PDA

View Full Version : Custom crossmember, replacement crossmembers... Track use



Iain
26-08-14, 03:13 PM
My crossmember is a little worse for wear, both sides have varying levels of damage around the tiebar brackets from small splits to 4-5 inch cracks. 3 years of XE road and track abuse and lowered rosejointed tiebar brackets are to blame probably.

Plan to replace it all in winter, just weighing up the options. Is it just worth putting a new standard/aftermarket one on? What's the best way of making a custom one?

At the mo thinking of a CDS tube welded between the chassis legs and box section either ends for OE tiebar brackets to mount to... But then should I do the whole lot 20mm lower so it's already in the right place for the anti-dive effect of the RJ kit I have on (which spaces it 20-25mm lower and puts more force on the crossmember?)

scott.parker
26-08-14, 03:26 PM
If you can find the counts wip I personally would try replicate what he did on the beige one he started.

Iain
26-08-14, 04:02 PM
Looks good. I was thinking of box style like he's done for the tiebar brackets, and boxing them around a CDS tube instead of his box at the front.

http://i248.photobucket.com/albums/gg167/Count85/Beige/Beige699.jpg

Benn
26-08-14, 04:51 PM
I'd tube the front, tag it to the legs, as you've said a box in the tie bar mounts. yours are already dropped down arnt they? So you wouldn't need to lower them more really.
Will look better and work better. You could even lover the rad for more air. Or do it so the oil cooler sits under the rad. So get max cooling.

Iain
26-08-14, 05:08 PM
Was thinking lower the cross member so they no longer need the spacers in so theyre closer to the cross member.

Benn
26-08-14, 05:11 PM
Sorry didn't know you ran spacers, thought the posh mounts didn't. THen yeah i'd lower them they so you can be spacer less.

scott.parker
26-08-14, 06:01 PM
Only thing is I thought it's easier to bend a tube compared to the box section stuff?

mowgli
26-08-14, 07:52 PM
you can bend both, but most metal bashers only have tools to cold bend round tube.

Mieran
26-08-14, 11:02 PM
http://s27.postimg.org/u2qyvd2cz/kevsnova3ke0.jpg

scott.parker
26-08-14, 11:43 PM
Worth a read...

http://www.homebuiltairplanes.com/forums/aircraft-design-aerodynamics-new-technology/3372-round-vs-square-tube-strength.html

Iain
27-08-14, 08:35 AM
That's far too technical for a Nova crossmember, I think CDS vs a reasonable wall box section would both be equally good here?

Mieran loving that, I have had thoughts about tieing it back into the turret rollcage bars but not sure I'd stop if I was going that mad.

Benn
27-08-14, 09:08 AM
Mieran pic is what i was thinking of...

Iain
27-08-14, 09:13 AM
Still needs boxes at either end if you're going to use the original tiebar brackets tho, kind of what I was thinking of but just one tube instead of 2 and boxed ends.

Iain
11-11-14, 09:49 AM
I was eyeing up the crossmember on mine yesterday with a view to tackling this soon.

To remove the old one, I am thinking of fitting the tiebar brackets in their LOWEST position, tacking them onto bars running between the chassis legs and down to the lower arm brackets to keep them in the right position, then cutting off the crossmember.

I am thinking of remaking the new one to match the lower tiebar positions, and also space it forwards a few mm (couple of washers in front of the horizontal bolt position) to gain some added castor lost by lowering it.

Thinking of 100x50 box section 3mm wall on the ends to mount the brackets to and box them into the chassis legs, and tieing them together in the middle with a run of 38mm CDS rollcage tubing I have.

RallyMarshal
11-11-14, 09:59 AM
Id remove the old one entirely, plate and strengthen it so the tie bar brackets dont need to be lowered anymore and refit the entire crossmember in the lower position by concentrating on making the chassis leg to crossmember mounts.

The rally Novas run a sumpguard obviously. This helps to tie the front brackets into the rest of the chassis. Perhaps some kind of "subframe" arrangement or strengthening bars that tie the front crossmember brackets into the main chassis legs and simulate the job a sumpguard does would be an idea to alleviate those specific stress points?

Paul..

Iain
11-11-14, 10:03 AM
That's the plan no spacers on the tiebar brackets, then I can use OE brackets and poly bushes too.

That's not a bad idea to tie it in backwards Paul, sure I've seen pics of that recently, I'll have to look into that when the engine's back in as there's not too much clearance around the tiebars currently although might be more obvious with the whole lot lower.

I'll gusset (triangular sections/plates) the square end sections to the CDS, and upwards into the chassis legs based on what we talked about it now being lower than original to brace it up the chassis leg a bit.

