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Minimum Lift to use castor plates

Posted: Sat Nov 27, 2004 10:30 am
by BigMav
For my LWB Mav what would be the minimum lift I need to use castor plates and OE bushes, I want to avoid poly offset bushes if i can. I'm likely to be getting a 75-80mm kit in a couple of weeks. I know every car is different with castor but thought there might be a rough estimate.

Posted: Sat Nov 27, 2004 10:51 am
by ludacris
I would like to know how far over castor you can go before there is a problem. I replaced a 4 inch with a 7 inch and left the castor plates that were already on the vehecle with no problems. By the sounds of it you are doing a 3 inch lift. Maybe you can get away with 4 or 5 degree castor plates. You could always use 30mm spring blocks to bring the spring height closer to castor.

Posted: Sat Nov 27, 2004 1:40 pm
by turps
ludacris wrote: You could always use 30mm spring blocks to bring the spring height closer to castor.


I think the plan is, he only wants that hieght. But wants good travel/handling.
Maybe using drop brackets is another idea. Should be the same as running castor plates. still dont know if this would work though.

Posted: Sat Nov 27, 2004 3:32 pm
by big red
stock bushes 0-3
offset bushes 2-4
caster plates 4-5 and 5-7
drop brackets 4-5 and 5-7
drop arms thirds 4-8
drop arms snake 4-6

roughly from what i hear.
check first though.

Posted: Sat Nov 27, 2004 7:02 pm
by BigMav
Basically I want a 3" lift, everyone seems to have a different idea as to what is needed. I didn't want to get castor bushes because they don't seem to flex well enough. I didn't want to go 4" because that seems to be the amount of lift when quite a few other mods are necessary and I will start having insurance and roadworthy probs in queensland. Some people think that the stock bushes will normally be ok so I guess I'll put the kit in and see what happens. Just wanted to avoid polyurethane shite if it was possible.

Posted: Sat Nov 27, 2004 7:13 pm
by Daisy
put the kit in first and take it for a drive.

If you have steering wobbles at 80-100 kph.. you need your castor adjusted.. so means bushes.

In my GQ wagon i put a 3 inch dobinson kit in her. and it ran good.. wobbled at 100 kph thou..

Removed lift and put a 5 inch lift in her and ran a 5 link.

Sold my old 3 inch to an UTE and he bolted it straight on and HAS NO WOBBLES.

Shows that no two GQ's are the same.

His measured higher than mine when i had it in due to its lighter load.

Go figure..

Posted: Sat Nov 27, 2004 8:08 pm
by BigMav
GQ wrote:put the kit in first and take it for a drive.

If you have steering wobbles at 80-100 kph.. you need your castor adjusted.. so means bushes.

In my GQ wagon i put a 3 inch dobinson kit in her. and it ran good.. wobbled at 100 kph thou..

Removed lift and put a 5 inch lift in her and ran a 5 link.

Sold my old 3 inch to an UTE and he bolted it straight on and HAS NO WOBBLES.

Shows that no two GQ's are the same.

His measured higher than mine when i had it in due to its lighter load.

Go figure..


Yeah I will do that and hope for the best. I will be putting in new Nissan bushes throughout at the same time so we'll see what happens

Posted: Sun Nov 28, 2004 8:29 am
by 4Speed
Sorry only just read all this quickly, so I might have missed something.
I ran 3 degree caster bushes on a four inch lift with out sway bars and it flexed to well, apart from adding bullet proof Tie rod and and lower control arms, all that was need was extended brake and diff breather's.
So only minor cost involved. Something to think about...cause I'm about to do the same sit up again on a GU.

Oh and no wobbles or vibrations @ any speed...

Posted: Sun Nov 28, 2004 11:53 am
by Area54
I'm same as 4 speed, (only read it quickly)

For the lift you are looking at, I would just go with a set of offset bushes. The caster plates will have too much caster for your application, the bolt on ones (7 degree - as in no drilling) will have way too much caster for your lift, and the drilled ones (5 degree approx - you need to drill the mount plates on the diff) are a pita fro small lifts - not worth it in my opinion. In both cases of caster plates you will need to adjust the steering stops out to limit the 'lock' you have as the tie rod will hit the bottom of the cast radius arm.

Contrary to what some may have you think you will not lose flex, provided you go with the correct urethane caster bush kit. Drop boxes are good for high lifts, but the legality and clearance is something to consider, although they do work well.

The shimmy on Patrols is a complex issue, and varies from vehicle to vehicle. Excessive caster will only add to it.

I'm goi ng back to caster bushes, in the past have had the bushes, then the caster plates, then the drop boxes, then back to the caster plates, now hunting for the right bushes.

I first changed fromt he bushes as my new coils were too high for the bushes, so on went the plates. Lost a lot of steering lock, but had no shimmy, and the caster was spot on at 2 degree pos. then the coils sagged, the mild shimmy started and found the caster at around 5 degrees pos :shock: , so on went the drop boxes (although chaging to alloy wheels as road wheels eliminated the shimmy - but was still there with the simexs and bent rims) front end then became very neutral and back to factory settings. Then DOT didn't like the drop boxes, and the battle scarring on the boxes told the story of how they can hang up offroad, it was very hard to find an engineer that could find a legal solution, so it was out with them and back to the caster plates for a temp fix. 7 degrees pos now on the caster with the plates :shock: and the shimmy is just waiting for an oppurtunity, the steering was terrible with no lock and very aggressive return to centre characteristics (as is the effect of caster) so out the plates came and just standard rubber bushes in at the moment.

Sorry for the long post, but this will highlight the dramas you can go through searching for 'FLEX' and fixes to the drama of a Nissan front end. Just keep it simple, fit the coils, have the caster accurately measured, then you will have the amounts in degrees you will have to correct.

Posted: Sun Nov 28, 2004 3:18 pm
by Camshaft1
I got 5inch springs and stock castor. no wobbles or vibrations. im only putting in offset bushes now cos the old ones are stuffed. but as someone said above every rig is different. put in the springs and take it 4 a drive. you might be surprised!