Mister Towed's Tai Chi build

[Mister Towed]

Originally Posted by Patton

Yes all you have to do is add lightness !

Ah yes, Colin Chapman's mantra.

[Patton]

All the bushes are as the factory fitted, rubber standard as Skippy's donar was part restored a long time ago and never finished I had nothing to do to the chassis so I haven't touched it, PAT

[Mister Towed]

Couple of potential Spyder donors going on ebay over the next few days:

http://www.ebay.co.uk/itm/2708634036...9#ht_500wt_949

http://www.ebay.co.uk/itm/1306115215...9#ht_510wt_932

Could be a good time to buy with Christmas soaking up people's budgets.

[Mister Towed]

I'm looking to buy my ply for the floor and cockpit walls over the next couple of weeks.

I'm going to use phenolic impregnated 12mm ply from a Norfolk lumber yard for the floor (thanks for the tip Psycho), but how many sheets of 9mm ply have people needed to do the walls?

I'm looking at using shuttering ply for these as it's much cheaper than smooth ply and will all be hidden under the trim panels once the car's finished anyway.

http://www.economytimber.co.uk/products

[davecymru]

It's also worth mentioning that if you get stuck on any Sunday afternoon sessions where you run out of material, B&Q do sheets of exterior ply, cheap(ish)

[Mister Towed]

I've spent the last couple of days rebuilding the front suspension.

My radical lowering job, cutting 95mm out of the front springs, threw up a bit of a poser for me when I found that there was still about 1/4" of daylight between the top of the springs and the upper spring cup with the top and bottom bolts fully tightened.

The solution was to put both of the 1/2" thick rubber bushes on top rather than one each side of the spring cup. I don't know what impact this will have on the life of the dampers though as the top of the dampers now contact the spring cups directly. At least there's now a tiny bit of tension in the springs at full travel.



I also now have a fully rolling chassis for the first time in months.



I've currently got 190mm ground clearance front and rear, but that's on 13" wheels and without the engine and gearbox in place. I'm hoping to end up with about that once the 14's are bolted up and the engine and box are refitted.

Next step will be refurbishing the front bulkhead then I might just be able to start building my Spyder.

[lancelot link]

All looking nice and tidy.....the colours pretty cool too...

[jmc14]

Looks great.

[Mister Towed]

Thanks guys, I'm pretty happy with the way it's turning out and it's nice to see some results for all the effort.

The colour's two coats of good old red hammerite and I'll be pumping it full of waxoyl shortly to stabilise the rust that's lurking inside.

It's blowing a blizzard outside at the mo' and I've got to go to work this afternoon so no more progress today I'm afraid.

[Mister Towed]

Cheap '61 Herald going in Surrey if anyone's looking for an early Spyder donor:

http://www.ebay.co.uk/itm/1406609315...84.m1423.l2649

Looks like it needs work but it will have a dateless reg.

[redratbike]

is it me or since the exeter show theres no cheap doner cars any more?

[Psycho pops]

Originally Posted by Mister Towed

I've currently got 190mm ground clearance front and rear, but that's on 13" wheels and without the engine and gearbox in place. I'm hoping to end up with about that once the 14's are bolted up and the engine and box are refitted.
.

Where are you measuring from ?
I have used a standard 1" Lowering block at the rear on a swing spring and I am measuring 180mm from the lower point of the chassis, Is that the difference a swing spring makes as I have nowhere near the set up you have at the back.

Pops

[Mister Towed]

Yes, I'd noticed that too. It looks like there's a massive difference in the setup between the standard Vitesse/Herald rear spring and the Spitfire swing-spring conversion.

I've put in a 4" lowering block plus I've dropped it an extra 18mm by cutting down three of the discarded top leaves and putting them between the top of the lowering block and the bottom of the spring.

This gives me a total drop of about 118mm and leaves 19cm between the ground and the lowest part of the differential at the back. My 95mm cut on the front springs has given me the same clearance at the front, but that's without the engine and 'box fitted.

One thing I have noticed is that when I lift up the back end now the wheels stay upright without tucking under at all. It looks like the radical lowering job limits the downward travel of the rear wheels so much that it's eliminated the dreaded jacking effect.

It'll be interesting to drive each others' cars once they're finished to see if there's any noticeable difference between standard spring and swing spring handling.

