Ford Capri Mk3 Track/Race Car Project

[fingers99]

With grinders you've really got 2 choices -- either buy 2 cheap ones (Aldi/Netto et al) -- which gives you a spare and enables you to have, for example, a flap disk on one, a grinding or cutting disk on the other, or buy a (fairly) expensive one from one of the major manufacturers. The later will probably feel nicer (less vibration, better balance, nicer switch) and last longer, but there is a utility to the former.

Currently I'm using an Einhell one which is the worst of both worlds: not particularly cheap and with a safety switch that obviously was not tested by anyone wearing work gloves.

[Will01]

Thanks for the advice, I went back to the supplier and said I was not happy, they told me I could get the Bosch upgrade for same price as current one I had. Very happy with result, maybe now I can get a proper move on with stripping the crud off the car. Pictures of bare metal paint/underseal stripping to follow.
I will buy a second grinder to use as you say in time, stops the faffing around. At the moment I just trying to get rid of original underseal so I can pot blast the underneath eventually.

[Will01]

So whilst i haven't been in the garage this week after work due to some pretty horrendous weather, i have been busy trying design my own Bias Pedal Box etc.
After looking to see what others have done with converting the standard pedal box, an idea i like very much. The real thing holding me back is expense, plus i think i can do better cheaper! After looking around i got some ideas about universal bolt on bias boxes e.g. Ian Nixon's Lada Bias Pedal box. This sits inside the engine bay and takes the brake input from the normal brake pedal after a little modification.
Pictures of the design will be posted up here once i have finalised, but the idea is to keep as simple as possible but still allow adjustment.
Some of the parts will be bought in e.g. Master Cylinders, Reservoirs, Balance Bar with dash adjuster etc. However in order to work with the pedal box in the car as standard, this will need a little modification.
First of all i have removed the standard brake pedal in order to measure and first of all check the Pedal Ratio. For a Bias Peal box to work i have adopted the standard feeling that anything between 5:1 & 6:1 should be ok as i will not be using a servo for assistance.
As standard the Capri Mk3 pedal is ~4.2:1 assuming contact with centre of brake pedal rubber.
To give details i have measured ~250mm this is distance between centre of Pedal pivot to centre of rubber contact patch.
The centre of the Brake actuator pin is ~60mm from the centre of the brake pedal pivot point, therefore 250/60 = 4.167. If the servo was still to be used this would be ok, but without servo assistance this will make the pedal very heavy. This probably would not be that bad for a few laps on track but any length of time would be very uncomfortable and considering i would like to drive on the road it is not suitable.

The problem however that i have found is although i could change the pin location for the brake actuation, it will foul with the pedal box.
Also i would like to keep the pedal semi adjustable to be able to vary the ratio slightly due to usage. Unfortunately i cannot just drill lots of different holes in the pedal for different ratio as the holes would overlap. Therefore i have decided to machine the pedal to have a slot to allow infinite adjustment between ~4.2:1 to ~6:1. Because of the material the pedal is made of i will need to beef up the pedal assembly and pivot point. I am going to try and use as many standard components as possible, but these may require upgrading later on.
Due to the brake pin fouling the pedal box i will recess the pin into the pedal so as to allow the pivot point to be moved closer to the brake pedal pivot.
This will be much clearer to see once pictures are added.
I still need to finalise my idea to be able to fix the pin in situ once the correct adjustment has been reached, but this will follow later.
Due to the design of the pedal box i may also have to look into moving the throttle pedal or changing this entirely. Hopefully i can just modify in such away so as not to affect this. If the accelerator pedal has to be moved then i will be looking into hinging the pedal from the floor. This will help with heal and toe as the current spacing of pedals is not much suited to this currently. Nothing a quick bit of modifying won't sort.

The next steps are to work out brake pedal movement with particular master cylinder, caliper sizes. Before anything is modified this will need to be worked out.
I will upload pictures of bought in parts as and when they come together. I am quite excited as this will be custom to my own car, if it works well i may look at sharing.

Master cylinder sizes have not been worked out yet, but this will depend entirely on which calipers i will use for the build as i have many to choose from.
I am still looking into materials for the actual bias box, but again details will follow.

