Mustang V6 Autocrosser named Mistress

I still think this should be a GRM project car.  You could easily get at least 5 articles covering this build.  Hold out for big bucks.

Have agreat holiday season!!

Over the course of the past couple of days I've read your entire thread from start to finish. What a read! Incredible work developing the car, and I love the analytical process and write-ups throughout. I hope you enjoy your retirement and get to enjoy the car for years before it becomes time to stop autocrossing. I feel like it's well deserved!

Thanks guys. I have a lot of fun writing these things. I am glad someone finds them useful and/or entertaining.

No One is Laughing -

Tow Hitch

Over the last 40 years I have had trouble with my left knee (my old diaper changing injury – another story). The knee was finally replaced two years ago leaving me with some lack of flexibility during the recovery. Climbing up on the trailer to get Mistress on and off was getting to be a little tricky. I reasoned that a winch on the trailer would save me climbing up and down. It could also be useful if the car broke down at an event. I have a “come-along” but that is tedious for routine use.

I put a small winch on the trailer to pull the car up. Nothing special. It has long jumper cables that can be run directly to the truck battery as needed.

I needed a tow point on the car to attach to. As is my way with things - I made one.  I wanted something unobtrusive, almost hidden. What I came up with was a simple ¼” rod bent in a “U” shape and welded to a bracket bolted to the front frame. I reasoned it did not need to be exceedingly strong since I was just pulling the car up a ramp. I calculated the maximum load it would see was about 2000 pounds based on the weight of the car and some geometry. It is not like we were pulling a wrecked car out of a ditch or something.

I was very wrong. The max load happens when lowering the car off the trailer. The car stops rolling for a moment, cable goes slack, car starts rolling, cable goes tight… Tow bracket snaps in half (ping!).

First event of the season and Mistress is rolling itself untethered off of the trailer towards someone’s pickup truck.

I leapt into action! On the second step I was realizing there was nothing I could do and that this was not going to end well. The third step was trying to regain my balance. The fourth step never happened.

They say you can tell how old you are by how much people laugh when you fall. Toddlers are a riot. In this case, no one was laughing.  I landed on both extended arms which promptly collapsed and planted my face hard into the asphalt.

People came running. I could not move at first. Calls to 911 were in the works when I was able to struggle to my side and was helped to lean against the trailer.  Somehow my arms and shoulders were not broken although they took quite a shock. Fingers not working at first. Face bleeding. Sunglasses mangled. Stunned but, somehow, I think I am alright…  No 911 call.

As Mistress rolled off the trailer it turned itself and rolled harmlessly onto the grass.

After sitting there for a while answering questions about how many fingers were being displayed, I was helped to my feet, patched up, and proceeded on a slow and slightly wobbly course walk accompanied by a couple of friends would not let me out of their sight. I was never alone the rest of the day.

The reasoning was that, if I stayed at the event, we had several medical people in the club who could watch me. Better than loading up and having issues alone on a country road two hours from home. Made sense  at the time but when I got home that evening my wife took one look at me (you idiot!) and drove me to emergency. No further issues found but I missed the next event and it took most of the summer to fully recover.

So… I needed a right and proper tow loop on the car. I bought a Competition Engineering C3435 from Summit. This is a robust 5/16” steel plate with a hinged burnout loop of the same material. You could probably pick up the car with this thing and shake it. Except, the car is made of sheet metal.

There is nothing robust on the front of the car except the bumper and I did not want to mount that high to work with the winch on the trailer. The winch is mounted fairly low and the angles would be all wrong for the last few feet. It is a short trailer.

The plan was to insert a heavy backing plate inside the radiator support frame for the tow loop to bolt into.

I started with a piece of 3/8” plate cut to match up with the tow loop.

This would be placed inside the radiator frame on the right side. There is a narrow opening on the frame at the bottom right corner where it could be inserted. But it has to be precisely placed and held in position to get the bolts into it. To allow this I used a 3/16” rod with a sharp bend in the end and tack welded it into a hole drilled into the corner of the plate.

Now I have a “handle” to insert the plate and hold it in position.

Using the tow loop as a template I drilled and tapped the backing plate.

