59 replies to this topic

[Bart]

Hey guys, im in the proccess of lowering a Nissan V8 in my engine bay (ill have some pics soonish) now the size of it is approx the same as a big block, i have seen some Toranas modify there front chassis rails, that is cut off along the sides of the rails and weld a plate to widen the area between the rails and make more room for the engine.
So my question is, would it be ok to weld the rails or is it some sort of high tensile steel??

Alternativley i will probably have to fit the engine from under the car but the middle/sump area of the front cross member is a little fat, top to bottom (some would say the fricken engine is just too bloody big lol) so the next question is if i go this route, can a front cross member around the sump area be safely cut and welded to make room for the engine block and sump or is the steel some sort of high tensile steel??
Obviously there is a limit on how much material can be removed for obvious reasons and some extra bracing would be required.

I believe Liter8 did something similar to his rails.
Kind regards

[Bart]

Had another look and figured if i go from under the car/under the chassis rails and if the cross member fouls on the sump, i have measured the cross member will be 1-1.5 inch too high, rather cutting the member i can space the member down by 1-1.5 inch blocks (alloy or steel) between the rails and the cross member, this will mean i wont have to cut the rails or the member.
What you guys reckon??

Edited by Bart, 01 July 2006 - 08:48 PM.

[makka]

I have seen the crossmembers spaced down (or the chassis up depending on how you look at it) for bonnet clearance. you could scallop and plate the chassis rails. the problem with this work is you need someone with their DLI ticket (I think thats what it called) to do the welding. Lucky for me, my old man has it!

[TerrA LX]

im a little confused with what is fouling here but if it is the sump, what about modding the sump or one from a nother model?


no offence but if you have to ask if i can weld something maybe you should speak to an engineer first, especially if rego is going to be an issue, might save u some heart ache.

[Bart]

Basically what i should have asked is, is the chassis rails mild steel like the rest of the car, i know it can be welded but will it substancially have a bad affect on the metal, in terms of brittlness??
I spoke to an engineer today and he isnt keen on cutting the rails, although there is another engineer who i think may not mind.
Anyhow i will see if i can space the rails from the cross member.
The area where its fouling is the engine is a fraction too wide and so it wont fit between the rails as im lowering the engine in, but from top to bottpm of the engine it looks as though (with measuring) the widest point of the engine will fit between the bottom of the rails and on top of the cross member with 1-1.5 inch spacers between the rails and member. I may find out tomorrow.

Edited by Bart, 02 July 2006 - 12:57 AM.

[TerrA LX]

sorry im not up on lc/lj to picture in my head your problem.
anyhow if u talken the mono chassis rails (body) then they are m/s, but im not keen on having to mod them, this is one of the most crutial parts of the car as mounts here and the load is quite high, but im sure if this is not what u talken bout as the block would have to be quite wide to foul here. that only leaves the crossmember and if modded to an engineer standard i dont see a problem with minor mods, but im concerned already one engineer has said no.
maybe some pics would be in order before further comments.

not trying to discourage you, take it as constructive critisisum.

[Bart]

thanks mate ill have another look tomorrow but i now believe i can get away with it by not cutting anything but spacing the rails from the member, i hope my measurements were correct but i will find out soon as i take the member out, lift the engine from under the car into the engine bay untill the engine widest point is approx 20mm front the bottom of the rails and then lift the member up under the engine.
Ill try take some pics.

[Toranamat69]

G'day Bart,

Where do you plan to get that 1 to 1 1/2"back from to get the front of the car down where it should be? by lowering the suspension?

If so all of your suspension points will be moving that far as well and you will be using up some your suspension travel to compensate.

if you drop the rear mount of the subframe down very far you will drop off the bottom of the chassis rails.

Just a few things to consider.

On the subframes, I have seen a few of these modded to go into other cars or to fit big engines etc and generally they look a lot weaker - they get scalloped out and then a little bigger plate welded in or something like that but a lot of their original strength would be due to the fact they are tube like in cross section.
I explored if I could go a fabricated front subframe but no one would comply it.
I found similar reaction from the certification guys about modded crossmembers.

The rules here in qld are crap for that sort of mod - there are no codes to classify the mod under so no-one will approve them.

M@

[lakeside]

^^^^^^^^^^^^^ save your self time and effort and consuld a engineer first as you will know what you can and cant do

go and pay an engineer to tell you the right way. It don't matter what we all think, it's got to be done right. The engineer is the one who is going to sign his life away on the work.