Benn
11-11-14, 04:38 PM
Am i right in thinking moving the tie bars over (so the end of the bar is in line with the lower arm) will help too? Seen this on another Nova... Guess it helps with pull of the tie bar... But not one you can do with std tie bars.

Think i'd be temped to use tacked in small bits of metal to keep everything in place...

Johnny A
11-11-14, 06:14 PM
a bit of sheet steel tacked in each corner is better than a factory crossmember ffs

BRoadGhost
11-11-14, 10:10 PM
From that link on square Vs tube, I surmised box is somewhat stronger in most stress / shear testing, but is approximately 30% heavier.

In this case I went for 3MM box and welded the lowered brackets to it; got the lower arm mount points inline at the same time and it's strong enough to jack the car up on at the center point. I've still got the pictures.

ben doodar
11-11-14, 10:21 PM
From that link on square Vs tube, I surmised box is somewhat stronger in most stress / shear testing, but is approximately 30% heavier.

In this case I went for 3MM box and welded the lowered brackets to it; got the lower arm mount points inline at the same time and it's strong enough to jack the car up on at the center point. I've still got the pictures.


Fire some pics up pal.

Iain
11-11-14, 10:24 PM
What size you go for BRoad? Original one measures up roughly 60x130 so figured 50x100 would be sufficient.

Maybe I'm over complicating it with the CDS, it won't give me anything extra other than space....

Benn
11-11-14, 11:22 PM
Mr Ghost's set up is what i was talking about.

Iain
12-11-14, 08:44 AM
Not brave enough to move the tiebar mounting location in/out, especially as I have bushes on the arms still, but pics of the materials used and implementation would be nice!

BRoadGhost
13-11-14, 07:59 PM
http://s29.postimg.org/414vws15j/L_Front_crossmember_03.jpg


http://s27.postimg.org/48snrwt0j/L_Front_crossmember_04.jpg


http://s29.postimg.org/oj42x0yc7/L_Front_crossmember_05.jpg


http://s14.postimg.org/nrt5uaitt/L_Front_crossmember_06.jpg


http://s18.postimg.org/a3ewnem3t/L_Front_crossmember_07.jpg

http://s29.postimg.org/et2wv8xjr/08_09_12_A.jpg

Iain
13-11-14, 08:07 PM
Great help thanks. For some reason I was planning on running the bar the other way up, so it's wider than it is tall.

What size box is that?

BRoadGhost
13-11-14, 08:55 PM
3MM wall; imo you want no thinner nor thicker

Iain
13-11-14, 09:00 PM
Good to hear was planning that. I mean what width and height as planning 100x50

BRoadGhost
13-11-14, 09:04 PM
Hmm too long ago to remember measurements; just get something a bit over at the shop & cut it down at the car. I think the smaller bits were just off cuts.

Benn
13-11-14, 10:13 PM
That looks good and strong.

pottersrebel
13-11-14, 10:19 PM
looking at the pictures id guess at 50 mm x 30/40 mm for the front bar and 30mm box section for the tie bar lengths

_Jake
15-11-14, 03:39 PM
Mine
http://i255.photobucket.com/albums/hh160/bodmin344/DSC01554_zpsb0c1183a.jpg (http://s255.photobucket.com/user/bodmin344/media/DSC01554_zpsb0c1183a.jpg.html)

50x100 3mm wall

Iain
15-11-14, 04:36 PM
Spot on what I was thinking of doing except after measuring having it straight across like that would make it quite tight for thr exhaust manifold?

BRoadGhost
15-11-14, 10:26 PM
Mhm + the extra weight; doesn't need to be that strong. In an impact it'll push the damage further in.

totalnova
15-11-14, 10:36 PM
Have a look through this, there is some serious cross member fabrication,

http://retrorides.proboards.com/thread/121358/beige-nova-project-parchment-rust?page=3

In fact the whole thread is welding and fabrication porn, shame it's not been updated in a long time

Southie
15-11-14, 10:44 PM
Have a look through this, there is some serious cross member fabrication,

http://retrorides.proboards.com/thread/121358/beige-nova-project-parchment-rust?page=3

In fact the whole thread is welding and fabrication porn, shame it's not been updated in a long time
The count had that thread on here also:
http://www.pngclub.com/forum/showthread.php?161851-The-Counts-Beige-Mk1

totalnova
15-11-14, 11:01 PM
Don't want to go off topic but does anyone know what happened to that car it looked like it was going to be epic.

