Lean On Me

With the new baby Holley Double Pumper installed the engine definitely runs a lot better. It idles very consistently at 800 rpms although it still lopes quite a bit from the mystery cam. I just finished swapping the cold 160 degree thermostat for a 180 and the idle seems to have increased slightly up to 900 rpms. I guess the intake mixture was too cold with the 160--the oil should stay a lot cleaner now too.

One big issue I still have is drivability at low rpms. If I open the throttle too quickly at say 1500-1800 rpms the engine will buck and backfire. The timing is fairly close to where it should be, and for now I have to assume the camshaft timing is correct, so Google says that my carb mixture is too lean. Now, I was actually thinking that I had the wrong power valve for my application which was making the mixture too rich when I cracked open the throttle. My Holley 4150 came stock with a 6.5 power valve which requires 13" of vacuum at idle to operate correctly. Since I'm only getting 8" I need a 3.5 or 4.5 power valve. But Google keeps telling me a backfire means lean not rich. So I pulled a spark plug to take a reading.

This plug looks very clean (except for the oil on the threads WTH). Too clean actually. It should be a light tan color and not this ghostly white. So she's definitely running lean. We had just driven the 'Stang back from a cruise-in so the engine had been running steadily at 2500 rpms for the last 30 minutes. So this plug is pointing to the main jets being too small. My Holley is stamped 4776-5 which means it came with 66 primary and 73 secondary jets. My old carb is stamped 4778-8 which should have 69 primary and 78 secondary jets as long as they weren't changed in the past. I think I'll remove the jets from the old carb and see what size they are.

The primary and secondary jets are located inside the front and rear fuel bowls, respectively. I removed the 4 retaining screws of the primary bowl on the old carb and then removed the jets. Instead of finding the stock 69 jets they were stamped 72! One of the side-effects of using a large carb on a small motor is that airflow is much slower than optimum, especially at idle and part throttle. The larger throttle plates don't have to open as much to supply sufficient air to the engine. This means that air moves slower through a large carb than it would through a smaller carb for any given volume, assuming that the smaller carb can handle the maximum flow required for the engine. Since carbs rely on airflow to "suck" fuel from the bowl, reduced airspeed means less fuel is being drawn in, making the engine run lean. So someone had previously increased the primary jet size to compensate for the slower airflow. Unfortunately that means I can't use these jets in my new carb. Jetting up from 66 to 72 is way too much. However, in a stroke of luck, I found a Holley jet kit on Amazon with same-day delivery! With this kit I'll have plenty of jets in all sizes to jet away to my heart's content.

While I'm waiting for the jets to arrive I reassembled the old carb and started removing the jets from the new carb. This is more difficult since the carb is still mounted on the engine but it's doable. I first siphoned as much fuel as I could from the bowl through the sight plug--the rest drains out when you remove the bottom screws.

I was able to remove the primary bowl with the fuel line still connected since it has a braided hose. Then I could just barely move the bowl out of the way and reach the jets with a screwdriver. 

While I was removing the jets the metering block came loose so I just removed it from the carb.

This made it a lot easier to change the jets. I debated back and forth about how big of a jet to go to. Holley recommends going two steps at a time when changing jets, but I'm not sure 2 will be enough. So for now I swapped the 66's for 68's.

While I was draining the fuel from the carb I figured it was a good time to swap out that glass fuel filter before it breaks and starts a fire. I picked up a cheap chrome filter for now. One of the cheap hose clamps was stripped so I had to make a run for a replacement. I also wanted to replace the two short pieces of rubber fuel line but the local Autozone didn't have any on the shelf. Eventually I'd like to replace it with braided line like I have feeding the carb.

With the larger jets in place I started her up to go for a test drive. It might have been psychological but the throttle response seemed much better, allowing a smoother start from standstill. However, as soon as I hit 3rd gear, a quick stab at the gas pedal produced another backfire. So I continued around the block and parked it without letting the engine fully warm up. Since it was still backfiring I figured it was still "way" lean and not just "wee" lean. I didn't want to go all the way to 72 since that would mean I could have used the primary jets from the old carb and saved the $60 for the jet kit. So I swapped jets again, but this time I jumped up 3 sizes to a 71. 

