Crush Tubes in chassis help

[James2]

Hi all im at the stage of redrilling my chassis to fit a s13 cross member in my series 1 910 for my sr conversion. I want to put crush tubes inside the chassis to add more strength. i plan on drilling a hole big enough to accommodate the tube from the roadside of the chassis and welding the tube in place from the roadside. My main question is the legality of doing this? Will i have a problem getting cert if i have welded to the chassis? and is the a better way of going about this? any help would be much appreciated

[broke]

Um.. don't do it. Just fit a CA 910 crossmember and modify it to fit the SR. Has to be a lot easier to do and certify than putting the whole Silvia crossmember and modifying chassis rails.

[Bartman]

910 CA Xmembers are made of unobtainium.
Somewhere there is a link to another datsun site where a guy did this. I posted it once, but can't for the life of me remember which built thread I posted it in.
You've got the right idea though. Crush tubes are a must.
I would question though, how hard is it going to be to secure the crush tube in place from underneath to tack it from underneath without the tube moving off axis?
Also, how same or different is the c2c of the S13 lower arm mounting points, to the 910 ones? If they're different to the 910, you'll get bump steer for sure. Unless that is you also fit the 910 steering rack too?

[DJZ]

I would definitely talk to a certifier before you go any further.

[James2]

cheers guys ill contact a cert guy for more info. ill let ya know what the go is

[classicdat]

Question, why from the bottom up? (I am presuming the 'Road Side' is the bottom of the rail) Could you drill the big hole (Tight fit to tube) on the top, use a big plate to clamp the tube and spread the load on the rail, thus negating the need for welding? Cert will be needed anyway I guess, so talk to the guy who is going to sign it off will be best. And get back to use with what you find.

[brocky41]

Much easier to cut and shut original x member in my opinion. If you wanna run s13 coilovers etc then just run the s13 arms hubs and struts. Is your 910 rack or draglink

[broke]

Much easier to cut and shut original x member in my opinion. If you wanna run s13 coilovers etc then just run the s13 arms hubs and struts. Is your 910 rack or draglink

+1. Or modify/make sump to suit

[Bartman]

It's definately do-able. And I've seen a build thread on some Aussie website where a guy did it. It looked really easy too. I just wish I could remember where I posted it.
Drilling four holes is much easier that cutting and welding things.

[James2]

Ok so here's what the cert man said:

The crush tubes need to have 3mm walls and be welded in place on the side you drilled the hole to fit the tubes. You can drill the hole from the topside of the chassis or the roadside, this doesn't matter (im going to drill from the roadside just because in my situation it will be easiest to get the drill in)

Thats pretty much it. Hopefully how i explained it made sense