The Search for Top Dead Center

I wanted to check my marking for top dead center on the harmonic balancer since I'm pretty certain it's not original and might not be accurate. I purchased a Competition Cams 4792 Top Dead Center Stop from Amazon.

I screwed this into the #1 cylinder in place of the spark plug. I had already removed the rest of the plugs so the engine would spin easily. Then I slowly turned the crankshaft pulley counterclockwise to roughly 20 deg after TDC and screwed in the piston stop until it contacted the piston.

I marked the balancer at the pointer with a piece of tape. Then I turned the engine in the other direction (clockwise) until it hit the stop again at about 20 deg before TDC and marked the balancer with a second piece of tape.

Now I could remove the piston stop and turn the crankshaft until the pointer was halfway between the two pieces of tape. The was now my true TDC. You can see the pointer is off by about 1.5 degrees so I needed to move it over. I only had to elongated one of the two holes on the pointer to put it in the correct position.

Good Carb, Bad Carb, Part 2

After having problems getting the engine to idle, and eventually finding junk in the fuel line and the Holley carb, I installed a new Edelbrock 1405 Performer 600cfm carb from Amazon. The carb drops right into place on top of my 1" spacer but the hookups are little different from the Holley.

I picked up some new 3/8" hose for the fuel line since the Edelbrock only has a single feed while my braided line is for a dual feed. The new carb came with a cheap plastic see-thru filter which was perfect to replace the defective chrome filter. Eventually I'll look for something that looks nicer but this was the cheapest way to get the carb hooked up. On the Holley the EGR connected to the rear but on the Edelbrock it connects front and center. I needed a longer hose to reach the EGR valve on the passenger side valve cover (upper left corner) so I just used the same 3/8" hose. To the left and right of the EGR connection on the carb are the two idle mixture screws, and next to them are the two vacuum ports. The left port, which is above the throttle plates, is ported vacuum, while the right one supplies manifold vacuum. Edelbrock recommends trying the manifold vacuum port for the distributor advance if you run a big cam so that's what I'll try.

The throttle linkage connected easily; I made sure that I had full travel before the pedal hit the floor. The return spring bracket from the Holley didn't work so I picked up a cheap Spectre Performance 4708 Throttle Return Spring Bracket for $8.10 from Amazon along with a Dorman 59207 Throttle Return Spring assortment for $6.84. I mounted the bracket on the intake manifold in an existing hole pulling from the rear. The springs come very close to the choke linkage at wide-open throttle so I may have to try something different.

Here's the passenger side where the manual choke cable attaches. The Holley had a bracket for attaching the actuating cable but the Edelbrock just has a hole and I didn't want to just bend the wire around the choke lever.

I bent a dogleg in the wire so it can't fall out, but I can still get the wire through the lever coming in from the side.

After double-checking all my new connections it was time to fire things up. I cranked the engine for a few seconds and then looked to see if fuel was filling the filter. Check. I cranked the engine for about 10 seconds to fill the carb bowls. Then I pulled the choke, pumped the pedal once and she fired right up! It idled a little too slow with the choke and when I tried to open the choke a little the idle slowed down too much and it tried to stall. So I kept my foot on the gas pedal until it warmed up enough to idle on it's own. When the engine warmed up all the way it was idling at 1000 rpm so I lowered it down to 850 and adjusted the idle mixture screws to get the fastest idle without being too rich. The only other adjustment I made was to screw in the fast idle screw one full turn to see if that would help with the next cold start.

The next day she started right up and the cold idle worked much better. I drove to the store and back I am amazed at how well the engine runs. The Edelbrock runs smoother than the Holley ever did and it's practically straight out of the box.

There's Hair in My Fuel

After installing the new distributor I finally got the car started but it still didn't idle very well. The exhaust tone even sounded different. I tried to adjust the idle mixture screws but something wasn't right.

The procedure for adjusting the idle screws on a Holley requires a little finesse. Before starting the engine you turn the idle mixture screws clockwise until they are fully seated, and back them out 1.5 turns. This is the recommended starting point for tuning. My Holley 4150 has 2 screws on the primaries, some have 2 more on the secondaries. Start the engine, let it warm up, and then you can begin adjusting the idle mixture.

Adjustment can be done 2 ways. First, turn one screw in until the idle slows and then back it out until you get the highest vacuum reading. Then, back the other screw the same amount. If the idle increased you should lower it back down and repeat the procedure starting with the other screw. The second method ignores the vacuum reading and you adjust the idle mixture screws to get the highest rpm.

The problem I ran into was that turning the driver side screw had no effect on the idle speed or vacuum. In fact, I could turn it all the way in which should cause the engine to stall, but it didn't. The passenger side adjusted just fine though. Holley says ineffective idle mixture screws are indicative of a blown power valve, which would dump extra fuel at all times. I'm not sure that a blown power valve would only effect one side of the carb but it's an easy replacement.

