David Jenkins
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| posted on 10/8/06 at 12:44 PM |
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Corner weighing
Thuoght that people might this article interesting...
LINK
Although it's written for the Mini, the weighing device does look very easy to build.
Apart from the gauge, I could easily make the other bits. Anyone know where I can get a suitable pressure gauge at a ridiculously low price? 
Not sure how to calibrate it though - my knowledge of dry-horlicks is abysmal.
David
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RazMan
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| posted on 10/8/06 at 12:57 PM |
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Great link!
I didn't have a clue what corner weighing entailed - but I do now 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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JimSpencer
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| posted on 10/8/06 at 01:30 PM |
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Hmmmm..
There is another way..
If you go and poke your head round a race car supplies shop you'll see lots of corner weight scales for a for £k's.. these give the weight
in Kilo's of each wheel, so its very easy to see what happens when you adjust something.
But you can replicate this method the Locost way!
Using (and I kid you not) some old school mechanical bathroom scales..
They'll need to weight up to about 160kg for our purposes and be spring based, not digital.
Got mine for about £30 the pair from the local discount superstore.
To use
Fisrt find a flat floor.
Secondly put the rear corners of the chassis on stands - ensure its the chassis NOT the axle/suspension
Disconect ARB's
Ensure scales read the same - stand on them - adjust the start point on 1 until they agree- they'll not differ much anyway.
Put under each front wheel, orientated so you can see the gauge... been there done that...
Insert suitable ballast into drivers seat (Missus plus tool box...  )
Give the suspension a bounce to settle the car.
adjust front spring platforms until you get to the point you're happy.
Remove stands from under rear of chassis.
Have the scales alltered out of synch? (NOTE the weight will alter but has the balance?)
If so adjust the rear spring platforms until you get the front back to where you wanted it.
Re-connect ARB's - if these change the balance adjust ARB mounts until they don't..
If like me you this sounds too locost to work the first time you here it, now borrow some big bucks digital kit to check..
It'll not be far out, certainly close enough, apparently this method was first used by a certain Mr Mallock and his race cars were none too
shabby..
The only thing I've found is that if you're aiming to get the weight different across the front down to Nil. It's very difficult to
get too (assuming no passenger) without the spring platform heights getting radically out. However its quite easy to get it close and then you start
to see an expontial rise in adjustment versus kilo change - so I would recommend you only aim for the 'getting it close' and stop when you
start to see huge changes for little benefit.
Hope this helps
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David Jenkins
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| posted on 10/8/06 at 01:39 PM |
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Good point - as long as you could get accurate numbers off the scale, it doesn't matter if it's displayed as "carats per square
cubit" or, more likely, a "bar" value these days. You just want "the same value" on each side.
As for weighing scales - my car weighs 600kg without people on board. Assuming a 60/40 split, the front wheels will be carrying 360/2 = 180Kg each.
I'd need to get a pair of 200Kg scales to be sure that I won't break them! Not sure how common they would be.
I just thought the pressure gauge thingy would be a simple way to get the same effect quite cheaply.
David
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DarrenW
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| posted on 10/8/06 at 02:05 PM |
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How about this?
http://cgi.ebay.co.uk/HYDRAULIC-PRESSURE-GAUGE-BASE-ENTRY-63MM-2000-PSI-NEW_W0QQitemZ140016259564QQihZ004QQcategoryZ48718QQrdZ1QQcmdZViewItem
£10 sounds suitably locost.
I dont see how it would need to be calibrated as long as you always used the one tool for all 4 corners. t will be a suitable comparitor and as the
article says you calculate front to rear split by percentages so wether the pressure readings is accurate or not is irrelevant.
I wonder if an old axle stand could be adapted fo rthe leg? This would give the height adjustment and keep it vertical and secure. The tricky bit
would be making the cylinder back plate so it will all fit inside the wheel.
[Edited on 10/8/06 by DarrenW]
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David Jenkins
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| posted on 10/8/06 at 03:00 PM |
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Might be too great a range - ideally you want to be about 2/3 to 3/4 around the scale when lifting, so that you get a decent number of graduations to
work with.
Still, at that price, it would be ideal for playing with.
David
UPDATE: I just bought me one of these from the same seller -
LINK -
"That'll do nicely, Sir!"
[Edited on 10/8/06 by David Jenkins]
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JB
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| posted on 10/8/06 at 07:04 PM |
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Corner Weights
I tried making a hydralic gauge like that a few years ago after seeing one like it made by Pace. I made mine out of a caliper and gauge, but never
used it as the garage wasnt wide enough and I couldnt get good repeatability.
I ended up with a balance beam and spirit level.
http://www.beardmorebros.co.uk/website%20pages/update_16th_June_2004.htm
Describes the method.
I now have some ex F1 digital scales.......
John
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David Jenkins
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| posted on 11/8/06 at 07:56 AM |
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quote:
Originally posted by robocog
Well spotted that man
Just got one myself :-)
Now for the clutch slave cylinder....
I bet that seller is suddenly wondering why he's selling a load of gauges!
If anyone has a good suggestion for a clutch slave cylinder that can be bought new quite cheaply then I'd like to know about it. Why new? It
means that I can put any suitable fluid in it, rather than brake fluid (as long as it won't corrode the bore or rot the seals).
