check there's definitely clearance in the area I've highlighted below. It's easy to bolt up the starter, it look correct but actua it's misaligned slightly causing engagement issues.

[revilla]

Yes that's a very good point. When I've converted a block I usually bolt up the starter motor and then slip a piece of cardboard up between the starter and the block. If you can slide it in and out in all areas you know it's clear (it's hard to get the angle to see otherwise).

And different starter motor designs do need different amount of clearance in different places.

[Videocameraman]

 The new motor is the only K model supplied by Redline and Demon Tweeks etc. so should be correct. It has the same number of teeth as the old one (10). The bottom of the flywheel teeth are just higher than the rest of the ring. Difficult to see in the photo but there is a very slight ridge up to the teeth so the bottom of the troughs are just slightly raised above the shiny area to the outside so should not get caught on a ridge coming out.  I'll check the clearance as a possibility.

[Mechanical Moz]

Is the distance from the motor mounting flange to the end of the pinion the same on the WOSP as it is on the old starter?