Since I had to cancel my SVA test, (rigorous reality check 3 days prior to date), have been checking around for the more specific IVA requirements.

Clearly, the plastic fuel tank is already well-known. After browsing thru article in May issue of CKC, seems that the other issues will be :-

1: Chassis # location - RHS of chassis
2: E-marked winscreen
3: Brake mcyl fluid identification (on reservoir cap
4: Mandatory dash warning lights, & identification of all controls
5: Headrests - height +/- limits
6: Tethered style fuel cap
7: Exhaust Noise - stricter limits
8: Anti-theft device, if no steering lock
9: Rear fog & reversing light operation
10: Bias brake controls permanently locked
11: Correct brake performance split.

This article goes on to comment that most modern cars, which use tandem brake mcyls, can achieve the necessary braking force of 30% of Design Gross Vehicle Weight, because they have diagonal split systems.

Diagonal split system = 1 front brake + 1 diagonally opposite rear brake.

However, the Sierra mcyl was designed for a front/rear split brake system, which, as the name suggests, couples the rear brakes together as one system half, with the 2 front brakes coupled together as the other half.

All fine and dandy while both halves continue working. If there was a failure in the front system half, the remaining rear brakes will now have to be capable of providing that 30% DGVW braking force, which might be difficult for some drum brakes.

What worries me about the CKC article is the seemingly blithe assumption that you can simply re-pipe up existing brakes in the diagonal fashion. This is definitely not the case.

Diagonal split systems were introduced for the increasing number of FWD mid-range, and smaller cars. These vehicles required a revised front suspension set-up, to accommodate the drive shafts, leading to the single-sided type of brake caliper, and a ground-offset (or scrub radius) reduced to zero, or even slightly -ve.

Where vehicles had a +ve g/o (scrub radius), any braking resulted in a degree of steer torque. This is acceptable while both front brakes operate together. When only one works, keeping the car in a straight line becomes much more difficult. We tried it on the test track, many years ago, just to prove this point.

Funny, I was reading the same article last week, and starting to panic a little bit!

The sierra master cylinder that i've got as 3 outputs - I'm guesing 2 for the front and a single for the rear.

As I'm running discs all round (donor was a 2.0l), and the brake proportion split is usually 60/40 front to rear (ie fronts lock up first), can it be assumed that the front 2 brakes account for 30% each and the rears are 40% combined? So a failure of either a) one or b) both of the fronts, or c) both rears, should still allow for adequate braking power overall?

As you say, it's not just as simple as re-plumbing the rears braking system to meet modern requirements!

ignore me

i don't think theres anything majorly difficult or different there though

[Edited on 27/4/09 by blakep82]

1: Chassis # location - RHS of chassis
Just has to be in the right place

3: Brake mcyl fluid identification (on reservoir cap
Has to be within 100mm of fill point, so an id place on the fire wall should be sufficient.

4: Mandatory dash warning lights, & identification of all controls
Just using standard identification logos, most lights come like that.

6: Tethered style fuel cap
Yes, thats a sod as I just bought an MK aero fuel cap a couple of months back. There is a small loop at the back so I think I could get around this with a bit of chain that loops through a breather pipe down the filler pipe.

9: Rear fog & reversing light operation
As someone mentioned. If you are using a sierra stalk set, add a fog light relay, with +12v to pins 85 & 30, run pin 86 to the fog switch then the switch to the gound link between the steering stalks ground feed (something like 56 or 56a I think).

Reversing light for a type 9 is no extra work. For a bec with reversing box, I guess a minor wiring addition (unless it has a switch built in)

10: Bias brake controls permanently locked

Blob of weld if steel or ally brazing rod?

11: Correct brake performance split.
Yep thats the sod, ive got rear drums. Gawd knows what I'm going to do. Can you get this tested at an MOT station?


That is of course unless the standard sierra master cylinder will pass as is?

quote:

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Originally posted by Charlie_Zetec
The sierra master cylinder that i've got as 3 outputs - I'm guesing 2 for the front and a single for the rear.

---

Thought I'd better post a sketch of what I meant.

Here it is.


PivRad_03

So, "Pivot Radius"=Ground Offset=Scrub Radius. Those using Cortina front uprights must not arrange their brakes into a diagonal split system.

Dunno about the Sierra upright. Anyone got suitable data for the Sierra pivot rad?

was wondering how you got on Dick - sorry to read this post.

Also scanned that article and had a panic when I read it.

Do people really think its going to be possible to pass with a front / rear split or are we going to be pee'ing about trying to get our cars through for nothing?

quote:

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Originally posted by Paul TigerB6
One thing an SVA tester told me last week was that rear reflectors will be required to be vertical for IVA - same as the fog light.

---

I think there's some misunderstanding about fuel filler regs.

The cap doesn't need to be tethered, it just needs to be of a type which the key can only be removed when it is locked, the tester I spoke to suggested fastening the fuel cap key to the ingnition key with a non removable (welded) key ring.

In any case the requirement may not apply, the wording of the regulation needs to be clarified. It says "(post 05/2009 vehicles only)"

Is that cars which are tested after 05/09 or cars with a manufacturing date after 05/09?

Kits are usually judged by engine age which would mean that unless you have a new engine your vehicle age would be PRE 05/09 and therefore the regulation would not apply.

The actual words of the regulation are below


"The fuel filler cap must either be tethered to the vehicle or be of a lockable type where the key can only be removed when the cap is locked or an automatically opening and closing, non-removable fuel filler cap (post 05/2009 vehicles only)"


Cheers

Chris

^ i think a magazine article is a bad place to take info from anyway. you're essentially making your own interpretation from somebody elses interpretations.

best just go by the manual

I like the idea of the welded key ring. It sounds like it would be fine (and given my ability to loose keys of rings would be a good idea anyway).

I spoke to the guys at GBS and MK a little while back and they said there were very little differences from their option between IVA and SVA. They didn't seem to think anything was worthy of panic. I guess see what they think next month after they have had a few people go though the process.

I expect the magazines in the next month or two will be highlighting any horror stories to do with brakes for IVA.

It will probably end up as something that can be fixed for £200-£300 worht of bits from a supplier or two.

Would it be possible to scan and archive the many mag articles which will be coming out shortly?

quote:

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Originally posted by blakep82
^ i think a magazine article is a bad place to take info from anyway. you're essentially making your own interpretation from somebody elses interpretations.

best just go by the manual

---

The biggest issue will be for those getting tests in the next few months after missing the SVA. Im hoping by the time mine is complete the IVA manual will alsobe complete, revised several times and have some clarity which the current editions dont seem to!

Mirrors look like a total faff too, must fold in and snap back into position, or be adjustable from the drivers seat. Means bike mirrors or anyhing are out

[Edited on 28/4/09 by alistairolsen]

I would have thought bike mirrors should be OK.
Does it say if you can do it by leaning over or not?
My interpretation would be can you do it with the seat belt on. Afterall if they got knocked you could just pull over, after all being hit head on you may want to inspect more that just the mirror.

Its a bit like the cross over brakes. If they fail, is the induced steering enough to cause a spin out or bad swerve or enough that you can compensate whilst coming to a stop (before you call a recovery truck). After all if the brakes fail its not like you are going to continue on with the journey until later.