David
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NS Dev
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| posted on 11/8/06 at 09:24 AM |
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cheapest new clutch slave (and one of the longest stroke oe ones) is a mini one, still £30 tho!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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907
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| posted on 11/8/06 at 10:18 AM |
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quote:
Originally posted by David Jenkins
If anyone has a good suggestion for a clutch slave cylinder that can be bought new quite cheaply then I'd like to know about it. Why new? It
means that I can put any suitable fluid in it, rather than brake fluid (as long as it won't corrode the bore or rot the seals).
David
And there was me thinking you had a lathe.
Paul G
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David Jenkins
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| posted on 11/8/06 at 11:48 AM |
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That was Plan B!
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se7ensport
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| posted on 11/8/06 at 02:02 PM |
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I've seen one of these Caraven nose weight
It has definiate potential although I can't currently work out how.... any suggestions?
best I have come up with is using two (due to the scale only going to 80kg) next to each other as a fulcrum and a long lever across the top....
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DarrenW
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| posted on 11/8/06 at 02:46 PM |
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its Friday afternoon so brain bnot working, but i wonder if the caravan nose weight gauge at 80Kg range would work if you used a lever and pivot point
between the gauge and the wheel?
I was thinking about the top sketch but probs no good. Bottom one replicates the cylinder idea but gets back to the problem of the gauge possibly not
reading high enough or maybe too big to fit under rim.
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DarrenW
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| posted on 11/8/06 at 02:52 PM |
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What about a load cell?
http://cgi.ebay.co.uk/PHILLIPS-WEIGHING-LOAD-CELL-PR-6201_W0QQitemZ250017189387QQihZ015QQcategoryZ50964QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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se7ensport
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| posted on 11/8/06 at 04:41 PM |
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Diagrame 1 would require you to have a very long lever, you have to lit the car + compress the nose weight.
load cell looks very interesting, assume you need another devise to be able to read it?
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kb58
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| posted on 12/8/06 at 02:52 AM |
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I can't see how the hydraulic one could work well. The fact one tire must be lifted 1/4" or so changes the loads on the other three
wheels... Reminds me a bit of the Heisenberg Uncertainty Principle, where the act of measuring something changes what you're measuring.
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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David Jenkins
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| posted on 12/8/06 at 07:55 AM |
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Reaching into the wheel:
I'm planning to make a swinging arm with a 1:1 ratio, leaving the master cylinder back near the upright. This means that the size of the
cyclinder is irrelevant (within reason). Good tip on the Landy parts!
Amount of lift:
That's mentioned in the article - but I was thinking of a piece of card or plastic on an elastic: you'll know when you've lifted it
just off the ground when the card moves. Even so - the auther suggests that it isn't necessary.
It may not work - but it's a cheap project so it's worth a bit of experimentation!
David
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DIY Si
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| posted on 12/8/06 at 08:05 AM |
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I think with a car as light as one of 'ours' tends to be, getting one wheel off the floor will alter the loads a lot. As the article says
a 3mm or so gap won't affect things, I think it will with these type of cars. Whilst slightly different, when I jack mine up from one corner
that end of the car is very quickly off the floor. The idea with the card is quite sensible and has been told to me by many others in the past.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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leto
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| posted on 18/8/06 at 02:46 PM |
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Good link there
The Castor / Camber Gauge looks interesting,
but £80 for a piece of board and couple of string is eee..... not locost.
I “computer-generated” something similar but you will have to make up you own “easy to use directions”.
CAMBER GAUGE
If you manage to figure out how to measure caster with it, please post here.
Cheers!
[Edited on 06-8-18 by leto]
“I'm gonna ride around in style
I'm gonna drive everybody wild
'Cause I'll have the only one there is a round”. (J. Cash)
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roadboy
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| posted on 18/8/06 at 06:12 PM |
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I would suggest if you are using the hydraulic type guage blow the tyres up hard to minimise the amount lifted before clearance, also make sure tyre
pressures are equal. Back off all shocks to full soft & loosen all bolts through suspension pivots if using bushes to eliminate sticktion, this is
not necessary with rose joints.
We always use proper corner weight scales as it is easier & more accurate, plus the factbwe have them.
HTH
Ian
Jude Performance Services
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roadboy
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| posted on 18/8/06 at 06:12 PM |
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I would suggest if you are using the hydraulic type guage blow the tyres up hard to minimise the amount lifted before clearance, also make sure tyre
pressures are equal. Back off all shocks to full soft & loosen all bolts through suspension pivots if using bushes to eliminate sticktion, this is
not necessary with rose joints.
We always use proper corner weight scales as it is easier & more accurate, plus the fact we have them.
HTH
Ian
Jude Performance Services
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JoelP
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| posted on 19/8/06 at 07:06 PM |
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lifting the wheel 3mm off the ground will add around 30lbs to the apparent corner weight, obviously depending on springs etc. Thats quite a large
percentage of the total i suppose.
To avoid the uncertainty of the tyres flexing, you could replace the wheels with bare steel wheels (ie no tyres). It should still clear the deck, and
will be a lot easier to judge the moment at which lift off occurs.
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JB
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| posted on 19/8/06 at 08:02 PM |
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Dummy Wheels
Very good point Joel P. Dummy setup wheels will make all suspension alignment so much easier.
If you are rich make them out of aluminium plate (or carbon or honeycomb) otherwise some stout plywood will do the trick.
They will make corner weighting, camber and tracking so much easier. If you get clever you can add bearings, wheels, rollers on the bottom to take out
side loads after you have lowered the car to the ground (on independant set ups)
I must make some before my next setup.
John
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