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Forums => Build journals => Topic started by: StefanN on 01 January 2019, 10:43:54 pm

Title: Bugatti Type 37 Build
Post by: StefanN on 01 January 2019, 10:43:54 pm
OK, so starting our first CK with my son. I've been interested for a while and then the GB meet at Stretton Circuit 2018 was the final push.

Our inspiration is coming from the Bugatti Type 37, a well trodden route for CK's and the quality of some of the cars I've seen is impressive if a little intimidating. We're lucky enough to live near the Brooklands Museum so have had a good close look at the T37 they have there.

Title: Bugatti Type 37 Build - mock-up and chassis build
Post by: StefanN on 09 January 2019, 12:14:50 pm
Have taken the CK from a quick wood and cardboard mock-up that gave us confidence that our outline design will work, through to rolling on 4 wheels.

Rear hubs
We got a standard hub from Gemini Karts but with the studs pulled. The hub has 4 holes on a 100mm PCD.
To allow the hub to fit the wheel we cut about 5mm from the inside face of the hub. Four M8 bolts then hold the hub and wheel nicely.

We cut my 50mm length of Oilite bushing into 4 and pressed these into the wheels using a long bolt, large washers and tightening the nut.  We had to ease the inside of the bushes with some wet and dry to help them slide onto the axle. We assume they got a bit compressed when we pressed them into the wheel hubs.

Following advice, we chamfered the edge of the keyway on the axle where the bushes will be.  The wheel spins very smoothly on the axle with no slop - very pleased.  A split collect on the outside of the wheel keeps it in place with a circlip on the end for good measure.

The attached sketch shows the set-up.

Front axles
The front axle beam is from Gemini and has 16 deg camber and 5 deg caster.  Replaced the bearings on the front wheels with 35/17mm bearings.    Turned a stub axle and welded it to the Gemini yoke at 16 degrees (should have gone for 17 deg for the tiniest bit of positive camber).

The front springs are 35mm x 4mm x 560mm (and about 80mm drop from memory), made by Midland Motor Springs.  They're held onto the front axle beam with standard exhaust U-bolts through a bit of plate.

Title: Re: Bugatti Type 37 Build
Post by: StefanN on 13 January 2019, 10:09:54 am
Built my rear engine mount inspired by Steve Coleís design
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 13 January 2019, 10:11:42 am
 :) Steve might tell where he got the concept from. Derek in Vancouver/Okanagan via me.
Stefan, with your rear hub mounting, if you dress off the small lip on the wheel you will get a better engineering solution as the hub will then bolt to a greater matching area.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 15 January 2019, 08:14:17 pm
I welded the engine mount into position today and added a domed bolt to the side to act as a stopper and warning in case the axle or main drive gear/sprocket move towards the engine mount.

I picked up and old leather armchair from Freegle and stripped the leather from it. Should be enough to cover the seat
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 15 January 2019, 09:04:55 pm
That's a good idea Stefan, now for the other side?
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 19 January 2019, 09:18:37 pm
I had planned to copy Geoff and use a hand drill as a steering mechanism.  I ordered a drill on eBay but when it arrived realised that the pinions were aluminium and I thought they were unlikely to last long.  So I put a request out on Freegle and was offered a drill.  This turned out to be a lovely old Record drill - too good to cannibalise.  I got chatting with the guy who had offered me the drill and interestingly he is building a plane in his garage.   Anyway, I decided to try the angle grinder idea that Rhys mentioned and am pretty pleased with the result.

Also, roughed out the main formers and the floor so the CK's shape is starting to emerge.   A good day.

Title: Re: Bugatti Type 37 Build
Post by: RhysN on 20 January 2019, 06:08:16 am
That's looking really good Stefan.
Title: Re: Bugatti Type 37 Build
Post by: ChrisS on 20 January 2019, 07:55:05 am
Love the angle grinder idea, what did you use a 4.5 or 9inch?
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 20 January 2019, 08:45:43 am
Itís from a 4.5Ē grinder that was ďnot workingĒ (Freegle again).  Removing the armature was a bit of a pain but just took time with a hacksaw.  There was also quite a lot of backlash which turned out to be a loose key in the larger wheel.

