Bump Steer

... or bumpsteer, arrrgh ... WHAT?
While chasing what possibly could make my car jump around on ruts, bumps and potholes like mad, I posted my questions in different forums, especially the german Seven-IG and the english WSCC-technical board. As always, the first answers get you more confused and you just feel dumb confronted with all that expertise. Then you start to read, ask more questions to those guys running theirs cars both on the road and the track.
The phenomenon is not easily explained, but I'll try. Imagine there is something wrong with your car's steering and/or suspension set-up. You drive around and you hit a pothole and the bumpsteer makes, like it says, that the car is steered in a different direction than your steering wheel points. As the affected wheel moves up and down, the wheel carrier moves in and out and steers the wheel. This is mostly due to a bad alignment of steering rack and wishbones.
Of course all this is far more complex and you could read your day (or week) away with expert literature. Two documents may catch your interest:
Doc 1
Doc 2
If you want more try the www or your nearest book shop.
Cheers.

Die hard, die harder

The estimated springrate of 275lbs/in is way too hard. I ordered a pair with 200lbs/in, set the tire pressure right and did some test drives with different toe-in. It is still a very harsh ride, but I'm getting closer to a good setup. I still have to see a pro for the best adjustments. Ride height is quite close to the road with 8cm.

A touch of yellow in the rape fields.
Cheers.

Tank venting valve

One of the reasons of MoT failure was a fuel leakage. On the top of the tank, I put some teflon tape on the threads of the fuel return line connection and the tank venting valve. Additionally, I connected a small piece of hose to the latter and guided it into the rollcage. The lower connection where the fuel is picked from the pump can only be taped when the tank is empty. For now I gave one more spin to the screwcap. Maybe this is enough, else I will drive as much as I can to empty the tank.
Cheers.

MoT (SNCT) - fail

The car didn't get approval from the technical authorities. The reasons are not severe. Two minor points not leading to failure, but mentioned on the report, are
- field of view (rock chips in wind screen)
- oil leakage ... also known as territory marking
The two important points are
- toe-in
- fuel leakage
The latter had been checked several times and I couldn't find any leakage. But then I filled the tank and drove the car and it showed that some of the connections on the tank are not consistent. I'll check that and will use some teflon tape to remedy.
Although I tried to set toe-in by myself, I didn't succeed. To be sure I will leave this job to a professional.
All in all the car is not very drivable concerning the suspension. It is very hard and follows every little bump and rut. Prior to set the toe-in, I will mount other springs with 200lbs/in rate. The oil temperature sender is dodgy as well and shows absurd values (46°C when cold, increasing up to 999°C).
Not yet finished, but close. Considering what else I changed on the car, I'm quite satisfied.
Cheers.

MoT postponed

More little works done since I had to postpone the MoT, awful weather ...
Next try will be on Saturday.
Cheers.

Resurrection

First drive since 18 months ... strange feeling, but great relief. Tomorrow MoT. Fingers crossed.
Cheers.

Cycle wings

The carbon look doesn't match my car's style, I intend to paint them yellow eventually. The goal was to have them the nearest possible to the rubber. Therefore I had to bend the cycle wing stays. The old fashioned look with the rounded tops makes that there is a difference in height, the stays being designed for the modern look flat top wings.With Morgan in mind, I thought that a little bit of wood is ok for my car, so now the spacers are made of timber (painted black after the pics had been taken).

Hot air vent covered with some mesh to prevent inquisitive looks.

Overall appearance ok on photos, but still some work to do before it is completely finished (if ever).
Cheers.

Toe in - toe out

Set the toe today, which is quite a lot of work if you have to adapt the parts prior to assembly and setup. First I had to cut the steering rack extensions. Those provided from Westfield with the wide track kit are a little bit too long, I cut three threads on every side. Then there is only one half nut delivered per side. To fix the extensions you need two. Starting from a full nut, I lathed two more.

Toe in toe out can now be set and after some driving controlled again and set anew if required. The graph shows what exactly this setting means. It is mostly responsible for the cars ability to corner. Toe out makes the car turn easier, toe in gives better straight on stability. The graph shows extreme settings, in reality we talk about 1 or 2 degrees.

The steering hub is covered with a bellow to prevent dust and dirt to enter.
Cheers.

Da booty 's ready

For once I'm quite satisfied with how it turned out. The goal was to have a boot with a hard cover, wide opening, but keep the rollbar and struts. With the fuel filler moved to the top, another challenge was to integrate it into the look. Talking looks, I wanted it to be close to the tonneau cover the car originally had. The result shows the upper edge of the bodywork covered with leatherette. The carriage bolts simulate the press studs you normally see there. Two chromed hinges are used to fix the cover to the rollbar basis. A cabinet latch is used to lock. A nicely chromed escutcheon covers the hole for the square drive.
Cheers.