[Psycho pops]

Hi Towed

Im no expert on suspension but have been trying to get my head round how it all works, I realise the more distance you put between the spring and the chassis then it dumps it lower to the deck but, does the strut length stop it going lower as this is the one point you haven't altered? Once your camber has been pushed out to the limit then it cant go lower, this would explain why you get no tuck at all now, does it also stiffen the suspension more as the spring must now be under a lot more tension..
I wonder what the effect will be on road holding, maybe someone with a bit of experience can answer.
Like you say when we finally get on the road we can swap out and see, your not so far from me, once its all done a summer meet up may be on the cards
Pops

[Mister Towed]

I'm no suspension expert either although I have dramatically lowered a Beetle before with no resultant handling problems. As it had started out its life as a semi-auto it did have the Porsche style double jointed rear drive-shafts though, rather than the swing-axles found in most Beetles and all Heralds/Vitesses.

I'd say that my lowering job on the back end is about equivalent to a 2" drop on an otherwise standard Vitesse, despite having put in about 6" of lowering blocks.

This means the back suspension is pretty much in the position it would be in if the Vitesse was fully laden with passengers and luggage.

The discrepancy is due to having removed about 300 kilos of bodywork, seats and glass which were compressing the suspension at rest.

The pictures below show my rear suspension set-up better than I can describe it:







The second picture shows the negative camber on the rear wheels, which isn't too extreme imho and the received wisdom suggests will improve grip during cornering.

http://en.wikipedia.org/wiki/Camber_angle

The third picture shows how the unwanted tuck-under effect has been all but eliminated by raising the spring in relation to the diff. I've jacked up the nearside rear and, if you look closely you'll see that the off-side wheel has also lifted off the ground even though the nearside wheel remains almost vertical.

This set-up should give me pretty flat cornering and definitely no rear wheel jacking.

I seem to recall someone giving Gary a hard time about his choice of donor a year or so back on one of these forums, claiming that his Spyder would be 'unsafe at any speed' due to rear wheel jacking (a reference to the mother of all American 'class' lawsuits brought against Chevrolet by the families of those killed in Corvair crashes).

The third picture here shows that it won't be a problem while Gary has sold more kits this year than most kit-car manufacturers sell in a lifetime so whoever you were, you can shove your criticism where the sun don't shine!

[Mister Towed]

Just in case anyone's unfamiliar with the swing axle jacking and tuck-under that I've been talking about, take a look at this:



What's happened here is that this Herald has first been thrown round a right hand bend causing the off-side rear wheel to droop to its full extent, effectively tucking it under the back of the car.

The driver's then suddenly switched to a left hand bend causing the outside edge of the off-side wheel to 'bite' the road surface and jack the whole back end up in the air. The resultant switching between oversteer and understeer as the suspension tries to settle itself down again is impossible to control even for a skilled driver and many a Herald/Beetle/Corvair made holes in the scenery during spirited driving.

Solutions included attaching straps between the drive shafts and the underside of the car body to limit the downward travel of the suspension, fitting a 'camber compensator', a double ended clamp that's still available for Beetles, to the drive shafts to prevent too great a difference developing between the two sides and, of course, the the swing-spring, which allows the leaf spring to slide from side to side, effectively moving the top mount of the rear wheel during cornering to keep the wheels more upright.

Phew, I hope that all makes some sense.

[Mister Towed]

'Bit of brain fade I'm afraid - I've just taken some measurments and my lowering block is 3" not 4". With the extra cut down leaves I've actually raised the spring by 95mm, which is exactly what I've cut out of the front springs.

[Mister Towed]

Dropped my engine and gearbox back into the chassis today and I was a bit taken aback by how much the weight of the straight six compressed the front suspension:









Methinks 95mm might have been a tad much to cut off the front springs with a Vitesse engined Sammio as I now have only 120mm ground clearance at the front.

I'll stick with it for the time being though as my old Beetle was considerably lower than even that at the front, and, although it did scuff the odd speed hump it drove fine. If the stance looks odd or the suspension bottoms out during spirited driving I'll source some new springs and give them a bit less of a shave.

I do like low cars though...

[davecymru]

I took 80mm off on mine (also a 2L) and i think mine is LOW.
Remember you've still got bulkheads etc. to fit! Maybe time to invest in some of the GAZ height adjustable shocks?

That aside it's looking really nice! Knowing what i know now, i sort of wish i'd stripped mine right the way back. but we live and learn!

[Mister Towed]

'Been fretting a bit over the 120mm ground clearance my Spyder's now got at the front end: will it foul speed bumps or bottom out on bumpy roads?

So I decided to shove a tape measure under my bog standard Saab 9-3 Vector to see how much more ground clearance I'd need to engineer into the Vitesse chassis.



The Saab turns out to have only 110mm clearance under the sump cover and hasn't fouled anything (apart from the odd pheasant) or bottomed out yet so I should be ok after all!