My Series III FHC is basically 3 inches above the deck at the back.
I need to raise the rear about 2 - 3 inches. I believe the ride
height should be 5.5 inches. I have had new springs fitted but to
no avail, ride height is still the same - low.
How can I adjust the ride height, I have not seen longer springs
available for sale through normal distributors. Does a different
shock adjust the height?–
neil01
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from neil01 sent Wed 20 Apr 2005:
Neil,
What’s wrong with your car that it sits so low? Rrear ride
height is not adjustable on these cars, nor does it need to be. If
yours is sitting low, something is wrong. Personally, I don’t
see how this is possible unless a) you’ve got the wrong springs in
there, or b) somebody’s done some modifications to the IRS. Keep
in mind if you change the ride height significantly from the
factory spec, your rear-suspension geometry will be pretty well
hosed, and you won’t be able to correct it.
That said, there are adjustable ride height shocks available.
Classic Jaguar, for one, and there are others. They are very
pricey, however ($175 ea, IIRC).–
Ray Livingston - '64 OTS Santa Cruz, CA
Santa Cruz, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Ray Livingston sent Wed 20 Apr 2005:
Ray can you please explain your alarming comments? There have been
no non-stock adjustments made to the IRS. The cradle bushes are
still the originals, the trailing arm bushes are new. It went into
a garage to get new springs but this did not correct the ride
height.
Als o I thought that people lowered the suspension for racing etc,
so I’m not sure how this makes the geometry uncorrectable–
The original message included these comments:
in mind if you change the ride height significantly from the
factory spec, your rear-suspension geometry will be pretty well
hosed, and you won’t be able to correct it.
In reply to a message from neil01 sent Wed 20 Apr 2005:
2’’ is a lot. You may have incorrect shocks (regarding spring
perch position), springs or tires that have too low a
profile. My '62 3.8 didn’t sit any lower after 40 years on
the original springs than when new and fitting new springs
later made no difference either.
Also I thought that people lowered the suspension for
racing >etc, so I’m not sure how this makes the geometry
uncorrectable…
Suspension movement is desgined to originate from a mean
position which is the set ride height. You’ve got camber,
toe, caster and bump steer. All these factors change as the
suspension moves up or down. On an E Type IRS you’d mostly
be concerned with camber because all the other variables are
somewhat fixed due to the design. The camber angle changes
quite a lot as the suspension moves. The aim is to keep the
wheel perpendicular to the road during various roll
attitudes of the vehicle.
So just lowering a suspension without addressing these other
issues does not work. The ride height camber would be wrong
and it would get worse as the suspension moved -so Ray is
quite correct.–
Clive Wilkinson
Georgetown, On., Canada
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Clive Wilkinson sent Wed 20 Apr 2005:
Ah OK, I thought it meant that the IRS / Hubs etc were shot because
the ride height had changed.
I think the shocks need to be checked to see if standard–
neil01
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from neil01 sent Wed 20 Apr 2005:
Neil,
Assuming the IRS assembly (cage, wishbones, hubs, half-shafts,
shock mounts) have not been modified, there are only two ways to
lower the ride height: a) fit shortened springs, or b) fit shocks
with one or both spring perches closer to the shock mounts than
stock. So, if you suspension is not modified, those are the only
two things you need to look at.
For racing, I doubt the suspension was simply ‘‘lowered’’. More
likely, they fitted smaller diameter wheels and/or lower profile
tires and/or modified the wishbones and/or half-shafts, and radius
arms, and all their mounting points, to get the geometry right
again.–
The original message included these comments:
Ray can you please explain your alarming comments? There have been
no non-stock adjustments made to the IRS. The cradle bushes are
still the originals, the trailing arm bushes are new. It went into
a garage to get new springs but this did not correct the ride
height.
Als o I thought that people lowered the suspension for racing etc,
so I’m not sure how this makes the geometry uncorrectable
neil01
–
Ray Livingston - '64 OTS Santa Cruz, CA
Santa Cruz, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from neil01 sent Wed 20 Apr 2005:
Neil,
Ray suggested that there were only two ways to lower the ride-
height on the e-type, this is not strictly true.