There are so many premade mounting points and on this particular one the handles came out at 90 degrees so Iíve got two threaded M8 holes I will use to mount it with.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 20 January 2019, 09:50:14 pm
The floor went in today and started on mounting the brake calliper, plus lots of little bits of fiddling.
Title: Re: Bugatti Type 37 Build - spring perch and steering box
Post by: StefanN on 04 February 2019, 09:38:30 am
Itís taken a few iterations but both the front spring/axle set-up and the steering box are in place.

We added spring seats/perches that will help ensure the axle doesnít rotate and hence keeps castor and steering geometries fixed.  We also changed the position so the spring is resting on the axle rather than hanging from the axle.

The angle grinder based steering box needed repositioning but is now in place and appears to be working well.  The second set of brackets in the photo above the steering are left over from the original position and I might remove them later.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 10 February 2019, 08:45:24 pm
Well we thought we had got away with putting the brake calliper too near the engine, but it just wasn't right and was making adjusting the engine position difficult.  So we cut the mounting bracket off and will re-position it some time this week.  The good news was that the welds seemed pretty solid - so my welding must be OK!  Lots of other jobs going on like cutting chain to length, cutting and fitting keys in the axle, planning engine cut-off switches etc....but nothing photo worthy.   The next milestone we're aiming for is a drivable chassis.

Title: Re: Bugatti Type 37 Build
Post by: StefanN on 16 February 2019, 07:01:28 pm
Took the governor off the engine today and started trying to figure out how to set up the throttle linkage  (all sketches/photos of other's set-ups welcome - I'll start a thread in the tech forum.)
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 16 February 2019, 07:33:21 pm
My"10 minute to make, zero cost" version.
The pivot is a 4 mm ss bolt, with a corresponding "rivnut" in the fan housing, or before I had rivnuts I used nuts and bolts after taking off the fan housing and using a locknut inside (nyloc) and standard nut outside. Please remember I will always try to find the absolute cheap arse way out! It is a dead copy of NR racing item, just a whole lot cheaper.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 24 February 2019, 07:55:54 pm
U-bolts made and switched on front axle.  Brake hose connected and bled...but brakes not working yet (hmmm).  Steering column bearing added.  Crankcase gasket replaced and engine run for the first time.  Torque convertor fitted.  Bolts all checked and Nylocks added where needed.

The Comet sprocket is directly above the main sprocket so current method of adjusting the tension won't work without masses of movement.   The chain is either too loose, or now about 3mm too short so re-thinking the engine mount.  Won't be a complete rework but does need a little rethink.

One day soon we'll drive the thing...one day soon.
Title: Re: Bugatti Type 37 Build - transportation
Post by: StefanN on 23 March 2019, 09:32:19 pm
I needed to sort transportation for my CK so tried my ageing Ford Galaxy.  It fits, but the boot was open more than I wanted.  With the front wheels off and the front cinched down to anchor points in the boot, it fits with the boot only open a little.   I made a connecting bar to go from the boot door latch hold the door in position, based on something similar  I'd seen for dog owners to create ventilation for their dogs if they leave them in the car.