[fingers99]

Something to look at -- if you've not done so already -- are the drawings for a few in Staniforths Race & Rally Sourcebook.

[Will01]

Hi Fingers, i will look it up although i have looked at many other sources to get inspriation. Maybe Staniforths Race & Rally Sourcebook will help me complete this easier. Thanks

As for Capri progress on the Shell, both myself and my wife had a day off yesterday so we managed to get cracking with a little more repair work.
First of all i started to strip the inner rear arches on both sides, inner lower rear corner area and floor area along the sill from the footwell area to front leaf spring hanger.
The pictures below show with just the hard heavy rubbery underseal removed, once my wife returned from her Hair appointment, she got cracking with cleaning everything back to bare metal so as to apply primer and finish off the repair sections made in previous weeks/months which were hard to access before the rollover jig was purchased.
There is still alot more to strip back as there is alot of crustiness underneath the car, however once the pot blaster is purchased it will be much quicker to clean back. The grinder is much better at getting through the thick underseal layers. The odd few areas show a little bit of rust, however nothing yet the worries me. Some of you may be saying why are you stripping it back completely, to answer this it is because on my last Capri someone had been very clever with covering up really bad patches and blending it in to look nice again. My last Capri had fibreglass inner arches which i only found when doing a little investigation.
More pictures will follow, but we are working away nicely to have a lovely grey primer underbody.
The next big job for the upcoming weeks is to get a good look and repair the front chassis leg, hopefully once we cut it off the metal work beneath will be ok, but maybe that is the optimist inside in denial.

If i haven't said it already the rollover jig has been soo handy and i recommend to anyone carrying out such repairs.
Apologies for not soo good photos, but my new Phone Camera is a bit poor!

[Will01]

I Forgot to add the Bosch grinder which we had as an upgrade is working a treat and has much smoother operation. It doesn't feel as powerful as some of the cheaper ones, but it does a good job and doesn't seem to get as hot as some of the cheaper ones. I am impressed so far, because if we asked the cheaper ones to do the same job i think they would have burnt out in 5minutes trying to take off the rubbery stuff underneath.
Now that Christmas is here, hopefully the repairs will get done pretty quickly and if i am lucky the underneath will be finished and painted.
Santa please send me a Watts linkage and Rollcage for Christmas.

[Rallyroller]

Hi Willo

Having had a few problems I am now back on my rally spider project. Today I have ordered the brake balance system.

In my case previous cars had the brake balance unit connetcted to the brake pedal. Then twin remote servos were used in line for front and back. I was never really happy with this. This time I have left the servo in place and will addapt a "universal" bias brake assembly to fit onto the servo. ( you can get servo mout ones but they are too long in overall length for my applicaiton.) Hopefully over Christmas I will get time to look at it.

You are right about the brake pedal actuation, and then you have the issue of master cyclinder sizes etc. Makes the brain work a bit.

One tip from experience- The one problem with bias brakes is bleeding them. I have had an idea which I suspect will work, but I will see.

Where the pipe comes out of the master cylinder - connect it to a tee piece. Then in one section of the tee put a bleed nipple. ( you can get 3/8" bleed nipple to suit.) The other end then goes onto the brakes as normal. Do this with both master cyclinders. My theory is that if you need to bleed one system, ( lets say the front) you connect a tube to the bleed nipple on the tee piece of the rear master cylinder, and put this inot a jar. Slacken this bleed nipple, and then bleed the front brakes as normal at the callipers. This will also allow the fluid in the rear master cyclinder to go into the jar. This allows the brake pedal to go through its full stroke, and make it easier to bleed the front. I think this should make it eaisier, espeacially if you are on your own. You just have to make sure the fluid does not run out. I will let you know if it works as planned.

Keep up the good work.

Nigel.

[fingers99]

With 2 master cylinders you're essentially bleeding 2 independent systems. So, longest run from (let's call it) cylinder A, shortest run from cylinder A, longest run from cylinder B, shortest run from cylinder B. It may help to adjust the bias towards the cylinder in question, but I'd not think it essential.

The alternative would be to use a vacuum bleeder -- you can pick up a Mityvac alike on an internet auction site now very cheaply.