Some cars were originally fitted with aluminium spacers at one end
of each rear spring, which, if removed will lower the ride height,
and if added will raise the ride height.
Admittedly the ride height will be affected by less than the
thickness of the spacers (about 1/2’’ from memory), but nevertheless
you could check this out.
Regards,
Garth.–
The original message included these comments:
How can I adjust the ride height, I have not seen longer springs
available for sale through normal distributors. Does a different
shock adjust the height?
I adjusted the front ride height on my 4.2. I used 17’’ for
front at first, too low. I readjusted using a 17.5’’
measurement and it looks a tad high. it looks like my back
end is too low. If I can move the rear up, then I might have
sufficient visual balance to live with it.
I am running 205/70 tires.
I have adjustable CJ adjustable shocks on the rear. The
lower spring perch can be adjusted.
My question is: Will I change ride height by adjusting the
spring perch upwards or am I merely compressing the spring
and adding preload?–
Gary Herzberg, 63 3.8 FHC 66 Series 1 OTS, 98 xk8
Montana, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Gary Herzberg sent Sun 8 Feb 2009:
Gary,
As far as I know there is no way of adjusting the rear ride height
on an E-type.
The rear can be affected by the torsion bars where one side will be
higher than the other if the bars are not both set the same which
is what happened to my car.
By adjusting the springs on the rear you will not gain anything at
all it just sets the damping and rebound of the shocks.
Did you measure the height at the front using the method described
in Haynes or the Jag manuals? Its the height from the floor to
something on the suspension I can’t remember exactly what it is on
a 4.2.
Dave–
The original message included these comments:
end is too low. If I can move the rear up, then I might have
sufficient visual balance to live with it.
I have adjustable CJ adjustable shocks on the rear. The
lower spring perch can be adjusted.
My question is: Will I change ride height by adjusting the
spring perch upwards or am I merely compressing the spring
and adding preload?
–
'61 OTS
Pershore, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Gary Herzberg sent Sun 8 Feb 2009:
Gary,
This topic has been beaten to a bloody pulp in the past. The
spring perches adjust ride height, period.–
Ray Livingston - '64 OTS Santa Cruz, CA
Santa Cruz, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Gary Herzberg sent Sun 8 Feb 2009:
Hi Gary,
I have CJ Aldan shocks on my car too. Adjustable damping/aluminum
body. Is that what you have?
I have the springs set at 1&1/4’’ inches from the lowest thread to
the bottom of the spring locking collar. I have no idea what
springs are on the shocks. I suspect they are stock spring rate or
maybe a slight increase over OEM rate. Try it and see how it is.
Your car may be equipped different so my setting could be useless.
I found 1/4’’ changes in spring height yeilded significant changes.
dave–
1969 BRG OTS
Skaneateles, NY, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Ray Livingston sent Sun 8 Feb 2009:
I spent some time in the archives. It is my thought that
raising the perches will increase ride height until you
reach the upper limit of the shocks.
Thanks for all the great advice. I checked the archives and
really try not to revisit problems that have been solved,in
the past.
Thanks for the advice. My Mt plates on my truck are ‘‘Obi
Wan’’ So I will go with the Force and fool around. Given my
climate and elevation, I’ll report back in June.
Thanks–
The original message included these comments:
This topic has been beaten to a bloody pulp in the past. The
spring perches adjust ride height, period.
–
Gary Herzberg, 63 3.8 FHC 66 Series 1 OTS, 98 xk8
Montana, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Gary Herzberg sent Sun 8 Feb 2009:
‘‘It is my thought that raising the perches will increase ride
height until you reach the upper limit of the shocks.’’ - Yeah, if
that happens, you’ve probably gone juuuust a bit too far…–
Ray Livingston - '64 OTS Santa Cruz, CA
Santa Cruz, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Ray Livingston sent Sun 8 Feb 2009:
With typical driver/passenger loading in the car and a full
tank of gas the early 3.8 liter cars had a 8 3/4’’ ± 1/4’’
set point measurement between the lower wishbone pivot point
and the ground.
