Saturday, December 24, 2016

Triumph Spitfire Chassis Restoration #19

I just didn't have it in me to go to work on Friday. There's nothing going on and I have some vacation time built up, so I took it off. Breakfast with the wife, a few errands and then over to the garage for a few hours. My garage-mate was there working on his Volvo V70R. That thing is a beast. 6-speed manual transmission, 340+hp turbo-charged station wagon. Wow.

I'll stick with my 63-hp Spitfire, thank you very much! The only things I wanted to accomplish today was to get the steering rack mounted and the anti-roll bar in. Got both done (well, the anti-roll bar isn't completely installed) and another major milestone is checked off...she's a roller!

Lots of tweaks, adjustments and tightening left, but it will roll!

I started with the anti-roll bar. I previously purchased blue Polybush bushings from Rimmer's. There are a few different colors but blue is the "soft" version. These are quite a bit more than the standard rubber ones but, for this application, relatively inexpensive so I went for it. I put some Sil-Glyde on the inside of the bushings and fed them over the bar to the approximate location. I also attached the new anti-roll bar links (these are "handed"), re-using the old end studs and attempted to re-use the old bushing retainer clamps along with new u-bolts that I sourced locally from True Value. The bushing retainer clamps were too beat up, however, and I'm not sure that the u-bolts are the correct size, so I'll be ordering new sets of these.

New bushing and link.

Link hand-tightened in.

I figured out that, though I tried to be very careful, I didn't weld the new mounting bracket in at the proper spot. I'm pretty sure that I'll be able to correct the error by taking advantage of the play in the link, but it definitely doesn't fit in as well as the driver's side, which wasn't messed with. Also, I'm concerned about being able to actually get the bolts started for the u-bolt as a dry fit didn't provide a whole lot of room between the bolt flats and the frame itself.

How the new mounting plate welded in. Not obvious by looking at the anti-roll bar, but it is off a bit.

In short, I mounted the bracket a bit too far forward and a bit too far in towards the center of the car.

The untouched driver's side. Obvious how much further "back" the bracket it.

Again, hopefully I'll be able to take up the slack using the play in the link mounting. I'm more concerned with being able to tighten the bolts, I think. Given my concerns and the need for new bushing retainer clamps, I'm going to order all new hardware here and will see how it goes when it arrives. Bummed out pretty bad about this because I took a lot of care in trying to make sure I got the clamp in the right place. It was pretty obvious, however, that it wasn't once I got a different look.

But, moving on, I got the steering rack in place. I had asked on my favorite forum what the deal was with mounting it. The workshop manual calls for pre-loading the mounting brackets so as to minimize the play in the steering feel. This was easier read than done because of the minimal contact surface available to prying stuff out. I was able to use three clamps, reversed to make them spreaders, and get them arranged this time to provide some tension.

Clamp contraption.

I then tightened down the mounting brackets to provide a snug, but adjustable, fit and tweaked on the clamps some more to get the required 1/8" space between the mounting bracket and the steering tube plate.

That's about an 1/8'.

After that, I put the front wheels on and got myself my aforementioned roller!


Yea!!

I had mentioned the incorrect brake clip in my last post. I got my old one cleaned up and got it installed. I'll be getting another one from Rimmer's in my next order as they are the only ones that I've found to carry it.

Brake clip installed.

Next was the steering joint. This is one hell of an engineered piece for what it seems to accomplish. Though these are still available from Rimmer's, if you order one over here, like from SpitBits, you'll get a regular steering knuckle. Not quite sure why Triumph designed the thing this way, but lets break it down a bit and see.

The original steering joint.

There are three main parts of the joint. Two appear identical (I didn't really look to hard too make sure) and in between these is a disk. The three parts are held together with four bolts, a pair of which are lockwired together at the threads.

The use of the lockwire holding the bolts together is an obvious safety concern. We used the stuff in the Navy quite a bit for vibration and shock resistance for critical parts. It would really suck to have your steering joint come apart on you so that my vote for its use here.