This did not seem to have enough thread engagement to be utterly fail proof so I welded Grade 8 nuts to the plate after aligning them to the threads using dummy bolts. I know the temper on the nuts is gone but I now have over ½” thread engagement.

The angle of the radiator frame put front of the tow loop too high on the car behind the facia. It also hit the intercooler. I knew this would happen and had a plan for it.

A manual hydraulic press is one of those shop tools you wonder how you did without for all those years.

You have to be careful with these things. The forces can get extremely high. This tool can snap those Harbor Fright C clamps in an instant and imbed shrapnel where you don’t want it.

With my tow loop bent as needed I completed the assembly with 3/8” Grade 8 bolts. I cut the excess off of my “handle” on the backing plate leaving just a bit sticking out of the opening in the frame.

I may have to rework it if I put a splitter on the car but we will figure that out when the time comes. In the meantime, this thing would rip the car apart if enough force were applied. It is placed right where the winch needs it and is almost hidden. Should have done it up right in the first place.

Brake Line Replacement – Antilock Brakes

You may recall that when I installed the supercharger I was bitching about how the antilock brake module had to be relocated and that it left the brake lines in a tangled mess. I finally got into fixing it last spring in conjunction with the radiator replacement. The entire front of the car was opened up exposing all the plumbing. It seemed like a good time to make things right.

This was not without some trepidation. I have never worked on this part of the braking system before and the warnings of “only the dealer can properly bleed the antilock brakes” were not lost on me. The nearest Ford dealer is more than an hour away from here. But it needed to be done and: 1 – I figured I could figure it out. 2 – The local car shops are very good. 3 – You can actually buy electronic tools to do this now.

When it comes down to it: You need to fake out the control system to cycle the antilock valves while actually bleeding the brake line at the same moment. We got this. I started the job.

First thing – I made a chart of where all these lines went. You could theoretically do one line at a time but in reality, they are all bundled together and you have to take more than one off to get them past each other. Getting them crossed up would be a nightmare. Make a sketch.

It is ugly but it served the purpose. At first I was going to just splice in short bits around the antilock module. After messing around a bit I decided to replace everything on the front of the car. The lines that run to the rear wheels have splice joints in the front wheel wells.

Notice the fittings are “poka yoked” (error proofed) so they cannot be cross connected on the assembly floor.

I bought some copper nickel line (easier to bend) and a brake flaring tool from Summit. I immediately had trouble.

The tool would not make proper flares. I played around with-it making flares until I could mimic what was on the car using a large thick washer as part of the first step.

Turns out I had two problems: 1 -  The dies on the tool for “Step 1” & “Step 2” were labeled backward. If you use them as labeled you get some of the weird flares shown below. 2 – Most of the flares on the car (but not all of them) are “bubble flares” not double flares. I was using the wrong tool.

The black piece above is an original from the car.

The flares I ended up with by using the tool backwards from its design and adding an extra step were actually double bubble flares. They had the exact shape of the original bubble flares but were actually folded over in two layers on the end of the bubble. I would say they are stronger than actual bubble flares. And they did not leak.

By the time I was finished with the project I had figured out the miss-labeled die issue and could also make proper double flares with the thing. This was good because Ford was not consistent. Some of the connections ARE double flares.

Worse than that, some of the fittings were English, some were metric, and on opposite ends of the same tube. EGAD! What were they doing over there at Ford?

I figured this out when some connections would just not fit up right. My new fittings from Autozone were not making up properly with some of the originals. Dangerously similar, but not exact. I finally took a caliper to some fittings and noted different measurements. Now I had something new to keep track of.

If you read about doing brake line work on these cars there are dire warnings about all this. Yup. It is true.

I finished all this work and then did an extensive brake bleed while cracking fittings along the way to get as much air out as possible. Then a leak check. This is when I found a couple of the English/metric fitting mismatches noted above.

To do the leak checks I put a couple of clamps on the brake peddle to hold it down for a couple of hours and then checked if it still had pressure and inspected for leaks.

I then had to put this on hold for a month while I did the radiator job. With the radiator installed it was time to finally do a proper antilock brake bleed job. At this point the brakes were very soft and spongy. The car was not drivable.

