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Things You Can Do To Your Motor To Improve It's
Performance And/Or Make It Safer For You To Play !!
What follows is a list
of thing that the more competitive amongst us do/have done
to our motor's to give us the edge!. If you have something
to add that I've missed then by all means send it in to
penninelandrover@aol.com
and I'll post it up. Just do what you can afford and
aspire to the rest!!
Engine
The bigger the better!!.
If it's on top of it's job, you won't have to rev it as
much and you're less likely to lose traction on hill
climbs etc. Do bear in mind however that a 4.6 V8 will
snap standard diff's and half shafts like they're tinsel
if driven incautiously. (See Axles section for an
expensive but effective solution). For us non-super rich
types, try to plumb for a 3.9 or 4.2. You'll get a 3.5 for
peanuts these days but it won't really be all that competitive
against the big boys. Also fuel injection is best as old
carburettor models can suffer fuel starvation on steep
inclines and stall.
There is the odd
trialler kicking about with a Discovery TD5 diesel in (with the injector
pump wound right up) and they acquit themselves pretty
well but ordinary diesels are to be avoided as they are
too slow to pick up revs and the
powers just not there when you need it.
Beef up your engine
mountings by replacing them with modified rear tie rods
cut down and bolted direct to the chassis at the eye end.
If you use standard
mountings and they're a bit old and weak, there's a real
possibility that if you go down a steep precipice drop,
your engine and gearbox will plough straight through the
radiator and beat you to the bottom of the hill.
If you decide to rear
mount your radiator to protect it, then make sure that its
well boxed in and that the fans are running on it
constantly. Also box in all pipe work where it passes
through the cab (or better still run it under the floor). If anything ruptures you really don't
want to be sprayed with boiling antifreeze (trust me, the
red blotches and weeping blisters it leaves behind really
aren't a look you want to explore).
Gearbox
For a standard
affordable option your best bet is the Range Rover R380
although an LT77 is not bad. Your best getting one which has a viscous handbrake which allows you to lock the
back wheels legally and then put full lock on and floor it
to turn your motor on a hairpin for tight corners.
Its always worth
considering pinning your centre diff selector permanently
in the engaged position as well,
regardless of which option you go for, so that it can't
jump out and leave you in two wheel drive halfway round a
section.
Put some brand new gear
selector springs in as well to stop it jumping out of gear
if you drop into a hole suddenly and jolt the motor (I've
been here and it's very frustrating and annoying when it
happens!).
Beef up your gearbox
mountings by replacing them with polyurethane rear tie rod
bushes bolted straight through for the same reason as the
engine mountings above.
If you opt for an
automatic gearbox to save all the hassle of worrying about
what gear to be in then make sure you select an actual
gear when on section, NOT Drive, or when you take
you foot off going down hill it'll just change up and run
away with you as there's no engine braking effect.
Axles
If you've got pots of
cash to spare then give this site a look.
www.ashcroft-transmissions.co.uk
. They sell seriously beefed up diffs and
halfshafts (for serious money!) which will allow you to
really get your horns out without snapping anything and
putting yourself out of the running. The cost looks brutal
but by the time you've bought and replaced ten second hand
diffs you could have paid for it and wouldn't have lost
any points either
Also get diff nosecone
protectors, particularly for the front, as this is the axle casings weakest point and
will jam your diff if you stuff it into a rock and crush
it in.
Snorkel axle breathers
are a good idea, bordering on essential, as they keep the breathing end well up out
of the mud and water and therefore the mud and water out
of your axle casing. (water isn't a good lubricator and
mud/silt is little better than grinding paste when applied
to diffs and cv joints).
Also give serious
consideration to moving the front brake hose mounting on
the chassis from in front of the spring tower to around
the back. There are two distinct benefits. Firstly the
odds of ripping them out on a rock or tree are greatly
reduced. Secondly, if you've got long travelling springs
and shockers, they're closer to the brake caliper and will
go further down before stretching/snapping. (stainless
steel braided hoses are advisable in any event for sheer
strength)
Change the gear oil in
your axles reasonably regularly. Even with the above
precautions, its amazing what gets in there and you don't
want to knacker your transmission for the sake of a bit of
clean oil, especially if you've invested in Ashcroft's.
Steering
If at all possible, make
sure your motor has full power steering. You can then turn
much faster on section (a button handle on the steering
wheel is best so you can steer one handed). Never, under
any circumstances, steer your motor with your thumbs
through the inner holes in the steering wheel. If you hit
something a bit crossways, such as a fallen tree, your
wheel can whip round with brutal speed and your precious
thumbs will snap like twigs, forcing you to stay at home
in the day and watch Loose Women and Jeremy Kyle on
the telly (I know, frightening thought isn't it! You can't
even change channel 'cos your hands are bollocksed).
Also would suggest that
you get some steel tube and sleeve the steering rods that
pass in front of the axle casing as they are very
susceptible to boulders etc and if you do catch them hard
enough to bend them, a bit of steel steam pipe will ensure
they bend a good deal less which may be the difference
between carrying on and a retirement/hasty replacement
with the resulting penalty points you get from missing a
section or two.
Definitely weld on a
protector bar under the front cross-member of the chassis. Suggest full
width between the chassis rails and at least as deep as the
bottom arm on the steering box as this ball joint and arm are
extremely vulnerable as well. Angle it slightly backwards
as well so that you slide over things instead of just
nutting them and stopping.
