Sept 28th 2013
Gale Hall
We turned up on September 8th (May 5th had been the last event) to a dry day with bright enough weather, but a cool breeze. It was a BTRDA round so there were plenty of cars and some of the Southern hot-shots were there.
In deference to the status of the event the hills were a bit harder than we are used to.
See how steep some of the slopes are in the background in this shot.
The first thing we noticed about the car was that the sharp transition from tickover to moving was still a problem. In fact it seemed to be worse.
I'd put some thicker oil in the dashpot to try and slow down the response to the throttle ( I never know if that's the right way round) but we still had an on/off throttle.
This was a real pain. Most of the hills were dry grass and dead bracken, so any sudden throttle movement could lead to a spinning wheel and sudden lack of progress.
I was trying to go softly, softly, I really was, but it just wasn't happening.
Not only was the engine picking up revs more quickly that I wanted, but backing off was also a bit sudden so instead of maintaining pace we slowed. So then I had to open the throttle again and the vicious circle was complete.
We had the good fortune to be running along with Andy Woodhead. I didn't know him as he said he hadn't been doing trials for a year, but he knew his onions and kept offering advice, which I would love to have been able to put into practice.
The problem seemed to be getting worse.
Someone pointed out we seemed to have a water leak. We couldn't find a source for it so carried on, thinking about topping up the radiator at lunchtime.
What really interested me was the performance of Joss Veale from Somerset who was storming up the hills (I mean he was doing well, not that he was going really fast). It interested me because he was using a car not unlike mine, in that it had a live rear axle rather than independent suspension. I'm sure he had some other nice bits on, like shockers and brake callipers as it seemed to have had a complete rebuild, to a very high standard. He is at 2 minutes 04 seconds in this video.
Lunch time arrived and we changed the dashpot oil back to a thinner one. I topped up the radiator. However I didn't actually check the motor was full of water (there is a high point which could lead to airlocks) and this was a mistake.
On the run back to the afternoon hills I noticed the car was pluffing ( very specific technical term) through the exhaust and wondered if we had some valves on the way out, or if the timing had slipped back.
The jerky throttle was no better. On one occasion we kangaroo-jumped from the start-line. It was a bit like watching a learner-driver.
Andy suggested that he didn't think that was what I'd intended to do. I claimed to have done it for comic effect.
But then the water temperature gauge started going very high and I couldn't budge it. I went back to the pits (in top gear, to try and get airflow through the radiator) and after releasing the pressure using a towel on the rad cap and jumping away as the fountain erupted, I discovered we had sod all water in the engine. There had indeed been an airlock, To ensure I filled it properly I took the hose off the thermostat housing (the highest point) and filled it through that until water flowed out of the thermostat elbow. (Luckily I am not running a thermostat, just a flow-reducing plate).
I dashed back to the course and we carried on. The car was running a bit better now and we got further on some of the hills. However, true to my constant-failing I had not walked the further reaches of the hills as we hadn't been bothering the higher parts. Suddenly I arrived at a gate I hadn't walked around.
....and arrived at a downhill turn, through a deep hollow from the wrong direction.
See Roland Uglow arrive about 4 feet to the left of my route
You may also notice his passenger Laura seems to attract
more attention than my passenger ,Ian.
This resulted in me getting my wheel hard up against the exit slope
(it's just cleared it here)
This had me leaning the whole car and crew's weight on the outside front wheel which was on full lock. Bystanders suggested I stop as the wheel might collapse. But I carried on and hit the post anyway, so I would have scored better by stopping where I was. Luckily the wheel didn't break. Still, I should have stopped. Looking at the pics that Glenn took you can see I was 4 ft too far across compared to other cars. This meant I was falling into the hollow instead of driving across it's rim.
So it was a rubbish day. The car hadn't worked well and I hadn't been able to compensate, even adding some of my own mistakes. There was also some some doubt about whether my rear brakes were working properly. Following a suggestion by Andy to test them it looks like they are sort of on or off with not much in between.
So. Back at the ranch.
I have designed a throttle mechanism to slow down the initial surge of power. However it occurs at the very smallest twitch of the throttle butterfly. In fact "twitch" is proper word, as we had found that my boots had been bouncing as the car bucked about and causing some of the unintended throttle action.
Looking for a Plan B I found a Weber 28/36 carb on ebay. It was only on my side of Kendal and went (to me) for just over thirty quid. My rationale was that if I fitted this and it worked better than the SU (which isn't actually and SU, you remember) then it may show the SU is at fault. Webers are not supposed to be as good at low speed torque.
However, it was choked and jetted for a Mini so the primary choke was just 23mm, which to my mind would allow gentle acceleration at small throttle openings.
Fitting it wasn't exactly easy as the stud spacings are different. I didn't want to alter the Suzuki manifold as I may want to refit the SU. I made a plate to fit which bolted at one end and clamped at the other. It sounds a bit Heath Robinson, but works very well.
Of course the new carb points directly upwards so a bit of my new bonnet bulge had to go to allow the bonnet to close.
Trying it in the drive showed that the progression from idle to power was much smoother. But I was still having problems with the miss-firing and at idle the plugs were sooting up. I tried changing the idle jets for smaller ones but that only partially worked and led to a less smooth transition.
Sooty Plug
It was whilst laying in bed one morning pondering on the meaning of life that it struck me.
Stupid really.
I had been obsessing about the mixture and tickover and ignoring the facts.
Clean plugs runs OK. Run for a while and they soot up then it doesn't run well.
What else could cause them to soot up?
A miss-fire. The miss-fire is causing the problem, it's not a symptom.
Coil Buggered
I tested the coil with my multi-meter and it was way below spec. I don't even know if it's the right coil for the ignition pack. Information is so hard to get on old ignition systems, although I do have a Haynes manual that gives the resistance specs for the coil. On-line resources fail to recognise that the 1989 Vitara has an old-fashioned oil filled coil.
I sourced a new Lucas coil from Powerspark in Birmingham. They helpfully suggested that as the data they have doesn't offer this type of coil for this engine I would be safer with the Lucas coil for manufacturer-fitted electronic ignitions as it was within the specs from my Haynes manual. They did a cheaper Own-Brand coil but thought the Lucas one would be safer.
It arrived next day and I fitted it. I ran the car for a few minutes and drove it up and down the drive. It seems better and when I pulled a plug it was not as blackened (just a bit darker than I would like).
I also found the source of the water leak which was (rather strangely) a sender unit in the manifold which I don't use, but is still there to block the threaded hole. Which it wasn't doing! I've tried it with some PTFE tape on the threads. If that doesn't work it's alloy welding I'm afraid.
Just a week to go before the next event, so I need to get the car up to my friend's farm for a run around for an hour or so.
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