There are also rubber grommets around the four bolts that completely isolate them from the center disk of the joint. I figure this is for vibration dampening to the steering wheel from the road.

Finally, and something I didn't expect to find, was a grounding wire that was twisted and mounted between the two knurled fittings on one side of the disk, hidden from view. It took me a minute, but I figured this out pretty quick.

The little grounding strap that could.

A vehicle's electrical system, at least for the Spitfire, is a simple 12-volt system. Like any electrical circuit, for current to flow and work to be done (like lighting a light, for example), there has to be a complete path from the supply to ground. So, a simple circuit to turn on a light could look like this:

Doesn't get more simple than this...except for the switch, maybe.

This picture shows electron flow, which while correct, may be opposite of what you are used to seeing depending on when you went to school. Essentially, however, for this circuit to work there is a wire from the battery to the bulb, and from the bulb back to the battery. In your vehicle, however, that would add complexity and about double the amount of wire, increasing cost and the chance of something breaking.

Instead, a vehicle's electrical system uses a common ground of the chassis. That way, instead of running an individual wire from every circuit back to the battery, you can run a much shorter wire to any point on the chassis and use it to act as the wire, saving money and complexity...and probably some weight, too. This circuit would look something like this:

Sorry, no cool animations.

In this case, the return conductor is the vehicles frame, body, whatever. And, since it is all a big hunk of metal and will conduct electricity, the returns can be separated by a huge distance with no impact on circuit operation.

Now that the basic electricity lesson is done, what does that have to do with the Spitfire's steering joint? Well, the steering column is resiliently mounted to the body (in the tub) for vibration control. This means the use of rubber or plastic, neither of which conduct electricity. On the steering column, however, is the horn, turn signals, headlights, and maybe an overdrive switch (if you're lucky enough). All of those switches need a chassis return path to work.

On the steering rack, at the steering box, is a ground point for several components on the front of the car. The ground wires all tap into the grease cap on the steering box.

There's a plug that goes in that threads into that hole, under which go the ground wires.

To provide a return path for the switches on the steering column, down the steering shaft, through the rubber-isolated steering joint to the steering box, that little ground strap is used. Whew...

Steering joint completely exploded.

After that, I didn't have a lot of time to dig into something new so I took a look at the motor again. Since I've been studying up on rebuilding it, I figured out that I should have been a bit more careful in spots while taking it apart. My biggest initial concern was that the main bearing caps are not only location specific but orientation specific. While I made a note of which cap came off of which bearing, I did not make a note of its orientation. I wanted to look into that.

As you can see, my concern was for naught as it's quite obvious which way the main caps are installed.

This is the correct way.

I didn't expect to be able to so clearly see the difference in just flipping the bearing caps around. All three main caps were similar.

This, is not!

Another way to tell was that each bearing cap was marked with a series of dots to denote if it was #1, #2 or #3. I doubt it's by coincidence, but while there were no matching marks on the block itself, each of the match marks on the bearing caps faced towards the front of the motor.

Bearing cap #1.

Bearing cap #3.

Another way that I could tell was the "shadow" the bearings themselves cast on the block and the caps. This is a bit hard to explain what I mean, and I didn't take any pictures of what I'm trying to explain. Suffice it to say there are several methods for making sure that are going in as-built!

And that was it. We are traveling for the holidays so there won't be any work done for a week or so. I do have Dorothy's parts Christmas list all filled out and ready to go and I'll be placing that order either tomorrow or Monday so everything is here waiting on me when I get back.

In the meantime, I hope you all have a Merry Christmas and a Happy New Year. Thanks for reading!

2 comments:

  1. Merry Christmas to you. Thanks for your loyal posting, entertainment, and education. You have some good momentum for 2017.

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    1. Thank you, John! Merry Christmas and a Happy New Year to you and yours.

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