Roll bar and struts

 

One of my goals is to build an aluminium hard cover for the boot. It composes of two fixed side panels and a center section that can be opened. The struts supporting the roll bar have therefore to go through the fixed side panels. Carefull measuring and then the hole cutter came out.
Cheers.

Hammer collection

Did a little bit of clean-up tonight and aligned my hammer collection ...
Cheers.

Running again

Film <<< (Uploading to this blog doesn't work for the moment, please click to go to youtube)
shows the ignition key, starter button, injection system, ignition coilpack, fusebox and Emerald ECU.
Cheers.

Error found - engine is running

Finally, after hours of work (mostly search), I found the error. I didn't take enough care when wiring the ECU and chose the wrong ignition driver for cylinders 2 & 3. Why the engine started with the wrong wiring, I don't know, but I will ask at Emerald to understand. To be on the safe side, I also changed the coilpack, HT-leads and sparkplugs:
- coilpack Bremi part# 11875 (less than half the price of the original from Ford)
- HT-leads Bosch 2x FD65 and 2x FD75
- sparkplugs NGK BP7ES
Cheers.

Bonnet fitting

The bonnet, as some other parts, is from Caterham. It comes with a protective foil (blue) which is a PITA to pull off, especially around the edges. During TechnoClassica in Essen yesterday, I bought adhesive rubber seal for the bonnet's locating surface. Some minor adaptations still have to be made.
Cheers.

Losing time

Spring finally arrived, 18°C outside, and still not ready. The engine doesn't start. After changing the crank sensor (left pic shows the new completed bracket), it took me hours to understand that there must be another fault. I found a connection between the ECU and the coilpack that is interrupted. Why it is, I don't know. I replaced the wire with a direct connection but still no spark on plugs two and three. Next thing is to order a new coilpack and HT leads to further investigate. Hope it is not the ECU ... again.
Cheers.

New crank sensor bracket

A design fault of my first bracket made that the sensor could touch the trigger wheel. With the new Marelli sensor, I had to design another bracket with a different bolt pattern. It is made of two parts: #1 fixed to the engine front cover, #2 angle bracket supporting the sensor (prototype pictured). This allows to set the gap between the sensor and the trigger wheel to the required 0.8 to 1mm. Not enough time left to solder the minitimer connector, the test if the sensor was the fault (engine not starting) has to wait for next time.
Cheers.

Bootlid - adapting the panels

The bootlid will be made of three parts: two fixed panels (left and right) and the center panel can be opened. When the chassis was stripped, I welded small brackets to the upper rails and cut 8mm thread into them. Now I can fix those panels to the brackets.

The Marelli sensors arrived from Emerald. As always I was quite impatient to receive the parcel. Everything is there and next time I will manufacture a bespoke bracket for that nice italian crank position sensor (Maseratis use the same !!!).
Cheers.

Bootlid - aluminium panels

Some more work done on the front cycle wing pattern.

Aluminium panels cut and bent to build the bootlid.
Cheers.

Cycle wing pattern

One of many challenges "on top" will be the DIY aluminium cycle wings. Today I started to build a pattern. The models are the original Caterham PVC cycle wing and a very light carbon fibre alternative. I chose beech because it is quite hard. This will be important when I wrap the borders. I'm curious to learn how to do it, but will probably stop doing it if it is too time consuming.
Cheers.

Rear numberplate

Looks easy, but if you want to have it in the middle and level, you have to spend some time doing it right. The licence plate light is a classic Hella item.
Cheers.

Crank sensor

After two small runs, the car refused to start yesterday evening. There are rub marks that suggest that the crank sensor was mounted too close to the trigger wheel. I suspect this sensor to be the reason, because the red LED on the Emerald ECU doesn't turn green when cranking (it should when it has a crank signal). A quick look at the Emerald shop shows that they have Marelli crank sensors in stock. The bracket I made is for Ford sensors. I have to design a new rugged sensor bracket and check the sensor position to prevent this kind of trouble.
Cheers.

Front numberplate

Not a lot done tonight 'cause car not starting, maybe a sensor issue ... i'll investigate when frustration has waned. Numberplate is on, though.
Cheers,

Happy feet

It's hard to imagine, but summer will come. One of the downsides of my car is the heat in the driver's footwell, especially with the big exhaust manifold I have mounted. When I made the new sidepanel, I left a hole in it to chase the hot air out of the car. Now it was time to build the heatshield susceptible to guide the hot air to the hole. So tinsnips out and cut some aly sheet, covered with heat reflective foil.

Fitted after cutting a hole for the steering shaft and bent to suit. Rear view shows how the heatshield should deviate hot air to the outside (hopefully).

Topview shows the whole manifold with the heatshield in place. I will report in summer if it works!
Cheers.