Tuesday, June 5, 2012

How To: Eat an Elephant

Another month has passed beneath the old chassis and I am slowly acclimating to the slower, more deliberate approach toward making progress on my Boss.  Inversely, I have “water over the gunnels” to an extent as I have endeavored to evolve the design and execution of the 4-link rear suspension to better compliment the proven function of the coilover front suspension I have for the car. 
Balance:  That’s the word.  The goal is to create a beautiful balance between the function and performance of the front and rear suspension systems.  As with most things, it is rare that those two systems are equally contributory in the equation when modifying a vehicle in the way that I (and countless others) have chosen to do.  I will not be satisfied unless my car performs as well as planned. 
Perhaps that is one of the reasons that draw “car guys” to the art.  Perhaps it is one of the last remaining frontiers where your “art” is as individual as your signature.  It becomes a part of you; a physical manifestation in metal and glass that represents who you are to a certain degree.  Whatever it is, I have come to love everything about it………..oh so many things.
The last month has been a flurry of small activities that are finally starting to show results of a larger proportion……with a few twists in between.  The biggest disruption to progress was a somewhat unexpected week in Europe dictated by my “day job” working on the new SRT Viper V10 engine program.  But hey…….a guy’s gotta do what a guy’s gotta do.
Custom Bilstein Rear Coilovers
A few months ago, I had the opportunity to run the rear shocks included in my 4-link suspension kit on the shock dyno and determined the damping curve to be less than required to achieve the suspension performance I required.  Further, the progressive rate rear springs were also not quite what I needed to get the system working together with the front suspension.  Since the “kit” shocks cannot be adjusted and the “adjustable” shock options that were offered were less than impressive, I decided to have a set of custom made Bilstein shocks made that would fill the bill and allow more adjustability on ride height as well as damping forces.  While the cost to do this would be rather considerable, the end result will be a much higher quality damper system that will match the front suspension in performance and function (read: Balance).  Coupled with that, these new shocks will allow me to use off-the-shelf racing coil springs of the exact rate I need to match the front suspension frequency on the dot.
After a few months of waiting, the shocks finally arrived and I am happy to report they look fantastic!  I will need to make some minor changes to the mounting scheme at the top and bottom, but they will fit like a glove and should work extremely well.  At the same time, I upgraded the spring seating hardware at the top and bottom of the shock to much higher quality pieces with some nifty features for good measure.  At this point, I am very happy with the shock combination I have and feel confident that with careful selection of the rear coil spring rate, I can get the suspension system working better than would have been possible using lesser components.

The custom made Bilstein rear coilover damper that I now have will replace the less capable damper shipped with the 4-link kit I purchased.  You can see the vastly increased ride height adjustment range in the Bilstein threaded body and each end of the damper has a precision spherical bearing rather than a comparatively soft bushing.  Everything about the Bilstein speaks of quality and capability and when valved to the application, this combination should be an outstanding performer.

If you like "cool" like I do, you will appreciate these adjustable spring seats.  This small cantilevered locking tab is simply toggled to allow most ride height adjustments to be made without tools and when the perfect height is set, you simply close the tab to lock the spring seat to the shock body.  Brilliant!

With the locking tab closed the spring seats are securely locked to the shock body.

Race quality parts on the street.  These upper spring seats appear on all four corners of my car and include these "diaper pin" safety clips on each upper spring seat location.

Steering Column Upgrades for Rack & Pinion Steering
As progress ebbed and flowed on rear suspension work, I decided to tackle some changes to the steering column configuration required for the future installation of a rack and pinion steering system.  The supplier of the steering kit included a needle bearing and support for the lower steering shaft that looks nifty in concept.  However, the idea of running a needle roller bearing directly on a mild steel, unhardened, welded seam steering shaft goes against everything my engineering mind could handle. So, in my usual “if-I-don’t-like-it-then-I’ll-invent-it” method, I designed up a ball bearing shaft support that uses a conventional, readily available ball bearing that fit the bill nicely and ensured the lower steering shaft would not be required to sacrifice itself as an inner bearing race, risking future failure with little warning.  This also keeps the bearing easily serviceable.  After a few hours on the lathe, the bearing and support were assembled and fit to the steering column with great success.  I finished the job by installing the universal joint included in the kit (nice piece) and the upper steering shaft and bearing.  The column now turns very freely and quite smooth with minimal effort.
I positively hated the lower steering column bearing solution supplied with the rack and pinion steering kit I purchased.  As such, I designed and machined my own solution.  My design uses an off-the-shelf double sealed ball bearing for shaft support and is pressed into the bearing holder.  The whole assembly is then bolted into the lower column tube for a secure assembly.  This shot shows the complete bearing holder assembly ready to bolt into place.