Southie
15-11-14, 11:08 PM
Don't want to go off topic but does anyone know what happened to that car it looked like it was going to be epic.
PM him, think he may still have it.... Probably sold it on though lol

_Jake
18-11-14, 09:58 PM
Spot on what I was thinking of doing except after measuring having it straight across like that would make it quite tight for thr exhaust manifold?

ive gone turbo and made my own manifold / downpipe so it wasnt really a problem for me, theres no reason why it cant be notched if your worried about manifold clearance, for example a 25mm notch in the box would be adequate room and still safe in my opinion.

Iain
02-12-14, 04:59 PM
This is what I am in the process of creating. It's 50x50mm box section with the relevant holes and captive nuts for the tiebar brackets, and 38mm CDS tube to tie them together across the front. It'll be stitched together then boxed over where the round meets the square, then attached up the chassis legs.

It'll be mounted about 20mm lower than a standard crossmember and 5-6mm further forward to gain some castor for free.

http://iainel.co.uk/images/forums/Misc/rps20141202_165308.jpg

Thoughts welcome.

Benn
02-12-14, 05:51 PM
That looks good and like it will be strong enough, plus get loads of space.

BRoadGhost
02-12-14, 10:52 PM
https://i.imgflip.com/eu29c.jpg

Iain
03-12-14, 08:36 AM
Well it'll set me up for it, whether the bottom bushes will take it or not is another thing. But I can double up the tiebar washer to take it back in 4mm.

BRoadGhost
03-12-14, 06:57 PM
Yeah polys can take a bit of deflection; rose joints are what you'll want on there in time.

Benn
03-12-14, 09:46 PM
Erm.. Don't you wanna pull the bar forward to increase the castor... Surely adding a washer will push it back. So you'll lose castor.

Iain
03-12-14, 10:36 PM
Yes weld the cross member further forward.. If it all goes wrong I'll use 2 washers to restore the original geometry

Benn
04-12-14, 12:12 PM
Ah sorry. Yes wasn't thinking.

Iain
23-12-14, 08:36 AM
Thought I'd put these pics in here to keep all the crossmember examples together for future reference. Pics of how it was built can be seen in my WIP starting here onwards:

http://www.pngclub.com/forum/showthread.php?114446-Iain-s-20XE-Trackday-Nova&p=2253592&viewfull=1#post2253592

Finished pics:

http://iainel.co.uk/images/forums/NovaWIP2b/025.JPG

http://iainel.co.uk/images/forums/NovaWIP2b/026.JPG

http://iainel.co.uk/images/forums/NovaWIP2b/027.JPG

http://iainel.co.uk/images/forums/NovaWIP2b/028.JPG

It's mounted 4.6mm further forward and 18.5mm lower down than standard.

Benn
23-12-14, 08:58 AM
Should give a nice set up on that.

BRoadGhost
23-12-14, 04:31 PM
Mmm should be good; no looking back now

Iain
24-12-14, 09:01 AM
Stumbled across some pics of Toymex's race car!

http://i367.photobucket.com/albums/oo114/toymex/novaevo2006_zps7c1e9e89.jpg

http://i367.photobucket.com/albums/oo114/toymex/novaevo2002_zpsa4960dd1.jpg

toymex
24-12-14, 09:19 AM
Stumbled across some pics of Toymex's race car!

http://i367.photobucket.com/albums/oo114/toymex/novaevo2006_zps7c1e9e89.jpg

http://i367.photobucket.com/albums/oo114/toymex/novaevo2002_zpsa4960dd1.jpg
It has worked very well on my car ,I am sure yours will work just as well

Iain
24-12-14, 10:28 AM
Cheers Jezz, just stumbled across it browsing back in your thread for inspiration, some nice little bits of extra bracing here and there on your shell too.

BRoadGhost
27-12-14, 10:28 AM
Yeah; this one's really nice, plus it's got the revision for the dry sump pump

Iain
30-01-15, 07:03 PM
Turns out you really need sleeves for the m10 vertical bolts to stop it crushing the box section.... I've found out the hard way

Anyone got any suggestions for retrofitting them into a finished cross member? Could I get away with just welding in from one end? Or put a huge steel spacer across the top to spread the load instead of pressure points under the bolt heads?

Balley
30-01-15, 07:09 PM
Drill a hole in the top, fit some 10mm ID tube in the hole. Weld up, jobs a carrot!

Iain
30-01-15, 07:16 PM
I was thinking of opening out the bottom hole, leaving the top one and welding it on the bottom then grinding flush. Then the top will crush down onto the sleeve?

Where would I buy 10mm ID sleeve?!

novarally
30-01-15, 07:34 PM
I was thinking of opening out the bottom hole, leaving the top one and welding it on the bottom then grinding flush. Then the top will crush down onto the sleeve?

Where would I buy 10mm ID sleeve?!

