Speedo sensor

[marlin]

The red arrow is the spacer I took out of the donor torque rail and used the donor bolt.  The blue spacer I had made up to support a large 12.9 bolt.

The blog shows the top mounting.

 

[marlin]

On the bottom there is a fitting post that must go into the front hole or the diff will wobble to top of the mounting plate.  I'm guessing this might be where your issue is?

Let us know what you find.

Marlin

[Mrbarry]

Brilliant thank you. I have found pictures of the top, the sides, arms cut off. All sorts. That’s the first picture of the bottom and mounting plate. The spigot you mention is clear in that picture, just need to get home so I can look at mine. 

[Mrbarry]

Finally had a spare hour.

The rear bolts where all sort of tight but I got a full turn on all three.

The front lower bolts where 12x50 with standard nuts, I’ll replace with cap screws and nylock nuts. These bolts where both loose, one rattling about, the other finger tight. They only went thru the lower holes in the did not the upper ones, they also lacked any spacers so could rattle about in the large diameter holes. 

[knights_templar]

If you havent I would also put some large flat washers on the bolts before going through the chassis plate, may be considered belt and braces but the more you support the plate the better.

I think you will be safe to use the speed sensor in its current position.

[Mrbarry]

Yeah I have made some 6mm thick stainless washers for the top and have some 3mm thick 40mm penny washers for the bottom. Will be trying it in the same position again later tonight. 

I’m going to the meet Sheffield way on Sunday and would like a speedo for the drive

[Mrbarry]

Well I managed to get it all done last night. It was 11:30 when I had finished so I didn’t test drive at all but the speedo sensor is just about on its 4mm limit and picking up the prop nicely.

I had to fit new plug and socket to the proxi because the other one was also destroyed, I have a theory here’s lol. First sensors just had the tip taken off so I adjusted the angle of the sensor to give a better rang, the last one was set well away from the prop, obviously the cable was not clipped well enough and got caught pulling the sensor into the bolt holes and bang. This time the cables are very much away from harms way. Annoying because I’m an electrical engineer and that’s a rookie mistake. 

As for the diff, it’s now fitted with cap screws and nylock nuts with large flat washers. All torqued to VFT, that’s not going to move now!

 

 

[knights_templar]

Finding two loose bolts would make me a little concerned.

Did they have any other lock system, although obviously ineffective, such as spring or star washers? IVA requires locking devices on on all nuts and bolts unless thread lock is used and the bolt marked as such.

Would a spanner check be prudent?, as you did not build the car, although in the builders defence there are bits on the car that have a tendency to have "issues". For example the Mazda rear hub to the lower rear wishbone, if you find that loose, come back to me, it may not just be a case of re tightening.

[Mrbarry]

I’ll check those then thanks. 

The bolts had thread lock and red match marking so had not come loose, the washers had dished like Belvedere washers because they where so thin and clamped over a large hole, I would say this had caused the appearance of loosening but with the same result, insufficient clamping force of the planes. 

 

As for spring washers, little understood they are, I had to to a presentation on the so called self loosening of fasteners as part of a HND, if you look up ‘junker’ and ‘self loosening’ I would never touch one, 9 times out of 10 they accelerate self loosening. I like star washers. But both star washers AND spring washers are single use and should NEVER be used in conjunction with a flat washer. You should also use two, one under the head of the bolt, one under the nut. They are not designed to provide clamping force as a result of their apparent spring action, they are designed to grip and resist rotation due to their sharp leading edges. Once removed they should be replaced. You can even get left and right handed  versions for left and right handed threads.

Waffling on a bit here sorry.

 

Will check the hubs later. This winter will see a bare chassis rebuild, I would like to reduce weight, increase reliability and whilst I’m on add a turbo to the mix. Also want to route the exhaust under the car (after much head scratching I have found a way) and put a resonator box in the boot with twin pipes exiting one each side of the diffuser. Im fed up of warning people not to touch the exhaust every time they get in or out already. Plus with no exhaust and the egg timer shape of the car it will be feasible to drive up onto 4 angle iron ramps for working underneath. Win win apart from the loss of boot space. 

[Mrbarry]

Right good news. Just fitted a pair of wheel spacer to the rear wheels and checked the hubs, they seem ok. But better still I went to get fuel and did a 10 mile test drive. Speedo is perfect. It’s never lasted that long so I’m hopeful now. 

Thnks for the help and pictures much appreciated. 

 

Car is now full of fuel ready for tomorrow’s meet, 160 miles round trip should test it well. 

[Mrbarry]

Well it’s been 300 miles now problem free. Happy days thanks guys for the help.