Perfect timing

After I posted yesterday, I remembered that the ignition timing on the race car was set to 10 degrees BTDC. I'd tried advancing the idle setting previously to give greater advance at the higher revs I tend to be using on the track but it hadn't helped.

What struck me yesterday was that my previous attempts were before I replaced all the ignition components.

So today I went out and advanced the idle to 16 degrees BTDC and suddenly the car can rev to 7000 (eek!) I've just taken it up the road and it seems to be going really well. It's hard to use 6000 revs and over on the road without going deaf from the noise, also at high speed the car doesn't track in a straight line on bumpy roads due to it being so low and stiff so I can't get the full potential but I'm much happier that it's all working now. I was worried that I might get "pinking" lower in the rev range with the extra advance but that doesn't seem to be a problem.

So rather than a rolling road session, I might be able to spend the money on a test session on track sometime instead. The only planned job I have left on the race car now is to finish making the new air box I started some time ago. I have all the parts for it, I need to find an aluminium welder to do a bit of work before I can continue though. Someone I know tells me they in turn know a good aluminium fabricator so I'll have to get in touch with them.

Now I need to work on some way of getting the car to and from the track without having to drive it since it's not a particularly pleasant vehicle to drive on the road. Back to looking at the van then I guess!

Confused

Tried the new carb. needles today and discovered that both options made the problem quite a bit worse rather than better. So I'm confused now since I wasn't expecting that. I've put the original needles back until I can come up with a better idea.

I think a rolling road tuning session may be the only answer to this.

Some success (I think)

Made a bit of progress on the race car. Last week I took advantage of a sale at Machine Mart to buy a hydraulic tube bender. That meant I could finally get on with fitting the drivers side door bar to the roll cage. The bar came with the cage when I first fitted it four years ago but needed bending to fit around the seat. It's now fitted and padded with the new padding that I also bought ages ago.

I also fitted solid spacers to the rocker shaft to replace the springs. These are supposed to give better location to the rockers but I'm not entirely convinced. Some of the rockers still seem to have a surprising amount of lateral movement in them. I don't think it will make it any worse though and the kit wasn't expensive so I'll see how it goes.

The new coil is finally fitted and working OK. I think the new ignition and distributor probably did make some difference after all since I realised that the misfiring is now higher in the rev range than before. Once the new coil was fitted, I took the car out on the road and it seems I now have a slightly different problem. The "hard" misfire at around 4500 revs has been replaced by a more gradual problem starting around 5500. After some experimentation I discovered that pulling the choke out a bit to make the mixture richer helps so it looks like I need some new carb. needles to give more fuel at high revs. I've ordered two different options from Burlen Fuel Systems so hopefully I can get this problem solved properly. I'm now thinking that I perhaps had two problems going on at the same time in the first place.

Since there's not much else I can do until the parts arrive, and work on the van has stalled, I'm off to Mallory Park to watch other people racing this weekend and catch up with some of the ex-TSSC championship Triumph crews.