Holley power valves are rated based on the vacuum that they operate. The stock valve is a 6.5 which requires an idle vacuum of 13" or higher to function properly. The correct power valve # should be half your idle vacuum, otherwise it could open too soon, and in worse cases open at idle. In my case, I'm only getting around 9" of vacuum at idle so I've known for a long time that my power valve is wrong, so this was a good time to replace it. I ordered a new 4.5 power valve from Amazon for less than $7. A week later it's $13.84, WTH Amazon?

Since I had to remove the primary metering block to replace the power valve I figured I would drop the main jets down from 71 to 70 since my spark plugs looked a little dark.

Here's the primary metering block from my Holley 4150. You can see the power valve screws in from the back side of the jets. What I wasn't expecting to find was a 6" hair coming from one of the passages. It looked like a strand of hair but it could have been a fine synthetic fiber. I tried to gently pull it out but it was stuck. I determined it was the port for the idle mixture screw and when I removed the screw the hair pulled right out with a big clump at the end.

The screwdriver is pointing to the passage where the hair came from. The idle mixture screw is removed and screws in from the side (the bottom in the picture). When I straightened out the hair it was about a foot long. I can't imagine how it got in there and I don't know if it came from Holley that way. I have removed this metering block once before and it seems I would have noticed this hair before.

I swapped the jets and the power valve and buttoned up the carb. After priming the engine fired right up but I could tell right away that nothing had changed. Fudge. It still wouldn't idle and the driver's side idle mixture still had no effect.

At this point I felt that the carb must have a blocked passage, especially since I already found some junk in there. I'm not too confident in my carb rebuilding skills so I felt it was best to just buy a cheap spare carb and rebuild this one later. I decided to buy an Edelbrock 1405 Performer 600cfm for just over $300 shipped.

When the new carb arrived I began removing the Holley. I started by disconnecting the fuel line and draining the fuel. When I pulled off the Mr. Gasket chrome fuel filter I noticed something wrong--it rattled when I shook it. If a filter rattles then it's loose inside which means fuel is leaking around the filter material. I looked in the outlet end and saw something was blocking the passage so I used a paperclip to try and pull out the obstruction.

Several plastic/rubber chunks came out, WTH? The one piece is curved so it's probably the seal around the edge. This kind of junk would cause total havoc with the smaller passages in the carb. When I drained the Holley fuel bowls more junk came out.

The larger pieces in the center of the blue cap are about 1/8" in size. No wonder the engine wouldn't idle. So the Holley needs a full tear down and rebuild. I'm glad I bought the new Edelbrock.

Door Alignment

Most of the body panels on my car are pretty darn straight, except for the passenger door. I've been meaning to look into this since day one but never got around to it, mainly because I can't open the passenger door very far when it's in the garage.

As you can see the door stick out at the bottom...

But goes in too far at the top.

As you can see the center part of the door where the striker is sits flush. My thinking was that if I adjusted the lower hinge only, I could push the bottom of the door inward and the door would pivot on the striker causing the top to come out.

The front of the door was already flush with the front fender so I didn't want to have to adjust the top  as it involved 6 bolts holding the top of the fender vs. 1 bolt on the bottom. But when I tried to adjust the bottom hinge I found I could only move the door in about 1/8" before the hinge ran out of adjustment. This meant I had to adjust the top hinge which was going to screw up my fender alignment. Oh well.

When I was done moving the hinges the rear edge of the door looked pretty good.

I couldn't get the entire trailing edge to sit flush since the angle at the top of the door doesn't quite match the rear sheet metal, but it's close enough. However, now the front fender was out of whack.

It wasn't as bad as I thought it would be, but I had to remove the kick panel to access a single nut keeping the fender from moving that 1/8" or so that I needed.

I'm pretty happy with final fit.

Packing Heat

Early Fords, and probably most other old cars, had a very simple heating system where hot coolant continually flows through the heater core. When heat is needed a trap door is opened allowing air to flow through the core and into the cabin. This works great as long as the heater plenum seals are in perfect condition. Otherwise, hot air seeps into the cabin even when the heater is off. On my car the plenum sits under the dash where it acts like a mini radiator, roasting my feet in the Florida heat.

Here's when the hot water from the engine leaves the intake manifold on its way to the heater core.

Here's the heater valve I bought that will let me shut off the flow through the core. It was advertised as having a 5/8" thread. And while it is indeed 5/8", that's not how pipe thread is measured. The old blue elbow is 1/2" npt, while the new part is only 3/8" npt. So I had to make a trip to the hardware store to buy a reducer.

