These articles are provided to assist other Austin
Healey enthusiasts in getting more out of their Healey. They are related to competition
performance and race tuning.
Disclaimer: I can take no responsibility for what you do to
your car in the privacy of your own garage. There is no guarantee that the
issues discussed here will be suitable for you, your car, or the purpose for
which you use your car. I can take no responsibility for anything you do to
your car - it is your car - you can do what you like - but don't blame me.
This information is based on what I have done, or researched - but it is not a
full step by step workshop manual guide - so if you don't understand the
implications or processes - then don't attempt it. E & OE. No animals were
harmed during the writing of these articles. I trust that covers all the
required disclaimers.......
Some Observations on Healey Sway Bar Fitment
*Competition
For those of you who have fitted a larger e.g. 7/8 inch diameter front sway
bar - and still have their front bumper bar fitted to the car - here's
something you may care to check.
On my BJ8, I noticed there was very little clearance between the bottom of
the bumper bar bracket, and the top edge of the sway bar arms. The shiny marks
on the bottom edge of the bumper bracket - and corresponding marks on the sway
bar at the 'corners' - confirmed my suspicion - the 'arms' of the larger
diameter bar were hitting the bumper bar bracket. This is a bad thing. If the
swaybar arms hit/ bind on the bumper bracket, they will limit the suspension
movement causing understeer.
However, the situation is easily remedied. Mark the width of the swaybar on
the bumperbar bracket - and the location of the two (per side) bumperbar
location bolts to the chassis (which helps when you go to refit the bumper bar
to the car - in the same location - later!). Remove the front bumperbar with
its brackets, and, using a large semicircular file (or angle grinder), file/
grind the offending area of the bumperbar bracket, in a nice 'scallop', so it
clears the sway bar 'arms'. You need to allow about an extra .25 of an inch
(probably more if you have standard springs) either side (especially to the
rear) of the rollbar diameter, to allow for the movement of the bar arms. The
depth of the scallop you file will (depending on how stiff your front springs
are) have to be at least .25in to .4in deep directly above the centre of the
rollbar - possibly more if you have original 'soft' front springs.
If you are driving close to the limit when the suspension becomes 'solid' -
i.e. when the swaybar arms bind on the bumper bar bracket - your Healey will
understeer badly. So - its worth checking - especially if you have a heavier
front sway bar fitted.
Copyright© Chris Dimmock 1999 - 2001
Oils ain't oils....
*Competition
So which type of oil should you use in a Healey overdrive gearbox? I spent
a hell of a lot of time quite a while back trying to research this
quandary.
Why is this such an issue? Primarily because the literature on the subject
is confusing and contradictory. Here are the basic issues I uncovered. It
appears the Healey gearbox/ overdrive requires a lubricant which satisfies
seven criteria:
1. Overdrives are operated hydraulically - ie pressure is
what makes the overdrive operate - so the oil has to also act as a hydraulic
fluid.
2. The Overdrive has a wet clutch - ie there is a clutch which
spends its life inmmersed in oil (like motorcycles)
3. Syncromesh operates
on the gears using friction - ie if you reduce the friction, (as in use a
'friction modified oil' ) - then the syncros won't operate correctly
4.
Temperature is also an issue - typically Non synthetic (i.e. mineral based)
engine oil is thinner at lower temperatures than gear oil (not such an issue
with synthetic engine oil)
5. Pre BJ8 gearboxes have brass rather than
steel syncros - and 'older' EP mineral gearoils apparently have additives
which attack the brass - (hence I believe the 'traditional' factory statement
about using engine oil rather than gearoil)
6. The oil has to be capable of
lubricating the gearbox - i.e. provide 'shear' protection in an environment
which is like a box full of eggbeaters i.e. gearboxes aerate oil by their
design. And - refer to point 1 above - no hydraulic system can operate
successfully with aerated lubricant
7. Gearboxes don't have a filter like
car engines - so having an engine oil which is designed to 'carry around' the
impurities in suspension (by addition of detergents) - so that they can be
removed by the filter - probably isn't a good idea in a gearbox - better to
let any imputities settle on the bottom...
