In an earlier post, I described bowtie6‘s frame failure.  Today, I have some pictures of the “issue”.  First, a little background…

Rear suspension

Rear suspension closeup

Soon after bowtie6‘s initial dismantling the frame was carefully inspected.  Although the frame was in excellent shape the rear differential mounting pins showed typical TR6 wear and tear: two of the four differential mounting pins were cracked.

Since a bigger engine was to be installed, we reconfigured the rear suspension.  A completely redesigned mount was made to hold the Nissan R200 differential as well as the coilovers that would replace the lever action shocks and springs.

The pictures on the right show the rear suspension from the passenger’s side.  You can see the coilovers, rear disc brakes and the suspension mount holding the top coilover perch.

This brings us to the following photo gallery showing the frame damage.  The frame rail has suffered a serious, unrepairable stress crack.  I have inspected the driver’s side and there too, I can see a stress fracture although it is not as severe as the one on the passenger’s side.

I’m sure there will be plenty of critics analyzing the frame failure from these pictures and coming up with all kinds of root causes for the failure.  Quite frankly, the thing is what it is.  I got 15,000 from what I thought was a very good frame but this endevour has proven to be more than this frame could handle.  The extra power the engine gained from the cam and head work plus the stress of getting hammered by the control arms caused the frame to eventually expire.  Since the rear failed this extensively, I have reason to believe other parts of the frame have also suffered stress.

As soon as the frame comes out again to see the light of day, I plan to do a full autopsy by cutting it up and documenting stress points, failure points and basically show where the frame held up and where it did not.  I’ll have that in a future article which should be very interesting to read.

And now for a little reflecting…

These frames are now 35-40 years old.  These frames are also marginal at best.  Sure, with the anemic tractor engine on the stock TR6 the frame will probably last, but not by much.   However, if anyone is thinking of adding any real horsepower then really think what you are planning to do.  These frames can be reinforced to hell and back (done that), boxed-in (done that), have gussets added (done that) and have every weld reinforced (done that), and yet they will fail.  Quite frankly, I am very happy this thing gave up the ghost – now a new frame is being built to last and handle the new ECOTEC engine with no “issues”.

All good things come to an end.  In this case, the “original” (and I say that loosely) frame has endured a frame failure.  Yep.  There is a tear several inches long on the passenger side along the rear suspension mounts.  Upon closer inspection the driver’s side has stress marks and I’m sure it is not far from failure too.

I noticed the problem back in November of 2010.  While driving, I started hearing some unusual sounds and sure enough after putting the car on jackstands a close inspection revealed the tear.  No pictures yet, but I’ll have some soon.  Suffice to say, the frame is toast and there is no way to repair it.

Unfortunately, the TR6 frame is extremely flimsy and quite frankly it is poor at best.  And no, I’m not saying this  because mine failed.  I’m saying this for the benefit of those folks that think they can put larger or modified stock engines and the frame will be able to withstand the extra power.  Well, if you believe that you are fooling yourself.  These frames are made of 10 gauge material and is not of the best design.  It is a “U” shaped affair with an extra plate, spot welded.  Add to that years of rust from within the tubes and you have a recipe for failure.  My frame was in excellent shape when I started the project and was reinforced and properly prepared.  Even after all that attention, it failed.

I’ve had several people ask why “original” frames have held up with V8’s and mine failed.  I guess it boils down to the fact that I have put 15,000 miles on my frame and have actually stressed it enough to cause it to fail.  So if you are considering something like what I have done with bowtie6, I would highly recommend thinking all your options.

And so the next step in the evolution of bowtie6 begins…

A new, bespoke frame is in the works.  The new frame is being made of square tubing with fresh stock.  No expense is being spared on the materials.  The frame will use the factory stock front suspension components with one big difference:  the springs/shocks are being replaced with true coilovers.  The great advantage of this will be there is no more need for a spring compressor since the coilover is not only adjustable but fully encapsulated and there is spring under tension to worry about.

As far as the rear suspension?  The crappy factory trailing arms will be ditched along with the Nissan diff currently in bowtie6.  Instead I will be using an 8 inch solid axle, with four point suspension, coilovers and swaybar.  Why?  Well, the IRS is really not an option.  For the expense of new halfshafts, new diff, and all the extra “stuff”, I can have a fully posi-traction custom built solid axle that will withstand plenty of horsepower…

Which leads to the next major improvement…

Yes, bowtie6 is getting a new engine.  The 3.4 litre V6 currently in bowtie6 is pretty much maxed out.  There is no more I can do to it.  Plus the ECM is not programmable.  So what are my options?  A brand new ECOTEC 2.4 litre 177hp crate engine and matching 5 speed gearbox has been sourced.  ECM reprogramming?  No problem – this engine’s ECM is fully re-programmable.  Needless to say, the sky is the limit…

I’ll have more info on my ECOTEC in the next installment.