Here's the new heater valve in place. Now my feet will be much happier. If necessary it only takes a few seconds to pop the hood and open the valve.

Master Of Cylinders

From day one my brakes have been quite disappointing. While every component of the braking system has been replaced, albeit 10 years ago, there are still issues that need fixing. To start, my lumpy cam only gives me 8" of vacuum at idle. This is a major problem since I have a power brake booster which requires a minimum of 15" to operate correctly. The only time my engine generates enough vacuum to properly operate the brakes if when the car is moving and I let off the throttle. Then I get only one application of the brakes before losing the power assist. This means at speed I have decent stopping power, but at low speeds I have to really stand on the brake pedal. Not safe (or fun) at all -- every quick stop was essentially a "panic" stop. I was all set to install a vacuum reservoir which would store up vacuum and give me longer braking assist, but then my booster failed.

While driving around the neighborhood the engine began stalling every time I applied the brakes. It didn't happen while sitting still, but once moving (and building up a vacuum in the booster) the engine would stall as soon as I hit the brake pedal. Luckily I wasn't too far from home. To isolate the problem I plugged the vacuum line running from the intake manifold and the booster. I've driven it with no power assist and made dozens of stops and the engine hasn't stalled once.

To troubleshoot the brake booster you hook up a vacuum pump to it, apply a vacuum, and step on the brake pedal. You're supposed to get 2 or 3 applications of the brake pedal before using up the stored vacuum, In my testing I only got one. I'm guessing that there is a leak in the booster that only manifests itself once I've built up vacuum and then applied the brakes. Maybe this is the only time the booster diaphragm moves, which would explain why I don't have a vacuum leak in the garage. Makes sense to me, I guess. Anyway, the booster is around 10 years old.

I decided to drop the idea of a power brake booster and go with a new master cylinder designed for manual disc brakes. It turns out master cylinder sizing is much more complicated than you could imagine. If the piston is too big then the line pressure may be too low requiring lots of effort at the pedal. And if the piston is too small then the line pressure will be fine but the pedal travel may bottom out. Wilwood makes a tandem master cylinder with a 7/8" bore that should be perfect for my application.

As you can see my existing master cylinder is almost hitting the shock tower and is partly covered by the export brace. Removing the booster will move the new master cylinder over 6" rearward, making access a lot easier. Unfortunately I'll have to rebend the brake lines since they'll never match up with the new position.

Here's the new Wilwood in place. It came with an adjustable push rod so I had it in and out several times getting the push rod the proper length. If I had been smart I would have worked on the brake lines now before bleeding the master cylinder. Hindsight... The front line goes to a distribution block before continuing on to the front wheels while the rear line goes to the SSBC proportioning valve.

This Wilwood is really a piece of art. I splurged on the polished version for an extra $50. Before being installed master cylinders need to be bench bled. Wilwood supplies the kit to do it (even though Summit let me order a second kit). Basically, you fill the reservoir with fluid and work the piston in and out. This forces fluid and air bubbles through the hoses and back into the reservoir. The only problem is that the little red fittings are cheaply made out of plastic and leak. Once I started this operation I had two slow leaks to contend with. Now you see why I should have bent the brake lines first. My attempt at reusing the existing brake lines didn't go so well either. The two lines are both less than a foot long and bent fairly easily. I first cut some wire the length of each brake line and then shaped the wire to the fittings on the car. Then it was just a matter of bending the lines to match the templates. However, I couldn't get a good seal when connecting the lines to the master cylinder. When I pulled them off I could see that the flares were poorly formed. So I ordered some new lines along with a nifty little tubing bender--what I should have done in the first place.

Here's the new lines bent to match my wire templates. I bought 12" lines, which were a few inches longer than the originals so I'd have plenty of room to make some nice defined bends. The old ones looked like they were hand formed--really sloppy.

Here's the new lines in place--no leaks so far.

UPDATE: July 2017

Wouldn't you know it, 3 months after I get the new master cylinder working and Wilwood issues a recall. They emailed me a shipping label so all I had to do was box up my old (new) one, ship it to them, have them repair it and ship it back to me. The guy on the phone said it would only be a 2-day turn around once they received mine but it ended up taking 2 weeks. So with shipping both ways it was closer to 3 weeks of down time. My son helped me take the old one off by crawling under the dash to disconnect the brake pedal.

Wilwood wanted me to remove all fittings and the pushrod before shipping it back so I used my combination square to measure the pushrod. When it came back I reinstalled the pushrod and adjusted it to the correct length before putting it back in the car. Last time I bench bled the master cylinder before I installed it but this time I figured I'd try bleeding it on the car. It sits very level in the car so I didn't think it would make a difference. It was definitely easier, I had my daughter pump the brake pedal while I watched the bubbles get purged.

