I’m still in a bit of a quandary about what happened to the chain and sprockets. I spent a while measuring it as accurately as I could tell and I think the driven sprocket was translated about 0.9mm to the right of where it should be and was at an angle of 0.3° to the drive sprocket. I’m not an expert at chains but that doesn’t sound horrendous.

All the same, I’ve adjusted everything and got the misalignment down to about 0.2mm and 0.1°. Time will tell if that’s sufficient. So, I’ve put it all back together with a new chain and new sprockets. There it is at the top looking shiny, in places. Note that you can see the split in the driven sprocket.

Although the misalignment seems slight, it does seem to tally that that was the problem. When I first put the ’08 engine in the car I left the same sprockets on as I’d been using with the ’06 engine. The drive sprocket was fine, or I’d never have reused it. I changed the 50 tooth driven sprocket after a single test session at Snetterton, because the engine was clearly running gearing that was too tall, for one that was 2 teeth larger and it’s run with that sprocket since. The 50 tooth sprocket shows some signs of wear, along the same line as what happened to the 52 tooth one. However, the 48 tooth socket that I used at Brands Hatch with the ’06 engine is absolutely untouched. That is, the sprockets in use with the ’08 engine have all worn. What’s more, looking at the chain I can see that it’s got too hot as quite a few of the oil seals seems to have disappeared. I must admit, I’ve often wondered whether a well-lubricated non O-ring chain would be better than the sealed O ring (actually “X ring”) one that I’ve got on.

I’ve decided to give this weekend’s race a miss; I just don’t have time to do all this and if I bent the car it would spell disaster. I wonder if I’ll be able to get the car on a dyno before the races at Pembrey?

9 thoughts on “Shine”

  1. Tim

    Probable a stupid question but are you using a decent O-ring chain lubricant? I don’t see any on the chain in the picture or on the car.

    1. I hope it’s a daft question! The chain’s lubricated with the lube recommended by the people who supplied the chain and sprockets. (Which, not surprisingly, they sell.) It isn’t an obvious colour though, although in the photo you can see a bit of overspray on the bit of brown paper that I used to catch the overspray. It’s down there because the lube’s applied on the inside of the chain, as recommended…

      I hope.

  2. Ahhh….OK. Thought for a minute you hadn’t been using any at all. I wonder if the chain/sproket miss-alignment on the 08 engine accounts for some of the loss of power. Sounds like you need a power commander and a RR session to sort it.

    I’m off to Brands tomorrow in the Phoenix for my first Sprint there….looking forward to it 🙂

    1. I did wonder if it was behind the power issue. It’s certainly been using power to nadger the sprockets. I already have the power commander but getting it remapped is clearly a priority. Problem is, so is everything else.

      Enjoy yourself at Brands! 🙂

  3. WOW you are not kidding about the short chain run.
    how are you checking yor alignment? you seem to come up with some exact figures.

    i agree a non sealed chain will be better than the sealed one. with the short run and it cooking the seals any way. with the use you are putting it to on the track a sealed chain is of no advantage. on the contary a non sealed chain can be cleaned and lubricated easier. using it on a car as well you are not to bothered about lube fling,(as long as it stays in the bodywork) it will be cheaper as well. you could by a roll of industrial chain, and have a new one each race.

    1. Chain length is pretty normal, in fact slightly longer than normal, for the Riot/J15 chassis. It is a bit short though. Alignment checking is done by an unholy collection of straight edges, feeler gauges, a digital inclinometer, spacers and a micrometer… 🙂

      Interesting comment about the chain, I have to admit I was wondering that, although I don’t really think I’m knowledgeable enough about chains. Where would I get a roll of chain from?

  4. Sorry if I state the obvious or seem to be trying to teach Granma how to suck eggs!
    1) When we were scrambling, solo and sidecar, we quickly learned to scrap o ring chain. Just cleaned basic chain carefully after each meeting and then boiled in good old fashioned tallow

    Are sprockets and chain compatible- Iam sure you will have checked but there are very close differences

  5. The bike racers use standard non-O/X ring chains Tim. But they do throw them away after each race! They use them because they actually have lower friction than the sealed chains.

    Stick with the tried and tested DID chains – I’m confident your problems were setup related. I think we give our chains a slightly harder life than a bike, even a race bike.

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