First Pedal In

Posted on June 10, 2016 by mark

Here’s the first pedal in, with the box fully bolted down. This is the modified OBP pedal box I made a while ago. OBP were great about what I’d done, especially after I emailed them and jokingly asked if my warranty was still valid.

After I’d bolted everything down, it then dawned on me that I didn’t have clearance to get the clutch-pedal pivot bolt in, so it all had to come out.

I also greased the bolt shank as well (copper grease) just for good measure. The bolt half way up the pedal is for the clevis, so care needs to be taken not to over-tighten or else the pedal won’t move as smoothly as it should do. I’ll get the rest of the pedals in this weekend. Speaking of clevises, the clutch master cylinder is a 0.72 bore, which is

It’s a great feeling to take parts I modified a while ago, and be bolting them into the car for good. Having them fit is even better. The only mistake I made is not allowing for the extra 0.75mm either part has for powder-coating. However, whilst snug, it fits.

There is no try, only do or not do

Posted on June 10, 2016 by mark

So, there’s always a short cut, and a proper way to do something – what you can see here is the top diff-cradle bracket. My problem was the clearance between the bracket and the chassis wasn’t sufficient for a lock-nut and using two thin nuts jammed against eachother isn’t a good solution.
So, given that, I’ve cross-drilled it and used a split pin. I’m also pretty pleased that the bolt shank to thread transition happens just through the bracket on the right, which you can see here. According to Carrol Smith, this is exactly the transition point.

So, I engineered it properly.

Air in a composite, under the microscope

Posted on May 15, 2016 by mark

So, a while back, I was making a trial part for the tub to understand how much resin a 12 layer infusion would take with a 10mm core. I cocked that up, but since then, I’ve also done an excellent infusion for my floor pan, and I wanted to compare the differences in them both for you under the microscope, because I’m that amazing, informative guy.

Pants Infusion – With Lots of Air in

In doing the infusion, I inadvertently admitted some air into the infusion, and it ran over the part. Also, I capped the infusion off once complete rather than letting the pump run for ages to try and pull the air out. Now I know better and know it should be under vacuum until it gels off.

So, what you can see here is a scale at 0.1mm per subdividing line. Ignore the 5mm bit. So, these bubbles are anything between 0.1 and 0.5mm wide. Wherever there’s a bubble, there’s a weakness. To the naked eye, they just look like a very fine dot.

Good Infusion, Where I Got It Right

So, this yellow bitch is going on the car. I had infused the resin at 28 degrees, with the mould also at about 30 degrees. I used a brewing mat under the resin to warm it.

This time, you can see no air bubbles, and the weave is easy to see. It’s at the same magnification as the part above, but it’s at a different weave. This is 300gsm twill weave (rather than 2/2 twill) but has less threads per twill than above – more tightly woven if you like. I also let the pump run all night to ensure absolutely no spare resin remained in the part. I also have a new technique to ensure there isn’t any air in the original input pipe, when it’s submerged in the epoxy.

Now, I’ve Keyed it!

In laying up the part, I put some strategically placed 1″ strips of peel-ply in where the chassis rails will be when it’s bonded in. Epoxy doesn’t stick to it peel-ply. When I took the part out and tore off the peel ply, I ended up with a nice keyed surface for the adhesive to the chassis. You can see it here. The crappy red fibers are just bits of the peel-ply I can’t get off. It’s incredibly thin nylon but the red threads are only at the edges. I don’t think they will (at all) compromise the quality of the adhesion.

3D Printing ideas

Posted on May 4, 2016 by mark

So, even though I’ve got my Velleman 8400 printer and not assembled it, I’ve been thinking of what to do with it. Needless to say, with 3D printing that started in the community there’s not only a great set of community based CAD packages, but people like Autodesk are in on it as well with TinkerCAD and a quite interesting suite of free apps as well (including using your i-device as a 3D scanner).

I think my first project (I have some 3D experience with CAD anyway) will be to rework my composite fuel tank. I had to junk the original plan – it wasn’t possible to really make a part from the moulds – I had returns greater than 90 degrees on some flanges and that just doesn’t work.

What I’ll do this time is print a framework that bolts together, and bond on to that framework a set of plastic panels. The end result will be a completed tank that can then be moulded from. I’m also going to simplify the design with far fewer faces, but some of the curves (radius curves so the carbon can go in) will be much easier to make more accurately. I think I’ll make two halves that slot into each other much like the top and bottom of a Matryoshka doll.

