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Moving rear diff back Q - mazda 808 springs

Posted: Mon Jun 16, 2008 9:25 pm
by dank
Ok while the forum is running hot tonight here's another question.

got the mazda 808 springs for my zook. fitting them tonight and the locating pin is 20mm further forward than the OME dakar 2 inch lift rear springs. 490mm vs 470mm straight line from front bush centre to locating pin centre.

I have redrilled the U bolt plate and spring perch 27mm to move diff back before hand with my OMEs. Locating the pin in this hole means that I am now 7mm rearward of standard.

If I reverse the springs the locating pin is moved around 4 inchs behind the diff due to the extra length in the back of the spring. redilling the perch say one inch behind stock hole will give a diff 3 inchs rearward of stock.

Question Is: Will the spring handle adversly if I run it backwards to move the rear diff back?

(not taking into account whether it would foul on the rear quarter/fuel filler etc)

Posted: Mon Jun 16, 2008 9:52 pm
by muz_ook
i run springs bacwards in my car, have had no problems at all......i think the only thing that could happen is you may wear the smaller bushes quicker than you usually would, but like i said ive had no probs.... ;)
Muz.

Posted: Mon Jun 16, 2008 10:01 pm
by dank
thanks mate... :D

Posted: Mon Jun 16, 2008 10:04 pm
by zookimal
Being spring under it may have more impact on pinion angle of the diff than SPOA if there is more arch in the spring for lift.

I would like to see how it works though. What are you plans for fitting a spring of that length in? Moving mounts? long shackles? extension? missing links etc?

Posted: Mon Jun 16, 2008 10:14 pm
by Dee
your tyres will eat the rear of your guards with 3" extension.

With only 2" ext, mine pumkin dinted my fuel tank, my rear shocks (upper steel casing/cover mostly) are dinted/damaged due to fouling fuel tank mounts, and my tyres got a bit sliced by the tin at the rear of the guard.

Under standing you've got the shocks & tank under control (will be interesting to see how the vit tank lifted goes!)

Maybe a guard lift all round could be in order? I'd say think about a virtal lift/guard cut & then pull out the BL but they have their good points (high transfer & fuel tank etc)

EDIT: Pays to read ALL of your post (inc. last line) :roll:

Posted: Mon Jun 16, 2008 10:19 pm
by dank
zookimal firstly cool username man...it rocks...

i'm going to use the main and second from the 808s and to get the lift use my 3rd and 4th from my OME pack so arch should be about the same as now. Going to see what happens using stock spring hanger bolt hole and 2 inch extended shackles. might have to redrill the spring hanger bolt hole forward to suit to get better shackle angle...we'll find out when I get the body back on.

Posted: Mon Jun 16, 2008 10:29 pm
by dank
Dee wrote: EDIT: Pays to read ALL of your post (inc. last line) :roll:
yeah man read the whole post!!! lol...you bring up a good point anyway dude.

I've looked at the rear quarter and I reckon that a fair chunk of it can come out. The only major issue is the fuel filler and I reckon I can leave the tub stock but cut out everything underneath and then fab up a stone guard for the filler hose. So it'll be a chop similar to a patrol rear quarter chop. Could then run a pretty cool upturned rear bar that runs along just under the fuel filler

If i run my diff 3 inchs back then i'll flip the u bolt plates for the shock mounts. I'll also prob run a new cross member a little forward of normal to get the tank as high as I can with my 2" BL . My issue is the fuel tank...I reckon even 2 inches lifted will still make me run a bumpstop that is a little bit long. but we'll see how things go....

Posted: Mon Jun 16, 2008 10:56 pm
by Dee
I cut away some of the "quarter" like they do on the GQ quater cuts, but found that wasnt the problem, it was up higher still, the rotation of the tyre "pulled" the lip on the inside of the wheel arch where the wheel tub joins to the fender/panel towards the tyre, underneath where the flare mounts onto the flat panel. This left a sharp knife edge to shred my tyres on.

Yeah i was a bit skeptical about the fuel tank too. see if you can push it rearwards an inch or more with ya custom x-member/mounts? get out a BFH and dint it where it will hit the pumpkin before you put it in! :D

Posted: Mon Jun 16, 2008 10:59 pm
by zookimal
Interested in progress on this one. I planned something similar a while back but gave it away after the fuel tank and fuel filler stalled my progress at the time (and lack of fab skills).

Keen to see the result. I would prob like to work it in to my rebuild plans.

Posted: Mon Jun 16, 2008 11:18 pm
by alien
why move the rear back so far anyway? better to move the front forwards and get the engine weight back a bit further to spread the load more... go 1" back on the rear and as far as you can on the front. Theres less in the way up front too!

Posted: Tue Jun 17, 2008 12:29 am
by dank
alien wrote:why move the rear back so far anyway? better to move the front forwards and get the engine weight back a bit further to spread the load more... go 1" back on the rear and as far as you can on the front. Theres less in the way up front too!
Why not? I'm aware of the advantages of moving the front forward, it would be ideal for me. The issue with front is that at this stage I don't want to do a full RUF chassis extension etc etc, so I am limited to what the drag link and steering arm are capable of in its current form without rubbing. If I pushed it I could go possibly another 10-15mm with my ruf setup but I won't know until I try it. Its just so easy to work on the car at the moment with the cab off I just want to get as much done as I can. Which means more time in the shed less time wheeling. Sometimes I wonder if these minute changes are worth the effort??..its fun trying though :armsup: (Admittedly I did feel a noticable change in the suspension after a 2 inch wb stretch...)