Last time I lost a lot of brake fluid while trying to bend and connect the new brake lines, but this time the lines knew where to go so I hardly made a mess. Bleeding the brake lines using the two-person method of pumping the brake pedal while opening the bleeder screws can prove to be quite tedious so I looked for an alternative this time.

I bought a Motive Power Bleeder with an adapter that clamped on the top of the Wilwood master cylinder.

This bleeder is designed for you to pour a quart of brake fluid in the pressure tank which will then fill the master cylinder as the level goes down. At first I couldn't picture how this wouldn't just fill the reservoir up to the top and make a mess when you took it off, but then I realized that the volume of air in the reservoir would remain constant, so the fluid level would never change as long as the tank had fluid.

After all this, the swap was successful. The brakes work great. So far...

Give Me A Brake

For the past four months, ever since I bought my car, I've been slowly deciphering what all the aftermarket parts are on my car. One of the biggest mysteries is the disc brakes. Obviously, 4-wheel disc brakes were not available on many cars in 1966, definitely not on the Mustang. A quick search on Google shows there aren't that many options available, especially for the rear, so it shouldn't be that hard to match something with what I have.

Here's a shot of the rear caliper taken from under the car. As you can see there aren't any markings at all.

This shows how the caliper is attached to the axle flange with some adapters. You would think that all I had to do was find a matching rear disc upgrade kit and I would be able to ID mine. The closest I could find is made by SSBC.

The caliper looks to be the same shape but the SSBC kit has some lettering on the caliper where mine are plain. One of my rear calipers is leaking so I need a caliper rebuild kit right away. Amazingly, SSBC doesn't seem to sell one. I guess they just want you to by another caliper.

Here's a picture of the same kit from Amazon. It's interesting how some of the hardware is different. I guess since mine is around 10 years old they changed things a bit. I'm still not sure if the calipers are interchangeable, and I don't know what to do about rebuilding my caliper.

Here's a picture of my contaminated brake pads. Now these do look exactly like the SSBC pads.

Here's a closeup of the leaking piston. I debated whether I could pull the piston out to measure the seal and order one based on the size but I didn't know if that would work. So I just cleaned everything up and put it back together until I could find the right seals.

After several months of not getting anywhere I happened to be browsing through the National Parts Depot catalog and was shocked when I read the description for one of their SSBC brake kits.

"These kits use calipers, rotors & pads from the SVO Mustang or Thunderbird Turbo Coupe."

WTH? Why didn't I find this out sooner. Unbelievably, this tidbit of information isn't listed on the NPD website, only in their paper catalog. And it certainly isn't revealed anywhere on the SSBC website. I quickly did a search and found that the '93 Cobra reused the rear brakes from the older T-bird Turbo Coupe.

Here's a picture of a '93 Cobra rear caliper. The caliper sliding pins are the same as mine and more important so is the parking brake mechanism.

Here's another shot of my caliper.

And here's a picture of my caliper mounting bracket. It looks like I finally hit the jackpot and I'll be ordering a rebuild kit along with some new pads right away.

Update: With new pads and a caliper rebuild kit in hand I went to work. The caliper came of easy but I had a hard time plugging the brake line. I ended up using two vacuum plugs, one on each side of the banjo fitting, but not without a lot of fluid and cuss words leaking all over the place.

Above is a picture of the new and old seals next to the piston. Notice how the new seal on the bottom left has a much smaller inside diameter than the old one. I was really worried it was the wrong size but I guess the old one stretched out after 10 years. The two smaller seals are for the parking brake, which I wasn't planning on touching as Ford doesn't recommend servicing it. If you look close at the side of the piston you can see a gouge/scratch that didn't look good.

I'm not sure if this was the cause of my leak, but I spent a couple of hours trying to buff it out. It ended up being much deeper than it looks and I ended up polishing through the finish layer of the piston. A remanufactured factory caliper is only around $60 so I didn't want to waste any more money or effort on this one so I decided to put it all back together and see how it held up.

Here's the piston ready to go back with the seals in place. You can see the parking brake mechanism poking out of the caliper--you have to rotate the piston as it goes into the caliper. You can also see that the caliper has a groove around the piston cylinder, but the outside seal is lacking any kind of lip to hold it in place.

This ancient pair of pliers worked perfect for screwing in the piston. They do make a fancy tool that does the same thing, but since my caliper didn't have any fluid in it the piston slid right in. If there is fluid in the caliper than you have to force the fluid all the way back to the master cylinder, thus the need for the fancy tool.

Here's what the seal looks like when it's fully seated. While it seems to be snug there's only friction keeping it in place when the piston extends to the left. As I said before, if this leaks I'll probably pick up some factory 1993 Cobra calipers. They aren't as clean looking casting-wise, but they are cheap.