I think the 'gear oil versus engine oil' issue is a bit of a red herring in
2001. The 1950's - 60's BMC 'gearbox oil strategy" - I believe - was based on
what was "practical & commercial & available" - rather than purely
technical issues.... and it doesn't take into account the technological
advancements made over the past 40 years - eg Synthetic oils. Would anyone
seriously argue that their car handled better on the original fitment crossply
tyres than on say Yokohama A008RS assymetric directional radials today?
Original BMC literature says said the Healey gearbox & overdrive should
use a MINERAL engine oil. But the exact same overdrive (which is fitted on the
back of the gearbox - and uses the same oil as the gearbox) on a big Healey is
also fitted to a Triumph - and guess what? Triumph's literature all says only
use a gear oil...aaaaaarrgghhh
Whats the answer? I asked everyone. You name a Healey racer or Australian /
English Healey specialist - and I have either phoned or emailed them. I even
emailed the manufacturer of the Healey overdrive to ask them why Austin Healey
& Triumph gave contrary advice on oil for their product. And guess what?
The correct answer is... that there is no correct magic single answer.
But - the best advice I can give from my research, is:
1. If you want to use a mineral based oil - Most experts agreed that Brass
syncro gearboxes (eg BN1 etc) should probably use engine oil. This is because
SOME MINERAL gear oils have additives which can corrode some brass syncros -
so to be safe - always use an engine oil if you have brass syncros or use a
SYNTHETIC gearbox oil.
2. However, if you do use an engine oil - all experts agreed that you
should NEVER use a 'friction modified" engine oil. Because a syncro cone
relies on friction - i.e. a syncros whole purpose is to 'slow' the gear, in
order for the gear to be easily selected - i.e. it relies on friction to
operate... . If the oil is too slippery (ie friction modified) - then guess
what - the syncro won't work - new oil and real slow graunchy gearchanges (do
you like that word - I do - graunchy) !! That is the major reason many people
use eg Penrite HPR (30 or 40) - a mineral engine oil which doesn't have
friction modifiers - in their gearboxes.
3. It was unanimous that lubricants have come a long way in the past 40
years. Just because the factory used a particular tyre 40 years ago - it
doesn't mean they would use the same tyres again today. My point - oils aren't
the same today as they were in the 1950's. Synthetic oils were not in the mass
market back then.
4. Engine oil tends to aerate more than gear oil - and tend to hold the
bits of metal etc. in suspension (the properties of engine oil are designed to
hold in suspension the by products of combustion - and remove them via a
filter) Gear oils are designed for a Gear box which doesn't have a filter
(note that your overdrive has a 'strainer' - not a filter)
Much of this research pointed towards a synthetic gear oil as the
answer.
My advice - read the stuff at Redline Oil website and make up your own mind, based on your
own use of the car. Personally - in my fully rebuilt, using 95% brand new
parts (all new gears, all new shafts, all new bearings, all new seals, all new
syncros - only used the 'original' selector forks & 3/4th syncroniser
& casing) gearbox in my Healey 3000 - and a fully rebuilt overdrive - the
transformation achieved by switching to Redline MT90 gear oil was amazing -
and that was after I tried 4 different brands of non synthetic engine oil .
Redline is not cheap compared to Penrite HPR 30 (which I was using just prior
to the change to Redline) - but believe me - either was my gearbox/
overdrive....... I've been running Redline MT90 in my gearbox/overdrive for
over 2 years now - and Redline 75W90 in the diff (either a Detroit locker
4.1:1 - or a Quaiffe 3.9:1 - depends where I am) and have quicker syncro, no
selection issues, and the Redline oil is coloured for temperature monitoring -
so you can actually tell by the colour of the oil (on the dipstick) how hot
your oil is getting.
Hope this helps someone else get more enjoyment out of their Healey.
Copyright© Chris Dimmock 1999 - 2001
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Armstrong shock arms -
a mostly ficticious story....
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*Competition
Once upon a time, a long time ago, near the mythical village of Birmingham,
there were 2 identical twin brothers - separated at birth - who were destined
to shape the lives of many, many thousands of future British car owners.
One of these brothers was born "visually challenged" - and was called
"Lucas". Lucas became quite bitter, and dedicated himself to ensuring that
everyone else should have some insight to his world of darkness. The other
brother - who exhibited large amounts of upper body strength - was known as
"Armstrong".
