Too Much Vorce...Part Two!

In my last post, I described how my new engine had destroyed the splines that drive the rear wheels.  I'm midway in repair now and decided to research the wheel.  I must have once known, but had forgotten, that a wheel is not one of the 6 simple machines.  A wheel and axle is!  So, I don't have a wheel problem, I have an axle problem! (for High Anxiety fans "It's not height I'm afraid of, it's parents!)".  

In this case, my wheel nearly fell off without it's axle! That clarifies the definition for me!  

Anyway, broken is broken.  So, we begin repairs.  

It took many hours of measurements to arrive at this blueprint.  This is also a lot of Aluminum to remove! 

In fact, there has not been so much Aluminum in the lathe bucket since the rivet checker project from 1997(?).

At least it's going to the scrapyard (about which I wrote a story as a teen) so it will get reused.  Aluminum is energy intensive to make but very easy to recycle.

The challenge here is to adapt my new Panasport wheels to the Honda S2000 suspension which has been installed to put the wire wheels in the right spot.  There's good and bad news here.  On the bad side, the wire wheel hubs are really long.  That means I need an almost 2 inch spacer to get the alloy wheels in position.  Had I realized that when I did the rear suspension swap, I may have gone alloy then.  The good news is, if that had gone the other way, I'd have had to order new, custom axle shafts and move the rear suspension points.  So, we turn some aluminum.

Metal turning or wood turning are very hypnotic, meditative acts.  When I'm deep breathing, I think about chips falling off of the work piece! This project gave me plenty of opportunity!  Here you can see the blueprint I'm working toward. 

A big challenge is fitting a 4x90 deg hole pattern into a 5x 72 deg hole pattern.  Actually that doesn't work.  So we're going to have to compromise some bolts.  You can see the outcome here:

It strikes me as a bit skeletal.  They are actually 1lb lighter than the wire rim hubs they replace, I guess because most of their original material is in the bin under the lathe!  Also, one bolt position had to be shared.  After discussion with a friend (Philip), I arrived at a double nut solution.  One end engages the S2000 lug nut and the other provides a spot for an MG lug.  

I'm very pleased with how they came out, and thanks to Scooby for the government work!

Above, you can see the double nut solution to the left.  Some threaded rod then becomes the last lug.  

There we go! And the wheels fit!

The front was easier but greasier!  I had to change the wheel bearings for lug nut hubs.  This involved repacking the wheel bearings.  This was the first sludgey car job I did with my Dad.  You put a tablespoon full of grease in the palm of one hand, and smash the bearing rollers down into it.  This means some clean-up!

Here's the new hub, packed with grease and in place.

And, finally, BB is back on the ground with new wheels!

Sadly, I could not do the victory drive because it was too cold for my racing tires.  They crack if you roll them below freezing because they are gummy like a school eraser.  But soon!

When I was a teenager, in the 80's, a major upgrade was to add "Mag wheels".  I guess that meant magnesium but most wheels today are aluminum.  I am impressed that BB is over 40lbs lighter and most of that unsprung mass.  The car's relationship to the road begins at the tire and then the wheel, so I am optimistic, but reality will have her say!

And, she did have her say!  This has taken so long to publish because I discovered some interference between the tire and the fender.  This was not terribly shocking as I knew I was pushing for maximum track on the rear end.  So, I removed the hubs, pressed out the studs, turned them down 2mm, pressed the studs back in, and went for a drive.  

Very encouraging that the clunking noise that I thought was coming from the S2000 hub splines, is totally gone.  I guess that clunk was what was slowly battering the MG splines all this time!  Very nice payback but there is a strange noise when I hit a bump.  Hmmm.  Did I drop a part of the exhaust?  Did my passenger side engine mount break?  Nope.  It's simply that the tire gets closer to the fender when you hit a bump.  Some chalk proved this although the GoPro video was also fun!

So I did the whole routine again.  This time I tried 3mm and things are getting close!  As I shave down the hub, the lugs project further through it.  I'm close to the pilot diameter interfering with the lug nut threads!  Also, the lugs are too long for the nut threads.  This is getting close but I intended it to be.  Maybe I should have done a 3D stack-up including the movement of the suspension but I think that would have taken more time!

Update from late April:

I had to shorten the lugs, which are apparently of uncutium metal!  That was a job.  I also lost an endmill to them.  Hopefully, that strength will result in them holding the wheels on against 1.2g of cornering force!

However, everything cinched up.  In the meantime, I discovered that the rear track is nearly 2" wider than the front track.  I guess that makes sense as I pushed the rear wheels out as far as possible when I adapted the S2000 suspension.  The custom front suspension gave no similar opportunity.  So, I added 1/4" spacers at the front.  Not even but closer.

And....BB drives fine!  Feels lighter but track time will be needed to see if that's just wishful thinking after the Winter work, or physical reality!  Updates as track time accumulates!  Keep on having #funwithcars !