So – Air is trapped inside the antilock module behind the little valves that pulse the brakes when the tires skid. This is also part of the traction control system. There are four little valves, one for each wheel.

Some cars have little bleeders on the antilock module allowing you to manually bleed the unit. Some cars do it automatically. This car has none of that.

Without special equipment you have to find a way to make the control module think it is happily driving down the road while it has one or more wheels skidding as the brakes are applied. As the car tries to recover from the “skid” by pulsing the little valves you have to bleed the brakes.

Driving on ice with loose bleeders spewing brake fluid all over the streets comes to mind. Probably not a good idea.

Riding on a creeper cart under the car while bleeding the brakes? Hmm, Car is too low for that and death is all too likely.

Ahh – Once again having a midrange scissors lift comes in handy.  And I have an old Harbor Freight diagnostic tool that can reset antilock faults (most diagnostic tools can’t do this). Speed bleeders (they have check valves in them so air can’t get back into the lines) come in handy also. In fact, they are necessary for doing this safely (see below).

Here is the set up: Remove one of the rear rotation sensors and let it dangle (now the controls think that wheel is not turning). Car is on the lift with all wheels removed. Engine running, in gear. It thinks it is going down the road at about 20 mph.

Open the bleeder on the wheel with the sensor removed. Have someone gently apply the brakes (my wife gave up a whole afternoon for this joyful exercise). The car will chatter the antilock valve for that wheel allowing the air bubbles through. Then shut down and bleed that line all the way back to the wheel (you have to purge the bubbles that were released). Put the rotation sensor back in position, and do the same for the other rear wheel.

So - All ya gotta do is reach into a spinning wheel well in an operating car... See some warnings below...

At each step in the process you have to reset the antilock module faults that will come up. Otherwise, the antilock system will stop working after the first attempt.

The front wheels are easier. They are never turning so you don’t have to mess with the sensors.  Otherwise, same procedure, car is in gear, thinks it is going down the road, brakes applied as brake is bled. Then purge the bubbles out of that line and reset the faults.

I went through this entire process twice. Used about a gallon of brake fluid.

And it worked! Antilock brakes bled and were fine all summer. You don’t need a dealer or a shop. You just have to be innovative, patient, and stubborn.

SAFETY - The operating car in the air has risk but it has no wheels on it. Secured on four good jackstands on pavement it is not likely to fall and if it did it would not go far. 

The risk is reaching past the spinning wheels. This is hazardous. Short sleeves, hair tied back, etc. are good ideas. Keep your wits about you and move deliberately. The moving wheels will not stop if you get caught in them. They won't even slow down a little. 

In fact - The speed bleeders could be considered an important safety device here. You can open the speed bleeder, put the car in gear, pump the brakes and take the car back out of gear to close the bleeder. Otherwise your arm is in there working the wrench the entire time. Even at idle speeds the wheels will kill you if given a chance. Don't give them the chance.

You also need the proper diagnostic tool to reset the antilock faults. 

This work was completed about a week before the first event. I was running out of time and not sure I would be successful. Even getting the car into a local shop was “iffy” because they all have a long backlog. Hate to admit it but, as insurance I bought a tool that can automatically bleed the antilock brakes on this car.

It is still in the box.

Pully Alignment Issues

Last season I had issues with the serpentine belt popping off in mid run. This happened several times wrecking the $25 belt and also wrecking the run. I started keeping two or three spares and changing them for every event.

On reflection this started happening after removing the AC compressor and replacing it with an idler. But at about the same time I also changed the power steering pulley to a larger diameter. This was to overdrive the pump and make the car easier to steer with all that caster dialed in to the front suspension. Something is not lined up with something else.

So - How accurately do these eight pulleys need to be aligned with each other?

We are dealing with a six-groove rubber belt stretching over eight pulleys. One of the pulleys is a spring tensioner that should take up any slack. Why does the belt come off in the first place?

Since this is an autocross car the engine RPM is constantly changing rapidly. That is the key. The centrifugal supercharger is also constantly changing load varying from perhaps 40 HP to near zero and back again. This means that the belt is constantly stretching and shrinking.