Suspension
Progressive springs are
the ideal, with extended lift shock absorbers (you do run
the risk of pulling out a prop shaft if you do due
the sheer amount of extra travel it gives though). You can
extend the internal shank of the prop shaft at its base to
stop this
happening if your a good welder but don't go too long with
the extension piece you weld in or it will either smash
the top universal joint on full compression or at least
jam it and stop you moving, costing you marks. (always make
sure that prop splines and UJ's are well greased and
serviced regularly as a semi seized prop will seriously
impede articulation of the axle it's attached to and they
have a nasty habit of accumulating mud in the splines
which doesn't compress particularly well. If your
someone with cash to spare then you can now actually buy
twin yoke propshafts to effectively double the extended
length without cutting and welding anything.
Also you might want to
consider multiple shockers on the front so that the
wheels don't bounce when you really put the power down and
you retain traction, particularly on hill climbs. Shock
absorber orientation is completely free and some angle
them towards the centre of the motor rather than straight
up so they don't restrict axle travel on full articulation.
You can try used (not
new as they're too hard) diesel heavy duty springs with 2
or 4 inch lift shockers which will give you improved
clearance and travel at a much cheaper price. You can buy
extended lift springs as well if your feeling flush (if
you don't you'll need to add spring locators sleeves at
the turret tops to stop the springs dislocating on full
extension and not
reseating themselves properly when they come back down).
You can also consider
"cranked" front tie rods. This involves getting the rods
chopped and an indent welded into it to improve your
turning circle without the tyres fouling on them. (You can
actually buy these ready made now. I've seen them on
Paddock Motor Spares website)
Avoid polyurethane
bushes. On the face of it they'll last much longer but,
they're so hard they impair free axle travel and transmit
all the hard bangs straight through to your chassis. Opt
instead for the ordinary black rubber ones as they're much
more flexible and will give a much broader range of axle
articulation.
Bodywork
Trim back the wheel
arches and rivet on some homemade mud spats (fork truck
curtain plastic is good). This will allow suspension to
compress freely without wheels fouling on the wings.
Similarly trim the front wings away diagonally at the
front of the vehicle to minimise risk of them catching on
canes / trees etc when making tight turns.
Its not a bad idea to build
an internal rollcage extension for the front end (or at
least the engine bay) in case
of rollovers to protect the engine bay and minimise the
risk of an enforced retirement. This can have the wings
incorporated into it which, if built right, will be able
to be lifted clean away for ease of engine maintenance. Make sure you mount it on
thick welded
soleplates on the chassis and bulkhead though so it won't tear or buckle
anything on impact (because, believe me, at some point,
sooner or later, you ARE going to see the world the way the
Aussies see it!).
Don't bother with a
front bumper. It just gets in the way and hits things or
the end gets bent back and jams on a tyre. Just weld a
piece of "C" section girder to the front dumb irons and
mount your towing point on this.
Fuel Tank
Mount your fuel tank
somewhere in the back body of the vehicle above the
maximum travel of the axle, rather than in the traditional
under seat position where it is extremely vulnerable to
rocks and general punctures all round.
Ensure that the filler
cap is of a type that won't leak if the vehicle should
happen to find itself upside down as you don't want to
find yourself sprayed with or lying in a puddle of high
octane firewater (It only takes a spark!. In any case
fuels damned expensive, why waste it on the ground!)
Make sure that the fuel
lines travel down the upper or inner side of one of the
main chassis rails, (well away from exhaust components)
where they are offered maximum protection from pretty much
everything. Running them through the cab is a definite
no-no in case of a line rupture. (You could box it in but
it's safer underneath the motor, where you aren't!).
Rollcage
Design is mostly
standard and laid down in MSA regulations although there
are a number of acceptable geometry options. However, when
welding in the cross braces between the front and back
hoops above the cab, try to keep them as close to the
outside as possible so they act as sliders when cornering
hard around trees and rocks. If you put them too far in
you can find yourself catching the hoop bend on trees etc
and being brought to an abrupt halt unnecessarily. Also
make sure you weld good thick sole plates (at least 5mm
thick) to the top and sides of the chassis wherever the
cage meets it and ideally make them at least a foot long
to spread the load/impact. It you weld it straight to the
chassis and it gets a bit thin later, it'll rip clean off
when you roll it and, after all, it's there to protect
your soft bits so it wants to be good and solid.
Wheels and
Tyres
750' x 16" rims,
preferably with offset centres are best (Discovery steel
rims are good). Turn the front
ones inside out as the offset will make the wheels stand
off the vehicle and give you a better turning
circle. Don't go any bigger than this with your rims as
the extra ground clearance will just cost you your turning
circle and therefore your manoeuverability.
Best tyres are Grizzly
Claw, Firestone SAT or Malatesta Kobra (although some use
the Insa Turbo Special Trak as well). You basically need a tyre with good
really deep grooves and a reasonably small block tread
pattern so that they "self clean" in between mud sections
and are gruesome enough to really bite in when you put
your foot down. A hard rubber compound is best so they
maintain the sharp cutting edges on the blocks for as long
as possible or you'll spend half your life using the tread
cutter to put them back again.
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