Also worked on the brakes, which were much better but still not good enough.  Going to switch to a single pot calliper at the back which hopefully will better match the master cylinder.  The calliper I've bought also has a mechanical parking brake on it, so that might work out nicely.
Title: Re: Bugatti Type 37 Build
Post by: Steve Cole on 23 March 2019, 11:53:44 pm
Amazing....a CycleKart into a Ford Galaxy,
I think it should be really named a Ford Tardis 🤔
Title: Re: Bugatti Type 37 Build
Post by: Graham Hill on 24 March 2019, 09:44:08 am
I rate that a success Stefan. But have you both got your chins on the dashboard?  :D
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 24 March 2019, 11:37:31 am
One of the guys in the VSCC does something similar, he has had a PVC cover made to attach all round, and some struts to hold the tailgate open where it needs to be.
Title: Re: Bugatti Type 37 Build
Post by: Chris Brown on 24 March 2019, 03:12:33 pm
Just bear in mind you can draw exhaust fumes in through the tailgate, keep the dash vents open and open the rear door windows slightly to maintain a through flow. You probably already realize that, but better to mention it than not.
Title: Re: Bugatti Type 37 Build - steering wheel mini build
Post by: Marek.Z.N on 01 April 2019, 06:27:16 pm
Hi all,
For Dad and my Bugatti build I have been put in charge of the steering wheel (which will replace the current..... interesting? wheel). it will be made of 4mm sheet aluminium and wood. To start with I created a cardboard mockup of the wheel to work out my measurements and then transferred that to the sheet of aluminium with a compass and scribe. Then I cut the outer edge using a jigsaw leaving about a millimetre to file down when finished. Anyone else building an aluminium wheel learn from my mistakes and use cutting lubricant/coolant otherwise the metal melts extremely quickly and ruins your blades. I have also cut out the parts between the spokes of the steering wheel but am trying to work out a faster way of filing down to the desired size without the risk of over cutting with a saw and ruining all the effort put in so far. If anyone has any suggestions for how I could do this I would appreciate it. Also any ideas with cutting, attaching and shaping the wood would be appreciated greatly. :)
Title: Re: Bugatti Type 37 Build - video analysis
Post by: StefanN on 02 April 2019, 08:20:01 pm
The meet up in Coventry was a great opportunity to drive the CK a bit.   Basically it all worked but it was really interesting to watch the video of it turning in slow motion because I could see how much movement there is in the front wheels.  My steering box has developed lots of play and the king pin arrangement has too much slack in it.

The key thing is that I'm confident the brake works enough and will improve when I bleed it some more.   Next step is to strip down the CK, weld the tacked on brake bracket and then clean and paint the chassis.  Then we'll reassemble the whole thing and start on the bodywork.

I need to come up with a solution to the king pin play, and also dismantle my steering box to see if I figure where the steering play has come from.
Title: Re: Bugatti Type 37 Build
Post by: Steve Cole on 02 April 2019, 09:54:38 pm
Yes the play can be sorted , the tube that the bolt goes in needs to be drilled out of a piece of round bar in a lathe rather than just a piece of tubing thatís close in size
Title: Re: Bugatti Type 37 Build
Post by: Rich T on 04 April 2019, 08:00:10 am
Bit confused where you might have King pin play.
 If you used a Gemeni axle, did you use their King Pin Spacer (& top hats)

https://www.geminikarts.co.uk/product/king-pin-spacer/

Cheers Rich
Title: Re: Bugatti Type 37 Build
Post by: Graham Hill on 04 April 2019, 10:38:39 am
 Hi Rich. I think you are correct, there should be no reason for king-pin play using the correct components. I am in touch with Gemini and am visiting with them to confirm this. Cheers
Title: Re: Bugatti Type 37 Build
Post by: Rich T on 04 April 2019, 12:36:28 pm
If you think the play is in the bolt, use a proper precision 10mm shoulder/M8 thread Shoulder Bolt (Shoulder Screw).
They would measure 10mm, unlike a common bolt.

Cheers Rich
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 05 April 2019, 11:29:23 am
Thanks for the ideas Rich.  I'll report back when I've figured out what's happening.

In the meantime, I've stripped the Bugatti right back and painted the chassis with Hammerite Smooth.  It's just as well most of it will not be visible because its anything but "smooth" - I used a brush.  Is there a trick to getting just the right amount on so it covers but doesn't sag?

