Chassis - cracked

[andy-white]

Hi,
Just wondered if anyone has come across this before - well spotted by eagle eyed mot tester.

[pic] http://photos.fotango.com/p/eba00287265f00000005.jpg [/pic]

I've heard rumours of chassis cracks before but never expected something this dramatic! It seems way beyond DIY repair - i have spoken to richard thorpe and tower view who are of the standpoint that the section needs to be cut-out and replaced with the aid of a jig to ensure correct alignment of the suspension mount.

It might be worth checking yours out next time your under the front end!!!



>>> Edited by andy-white on Monday 14th February 21:40

[planman350i]

sorry to hear of it - looks pretty small though. If its any consolation theres a few welds in my chassis. I've got the receipts from RT to prove it!

[andy-white]

Small - in this case 2 inches is more than enough

I'd hate to see much worse so near to a suspension mount. Have you got a pic of a REALY bad one? (perverse interest!)

[planman350i]

I've no worse pics to show (did not realise red line is full extent of crack!), but can repeat choice parts of my history if its any comfort:

"chassis renovation shows rear outboard chassis mouting plate rusted away"

"hole in rear subchassis tubing at nsf corner"

"crack in nsf chassis found!!!"

"replacement tubes welded in to chassis at osf and nsf, top tubes reinforced"

I can only presume from above that cracks are pretty common place (or mines a particularly bad example)!

p.s. good luck with repair.


>> Edited by planman350i on Monday 14th February 22:35

[FrenchTVR]

Mine has had both front upright/diagonal tubes repaired by the previous owner. I replaced the cross tube where the diff mounts onto the spine as it had rotted out at the bottm. Surrounding tubes were solid. Also repaired a break in the chassis next to the o/s fuel tank. It had been "repaired" before but the copious quantities of weld around the break hadn't actually done any good.
I have just found another couple of cracks in the outrigger to spine joints. Here & Here
I believe that once they start to crack you end up chasing the stress cracks around the chassis.
I am currently rying to get hold of another chassis. Either a good one to replace mine with or a ropey one to make a jig from.

As previously said, good luck, you are not alone

[350matt]

Just grind along the crack to get good penertration, and weld it back up, then whack a plate over the top and seam weld it, best to do this with the bottom wishbone removed to minimise any residual stress.
Mine has a few cracks, mainly where tubes join each other, I buzz-em back up then gusset that corner with 1/8" plate - tends to stop them coming back.

Matt

[FrenchTVR]

350matt said:

gusset that corner with 1/8" plate Matt

Thats what i'm planning to do, also intending to do that with the new chassis, get it blasted, gusset it out and repair anything that needs it, then galv and powder coat.

[rev-erend]

Nah .. bit of filler with under seal on the top ..

Only kidding : I'm with Matt on this one.

I'm sure Richard Thorpe's solution is the best but Matt's solution should be adaquate ..

[Graham]

Yep that happened to me on the racer. you also need to check where the turret joins the chassis tubes at the top.

mine cracked at the bottom and pulled away from the tubes at the top. the turret in effect twisting forward. the wheelbase was 2 inches longer on that side !!!!

plus i think there was another crack half way up the turret...

so make sure you have a good look at everything

G

[richa]

Been there, done that

Here's my 'before' cracks (OS outrigger joint with 'backbone'.


And this is the repair, with extra bracing.


Rich.

[rus wood]

My 390 (pre A frame) had persistant cracks where the rear outrigger support joins the rest of the chassis - the fuel pump etc are mounted on this bit. Terry Lendrim (spelling ?) faxed me a mod that was welded on by my local garage - no more cracks since. I would have put this down to excess driver gravitas because the cracks were right under my A**e, but the passenger side went as well.

I also had cracks at the front end but this was solved under warranty by the factory by replacing the whole front.

Russ

[andy-white]

Frankly I cant believe cracks are so common place! Makes one wonder if tvr bothered doing any fatigue anyalysis when they designed the chassis.

I have the facility to do as mat says, weld and plate the thing, but I was a little nervous doing so given RT’s comments about jigs e.t.c. I was happy at paying the £500+ to sort the problem once and for all but if its going to keep happening in various places I think the cheap fix might be the better option.
The crack hasn’t spread through the plate entirely so I cant see it having moved.
Welding it up should be ok

[kevinday]

andy-white said:

Frankly I cant believe cracks are so common place! Makes one wonder if tvr bothered doing any fatigue anyalysis when they designed the chassis.

Andy, that's a bit unfair, your car is over 15 years old now.

[350matt]

Fatiique analyisis????? in '80's???? by TVR??????? Come off it, I doubt its done even now. Bear in mind the chassis was originally designed to take Pinto power and bunging in a rover V8 was more of a spur of the moment thing, if things didn't break in the first 100miles, then off they go.

Here you are Sir your new car ....let us know how you get on with it..

Matt

[suffolkfox]

Have to say the 'project' also had a darn sight more than cracks. As suffolkfoxy was reversing it up the drive I thought she'd got a flat tire on one side. When I looked, the rear outrigger tubes were cracked, and the offside one had snapped and had dropped by virtually the thickness of the tube . Propped up using jacks, measured alignment all round and checked angles, then shielded the fuel lines and welded up with FAT welds as a temporary measure. Russ, if you still have the info regarding your weld-up I would be interested in a copy for the final bracing job.

[2 sheds]

Big wedges are prone to cracking especially with big front wheels, i have seen / heard of several SEACs cracking here , all had 16x9 tuscan wheels which probably didn't help.

Tim