jw4 Smokey's JW4 Formula Four Rebuild Thread

[Mark (smokey mow)]

I've managed to steal a couple of days in the garage this weekend to work on the JW4. There's not much to show for yesterday's efforts which consisted of lots of cleaning and painting of parts, but today I set to work on one of the bigger jobs that I've been putting off for ages.

I've known for a while that the roll bar fitted to the car doesn't comply with the MSA regulations and I've never been happy with it's mounting points either so both of these would need to be altered at some point. Normally I would have been concerned about originality when altering the chassis but as the roll bar isn't an original part I'm less worried about changing it out for something different.

No pictures, but out came the angle grinder and the roll bar was soon cut from the chassis, then the redundant welds were all sanded flush with the tubes.

The other reason for removing the roll bar was so I could get on with the second major job; trial fitting the bodywork. The bodywork was bought new in the 1980's and has never previously been fitted to the car so I was a little apprehensive about how easy or difficult it may be. Thankfully the GRP hadn't misshapen too much over the years of standing but it was still a pain of a job and quite a bit of fettling and pulling was needed to get it clipped over the chassis. Those that have ever fitted GRP bodywork to a Westfield will understand how difficult it can be to bend and shape if left standing for a while.

It's only loosely fitted so far and it needs to come off again for some more trimming but overall I'm happy with the fit. At the end of this weekend this is how the car now looks

[SootySport]

Pale blue eh,  That'll look good when it's finished.

[tisme]

Just out of interest - what's the position regards role bars (and other safety devices) on older or classic racing cars?

 

Obviously safety comes first but does it sit well with the historic look and feel?

[Mark (smokey mow)]

Just out of interest - what's the position regards role bars (and other safety devices) on older or classic racing cars?

Obviously safety comes first but does it sit well with the historic look and feel?

All my JW4's fall within Period G in the Blue Book (1966-1971) and as such are outside the exemption that periods A-E pre-Dec 1960 for single seaters benefit from which means they can run without a roll bar. Consequently whatever I fit has to meet the current requirements of section K of the MSA Blue Book as follows:

* min 42.4mm dia x 2.6mm CDS tube

* Min 900mm high from base of cockpit or 920mm measured along line of drivers spine.

* 380mm wide inside main tubes at a height of 600mm above base of seat

* Top hoop radius minimum 100mm measure on centre line of tube.

* Min 1 rear brace at max 60 deg angle to horizontal

Derek Minter was a brave man racing in the 60's with the original design of roll bar.

The roll bar on my Mk3 exceeds the current standards and is of a larger diameter tube than is required.

The design of the roll bar on Bob Dustan's old car is probably closest to what I'm hoping to achieve, and isn't too obtrusive.

[XTR2Turbo]

Mark. I am liking your new work bench. Looks quite meaty. What section are the tubes / wall thickness?

[Mark (smokey mow)]

Mark. I am liking your new work bench. Looks quite meaty. What section are the tubes / wall thickness?

It's all made out of 50x50x2.0mm steel box

I was trying to keep the weight down so it's easier to move. The frame weighs in at 50kg and the 18mm plywood top adds another 25kg. I designed the frame to carry a 250kg car but in my conservative calcs I didn't account for the additional strength that the plywood would add to it so in reality it will probably take more

[Dave Eastwood (Gadgetman) - Club Chairman]

Mark. I am liking your new work bench. Looks quite meaty. What section are the tubes / wall thickness?

 

Looked promising as it was being built, looks even better now with the car on, and it gives a sense of the scale.

[XTR2Turbo]

Thanks.  Need a project for my new welder.  I did make a mobile unit for my car to sit on but fancy a mobile workbench / storage unit.

 

David

[Mark (smokey mow)]

I finished work for Christmas last weekend and having managed to get the present shopping completed early this year It gave me the chance for another day working on the JW4.

With the body fitted I could turn my attention to fettling some the fibreglass to improve its fit and also open up some of the many holes that the wishbones to pass through. Several of the existing holes were not quite in the right place so working slowly I opened them up until the rose-joints and wishbone tubes all cleared. I'll finish them properly when the body comes off again for chassis painting. As can be seen I also couldn't resist the urge to fit the front and rear uprights

[Mark (smokey mow)]

Nothing is bolted up properly as yet as it all will need to be taken apart again before final assembly.

I've also spent a few evenings cleaning up all the components needed to assemble the rear drive shaft housing and whist some of them needed nothing more than a quick degrease and polish some of the other parts needed repainting.

For small parts I've been using one of the DIY powder coating kits but curing the powder has been problematic up till now as I'd nothing better than a hot air paint stripping gun for the purposes. For the sake of £20 I opted to invest in a small toaster over, here painting a pair of steering arms.

[XTR2Turbo]

good skills.  I bought an oven in the sales last year for £80 to use with my powder coating kit.  My plan is to mount it on a steel box frame with a spray booth in the area underneath..

 

I could have used my Kitchen oven as it never sees food    but didn't want to carry parts and risk dropping powder on the lounge floor.

 

Have you tried using spray etch primer under the powder.  That is what the chap at Stoneleigh selling the kits reccommended.

[pete g]

try heating up the part first in the oven and coat hot . doing alloy parts like this is better.

you can then always re heat in oven to finish off if needed

[Mark (smokey mow)]

could have used my Kitchen oven as it never sees food    but didn't want to carry parts and risk dropping powder on the lounge floor.

 

Have you tried using spray etch primer under the powder.  That is what the chap at Stoneleigh selling the kits reccommended.

I thought about the kitchen oven but decided against it because of the smell

I've used etch primers when wet spraying before but not with the DIY powdercoating although I do tend to go for a Zirconium Phosphate pretreatment on the larger parts when getting them coated professionally.

[Mark (smokey mow)]

With everything painted the assembly of the rear drive shaft housing could be completed. I was slightly apprehensive at this stage as it's been built from parts collected from all 3 cars but thankfully after a small amount of fettling it all went together ok. Even the driveshafts which are modified and shortened mini shafts turned out to be the right length

The eagle eyed will have spotted the mechanical fuel pump mounted off the back of the housing driven by a cam on the driveshaft; I'm still trying to decide what to do about fuelling at the moment. One problem with the JW4 was that when the car was stationary the fuel had to be pumped by hand as the mechanical pump would only operate when the car was moving. I'm therefore temped to discretely install a small solid state electric pump to overcome this issue.

The final job of today was to fit a pair of mini wheels which I had kicking around the garage, and to also install the seat and steering column.

[luxseven]

Looks like a racecar to me

Brilliant!
Cheers.

 

Jos