A Tilton type bias system would probably function in a similar way.

[Will01]

I have a pressure bleeder, its great for getting fluid in the system. Then I just finish off with manual bleed.
After bleeding many systems in the past i have found out the hard way to bleed it properly. The E-Type system is particular difficult mainly due to access on the rear circuit! Anyway I will see how it goes when this one goes in, maybe build in a few quick access points to aid bleeding.
Last year my Dad bought a really clever and neat brake pipe flaring tool which is quick and easy to use. I just need to buy in the parts and have a few made and we will be there. Thanks for the advice guys. Will

[Will01]

So i think i have had a pretty successful weekend.
Good news is that a few small repairs have been made and also managed to cut out and replace the crappy chassis leg with a new one off a scrap Capri.
I am now completely shattered, but am very pleased with the progress. Only problem i found is that the passenger side sill which i have not replaced is a bit crusty and i am not happy with it. Therefore i decided to buy another one so i can make neccessary repairs.

[Will01]

Few more pictures

[Abarthnorway - Remi L]

A proper way to celebrate Christmas!

[Will01]

Happy New Year to everyone, hope everyone had a great Christmas break.
I myself spent most of the time in the garage trying to finish off all the rust repairs to the Capri shell. I can now say that all major rust repairs have been sorted. I also found that previous repairs i had made which i was not happy with were removed in order to tidy everything up a little more.
I did find that i eventually emptied by 20litre bottle of Argon/CO2 gas which did surprise me!
Luckily enough the day before Christmas Eve i managed to pick up a pattern sill which i could use to cut up for repairs, i know that some of you may say why did you not remove the entire sill and the simple answer was that i really did not think it was necessary at the time. I am happy-ish with the repairs and a little filler will help tidy everything up. The majority of the sill was in great condition just the two ends which were ropey.

Just so everyone knows i did spend Christmas Day at home with the family and did not venture out to the garage, it was a struggle but managed to pull myself away for a day or two.
To my surprise my wife bought me a nice pot blaster to help strip the paint and surface rust off the Capri and many other parts we have, spot on present. She also purchased a good few books for me to read in the evenings which were written by Carroll Smith Prepare to Win & Tune to Win. In my opinion very good books and i will be purchasing the Engineer to Win book very shortly. Highly recommended if you are thinking about building up a race car from the ground up.

So the rear of the sill had a repair previously carried out by myself a few weeks back and if i am to be perfectly honest i hated the repair it just looked poor! Therefore the sill i bought spare was used and cut up to give a better repair.
Later on in the holidays i did make another small repair to the sill area, however again i just was not happy with it so again i cut out a large section and welded in a panel cut from the spare sill.
The next main area was then to tidy up the bonnet slam panel above the passenger Headlamp bowl, it was completely rotten. The only thing left to do was cut out ad rebuild. It might not look factory standard but i am really happy with the repair.
After these repairs were made i then went back over the previous repairs made and added a few extra welds where i had originally spot welded panels in situ. To do this i drilled a few holes in the spot welded panels through one piece of steel and then plug welded then with the MIG to give an extra back up. I only did this as i found one or two spot welds that had popped, so i just wanted to make sure the panels were more secure. Last thing i need is a car which starts undressing itself on the track or road!

So now all the rust/rot repairs have been finished the next job is to start upgrading the strength of the shell. This will involve gusseting the inner wing to chassis rail/bulkhead area in the engine bay. I will also add inner wing strut walking plates that are present on all V6 Capri models and seam welding a few select areas as the factory teams did to works Escorts. As previously mentioned i will not be seam welding the entire shell but just a few select areas. Although i will need to refill my gas bottle before doing any more welding.

The feedback i can give so far is make sure you have a decent welder! I know it sounds simple but i have found my welder to be a bit of a nightmare whilst undertaking this type of restoration. We are going to look into upgrading or replacing to see if we can sort it out a little better. We found it would weld really well but then if you turned the handle or bent the feeder cable too much the rolle ron the welder would slip and the quality of the weld would deterioate badly. This meant that alot of weld/gas was wasted as it had to be ground down with the grinder, not to mention using lots of flap discs to clean everything up!

