Chassis progress



Chassis progress

The chassis moves into the blasting cabinet at Aliblast Services, how long has the Mini shell been there?

What an environment!

The chassis in primer

The chassis was primed in black etch and then given two coats of Por15 hardnose.

 

Decided to design my own chassis jig so I can protect the paintwork and turn it over more readily. I fab'd it out of 2" x 2" ERW (2 days welding). The basic design was similar to the one at Aliblast without the adjustable height (see above).

Custon design jig



The finished chassis  on the jig

References

 

Contents http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html



Front Brakes

Willwood front brake conversion

The Sylva kit comes with solid discs and provision for HiSpec 4 pots. I decided that I wanted Willwood Midlite 4 Pot callipers and vented discs being an upgrade on what was designed. I have this configuration on my Westfield and I don't want lesser brake power on my Sylva compared to my Westfield SEIW. The front upright is straight out of the Triumph/Caterham parts bin being originally designed for a Spitfire.

Willwood make a conversion kit BK23K which includes discs, callipers, bolts and adaptor brackets. However they do not supply a set of fitting/modification instructions. The vendor merely gives the advice that "Wheel hub disc mounting face will need machining". In fact the vented disk provided is not even a good fit on the wheel hub, it is in fact off another car and the holes for the wheel hub have been added.

As supplied Caterham bits

The following information should help someone make the modifications without the head scratching I went through.

Process

1) Remove the wheel hub, and remove the wheel bearings and studs (pressed into the machined alloy billet).
2) Mount the hub in the lathe and remove 2mm from the face that contacts the steel disc all the way down to the size of the disk inner hole. This from memory is 62mm. I don't recommend any more than 2mm as this will make the body of the 4 pot protrude beyond the wheel hub face.
3) Thoroughly clean the part of any swarf.
4) Machine the forged steel upright in the area of the steering mounting. This is tricky to set up in the mill (I used a cast iron angle mounted on the bed). Remove sufficient material to give you a gap between the rear of the vented disk and the steering arm attachment.
5) Reassemble all the stuff with the new disc in place, check for clearances.
6) Select shims (I used 2mm washers) on the mounting points of the calliper to centralise it relative to the new disc.

Modified using Willwood bracket

Modification

Improved bracket

Due to a screw up by me at the early stages of trying to make sense of all this I decided for some reason to try and modify the mounting bracket. This resulted in a request to the vendor to get a replacement. He said yes sir that will be £80 + vat please. I looked at the part and decided it could be improved (too many parts, 3 parts into one) and not that difficult to make in the first place. Using my home modified CNC milling machine I put it to work.

I hope you have more luck than me making this modification, the information above should help.

References

 Motorsport Tools very helpful.
http://www.motorsport-tools.com/caterham-7-wilwood-brake-kit-midilite-4-pot-calipers-247-x-20mm-disc-p-250526.html

Contents http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html





Solving the Fuel Gauge

Fuel system linearizer

The tank shape derived to gain extra foot well space for the passenger is not without it's problems. It is decidedly non linear when it comes to attaching a fuel gauge.

The results adequately show the inverted "L" in terms of linearity. As the tank is filled the resistance reduces linearly until 13Litres or 50% then the resistance changes slope making the last 50% equal to about a quarter of the change in resistance. So in practical terms when the gauge says 3/4 full it is only actually 1/2 full. Not very nice!

I invented a little box that corrects the above problem. If you are interested in the solution, I have added a link for the technically minded:
http://www.alastair-reynolds.pwp.blueyonder.co.uk/fuelsystemlinearizer/index.htm

References

Contents http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html

Suspension bushes and brakes

Aliblast completed the painting of all the suspension arms so I took them round to Colin at Regent Motors who let me use his 20T press. Most of them went ok except the cantilever top front arms that needed a special spacer to let me get into the bushes with the press. I used an old tailstock from a Myford Super 7 and a wheel nut + washer.

I made an alloy drift for the rear wheel bearings that needed pressed in.

Having difficulty identifying the rear brakes. I thought they were standard brakes off a Golf MK4 but it turns out they are VAG Hydra OEM's from Rally Design (believed to be Passat parts). The disk is a MK3 Fiesta 230mm x 10mm.

I want to uprate the front brakes to vented and Willwood 4 pot, I sent 2 emails to Rally Design looking for advice with no reply so far. I don't think customer service is their strong point.

The

The chasis painting is next, I made up an adapter for Alastair McGills chassis jig so he can paint it once he has given it a light blast. I am currently waiting on Frost Restorations delivering more paint.

References

Contents http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html

Chassis welded and ready for painting

The chassis now delivered to Aliblast services for sand blasting and painting with PoR two pack chassis paint. The items that are non-standard are as follows:

* Increased passenger leg room requiring a custom fuel tank (see below) and some metalwork changes to the foot well.

* GRP racing seat installation requiring mounting lugs to chassis and change of steering position where the column exist the chassis, more forward and lower.

* Mounting lugs for Battery Fuse Box and Offside Fuse Box. This enables the use of VVT ECU from Ford Puma.

* Mounting lugs for Focus header tank which is a good fit in the J15.

* Add extra steering bush at end of column

* Mounting points for anti-roll bars.

The fuel tank arrived from Allyfab (Bryn Jones) fabulous job, even sorted my cockup with the return pipe.

The wiring harness is in production.This involved production of circuit diagram, ecu mapping to Battery fuse box chart and Chassis loom routing chart. All of this information can be sent to you if it is of any use to you.

Off to Stoneleigh for more bits! There may be a delay before more progress can be reported!

Gear stick, ancillary harness, serial plate

 

The gear stick is from the Puma donor, which is too long so off came about 50mm and added the racing Puma knob purchased s/h off where else:- ebay

The wiring harness is divided into two like the Puma: The Battery junction box and ECU and the lighting and ancillary harness or Offside fuse box in this case. I created a harness jig based on the accurate measurement of the chassis. This allows me to move the chassis around and still work on the wiring.

After reading the Locost forum on such matters, I came to the conclusion at least two locations for the VIN are required. One that cannot be removed and one on the nearside chassis member that is more obvious to the inspector. The chassis number cannot be punched into the chassis without cutting a bit out first. I plan to weld a plate in instead. The bulkhed is the only other place that has enough strength to have a naked punched serial number.

 

Nearside chassis location

References

Locost thread on VIN: http://www.locostbuilders.co.uk/viewthread.php?tid=166395

Contents http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html

Revisit the steering coupling

A very nice chap called Angus had a look at my steering couplings and offered the opinion that it may foul the inboard suspension cantilever. After much angst I had to agree with him so I spent the next day modifying the steering so the shaft now comes out into the front foot well where the designer intended. It involved fairly extensive mods to the foot well, lower bracket and lower bearing position.

The plate illustrated below was uprated to 3.5mm and hung upside down.

 The coupling now exits in it's original position as designed but needed a repair to the footwell.

This is as low as the steering shaft can go so if it is wrong now then that would be a problem.

References

Contents http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html