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My understanding is the SC timing set is to accommodate the SC cam being a different timing to the NA timing set, iirc its like 6º more advance or something, the factory rather than grinding a different cam they just made a different timing set to advance it.

So if you use the non SC timing set you will have to adjust it a fair bit to get back to stock settings. But if you are using an aftermarket cam it doesn't matter and you can use the 6150

that makes sense and to the point they'd spend less making an alternate sprocket then another whole camshaft for limited series engine.

ill order another 6150 and gasket kit, hopefully be all good then.

It might be possible they have designed it with more clearance for what ever reason. Looking at the tooth design, they are sloped so they always will try to self center, a bit of movement is a must for gearotor pump due to variation in timing cover oil pump housing location and placement on the block itself. If they were rock solid on the crank there is risk of breaking the pump gears.

Actually this happens to some performance engines where crank flex at high rpm causes the gear and rotor to jam up and break. It might be the reason for the extra clearance as for these are meant for performance engines. I recall mine being snug but I didn't compare to a OEM one as I went from the older 2 flats oil pump design to the VR only 6 spine drive oil pump, becasue the drives are different it wouldn't fit anyway to check, I would of needed a late VR one on hand, so maybe it was more loose than I though it was?

Maybe it might be worth asking them why it would have extra clearance, maybe they have done it for the above reason or maybe it was just the batch where they made them too small?

Thanks Vlad.

def was alot more play over stock, but in saying that it hasn't mashed it, just rubbed the face where it contacts, not enough to pickup with finger nail. So you maybe right. i found this place, for $150 it's worth buying another, if it's the same then it's ment to be.

https://www.ebay.com.au/itm/Rollmaster- ... 1438.l2649

I'm interested in getting the vernier ones for my next build. Should be much easier to dial the cam in spot on and better quality by the looks. The sprockets are a darker metal from the nitriting and I noticed the cap head screws have serrated washers which is well thought out.

I'm and guessing these are used in speedway a lot.

looks like you get one for about $100 more. Tempting.

https://www.ebay.com.au/itm/ROLLMASTER- ... p6U1ZEX_oQ

That's the one I was looking at. I noticed it has degree Advance and Retard scale engraved in the center hub too.

ive ordered the CS6240 we'l see how it is compaired.

new rollmaster kit arrived today, much better fit for pump gear, the crank gear is also one piece.

Wow, nice sprockets ... cheap chain.