Chassis alignment problems

Trip

Trip

New Member
After endless time and money thrown on the car getting it ready for hill climb, i took the car for wheel alignment and to my horror, i found out that the front sides do not match.

Basically i have done the castor mod and have Tein adjustable top mounts and here are the results. Camber and castor is way off left and right.

FRONT Left , Right
Castor: +3.36 , +1.91
Camber: -0.71, -1.51
Toe: +0.1, +0.08

I am not worried that i didn't get a lot of adjustment for both camber and castor. What i am very worried is that both sides are WAY OFF. The guy at the alignment shop checked the car seams from the bottom and engine bay and he didn't find and signs of previous bumps.

Is it a common problem due to age or is it the unlucky few who have such problems ?

What did others do (if any) to solve it ?
 
PobodY

PobodY

Moderators
Staff member
When I was told by an alignment place that my chassis may be bent, it turned-out to be the wishbone. - It was bent just enough to throw everything out, but not so much that it was obviously bent when you looked at it.

Worth checking anyway.
 
Trip

Trip

New Member
PobodY said:
When I was told by an alignment place that my chassis may be bent, it turned-out to be the wishbone. - It was bent just enough to throw everything out, but not so much that it was obviously bent when you looked at it.

Worth checking anyway.
Click to expand...

Worth checking.

I wonder what results other people get when an alignment is done.
 
S

steve963

Active Member
my wisbone was bent, one wheel was about 10mm further back in the wheel arch! car pulled to the left all the time, new wishbone and its perfect!

the bit what goes through the back mount bends
 
P

pulsarboby

Guest
ev those readings arent way off
the castor mod is obviousle affecting the castor setting so you may have been slightly out when you drilled the turrets so you need to check and maybe elongate the hole slightly to give you a bit less castor on the side thats kicking forward.
camber and toe he should be able to adjust by loosening the bolts to struts and adjusting the tracking

from what i can remember with mine im running +1.2 castor (without the mod) and around +1 camber, toe ive found best at 0
 
Trip

Trip

New Member
pulsarboby said:
ev those readings arent way off
the castor mod is obviousle affecting the castor setting so you may have been slightly out when you drilled the turrets so you need to check and maybe elongate the hole slightly to give you a bit less castor on the side thats kicking forward.
camber and toe he should be able to adjust by loosening the bolts to struts and adjusting the tracking

from what i can remember with mine im running +1.2 castor (without the mod) and around +1 camber, toe ive found best at 0
Click to expand...
I just ordered the Sealey turn tables and the magnetic camber castor gauge to experiment at home. I will put the top mounts in standard holes and check from there.

Its either the holes not set right, or a bent wishbone or a bump in the chassis.

Hopefully its the first two. Untill the Sealey goodies arrive, i'll measure the chassis to compare left and right.
 
campbellju

campbellju

Moderators
Staff member
Hello Trip. Just seen this. Its not way off. I don't have the Nissan manuals to hand to see what they recommend but castor is not as sensitive as camber and no where near as sensitive as toe. Those gauages estimate the castor angle anyway.

Your higher castor side has lower camber so it could just be everything triangulating against you.

If you weren't aware, when you modify your toe you alter the camber. When you compress your suspension you gain some negative camber, positive castor and toe in.

When you change your camber on the top mount in its normal poition you also directly change the king pin inclination.

Also, if you put a jack under the strut and put it under pressure it can make the difference of 0.5degs camber.

Recently I've been playing with KPI to more clearly understand its effect. Its not important for here but what is important is to understand the principle that all your suspension joints are connected so it takes a long time and a lot of patience to get them honed in.

1. Set your the top mount so their positions are as equal as possible. Then your castor and king pin inclination should be geometrically close

2. Check your steering wheel is centered and the number of turns on your track rod ends are roughly equal then get your toe close to zero.

3. Set camber using the camber mod at the bottom of your strut to -2.0degs

4. redo toe, redo camber, redo toe again etc. If your toe and camber is right then your measured castor is fine if its within 1deg, its not that critical.
 
Trip

Trip

New Member
campbellju said:
Hello Trip. Just seen this. Its not way off. I don't have the Nissan manuals to hand to see what they recommend but castor is not as sensitive as camber and no where near as sensitive as toe. Those gauages estimate the castor angle anyway.

Your higher castor side has lower camber so it could just be everything triangulating against you.

If you weren't aware, when you modify your toe you alter the camber. When you compress your suspension you gain some negative camber, positive castor and toe in.

When you change your camber on the top mount in its normal poition you also directly change the king pin inclination.

Also, if you put a jack under the strut and put it under pressure it can make the difference of 0.5degs camber.

Recently I've been playing with KPI to more clearly understand its effect. Its not important for here but what is important is to understand the principle that all your suspension joints are connected so it takes a long time and a lot of patience to get them honed in.

1. Set your the top mount so their positions are as equal as possible. Then your castor and king pin inclination should be geometrically close

2. Check your steering wheel is centered and the number of turns on your track rod ends are roughly equal then get your toe close to zero.

3. Set camber using the camber mod at the bottom of your strut to -2.0degs

4. redo toe, redo camber, redo toe again etc. If your toe and camber is right then your measured castor is fine if its within 1deg, its not that critical.
Click to expand...
I am definately going to play with the settings now that i have the tools :-D. I am also designing my own top plates and will send them for laser cutting.
 
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