I didn't get to test drive the car for a few days until we went to a cruise-in at the local Rock 'n' Brew. She started right up and didn't backfire once on the trip there and back. The clutch still chatters a little, but not nearly as bad when I first drove the car. Right now the only drivability issue is when I try to crawl through a parking lot. While in 1st gear at basically idle speed the engine starts to buck. It's easily stopped by pushing in the clutch, increasing the revs a little, and letting the clutch back out. 

I'll drive it a few more times before I do any more fine tuning. Ideally, to read the plugs you should drive at cruising speed for a while and shut down the engine and coast to a stop without letting the engine idle. Then you can pull a plug while on the side of the road. This will narrow down the reading to just the primary jets. If the primary jets seem good I'll then have to tackle the secondary jets.

What I'd really like to do (someday) is install a wideband oxygen sensor. This would require welding bungs in the header collectors for a pair of O2 sensors. Then I could install a gauge that would monitor the air/fuel ratio taking all the guesswork out of jet selection. Since I can't weld I would have to either take my car somewhere and let somebody else monkey with it or remove the headers and take them someplace. Maybe if and when I have to remove the transmission to fix the leak I'll try removing the headers since I'll have to remove the rest of the exhaust anyway.

Braking The Park

From day 1 the parking brake has been missing in action. The previous owner told me it didn't work and he was right. I wasn't very optimistic about this being an easy fix since I have rear disc brakes and they probably weren't going to just bolt up to the stock parking brake setup. First thing I noticed was that one of the brackets was pretty bent.

It wasn't too hard to straighten out the bracket somewhat but I couldn't get the cable housing under the clip at the top of the photo. My car wasn't jacked up high enough to use two hand so I had to zip-tie it for now. You can also see return spring, which is actually pulling in the wrong direction. It's supposed to pull that lever towards the rear of the car, not forward, to keep slack out of the cable and help return the parking brake handle. When I researched the proper spring setup I found it attaches to a hole in the frame rail. My car has sub-frame connectors welded in so that hole appears to be covered up. I had to leave this spring off for now--it doesn't even look to be the right one.

Here's the rear disc caliper showing how the parking brake cable attaches, right behind the coiled spring. Since all this looks like it's hooked up correctly, including the new cable, I'll assume everything is good to go and just needs to be adjusted. Before I started working on this the parking brake handle would just come all the way out with very little resistance. It did hold the car but only on a flat surface. So all I did was tighten up the equalizer bracket to take out most of the slack in the cable. Bingo! Now the parking brake works, as well as it was designed to work. All I have left to do is fix the return spring.

You can also see in the first photo that the exhaust pipe (among other things) is covered with oil. It's a very heavy, clean oil that I'm certain is coming from the transmission. I haven't been able to pinpoint where it's leaking, but I'm hoping it's from the top cover. I was told the transmission has been recently rebuild and it's common for Ford Toploaders to leak if the wrong top cover gasket is used. The top cover has a vent hole in it that needs to be baffled by the gasket or else it will leak. So I'm hoping that either the gasket is wrong or even absent so my leak is relatively cheap to fix. The problem is I will probably have to drop the transmission in order to replace the gasket. This also involves removing the exhaust and driveshaft which doesn't sound fun. I've read it may be possible to actually reach the bolts on the top cover while the transmission is still in place. I'll have to check it out next time I jack the car up high enough.

Hold The Brakes

Before I took my car out for its first run in 6 weeks I did a quick check of the lights. Uh oh. No brake lights. When the rebuild the brake pedal assembly I noticed a loose terminal on the brake light switch. I ordered a new one along with new plastic bushings. When I installed the new switch the new bushings got rid of all the slop. However, the switch design relies on a certain amount of play. As the brake pedal moves forward the master cylinder push rod resists for about 1/16" which depresses the spring in the switch. Without that 1/16" of play the switch wouldn't work.

First I tried making a shim so the master cylinder push rod wouldn't have to move as fas to hit the switch. I cut apart the old switch and salvaged a plate that I stacked on top of the same plate in the new switch. But when I installed this new setup the brake lights stayed on all the time. There just wasn't enough play in the linkage. So I took the switch back out and removed one of the plastic bushings, more like a sleeve actually, that went in the hole in the push rod and slid over the pin on the brake pedal. With this bushing in place there was zero play in the linkage. This time when I put the switch back in it worked. I left the shim in place and the switch is pretty sensitive--it doesn't take much pedal pressure to activate the lights. I'm concerned the brake lights might accidentally stay on but I'm not sure there's enough movement without the shim. The master cylinder push rod is a newer replacement and looks nothing like a stock push rod.