Title: Re: Bugatti Type 37 Build
Post by: Chris Brown on 05 April 2019, 11:41:02 am
I've never had much joy with Hammerite, for exactly the same reasons. I tend to use Blackfriars these days, does the job, and cheaper.
Title: Re: Bugatti Type 37 Build
Post by: Rich T on 05 April 2019, 03:51:42 pm
Hammerite....In the past, Iíve had some ďluckĒ with both smooth & the other type, using cheap oven cleaning/washing up sponges (the sponge side), and dab it on!  The smooth has dried smooth!
I Can only suggest try it on a test/practice piece and see if the technique works for you?

Cheers Rich
Title: Re: Bugatti Type 37 Build
Post by: Graham Hill on 06 April 2019, 10:47:07 am
 Is it me???. What's wrong with a spray can Stefan ???
Title: Re: Bugatti Type 37 Build - Bodywork frame
Post by: StefanN on 20 April 2019, 07:29:12 am
Slow but steady progress on building the bodywork for the Bugatti.   The tub is now in, glued, screwed and fibreglass reinforced where needed.  Made the bodywork formers thicker at key points and added the stringers/longerons to the bonnet area.
Title: Re: Bugatti Type 37 Build - bodywork
Post by: StefanN on 24 April 2019, 10:46:01 pm
Worked with flexiply for the first time today to make the bonnet and am pleased with the results so far.  Still need to fibreglass the inside to stiffen it up.
Title: Re: Bugatti Type 37 Build
Post by: ChrisS on 25 April 2019, 10:37:28 am
Now it's a Bugatti !
Title: Re: Bugatti Type 37 Build
Post by: Chris Brown on 25 April 2019, 11:40:31 am
You're well ahead of me, at best Iíll have the lower part of the front bodywork done for Stretton. Yours is looking good see you in May.
Title: Re: Bugatti Type 37 Build
Post by: Steve Cole on 25 April 2019, 06:09:38 pm
Oh yes, just needs a bit of blue paint and itís done 😉
Title: Re: Bugatti Type 37 sawdust, epoxy, fibre glass
Post by: StefanN on 26 April 2019, 06:36:14 pm
sawdust, epoxy, fibre glass...goes on and on and on....
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 02 May 2019, 05:48:40 pm
Have decided to throw on some colour for Stretton even though weíve  not got the finish we wanted.   Wheels have new tyres.  New carb fitted.  Rusted cross member on trailer welded and new floor cut.

Now Iím bleeding the bleeding brakes again.  This is much harder than it ought to be.
Title: Re: Bugatti Type 37 Build
Post by: Steve Cole on 02 May 2019, 07:14:07 pm
Wow the body looks amazing Stefan
Title: Re: Bugatti Type 37 Build
Post by: Chris Brown on 02 May 2019, 07:47:44 pm
Looks great, well ahead of me, I'll do a test drive tomorrow, the most I'll have by way of a body will be the lower front panels.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 02 May 2019, 08:22:24 pm
Thanks.  I've not started on my tail so will be looking for lots of ideas and tips at Stretton.
Title: Re: Bugatti Type 37 Build - steering v3.0
Post by: StefanN on 11 May 2019, 11:10:53 pm
Worked on replacement steering today.  Thereís quite a difference in size between the previous drill and the one Iím installing.
Title: Re: Bugatti Type 37 Build - rear view mirror
Post by: StefanN on 12 May 2019, 06:35:29 pm
Not enough time to get into the next stage of the new steering so made a rear view mirror frame
Title: Re: Bugatti Type 37 Build - steering
Post by: StefanN on 14 May 2019, 01:56:11 pm
I built a fixture and mounted the new steering in the Bugatti to test it out.   It looks a bit like a Howitzer and I guess the weight at the front of the CK might help a little with handling?!