Posted: Tue Jun 17, 2008 12:39 am
by alien
dank wrote:
alien wrote:why move the rear back so far anyway? better to move the front forwards and get the engine weight back a bit further to spread the load more... go 1" back on the rear and as far as you can on the front. Theres less in the way up front too!
Why not?
I like your style =)

Posted: Tue Jun 17, 2008 7:05 am
by GRPABT1
cough *ute chop* cough lol

Posted: Tue Jun 17, 2008 7:57 am
by moose
my rear shackles , with the 323 springs fitted ,
standard position front mount , centre redrilled back 40mm , no mods to spring perch !!

Image

Posted: Tue Jun 17, 2008 8:52 am
by sierrajim
Re your fuel tank.

Cut a hole in the floor, raise your tank through that then box it back in. This will also allow you to raise your filler and get it away from the wheel.

Posted: Tue Jun 17, 2008 5:29 pm
by Guy
moose wrote:my rear shackles , with the 323 springs fitted ,
standard position front mount , centre redrilled back 40mm , no mods to spring perch !!

Image
This mod requires at least one vodaka and orange UDL to perform .. :lol:

Posted: Tue Jun 17, 2008 5:45 pm
by Spike_Sierra
does anyone have measurements for these 808 springs and 323 springs.
picked up some rear springs from a wrecker the other day for loose coin
and they are 50mm wide and 47inches or 1190mm long. I would like to know what they are out of. Came from a 4 stud diff, looked pretty small.

Posted: Tue Jun 17, 2008 6:12 pm
by dank
my 808s are 1100mm end to end.
The 323s are 1150mm going by Moose's measurements on Auszookers.

Posted: Tue Jun 17, 2008 7:43 pm
by built4thrashing
not to mention the cableties. Moose you could improve ya shackle angle a little if you mover front mounting bolt hole forward and it will also give a small lift.

I agree the benifits with extending wheelbase is greater at the front than the rear. Not sure if all the hassle is worth the end result.

Ill be doing a similar mod but i plan only to move diff back 30mm. Im going to redrill the front mount 25mm forward and drill the diff locating plates to position diff where i want it. not sure if ill be using 808 or 323 springs yet (prob the 323 as they are longer) A longer spring you will give you more flex with the diff in its original position. Extending wheelbase will only improve stability on steep up and down hills.

B4T

Posted: Tue Jun 17, 2008 8:34 pm
by Gwagensteve
What needs improving about that shackle angle Built4?

Steve.

Posted: Tue Jun 17, 2008 8:51 pm
by 11_evl
use a vitara tank. mount the rear directly to the round pipe at the back and make brackets for the front of the tank. the filler pipe than sits above the rail and has plenty of clearence.
well thats what i did anyway :D
im using an efi tank but with carby internals

Posted: Tue Jun 17, 2008 9:19 pm
by GRPABT1
I agree steve I reckon that shackle angle is perfect.

Posted: Tue Jun 17, 2008 9:33 pm
by dank
11_evl wrote:use a vitara tank. mount the rear directly to the round pipe at the back and make brackets for the front of the tank. the filler pipe than sits above the rail and has plenty of clearence.
well thats what i did anyway :D
im using an efi tank but with carby internals
Thats exactly what I was mocking up today when I got bored. the tank sits nicely in that space once all of the old tank mounts have been cut off. just gotta fab the mounts and decide whether to chop out my old shock mount cross member and relocate the shocks mounts and swap the u bolts to run the shocks in front of the diff housing.

Posted: Sat Jun 21, 2008 11:11 am
by zookimal
Did you end up running these reversed Dank?

Posted: Sat Jun 21, 2008 11:39 am
by dank
been away for work. It'll be determined by a few factors. depends on how I can mount my fuel tank. I dont' really want to cut out my floor to raise it that much even though its a good idea. i should be able to get it about 2-3inches higher than a stock tank which combined with 34s and a 3mm gal bashplate with 12mm of foam between for shock absorbtion should keep it up and protected out of the way enough. i'll post pics and stuff when I'm done.

Posted: Sat Jun 21, 2008 12:46 pm
by GRPABT1
Not to sound insulting or anything but what do you think 12mm of foam will do with a tonne of vehicle weight when you come down on a rock? Fark all i'd say, can't hurt though I spose.

Posted: Sat Jun 21, 2008 1:35 pm
by dank
eva foam is quite dense. you can imagine having a 10mm gap between your bashplate and tank... A rock comes up and with no support in the middle of the bashplate the rock will come right up and dint the bashplate and tank. If that gap is filled by a dense but slightly forgiving material like EVA its possible that the damage will be reduced by spreading the load across the whole bottom of the tank and into the mounts . In theory it sounds good. Could be more physchological protection though. We'll have to wait and see! better than nothing is my view :D anyway this thread is about springs and diffs not bashplates.