IVA fixes part two

Even though I feel like I've not spent much time in the garage, I really feel like I've made progress since last week. So here's a bit of an update.

Design weights.

While the process of updating the weights was quite simple, it's left an unintended consequence. The design weights are used to define whether the brake efficiency is correct. For my test it was 66.88%, and given the limit is 60% I'm not overly impressed. I expected the brakes to be much better, even without the brake booster. 

Turns out I was right to be unimpressed. Because now I've updated my design weights, my brake efficiency is only 57%. Which isn't enough for a pass. I did think about updating them again but that seemed inappropriate (even if they would have let me do it). So the alternative is to have them retested. I've confirmed it with DVSA that a retest would be done which is one half of the battle. 

The other half is the brakes themselves. Why is the efficiency so low? Turns out it's a self inflicted issue, reusing brake parts. I thought I was clever to reuse the parts, as I avoid the issue where brand new parts have very little effect until they're bedded in. Problem is I didn't record what pads go with what discs, so I now have this;

Given how much braking was done for the test, these should have been shiny. More importantly they should have been shiny all across the surface. And braking 101 teaches us that the further away from the centre the more the braking force, and guess which part of the disc isn't being scrubbed by the pad?!!

Simple fix though, new pads and discs are on their way from Autodoc. Febi Bilstein parts, front and back for £131. That'll teach me not to be too clever. Since I'll be driving to the retest I'll just make sure to give them a bit of time to bed in. Even if it means a slight 'detour' to the test. 

I am hoping it means that more force can be applied to the pedal before the wheels lock. Given the nearside showed 134kg and offside was 194kg, even addressing that imbalance should be enough for the car to pass. I need another 25Kg of force to pass, with 60kg between the two sides locking up I am hopeful/confident that a retest will be very simple. 

Oh, I do need to drop the tyre pressures, they were quite high to pass the self centering but now that's done I can get them back down. Again that means more grip and higher braking effort. 18 psi seems to be a good place to start.

Brake pipe issue

On to defect two, brake pipe touching the brake lever. Here's the before photo, with the clutch lever depressed;

This is quite a clear fail that I should have spotted, but as a lone builder it's difficult to predict. It goes to show that having 'someone else' take a look at things can help, ideally a fellow builder but anyone with an interest in cars will help.

In any case, it's just a simple reroute, I had to release the clamps to do it but now everything is clear.

This does highlight an extra job though, That boot on the slave cylinder has seen better days. New ones are £13 so I'll add that to the 'post-IVA' jobs. That might explain why the clutch pedal fades over time. Just looking on MX5 parts I can see a rebuild kit for £22 that contains a cylinder and boot, but since a new one is cheaper it makes very little sense not to simply replace it. 

Exhaust bolts

This was simple to fix, a nice sprinkling of nuts and clamps to resolve. 

The bottom one was interesting, the original nut was a nyloc but it didn't engage fully. I've replaced it with a standard nut and threadlock, hopefully that will improve things. It's not as if the clamp is going anywhere if the nut comes off.

Indicators

I wanted a solution that didn't need bodywork modification, so a light pod made the most sense. The problem is the pod had to deal with the bulb bayonet fitting. Even though I bought a pair of low profile ones, they were still long enough to warrant an extension to the pod.

And of course, the side lights are next to them, so it occurred to me that the indicators would be blocking them from certain angles. Despite the bodywork permitting the original fitting to work, it had to be raised. 

So I now have this;

The lights were only 1 inch too low, I've raised them 1.5 inches so they should be good now. Of course, the car is in the air so I can't measure them just yet. If they're still too low I'll block out the bottom of them like the examiner suggested, I just didn't want to do that as the first choice. 

I've got one more job to do on the indicators, the fixings above are just self tapping screws and not radius compliant so I need to replace them with cap head bolts. Not an issue, I just didn't have them to hand when I did this job. 

Rear number plate

This is printed now, to the correct size;

It mounts the same as the existing one, but is rounded off and to the correct size. It needs a light sanding then screwed on, but the rear of the car is at the back of the garage, and needs me to open the garage door to the elements. The current weather isn't just good for ducks, it's getting pretty close to what Noah needed. So I'll leave this as is.

Fuel lines

Leaving the best til last... this is what I started with;

It's very clear why it failed. First job was to get the pipes off the clip, and several bashed knuckles later I got them off;

At this point it was clear that my plan of just moving the pipes over the clip wasn't going to work. It would have left the pipes at the same height and there's just not enough space. 

The first job then was to cut off that clip;

The pipe was then able to drop down to the rubber part of the mount where there is much more clearance. Using a piece of wood for a brace against the body, I was able to put a kink in the pipe;

This gives plenty of clearance around the chassis and the gearbox mount so I'm happy with the positioning. The problem is that without that pipe clip there's about a metre of unsupported pipe. Given the pipe can move enough for me to put a kink in it, I obviously need to reintroduce new supports. I don't have a 'central' support anymore so I need to add one before the mount and one after the mount. Neither are difficult, a hole and a rivnut gives me a method of securing, then a metal covered 3D printed bracket will provide the support. It's just really unpleasant to work underneath the car when it's on axle stands. 

All this means that after this weekend most things will be sorted. I will need to wait for the brake parts to arrive, then I can book the retest. As I'm waiting for brake parts I've also ordered the clutch slave and I'll replace that at the same time. 

I guess the last battle will be the weather. Apparently the wet weather will be with us for a bit longer (thanks Punxsutawney Phil!!) so I'll have to delay the retest until the weather is a little drier.