Now just need to find a couple of 9/16UNEF nuts (no so common Iím told) so I can attach the steering column.
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 15 May 2019, 07:54:56 am
24 TPI? Stefan.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 15 May 2019, 11:29:20 am
Yes I know!  I measured the thread gap so am pretty certain.  UNEF (extra fine) exists but is not very common.    Apparently its also used on the MG Midget Mk1 steering column but at £5 per half nut I'm looking for a better solution.  If I can't find the nuts at a reasonable price I might adapt the drill chuck and use that to weld the column to or rethread the shaft to M12.  I've also emailed a fastenings supplier to see if they've got them.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 15 May 2019, 07:11:45 pm
worked on installing the new steering today...not much look at so instead here's the finished rear view mirror....."all the better to see you with"  :)
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 15 May 2019, 08:14:36 pm
Is this so you see us as we come up to lap you? :)
Title: Re: Bugatti Type 37 Build - tail
Post by: StefanN on 18 May 2019, 08:05:30 pm
Made some progress on the tail this afternoon.  2 plywood formers and ply on the sides.  Still need to glue and glass it.  Then I'll have a go at the top curvy bit - probably from foam.
Title: Re: Bugatti Type 37 Build
Post by: Steve Cole on 19 May 2019, 09:58:56 am
Wow, that looks nice Stefan
Title: Re: Bugatti Type 37 Build - Jaeger
Post by: StefanN on 23 May 2019, 06:40:24 pm
So when I canít be building I work on flummadiddle.

My Jaeger car watch/clock started out as an alarm clock - £2.50 in the charity shop

Title: Re: Bugatti Type 37 Build - front apron with louvres
Post by: StefanN on 04 June 2019, 09:55:21 pm
I made a louvre die and the front apron.  I was pleased with how the louvres turned out given the low tech approach.
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 05 June 2019, 07:25:47 am
Great work Stefan.
Title: Re: Bugatti Type 37 Build
Post by: ChrisS on 05 June 2019, 07:56:27 am
That looks really good Stefan, I cheated on my apron but I wish I hadn't now. Did you use a hammer, or press it somehow?
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 05 June 2019, 08:35:39 am
Thanks.  I used a hammer.  A press would have been more controlled but not really needed this time.   Putting the curve into the apron has been tricky with the louvres in because they create weaker areas in the ali, but had to put the louvres in first.

Iím happy to for anyone to borrow the die to try for themselves.
Title: Re: Bugatti Type 37 Build
Post by: Chris Brown on 05 June 2019, 08:46:33 am
Looks good Stefan, thankfully only one of the inspiration cars I'm looking at doing has louvres, I'll probably do the same as Graham and use commercial vents.

Correction, the Morgan has them, but as I won't be using aluminium for the body I'll inset commercial louvres.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 05 June 2019, 09:59:12 am
The Bugatti is all louvres...they're everywhere!  I don't think I'll replicate them all but I might put some faux ones on the bonnet.  The very back of the tail has a set of louvres which I will put in to help with engine cooling.  Talking with Marek, we realised a fake fuel filler in the top of the tail will also make an excellent chimney for hot air to escape.
Title: Re: Bugatti Type 37 Build
Post by: Slack Alice on 05 June 2019, 08:47:12 pm
Superb job Stefan...pity no one will appreciate the graft that went into making the former!
Title: Re: Bugatti Type 37 Build - snow
Post by: StefanN on 06 June 2019, 06:39:11 pm
First stage of shaping the tail done.  Also made one of the tail vents...no risk of the engine catching a chill, but will help release some of the heat.
Title: Re: Bugatti Type 37 Build - aluminium cowl
Post by: StefanN on 08 June 2019, 07:18:02 pm
While glue was drying on the tail I had a go at shaping an aluminium cowl.   Iím pleased with it so far.  Now need to smooth out the hammer marks.
Title: Re: Bugatti Type 37 Build - tail fibreglass
Post by: StefanN on 13 June 2019, 09:21:45 am
I laid up 3 layers of fibreglass on the polystyrene buck having covered the polystyrene with PVA and ali foil which did a good job of protecting it from the polyester resin.  Itís now set, trimmed and ready to be attached permanently to the rest of the tail.  Filler and sanding will start when the rain stops.
Title: Re: Bugatti Type 37 Build
Post by: Chris Brown on 13 June 2019, 09:34:23 am
If you mix up 3 parts of gelcoat to one part of laminating resin, you'll get a glazing resin, which will mean you've got a smoother finish to start with.