You might be lucky and find a tube with 10mm ID, but the easiest way will be to put a 10mm drill through some steel bar.

Iain
30-01-15, 08:08 PM
Found some 16mm OD and 10mm ID CDS on eBay for about 12 quid posted so that'll do me fine. Probably tack it in from one end and let the box crush onto it. Thanks guys

turbojolt
30-01-15, 10:19 PM
Found some 16mm OD and 10mm ID CDS on eBay for about 12 quid posted so that'll do me fine. Probably tack it in from one end and let the box crush onto it. Thanks guys


could you not off robbed the tubing from my scrap front end

Iain
30-01-15, 11:02 PM
Standard ones aren't really usable thanks anyway :)

Benn
30-01-15, 11:23 PM
Found some 16mm OD and 10mm ID CDS on eBay for about 12 quid posted so that'll do me fine. Probably tack it in from one end and let the box crush onto it. Thanks guys

Id think thats prob the best way. Or weld both ends in.

Iain
30-01-15, 11:24 PM
Would ruin my lovely stonechip finish though :( :(

Benn
30-01-15, 11:27 PM
Its stonechip... redo it. Cost like a pound.

BRoadGhost
31-01-15, 04:37 PM
Paint finish on a front cross member will be the last thing on your mind with a wheel moving around in it's arch

Iain
31-01-15, 10:31 PM
Ha ha that puts it into perspective... Tbh the standard one is only spotted in and not welded top and bottom so it doesn't need much to secure in place :)

Benn
31-01-15, 11:01 PM
So what you welded them in both sides?

Iain
01-02-15, 12:31 PM
Not touched it yet. I'll be opening out the bottom hole and welding it into thr bottom as that has a huge spacer to pull through rather than just a bolt head. Then the top will pull down and clamp it on tight.

Balley
01-02-15, 12:52 PM
I would seriously consider welding both holes. In my opinion for the extra time it would take it would be 100% worth it. It will be much stronger in the long run. As Benn says its only stone chip.

Iain
01-02-15, 01:22 PM
Ideally I'd have put the tubes in the box section beforehand and a few tacks would have sufficed to keep it in the right place so don't think it'll give much more benefit. This way the original 10mm hole is retained at the top stopping the bolt head pulling through downwards too.

Will get pics when I do it. :)

Iain
10-03-15, 03:30 PM
Crush tube pics for thread completeness, as I've just seen Chimp's thread where he's done similar.

10mm ID 16mm OD steel CDS tube, length off eBay

http://iainel.co.uk/images/forums/NovaWIP2b/050.JPG

Bottom holes drilled out to 16mm using a step drill bit

http://iainel.co.uk/images/forums/NovaWIP2b/051.JPG

Then welded in

http://iainel.co.uk/images/forums/NovaWIP2b/052.JPG

Crush tubes in place

http://iainel.co.uk/images/forums/NovaWIP2b/053.JPG


I urge anyone doing a custom crossmember to put these in, mine was 3mm wall box and still crushed.

bazzap8389
10-03-15, 04:25 PM
Good job Iain looks the part :)

TOZNOVA81
01-04-15, 08:34 PM
Have just done this with my crossmember.

https://scontent-lhr.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/10559848_10153252181608023_2156008056351057248_n.j pg?oh=b02369fc65fe130d57faf5e710aaba8b&oe=55AD8E0A

https://scontent-lhr.xx.fbcdn.net/hphotos-xfp1/v/t1.0-9/11025744_10153253134768023_2435312522915995866_n.j pg?oh=b1cd799f309f725fd97062163a4f094b&oe=5570EE7A

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xap1/v/t1.0-9/149350_10153253134783023_4937851571689668741_n.jpg ?oh=4907eda9823d3e48c375aa54677a5c24&oe=55A6A1FB&__gda__=1437517095_ef3f57d0e27f0805c034dc94eccbb8f 8

Iain
01-04-15, 09:21 PM
Crush tubes!!! lol nice work

TOZNOVA81
01-04-15, 11:04 PM
:thumb:

Jedro
02-04-15, 07:22 PM
double 40mm x 40mm box section with homemade rose joint arms/tie bars set up
http://i1072.photobucket.com/albums/w370/JedDixon88/Photo1650_zpsv6ch2yfg.jpg

TOZNOVA81
03-04-15, 06:58 AM
double 40mm x 40mm box section with homemade rose joint arms/tie bars set up
http://i1072.photobucket.com/albums/w370/JedDixon88/Photo1650_zpsv6ch2yfg.jpg


Is the tow hitch going on there too? lol

Jedro
03-04-15, 09:19 AM
haha no, nearest thing i could find to stop it rolling away