From the back, you can see the details of the holder and retention screws.

I prepared the inside of the column tube with a tootsie roll sanding plug on my die grinder to remove all burs and weld seam fuzz.  I drilled the three mounting screw holes prior to powder coating the tube.

Here is the lower steering shaft bearing assembly bolted into place.

And finally, the lower steering shaft universal joint is installed per the rack and pinion kit instructions.

A close-up view of the lower shaft bearing / u-joint interface.

New HTP Invertig 221 AC/DC Inverter Welder
Yep…..I finally pulled the trigger.  After several years researching and driving TIG welders of all shapes and sizes, I finally took the plunge and purchased a new, inverter-based, TIG welder!  I am not sure I have ever researched a tool purchase more than this one to be honest.  At the end of the day, I wanted to be sure I made a purchase that offered the maximum capability available with the best customer support, warranty and reliability.  At the same time, I have closely monitored the evolution of inverter-based welders and became convinced that the increased capabilities and features of an inverter were worth the extra investment, but the penalty was a cost factor roughly twice what a conventional transformer machine would carry. 
I researched all of the major welder offerings from Lincoln, Miller, ESAB, Hobart, etc. in both transformer and inverter designs.  I eventually drove all of the machines I could get my hands on and can say that none of the name-brand machines were particularly deficient in any area.  Some were definitely easier to use than others and some had more “little’ features than others, but all were pretty good overall.  Ultimately, I purchased the top-end Invertig 221 offering from HTP.  This machine weighs a scant 40 lbs. yet packs a whopping 220 amps of welding power.  Also, every single part of this machine is absolutely top quality; from the CK #17 torch, to the finest pedal I have ever seen on a commercial machine, to the best ground clamp in the business.  No junk here!  With a little study in the manual, I was able to light up on some steel scrap in the shop with little drama and start laying reasonably decent beads straight off even though it’s been over 20 years since I last drove a TIG machine regularly.  This machine is truly impressive.
HTP is an American company headed up by a straight-shooting gent named Jeff Noland.  I met Jeff a few years back at a trade show and he allowed me to drive all of his welder offerings and answered any questions I had.  To this day, I have been able to get Jeff on the phone whenever I had need to and he has always come through with answers in a most professional manner.  In fact, everyone on his staff that I have ever dealt with was exceptionally helpful.  Couple this level of customer service with an outstanding, no-questions-asked, warranty AND a machine that outperforms all other machines in its class and the combination is one I felt very comfortable investing my hard-earned bones into.  Check out HTP here:  HTP Invertig 221H
Knowing that a lot of the remaining work ahead of me will require more welding precision than a typical MIG welder can provide, I can now focus on learning the intricacies of this new TIG machine in preparation for the more delicate work ahead.  And you never know…….it might come in handy down the road on a “paying” job.  In the meantime, I plan light-up on just about everything I can to get into the groove of TIG welding as quickly as possible.
There it is!  The HTP Invertig 221H is a compact and very powerful TIG welder that took me several years to justify.  Now I have it and I am thrilled to get to work!

The simple control panel is very high quality and is protected by a polycarbonate shield when welding.

At only 40 pounds, this TIG machine is remarkable small, even compared to my Lincoln PowerMIG 180C MIG welder.  But don't let the size fool you!  This machine packs a full 220 amps of welding power yet only requires a 30-amp breaker.  Nifty stuff!

So as the title suggests, as my frame of reference continues to refine itself and I realize the cumulative progress that is made by linking all the little jobs together, I have discovered the secret to eating the proverbial “elephant”:
One bite at a time.