You'll need to abrade the moulding to give the glaze a key, it's normally applied when the laminating resin has just gelled.
Title: Re: Bugatti Type 37 Build
Post by: Slack Alice on 13 June 2019, 11:08:22 am
Looks good Stefan...Iíve been considering how to make the radiator cowling for the GN.
Seems like a lot of work! Have I really got to make a wooden replica and take moulds off etc?
Meanwhile, chassis works continue....!
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 13 June 2019, 03:49:46 pm
I use a much smaller bubble foam than Stefan used, .
No Slack Alice you do not have to take moulds. The grilles I have made have been foam, and the 2 or 3 layers of close weave fabric, not CSM. A light sand, then skim coat of filler has been more than adequate before paint.
If you are doing it with wood, why even put a layer of glass on top? Use it smoothed off and painted. Some of the pattern maker type timbers (obechi, poplar etc) are very easy to work as you don't have grain to cope with near as much as "soft wood".
Title: Re: Bugatti Type 37 Build - CVT question
Post by: StefanN on 30 June 2019, 09:26:30 pm
Life's been busy for a couple of weeks so have made limited progress on the CK.  Now of course, it's a mad rush to get ready for Stretton.   I'm stuck on how to make my radiator so it'll just be the wooden buck bolted onto the front.

Need to: fit the tail to the main body, cut various air and clearance holes, paint lots of bits, finish and fit the new exhaust, sort an idle problem, change the throttle cable, change a few nuts to nylocs and finish some jobs on the trailer.  Marek is fed up with sanding but has nearly finished the steering wheel.

So a CVT question.   How wide is the bronze idle bush on your CVT?  Mines about 10mm and sometimes partially slides into the outer section of pulley leaving only about 5mm in the gap.  This should be enough still but I don't understand why it isn't wider.
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 01 July 2019, 06:17:57 am
What make is the CVT Stefan? With both varieties I have here I can't see how the bush can slide into the outer section as the black bit with ribs on the outside takes all the space.
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 01 July 2019, 07:46:54 am
Itís a Comet Torque-A Verter TAV2 30.

The keyed and lobed part has two flat sections that key with the outermost metal cone/disc.  It also has a chamfer/taper on the other end.   What Iíve not checked is whether it has to slot into anything on the outer pulley disc.
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 01 July 2019, 08:52:45 am
First up, ignore my previous. I have just checked, and yes it does slide under the outer cone, but only when it's closed, ie when the belt will be at the "high speed" mode. The sleeve is just there as something for the belt to run on at idle mode.
The keyed and lobed part flats should match the hole in the outer cone which is not a round hole, has matching flats for the other part.
Title: Re: Bugatti Type 37 Build
Post by: Slack Alice on 01 July 2019, 06:05:19 pm
Hi Stefan...my sleeve measures 1/2 inch.
Title: Re: Bugatti Type 37 Build - exhaust
Post by: StefanN on 02 July 2019, 06:25:46 pm
Installed my exhaust today and pushed on with the myriad little jobs that need finishing.
Title: Re: Bugatti Type 37 Build - stability
Post by: StefanN on 09 July 2019, 09:35:42 am
Stretton was the first real test of the Bugatti and it felt a bit unstable at speed and definitely tippy/unpredictable in corners.  So the search for stability starts.   I'll create a topic thread in the Tech Forum for the general discussion.  I'm going to double check the toe-in and castor.

One difference between my CK and many others is that my spring is clamped to a perch on top of the beam axle, rather than hanging below.   The rest of the front geometry means that the chassis rail is level - ie, this is not making my ride height higher than intended.  Given it is all bolted together and the beam drops, I can't see this making any difference, but I'd be interested to hear alternative theories on this question.
Title: Re: Bugatti Type 37 Build - alternative pull cord positions
Post by: StefanN on 09 July 2019, 03:53:44 pm
Rather than make another hole in the Bugatti tail.  I'm thinking about routing the starter cord to somewhere else - either below the side rail so its under the tail, or forwards to the gap between my back rest and seat cushion, or possibly to the side wall just in front of the tail.   Obviously I'll need to remove the metal cover and create a new hole for the cord to exit from but will be removing that anyway to fit a Hall effect sensor.