The story of Lucas is well documented (mostly in Braille). This is part of
the story of Armstrong - the younger, and stronger, brother - who went on to
pioneer shock absorber damping to generations of British vehicles.
Armstrong - although credited with huge amounts of upper body strength -
had little or no stamina (due, I think, to a genetic design defect). He was
able to resist and contain huge forces - but generally only for a short period
of time. Left under physical stress for any length of time, he would, without
warning, spew copious amounts of a substance resembling light oil from his
armpits. It was this socially unacceptable personal behavior which I believe
prevented him from attaining international acceptance in the motoring
industry:- this behavior remains a repeatable mystery to this day by all his
siblings & descendants. This weakness - not unlike the fabled Achilles and
his heel - is know in medical circles as "Armstrong armpit".
Sprite owners front shocks appear to be descendant from "Rear Admiral
Armstrong"- known as "Lefty" to his mates - a distant relative, who,
unfortunately lost an arm in a horrific naval accident. Although physically
different in appearance, these single arm front shock absorbers also exhibit
"Armstrong armpit". It should be noted that all big and little Healey rear
shock absorbers are descendants of "Lefty".
As we move forward to the late 1990's it has probably become evident to
most Austin Healey owners that the Armstrong's have left many descendants -
often identical in external appearance and features - except for slight
differences in their internal valves, and arms (quantity, as noted above, and
length/ shape) - but all identical in their affliction with "Armstrong
armpit".
I am not aware of a permanent cure for "Armstrong armpit" - other than
rebuilding by a competent expert - or replacement with rare NOS items.
The Armstrong family tree provides some benefits to Healey owners, and it
is worth looking out for some of Armstrong's family, siblings, descendants and
close relatives. For example, I have several sets of old front shocks, which
although they look like a Big Healey front shock (some stamped 0008, some
stamped 6945 - underneath the shocker in the machined recess - and came from
Wolsley sedans), have arms 12mm, and 8mm (respectively) shorter than a Big
Healey front shock - and this effectively moves a Healey's camber from the
(standard) 1 degree positive camber to 1- 2 degrees of negative camber,
depending on which shock arms you use. Both my Healeys had these (shorter arm
front shocks) fitted to them. Definitely safer than bending arms.... You may
also need to fit shorter (or adjustable) trackrods to your car if you alter
the camber by more than 1 degree.
If you want to alter your camber - keep an eye out for some of these
shocks....
Copyright© Chris Dimmock 1999 - 2001
Front Suspension, camber and tyres
*Competition
What do you use your car for? If you just drive it around on the street -
then I can't help you too much past this point. Most big Healeys have 1 degree
positive camber as standard, and about 1mm toe in - so the outer edge must be
the edge that wears first in straight line driving (i.e. - lets ignore the
dynamics of cornering for a minute). Negative camber and toe out will wear the
inner edge in straight line driving.
If you want front negative camber - to make the front of the car 'bite'
better, and grip harder - this article may help - but it will move tyre wear
from the outside edge to the inside edge of your tyres if you drive around on
the street.
As a tyre corners hard, the outside tyre rolls over into a positive camber
situation. As you turn the wheel - the caster applies some negative camber.
When you start playing with camber - your final goal is to have the loaded
tyre as 'vertical' as you can get it - to get more rubber on the road under
hard cornering. On a Healey, with Yokohama A008 tyres - you actually need
about 8 degrees total negative camber at 20 degrees turn in to achieve a
vertical, fully loaded tyre. This total required negative camber is
effectively caster plus static camber. Most standard Healeys have 1 degree
positive camber, and somewhere between 0 degrees and 3 degrees of negative
caster..... so getting this much neg camber is a bit of a task - and most
never achieve anywhere near it...
If you want to change your camber to negative - there are four methods I am
aware of:
1. You can bend the front shock arms, effectively shortening them - but I
wouldn't ever recommend this - no one seems to know what the arms are actually
made of - or how they are made (cast? forged?) - and the metalurgy could be a
bit risky. I know many guys who have done this - I won't.
