Friday, 30 May 2008

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!

Thursday, 29 May 2008


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.

Sunday, 25 May 2008

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.

Saturday, 10 May 2008

More problem tracing, and a show

I spent some time today trying to track down the "misfire at high revs" problem on the race car. I fitted an electronic ignition unit but it hasn't helped. It wouldn't fit properly in my distributor due to (I think) wear in the shaft so I used a brand new Lucas distributor body I'd had in the garage for a while.

I've tried a lot of things now so here's a list (more for my reference than anything)
  • Changed condenser (no change)
  • Changed points (and then changed back as the new ones were rubbish, but didn't alter the misfire anyway)
  • Tried a different coil (didn't help)
  • Made the mixture richer than normal (made things worse so I put it back)
  • Made the mixture leaner than normal (didn't help so I put it back)
  • Got rid of the points and condenser altogether by fitting a magnetronic system. This also meant fitting an entirely new distributor (still no change to the misfire)
  • Changed the main HT lead from the coil to the distributor (no change)
I'd like to try changing the coil again for a brand new one. I ordered one but unfortunately I've been sent the wrong part so it will have to be exchanged before I can try that. Otherwise I'm running out of ideas.

I also drained the oil catch tank today and was somewhat alarmed when almost a litre of bronze coloured water (or what appeared to be water) came out along with the expected small amount of white frothy oil/water mixture. I can only assume that it was a years worth of condensation as I hadn't drained the tank for ages. There did seem to be rather a lot of it though and it was a strange colour. I'll have to keep an eye on the tank and see if it starts to build up again.

In between all this, and trying to do some overtime for work, I went to the Bronte Vintage Gathering which takes place not far from here. Spent a couple of hours viewing an assortment of classic cars, tractors, commercial vehicles and steam traction engines. Also the obligatory stalls, mostly selling tat. I bumped into Dave M there showing off his Triumph Dolomite. Only took the one picture but there was quite a lot going on around the field. Filled some time anyway.

Thursday, 8 May 2008

A day on the track

Managed to get about 350 running-in miles on the racecar in the end, mostly touring around the Yorkshire dales. Using 97 octane "super unleaded" cured the pinking but not the high revs misfire. I Changed the oil and then went to the CT trackday at Cadwell Park on Tuesday.

We had a great day for hooning around the track which is probably my favourite UK circuit at the moment. I think everyone enjoyed themselves and no-one suffered any major problem (or at least no problem that couldn't be dealt with). I didn't take part in all the Triumph sessions so took the opportunity to take a few photographs too. Sadly I only had my pocket digital camera with me. I could have got some much better images with the big camera but then I was supposed to be there to drive!

Unfortunately my car was suffering from a misfire all day which limited my revs to between 2000 and 4500, in turn limiting my top speed somewhat. I spent most of the day trying to cure this problem but only managed to find ways to make it worse. When it was working, the car was going better then ever. It seems to have more power and torque than last year. I can only think that this is due to my having finally got the exhaust manifold to seal.

I've ordered a new coil and an electronic ignition module to eliminate the coil, points and condenser from the misfire problem. I already tried changing all these parts but I don't trust the quality of some of the modern components so I'm going to try the electronic route instead, at least for now. If that doesn't help, I'll have to go through the wiring and make sure there are no problems there.

I'm still waiting for some ATF for the van so no more progress there yet. I'd like to get that back on the road again before long.

Friday, 2 May 2008

MOT update

Car failed the MOT yesterday morning on two minor items. Rear brakes binding (my fault, I'd overdone the handbrake adjustment the previous evening) and indicators not flashing quickly enough. That latter one turned out to be the battery being flat combined with the alternator not generating the required voltage at idle as it was fitted with an extra-large pulley to stop it getting very very hot at high revs on the race track. I refitted the smaller one and it now runs a bit hot but it does charge the battery and the indicators work. Got the car back for its retest before the end of the day and it passed no problem that time.

It's now taxed for the next six months and I've done about 30 miles today as an initial test run and all seems fine. The only problems being that I'm now deaf (the racecar is very noisy inside) and it's misfiring above 4500 revs under load but I suspect that may have a lot to do with the fact that I'm running it on 95 octane fuel as an experiment and it may be "pinking". I think I may need to go back to the more expensive variety of fuel. I may try fiddling with the ignition timing as well to see if that helps in the meantime.