Any thoughts?
Title: Re: Bugatti Type 37 Build
Post by: Chris Brown on 09 July 2019, 04:31:11 pm
When you remove the pull start, you'll find you can reposition it so that the it faces forward without any problem. There are six holes in the pull start housing and at least three threaded bushes in the fan housing. Just remove the bolts and rotate the pull start housing to the position that suits you.
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 09 July 2019, 06:05:21 pm
All of mine have had the cord through the back rest using what Chris has suggested.
Title: Re: Bugatti Type 37 Build - diet
Post by: StefanN on 21 July 2019, 07:59:59 pm
Having weighed the Bugatti and given that I wanted to lower the seat to drop the centre of gravity, I stripped down the seat cushion, took out some foam, pretty much removed the rails and drilled some lightening holes.  Incredibly, that removed just about 1.2kg.    I've dropped the driver position about about 100mm.  Now just need somewhere to test what different that change has made.
Title: Re: Bugatti Type 37 Build - rear wheel to hub improved
Post by: StefanN on 21 July 2019, 08:39:38 pm
I took the lip off the inside face of the pit bike wheel SDG hub.  This means the hub from Gemini and the inside face of the wheel hub sit flush to each other - a better solution I think.
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 21 July 2019, 08:56:51 pm
I agree that's a much better idea. It only takes a few minutes with a flap disc on the grinder too. Do you have a support for the axle at the outboard side of the wheel Stefan?
Title: Re: Bugatti Type 37 Build
Post by: StefanN on 22 July 2019, 11:37:09 am
Do you have a support for the axle at the outboard side of the wheel Stefan?
Both inside and outside.  My original thought was to only drive one wheel.  I couldn't find 35mm OD/25mm ID bearings (except v expensive ones) and given the freewheel only moves a bit relative to the axle I made up Oilite bushes to replace both the bearings.  These hold the wheel nicely on the axle.  The Gemini wheel hub helps to prevent the wheel from sliding along the axle and also transfers the rotational torque to the wheel.

I have been considering how to improve this set-up, although so far what I've got seems to be working.  The central bore on the SDG hub tapers to a 25mm hole (sometimes just under) and the outside of that section is roughly parallel at approx 40mm diameter.  Unfortunately the inside is a cast finish and so not a surface it would be easy to mate up against.
Title: Re: Bugatti Type 37 Build
Post by: RhysN on 22 July 2019, 12:01:41 pm
I just spent a lot of time with files, dremels and such to go right through. My outside bushes for Kim were steel as I never intended one wheel drive, mounted where the bearings would normally seat. Because the axle (ex hire kart) was 30 mm it took a lot of time, and turned out unbelievably true when the bushes were installed.
I do think the axle needs to go right to the outside to support the wheel more positively, and then the hubs are really left to only support the inside, and to drive.
On the outside I drill and tap into the end of the axle, then a heavy washer (or my cast knock offs) can be tightened against a lock collar inboard of the hub. Belts and braces.
Title: Re: Bugatti Type 37 Build - Bonnet hinge
Post by: StefanN on 20 August 2019, 09:07:42 am
I couldn't find a bonnet hinge in the right size at a reasonable cost so made one out of 50mmx40mm pieces of 1mm aluminium.  The rod is 6mm.
Title: Re: Bugatti Type 37 Build
Post by: Slack Alice on 20 August 2019, 10:13:22 am
Thatís an awful lot of work Stefan!  Brilliant job though. The former would have challenged me!
Title: Re: Bugatti Type 37 Build
Post by: Marek.Z.N on 21 August 2019, 09:19:28 am
it looks even better in person. And it didn't take you too long once you had made a good jig