2. The better way is to fit the shorter front shock arms off other british
cars - Wolesley sedans are the 'best' donors I've found. If you measure the
length of your shock arms, centre to centre, with the shock arms installed on
the shock, and you'll find that healey ones are 'about' 216 - 218mm long - try
to measure them, and you'll see why I say 'about'.... You can get shock arms
off other British sedans which are around 208mm, down to about 200mm long,
trunion bolt center to shock arm pivot center. About 4.5mm = 1 degree of
camber - so if you have a standard Healey setup (1 degree positive camber) -
and you go to 200mm Wolseley arms - you get nearly 3 degrees NEGATIVE camber.
But this modification (and most modifications which change camber by 2 degrees
or more) require a few other changes - like making your fixed length steering
arms adjustable, so you can shorten them to match the reduced shock arm
length. You can't adjust the huge amount of toe out these shorter shock arms
give by just shortening the centre fixed steeering rod - you will run out of
adjustment - and the steering arm and idler arm - which must always piont
forwards - will splay out at up to a 45degree angle. You'll need to align the
idler arm and steering arm so they are pointing straight ahead - then shorten
(and make adjustable) the fixed length side steering arms. If you aren't
capable of doing this yourself - do some more research - and get a qualified
suspension expert to look at what you are trying to achieve.
3. Use 'camber bushes' - offset bushes on the top trunion link of the king
pin. Typically - these give around 1 degree of adjustment.
4. Another option if you are starting with a bare chassis is to move your
front shock locating plates 'inwards' - same scale of distances as in 2.
above. If you do this - then also move them "back" - and get some more caster
while you are at it..... Healeys don't have enough caster to start with - and
more caster = less negative static camber is required. But do your maths
before you try this - and seek the serrvices of a professional welder or body
aligner!! - and often your wishbone locating mounts on the chassis rail will
also need to be altered - so that everything lines up when you are
finished
Remember - more caster = heavier steering - but better cornering grip.
As always - measure accurately - know what you are trying to achieve, and
what you want your car for. Everything is a compromise...
Copyright© Chris Dimmock 1999 - 2001
Fuel delivery pressure issues
*Competition
Both SU's and Webers are very prone to leaking if your delivery pressure
(totally different issue to volume) is excessive - irrespective of how
good/new the float valve is. Most 'modern' type non SU fuel pumps operate at
too high a pressure.
Why is this important? Because too much pressure can push the valve off its
seat and cause a excessively rich air/fuel mixture - or worse - flooding. Too
little pressure (or volume) - air/fuel mix is too lean.
If you don't have the equipment yourself - then most workshops that have a
dyno setup, would be capable of measuring the:
1. Fuel delivery pressure:
(basically disconnect the fuel line from the
carbs, connect a low pressure guage (ie something that accurately reads 0
-10lb) securely to the line, start the pump, and look at the guage. Delivery
pressure for either SU's or Webers should be in the 3.5 preferred - 4 max lbs
per square inch range - unless you have made major mods to the carbs
themselves (eg a large ball bearing inside a weber instead of a std valve)
2. Fuel delivery volume:
(basically disconnect the fuel line from the
carbs, start the pump, and use a stop watch to ascertain how much fuel is
delivered into a measured container over a measured amount of time). Most
modern pumps deliver enough fuel. Your fuel volume requirement is obviously
based on the state of tune of your engine; and how you drive it.
If the volume is ok - but the pressure is too high - then you have 2
options - you can get a lower pressure pump - or fit a regulator. If you fit a
regulator - my suggestion is the old fashioned Malpassi 'filter king' combined
fuel filter & pressure regulator. They were fitted to italian high
performance cars - like Masseratis - and are very 'period' in appearance. They
often come up on ebay around $US50. Try searching for 'filter king' on Ebay.
Most 'speed shops' sell just plain modern regulators. The 'flat' type
regulators - usually annodised red or blue with a dial on top - seem to fail
after about 12 months - from my research.
Once you have the regulator - fit it near the carbs - then back to the dyno
man with the pressure guage - and adjust it to deliver 3.5lbs per square inch
pressure - then recheck the delivery volume. The dyno man should be able to
tell you what volume you need for your engine - which obviously depend on its
state of tune.
The Malpassi regulator/filter is sort of cylindrical, alloy on top, with a
glass filter bowl, and removeable paper filter and looks
period.
Copyright© Chris Dimmock 1999 - 2001