[Bart]

^^^^^^^^^^^^^ save your self time and effort and consuld a engineer first as you will know what you can and cant do

go and pay an engineer to tell you the right way. It don't matter what we all think, it's got to be done right. The engineer is the one who is going to sign his life away on the work.

Yes youre right, just wanted other ideas before i go back to him.

[gtrboyy]

If your not allowed to modify the chassis rails in the back of a car then your probably not allowed to modify them at the front either.You could modify the centre of thr x-member but you will still have check with an engineer as the others have stated.

[Bart]

Surprisingly, custom manifolds will be ok, iv had the motor in the bay but not all the way down to the member, which is the problem, because the engine is a fairly wide V the exhaust ports face down wards more than say a 308 which ports face a little more directly out sideways towards the rails. So the manifolds will face downwardsish with the Nissan V8.
I was worried about this also but looking at it tonight that is the least of the problems fortunatly.

[Bart]

one thing also is, you may be able to add a front rail stregnthening kit.

Ive seen it on an lx track car where theres a certain way in which they brace the two rails togethers and also strengthen each rail individually so they can be cut reweled and hold greater front end stiffness.

Just out of curiosity how are you going to mount your manifolds/extractors in such tiny space?

would love to see pics of hows its progressing

Yes agreed but will the engineer like this idea as much as i do???
Im still toying with it so i should come up with something soon i hope

[TerrA LX]

pics??????

[Bart]

pics??????

Yeah sorry mate theres not much to photograph yet, i have to pull out the front cross member and lift the motor in from under the car into the bay, apparently the new Fords do it this way for there quad cam V8's??
Anyway im not keen on pulling out the member as the bolts which hold the member also hold the chassis jig which i dont like to lossen untill the other sill is welded on, ill see if i can manage pulling it off without disturbing the jig too much, as im itching to get this bitch in.

[lakeside]

is there any good reason why you can't cut the sump

[Bart]

The sump dosnt seem to be the problem its the width.

[Bart]

The sump dosnt seem to be the problem its the width of the motor.
Oh I see what you mean, insted of spacing the member from the rails i should cut the sump, I have taken the sump off totally as i trial fit the motor.

Edited by Bart, 03 July 2006 - 11:03 PM.

[Bart]

G'day Bart,

Where do you plan to get that 1 to 1 1/2"back from to get the front of the car down where it should be? by lowering the suspension?

If so all of your suspension points will be moving that far as well and you will be using up some your suspension travel to compensate.

if you drop the rear mount of the subframe down very far you will drop off the bottom of the chassis rails.

Just a few things to consider.

On the subframes, I have seen a few of these modded to go into other cars or to fit big engines etc and generally they look a lot weaker - they get scalloped out and then a little bigger plate welded in or something like that but a lot of their original strength would be due to the fact they are tube like in cross section.
I explored if I could go a fabricated front subframe but no one would comply it.
I found similar reaction from the certification guys about modded crossmembers.

The rules here in qld are crap for that sort of mod - there are no codes to classify the mod under so no-one will approve them.

M@

I have HQ stub axles so that lowers the car approx 1 inch, with a longer springs alreaady in i can get the suspension travel back somewhat.

[TerrA LX]

still cant see (pics) the problem yet!

maybe take a shot pointing at the porblem with the rail or install a template (cardboard) etc.

we are dieing to help!

Edited by ALX76, 03 July 2006 - 11:39 PM.

[Bart]

still cant see (pics) the problem yet!

maybe take a shot pointing at the porblem with the rail or install a template (cardboard) etc.

we are dieing to help!

lol
Thanks mate sorry guys, i still need to modify the jig as its in the way of the engine going in from under the car/engine bay, i have to cut the ends of the jig off then i can get down to business AND ill take pics.
Christ i hope it fits this way lol

[Bart]

Aprox marked out where the notches should be cut if i install the motor from under the car

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widest point of the motor

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[TerrA LX]

alrigth i take it the line of the rocker cover tn the last pic is what is givving you trouble at the line drawn on the rail.

u need some heavy mods to strengthen if you perform this "notch" especially at the rear were they curve down to the chassis connector otherwise the car can fold up on you.

better if you can lower the motor as you suggest even going to the extent of a new Xmember.

Edited by ALX76, 04 July 2006 - 01:51 AM.