Later 4.2 liter cars had a more complicated measurement
system of 17 13/16’’ between the ground and a projected
center line through the center of the stub axle. Then
measure the lower wishbone pivot point to ground and
subtract from the 17 13/16 should leave 3 1/2’’ ± 1/4’’
Frankly this is almost impossible to do correctly and so I
always went with the 8 3/4 ‘’ between the ground and lower
wishbone pivot point.
I’m not aware of a dimension for the rear road height so I
always adjusted to get the drive half shaft parallel to the
ground. You can do this by adjusting the platform on the
shocks. Ideally measure the weight on each wheel after
adjustment and make sure that both front tires and both back
tires are the same.
Make sure you push the car back and forward a few times to
remove tire scrub after loading the springs and after each
adjustment.
In reply to a message from alex paterson sent Mon 9 Feb 2009:
Alex,
You’re describing the front suspensio nprocedure, right? The 3.8
version gives different results for different tire static radius –
and 185-15 radials are significantly lower than the Dunlop RS-5
bias ply tires that were OEM on the Series 1.
The Service manual gives a rear ride height procedure for the 3.8 –
and no different procedure for the 4.2 or S2 – that is not
affected by tire static radius.
In later versions of the 3.8 service manual There is a
specification for a rod that holds the rear in ‘‘mid-laden’’ position
in the service manual. Seems that if the car is loaded to spec and
the distance where that rod attaches is like that specification,
the ride height is correct.
Somebody mailed me pages from the earlier 3.8 service manual,
before the mid-laden rod showed up, and it said to measure ground
distance to the two pivot pins in the lower A arm and subtract the
two. The difference should be 1 9/16’’ ± 1/8’’ for mid-laden
position. Loading is full fuel and oil and coolant, 170 lb in
front of the drivers’ seat, 56 lb in front of the passenger seat to
get that height.
Jerry–
Jerry Mouton '64 FHC 889791 ‘MIK Jaguar’
Palo Alto, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Gary Herzberg sent Sun 8 Feb 2009:
Gary,
On this list I don’t think anyone minds going over any problem
again. If you think I’m being ironic, you haven’t been watching
the list! ; -) Ask away.
Jerry–
The original message included these comments:
Thanks for all the great advice. I checked the archives and
really try not to revisit problems that have been solved,in
the past.
–
Jerry Mouton '64 FHC 889791 ‘MIK Jaguar’
Palo Alto, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from mouton sent Mon 9 Feb 2009:
Well, I think I got it. The Force was with me.
My 3.8 is at 8’’ to the fulcrum center, 3/4’’ lower than the
spec and right where I want it.
After fooling with the 4.2, I moved the rear spring perches
up about 1.25’’ from the bottom, loosened front a arms,
lowered the car unto trash bags to allow the wheels to
settle and remeasured front and back. My front is now 12.5’’
to wheel center, 9’’ to fulcrum pivot which gives me the
specified 3.5’’ difference.
I am going to leave well enough alone now. I was afraid I
would have to pull the front end apart again - for the 5th
time this winter. Since it’s snowing out, I’ll have to wish
for Spring.
Thanks for the help.–
Gary Herzberg, 63 3.8 FHC 66 Series 1 OTS, 98 xk8
Montana, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from mouton sent Mon 9 Feb 2009:
Yes the height will depend on tire size and the measurement
given was for the standard x ply tires. I forgot about that
.Radial tires deform more and so the measurement will be
lower and probably the 8’’ is correct.
When load is placed on the lower wishbone due to cornering
you dont want the front to lift so it has to be parallel to
the ground or slightly higher at the wheel to induce squat.
There were a number of setting bars introduced for caster
etc is this what you mean?