body strengthening

[khughes]

sorry to go into this again but i just recieved an email from stewart Wilkins after i asked them about strengthening up the 240k.

Basically he stated that the 240k body is already very strong, and doesn't need stitch welding along the suspension towers. He did recommend a roll cage (which we all expected) and a front strut brace.

He said that if there was a weakness, it could be that the layers in the chassis rails may seperate, so that if the bottom seam was fused together it would enormously increase it's strength.

now i am not 100% sure where he is talking about, can anyone give me a clue?

I was looking at the rails in the engine bay (right under the firewall) on the weekend (finally finished stripping!), i noticed that the welds between the top of the engine frame rail and the firewall wasn't that crash hot (leaving fairly large holes, but this could just be cosmetic).

Don't suppose anybody knows where a strut brace can be bought? (SWR was over $300 for an adjustable) if anybody has some influence, maybe we can get a few of us together for a good price?

[aarc240]

Have a look at the frame rail from below and you will see a vertical edge.

If you have a factory manual, go to section 'Body and Frame', 'General Description' and there is a detailed line drawing of the body. Fig BF-1 for sedan, BF-2 for hardtop.

Section D-D is the relevant view. The bottom of this could be welded or 'fused' to increase the strength but I've yet to see a car that needed it, even after extensive use on VERY rough dirt roads in Central Australia.

The price for the strut bar is within reason given the labour involved in making the part. I sure wouldn't do another for any less!

The roll cage might be good for strength but keep in mind that as soon as you install one then the car can only be registered as a limited use dedicated rally car.

That unfortunately is a fact of life throughout Australia now under the National Code Of Practice unless you are prepared for the expense of type approving the car (and therefore any other with the same body) with a specific design of cage installed.

What sort of 'large holes' remain?

[khughes]

Thanks, that explains it well, and certainly it saves me the trouble doing it then!

you scared me there for a second, as i have a 1/2 cage installed (i was assured it would be okay since my car will be registered as a 2 seater now). I checked the NCOP and a 1/2 roll cage is acceptable(as long as it doesn't go forward of the front seats)

I know it isn't as strong as a 6 pt, but atleast it should give some side to side bracing, My cage isn't attached to the roof where the B pillar would be.. not sure if any are.. but i would assume that in extreme circumstances some flex could occur here?

not the greatest photo.. but you can sort of see the hole i am referring to

[Mat Big Hat]

kent, is going to be a dedicated track car? the reason i ask is that the absence of a b pillar may be the weak link in chassis rigidity. perhaps the cage will compensate to a degree, but there's going to be some twist depending on how much you thrash it

[aarc240]

Technically it's a roll bar with rear support legs, which is how it's viewed in NCOP documentation.

We use a similar setup but include brackets welded to the body sides and to the roof rails.

By positioning/shaping the rear legs to stay out of the rear seat occupant safety zones you can retain the 5 seat certification when lap/sash belts are installed in the front

Remove the rear seat when using harnesses to comply with the law.

Those holes are interesting!

Our earlier hardtop doesn't have them so unless they are obviously blow-throughs from welding I would suspect that Nissan changed that area to comply with crash testing.

Be careful with reinforcements - you will likely need to talk to your engineer as any changes there are going to need a good deal of thought to ensure crash loads are distributed properly. Or at least in a manner that Transport will accept.

[khughes]

It won't be a dedicated track car, mostly a weekend cruiser with a fair bit of fun on the track (maybe 2x a month).

The Car is a 7/74 model, so i am surprised if this was a structural change that early on in the cars life (though i guess anything is possible). I don't remember if the other side is the same, maybe it is as you say, a defect in welding, it certainly isn't that clean a weld. Has anyone got a later model car they can check this area for me?

Talking about crash loads, is it easy to get reinforcement bars installed in the doors and the dash area? i know this was a requirement for import cars if they did not already have them, but how easy would it be to get these put in. Hopefully it would never be needed, but if you do get hit side on, it would be nice to have a little protection (certianly worth the money for my life!).

[aarc240]

Not too hard in the doors, basically a 'hat' section with the flanges against the skin and 'ears' at each end which are either welded or rivetted to the front and rear of the inner door shell. I use 1.5mm thick C1030 bright rolled steel sheet to make them.

Lot's easier with the skin off but doable, just takes a bit of wiggling and swearing to get them in position.

They need to be reasonably close to the door latch mechanism (not the exterior handle) and work better with the later 'bear claw' latches.

Dash area, I really can't see much advantage.

However if you are referring to the A pillars being pushed in then that may be worthwhile although a lot of work.

Only way I can see would be to lift out the dash shell, add folded/formed sheet steel sections inside the bottom edge and some decent folded sheet steel corner braces / mounts from each end of the shell to the A pillar.

That way a side impact pushing the A pillar in would dump some of the load into the now strengthened lower edge of the shell. Take more to bend the shell so more energy would be dissapated in doing that rather than pushing the A pillar into the space your legs need.

The doors sound like a pretty smart move which I hadn't considered even after done them for compliancing grey imports.

Most all the mods on ours have been the old story - less weight more speed and bugger the consequences.

[aarc240]

Forgot a couple of minor points.

Make the hat section as deep as will clear everything inside the door. A length of rectangular timber makes a good test gauge for clearance.

35 to 50mm wide plus the flanges is pretty good.

Put a curve in them to get a close match to the skin shape and dab plenty of bitumen body sealer into the resulting gap after installing.

No sealer and they will drive you crazy when the skin and bar start vibrating against each other.

[Noddle]

Don't suppose anybody knows where a strut brace can be bought? (SWR was over $300 for an adjustable) if anybody has some influence, maybe we can get a few of us together for a good price?

Are you a Handy Man, have access to a workshop, welder, oxy etc..?

why not make one your self ?

I was looking into making one, done some rough drawings to get an idea what I needed, This may give you an idea on how to make one

Nigel

[khughes]

I wish i was!! it would make things 1000x easier!

[240kconvertible]

I'm very close to getting a strut brace made up custom by the engineer doing the hard yards to my K, maybe we should get together and have a bulk batch made up???

I will be getting one custom made regardless of what happens as I really need it (no surprise here) and can't be bothered doing it myself. I will post a price my engineer (cobra craft) gives to me for the strut brace shortly.

My vert should have been in the engineers shop by now but as they have been really busy catching up to the new year and I haven't finished all the welding that needs doing before it is finally ready it is booked in for the end of Feb. Fingers and toes crossed by everyone who reads this that it goes in in time.

If I could produce a propper weld I'm sure it would have been finished at the engineers by now, but the truth is I can't weld for $^!#..........if I wasn't scared of being payed out for the next few years I would post pohoto's of the welds I produce, but thats not going to happen so lets just forget about it :tapemouth

P.s I have an oxy welder in my garage (190 amp) that we can use but I don't really know how.

[Noddle]

I'm very close to getting a strut brace made up custom by the engineer doing the hard yards to my K, maybe we should get together and have a bulk batch made up???

Did the engineer create any drawing, ie Auto CAD .DWG files that I may be able to get my hands on ?

Nigel