A hard gear change or touching the rev limiter jumps several hundred RPMs in an instant while putting enormous instantaneous load on the belt (and the valve train, and the drive train). A snapping rubber band moves quickly but still takes time to snap. The spring loaded take up pulley has inertia and also takes time to move. Not a lot of time, but it is not zero. Parts of the serpentine belt will go dead slack for a moment through these transitions.

Worse than that, the belt is whipping around the pulleys, and the centripetal force is trying to pull it away. It is being flung off with every curve.

So, the belt is entirely disengaged from at least some of the pulleys every time I shift gears and squawk the tires. As the belt wears and loses some of its integrity (stretches more) the same happens while spinning the wheels out of a corner.

The belt is “thrown” constantly from one pulley to the next. The pulleys have to be aligned well enough to “catch it” when it is thrown.

The six grooves on the belt are 4 mm apart. To catch the flying belt each pulley should be aligned within half that distance to the previous one. Or we could just say get them all within 2 mm of the crankshaft and be done with it. There is our target.

Two mm (0.08 inches) is not in the territory of laser alignment, dial indicators, or even calipers. You can see it and measure it with a good scale. But you need a good reference point and that would be a good straight edge.

What I used for a straight edge was aluminum tile edge trim. Most building supply stores have it in six-foot lengths. It is very light, easy to cut to length and, if it has not been beat up, very straight.

How straight? Checking a piece against the bathroom mirror – Very straight. I would say that it is withing a couple of thousandths. Good enough for this. And it comes in all sorts of designer colors! I chose black.

I made two pieces for short & long measurements.

The various pulleys all have different thicknesses on their edge flanges. Some are stamped steel, some phenolic, some machined aluminum. The cast aluminum harmonic balancer on the crankshaft has the thickest edge. With my short straight edge held against the flange of the harmonic balancer the belt measures 7 mm away.

Seven mm is the reference. In a perfect world the belt would measure 7 mm from the straight edge at the entry and exit from each pulley.

So here is the first round of measurements:

Pulley                      Gap (mm)           Miss-alignment

Crank                                   7                             0

Power Steering                8                             1

Alternator                          7                             0

First Idler                            5                             -2

AC (New Idler)                  3                             -4

Supercharger                   7                             0

Tensioner                           6                             -1

Water Pump                      -                              -

And we have a winner! The new idler replacing the AC compressor is way out of whack. It was also not parallel to the overall plane of the other pulleys.

In the photo below you can see a gap between the straight edge and the pulley near the bottom. But the straight edge is touching it at the tip (where the white line is painted on).

Not only is this pulley out of place to catch the belt it is also throwing it crooked to the next pulley.

The misalignment was easily solved by adjusting the rear mounting bolt holding the pulley bracket.

I used some numbered drill bits as thickness gauges to guide me as to when the pulley was parallel to the straight edge (I don’t care what the gap is as long as it is the same in both places).

The drill bits are easier to use than feeler gauges in this situation. Keep adjusting until you can find a bit that is barely touching both sides of the pulley.

This got the pulley aligned but it needed to move about 3 mm towards the engine. I could not do this adjusting the bracket. It is doweled in place.

I had to adjust the bushing behind the pulley.

Neither my local hardware nor Amazon had a suitable part. I could either grind the bushing or adjust how the bearing is pressed into the phenolic pulley. I decided to use the press because if I went too far I could always push it back a little.

I did not have a die to match up with the outer race of the bearing. So, I made one from a strip of brass.

And carefully moved the bearing 3 mm in the pulley. Took two attempts.

Final measurement on the AC Idler pulley 6 mm for a difference of -1 mm. On target.

Note that in my measurement chart above the First Idler was at 5 mm for a difference of -2. This pulley works on the back side of the belt (no grooves) so it was just registering part of the offset of the AC Idler. With the AC Idler fixed the First Idler was spot on.

Also, I did not measure the water pump pulley because it also works on the back of the belt and is less than an inch from the crankshaft. It does whatever the crank shaft pulley does.

Errors in this measurement method could come if the surface of the harmonic balancer is not exactly perpendicular to the crankshaft (runout). I did not check for this (could put a dial indicator on it and bar over the engine to see how the reading changes). I expect it to be minimal since this is a machined surface on a major rotating part.

So here is to a new season and running all through it with the same belt (fingers crossed).