I will make the panels out of (maybe) 3mm polypropelene sheet. It has great release properties, but then of course, is difficult to bond to the framework. Nothing that a good keying and epoxy won’t fix. I can use other plastics of course, and if I’m a little rough with the cut, then I will fill the gaps with wax. It’s only a tank and not a display item.

A great company to use

Posted on April 29, 2016 by mark

Right – I’ve been getting the chassis prepped and around this time I’m also been getting other jobs done, namely getting the gearbox and diffs checked. I’ve found three great companies in Yorkshire that have helped me and I thought I’d share here.

Gearboxes

I went googling for gearboxes in Leeds and found Stephen Brear. They don’t have a website I can find, so I’ve linked to their Facebook Page. From the first call, they were very friendly and flexible about when I was going to drop my gearbox off. Over I go and pull in to their not inconsiderable yard. They were also very well referenced from what I could find – mainly I think they work for the trade.

Out comes Stephen (I think) and he brings a label to attach to my gearbox with my details on (very reassuring). I complimented him on the professionalism of his approach and he said “we do this for all the straight cut gearboxes … all the race stuff goes in the big safe“. Talk about feeling important.

We then discussed timing and he advised they could do it as a spare time job if I wasn’t in a rush, but call if I suddenly needed the car and they would rush it through. Following on from that, I get a call a week later informing me it’s sorted – no issues apart from a sloppy input shaft bearing that won’t matter when the gearbox input shaft is in the flywheel.. Then he rounded it off with “see you this friday … all in £40 – we’ll buy the team fish and chips with it on Friday”. Bargain.

Differentials

I also asked Brears if they handled diffs, and got a resounding No. Not in a bad way, but in a we know what we do well, and that’s what we do sort of way. They recommended Transaxle Services in Halifax. Again a company without a website, but a great guy to call. Super helpful. I dropped it off yesterday (in a secure drop off spot – I couldn’t get there during office hours) and called in today to see if it was there and had been collected.

Better than that, I got a really enthusiastic conversation about the slightly greater backlash in my diff than necessary, and the fact that it shouldn’t be a problem on the road, but should definitely be sorted for circuit use.

I’ll be done in a week, and i was reassured it wouldn’t be a major job – fantastic service.

Powder Coating

The chassis needed blasting and coating, and having taken a recommendation I went for CAS Coatings in Bradford. What a top bunch of guys. I dropped the chassis off behind their workshop which is in an old yorkshire mill. Once I’d done that and found my upstairs to the office, I got a very friendly and professional welcome. These guys are very busy and seem to move quickly wherever they go. We talked colours and requirements. I knew the chassis was too big for their blasting facilities, so it needed to be outsourced. I was expecting at least a week’s wait. No chance – 3 days later it’s blasted and I get a call to come over and put the release tape on the parts I want to not have coated where I’m going to be bonding CF structural parts in place.

I got there and the chassis was laid out for me. They even checked the tape to be sure I was using the right stuff. It took an hour to tape up and then off I went. 2 days later it’s coated. I haven’t been able to collect it yet but the price was brilliant.

Candy Blue, no less.

Milestone

Posted on April 20, 2016 by mark

The chassis is off to the powder coaters.
Woo hop.

Posted on April 1, 2016 by mark

So, I ordered a pair of these from eBay the other day – and they came. They’re bigger than they looked in the photo.

This is the photo from eBay. I thought “hmmm – that’s probably a 10mm bore hole, and that’ll do nicely”. They’re nicely made – machined from solid and the bush is very secure in there – no complaints.

Below is the reality … they’re HUGE.

That’s a pound coin on top. The bore in the bush is 15mm, and the mounting holes are 14mm. Far too large for my needs. I will have to decide what to do to reduce them.

I’m thinking of borrowing a friend’s lathe and machining a set of inserts – the mounting bolts only need to be m8, and you can’t buy a m15 bolt. I can either ream it out to 16mm or make an insert and take it down to 10. 3mm thickness in the walls will be more than sufficient.

Do I need blanking plates?

Posted on March 9, 2016 by mark

This is a bit of a rhetorical question, but this is now it looks with the dry sump in place. One of the gaps is about the sump, and the other is because the bell-housing is generic for both hydraulic and lever clutches.

This is the dry-sump gap. Other solutions people have had success with is a thin aluminium plate. In a following post I will disclose my genius idea, but it basically is about putting in a full under-skin to the car so crap won’t come dashing in quite as easily.

This is the clutch hatch. Sorting this is easy – I will come in from the back and make a blanking plug, and then take a mould off it. this should more or less give me an air-tight fit. Once I have the part, I will drill through and tap an m4 thread. then the part can just be bolted through with a bit of thread-lock