Anyway now the real fun and development of the car can begin.

[Will01]

So whilst i am not really able to progress the shell build at the moment i thought i would start thinking about the brakes again.
After going through the motions and trying to work out the brake pedal a bit, i have now decided to go for a simple modification to the brake pedal so as to avoid any complexity where it really isn't needed.
Before i mentioned that the brake pedal has been measured to give an ~4.2:1 ratio at centre of contact patch & that i would prefer to have an option for 5:1 or 6:1. I have now decided that i will not make the brake pedal ration infinitely adjustable with a slide as you can change the ratio slightly depending on where the drivers presses on the pedal rubber.
See attached spreadsheet, this shows measurements for basic Capri pedal & modified positions for mounting holes to change ratio.
Also see attached new design for pedal modifications.
I worked out that probably the best position for the pedal @ ~5:1 ratio is 50mm from the pivot point & ~6:1 ratio is 40mm from the pivot point.
Because the holes overlap currently i will be modifying the pedal to have thicker section as i don't want the plastic bushes to move around since they won't be fully surrounded by material. Also i will be replacing the plastic bushes with metal ones eventually, although i need to think about material choice first unless someone has a good recommendation?
I still need to modify the pedal box to allow the bolt to arc fully for full pedal travel and not bind on the housing, this should be relatively straight forward.
Next after this is to make up an adjustable turnbuckle to connect the brake pedal and balance bar, although i will only do this once i get hold of a few parts to make up the Bias Box.

[Will01]

So whilst i am busy thinking about things to fabricate over the next few weeks whilst i am waiting for welding gas, i thought i would put a question out there to people.
As i have spoken about already you may know that i will be building a Watts linkage to fit onto the Capri. An important part of this is to understand how the diff moves through bump and droop. This is going to be a little difficult as i will still be using leaf springs and it will be very hard to compress whilst on the car. Obviously as the diff goes through bump it will move in an arc as the leaf spring compresses and straightens out, which effectively changes the distance between the front mounting point and centre of axle tubes. Until i can actually measure this difference i am going to have to assume it stays constant but be aware of this movement.
From the reading up i have been doing over past few weeks i think it is best to build my own Watts linkage as i really don't like the idea of using the ready made Atlas Watts linkage which pivots on the diff housing cover plate.
Before i make this up properly i am going to need to mock up something, part of this is going to involve making adjustable solid shock type linkages which can be used for suspension design. These will never be used on the car except to get suspension measurements. My idea was to use some old shocks i have which are knackered but obviously will give me a max and min position for movement. Is it sensible to drill a hole in these to let out the fluid?
The next thing i will do is make up a basic link bar to fit where front of leaf mounts and fix to axle so that i can replicate a basic movement.
Then for the Watts link mock up i will use PVC tubing to get a rough idea of link bar length and crank bell length to see if the Watts linkage binds or not through full suspension Bump to Droop.
I have done a bit of research online also to see how others have mocked up, many systems seem to be mounted in Single Shear, although with the forces involved i think it would be best to make sure everything is mounted in double shear. This is another reason why i don't like the idea of using the ready available Diff cover mounted Watts linkage, as all the cornering force is going to be applied to the little diff mounting bolts, which could also lead to gasket failure and a weeping differential. See picture to show cover mounted system.
These are normally used in Rally cars e.g. Mk1 & Mk2 escorts, but since my Capri will be used on track the cornering forces transmitted through the suspension side to side will be higher.
Once i have taken more measurements and mocked up in CAD i will upload a few pictures to give a basic idea of what i am planning. As mentioned before the great thing about swapping the Watts linkage around is that the Roll centre is not fixed to the centre point of the axle, which then means i can also vary the Roll centre easier since it would be mounted to the Chassis.
Just to clarify:
- Fixed Diff mounting Watts linkage has roll centre fixed in centre of axle mounted on the diff with link towers coming down from the Chassis
- Upside down Adjustable Watts linkage will have adjustable roll centre however the pivot point will be fixed to the Chassis and the link bars will attach to the axle tubes.
Since i already have some leaf springs i may also make up a little test rig to see how the leaf springs compress and length changes using the Hydraulic press.
Does anyone have any advice?