Contributing to the problem is the fact that I have a power brake booster. I have searched and searched online for the manufacturer and installation instructions but have been unsuccessful. It could be because my setup is at least 10 years old and is either not produced anymore or has been updated so mine doesn't match any photos. It came with a bracket that mounted on the brake pedal and moved the mounting point for the master cylinder push rod. The reason for this is to reduce the pedal travel. However it has two negative side effects. First, it increases pedal effort by almost double, and second it creates a severe misalignment in the push rod. When I reassembled the brake linkage I left this adapter off so that's probably why I had so much trouble getting the switch to work.

Here's a shot of the old setup. The adapter is the silver chunk of metal to the left of the brake pedal. The gold master cylinder push rod is attached to the bottom left of the adapter. As you can see the adapter moves the end of the push rod about 3/4" to the left, putting it out of alignment with the master cylinder.

Good Carb, Bad Carb

The big Holley is probably at least 10 years old and has been sitting for most of that time so it's probably due for a rebuild. Even after spending the time and money to rebuild it I'm not confident it would ever perform well since it's so big. So I bit the bullet and bought a new carb. I wanted to stick with Holley, specifically a smaller double-pumper, because I like the looks and I could keep my fancy braided dual-feed fuel lines. I also wanted to keep my manual choke setup. The smallest 4150 double-pumper that Holley makes is a 600 cfm. I ordered 0-4776S which has a manual choke and silver finish.

The shiney new carb bolted right in since it's externally identical to the older carb. I need to replace that glass fuel filter soon--too much of a fire hazard. The engine fired right up since I had primed the primary bowl. I was able to set the idle down to 800 rpms whereas before with the older larger carb I couldn't get the idle below 1100. The engine sounded great and revved nicely but it would put out a bit of black smoke when I gave it a lot of gas so I think it's running rich. I took the car off the jack stands and backed it out of the garage for the first time in 6 weeks. Right off I noticed the clutch shudder was still there. As a drove around the neighborhood I also noticed the throttle response was actually too much. It was hard to accelerate smoothly. It reminded me of when I installed a twist throttle on my Honda ATV. I mistakenly hooked the cable to the two-stroke position instead of the four-stroke. This caused the throttle to open way too quickly. Now my Mustang felt the same way. Time to look at the linkage.

I had connected the throttle rod and return springs the same way they were on the old carb. The rod is attached to the carb so close to the pivot that there is only about 1.5" of travel with poor leverage near full throttle. So I swapped the attachment points for the rod with the return springs.

Now I'm getting about 2.5" to 3" of travel giving a much slower throttle opening with easier modulation. I still need to find a bushing for the end of the rod. A lot of other setups have the return springs attached to the bottom of the throttle linkage, pulling from the right. I might look into switching my setup that way since it looks cleaner. Although, right off it seems that having the rod and springs both pulling from the same side puts added tension on the throttle shaft causing addition wear.

Intake Manifesto

Gaskets? Check. RTV? Check. Expertise? Yeah, right. Replacing the intake manifold on a small block Ford isn't really that hard to do. It's basically only six steps: remove the distributor, remove the carb, remove the manifold, reinstall the manifold, reinstall the carb, reinstall the distributor. Of course, each step actually involves many other little steps, but who's counting. As long as you perform each step "correctly," then there won't be any leaks later on.

Step one: Remove the distributor. Easy. Remove the cap, unplug the vacuum line, and take out one bolt. But not so fast. The distributor can go back in with the rotor pointing in like 20 different directions and only one will work. The best way to ensure that it goes back in oriented the same way it came out is to turn the crankshaft to TDC so the rotor is pointing at the number one plug wire. That way you know where it's supposed to be pointing when your done. Google told me this points the rotor towards the driver at about 1 o'clock.

As you can see mine's more like quarter to 12. Not a big deal except that the vacuum advance canister isn't pointing to the front like it should be. The gear on the distributor causes it to rotate when you lift it out.

The rotor rotated to about 10:30 so if I line it up to where it originally was then it should rotate to the customary position.

Step two: Remove the carb. Pretty straightforward. Remove the linkage, remove the PCV hose, disconnect the fuel line, and undo the four nuts. Before I lifted off the carb I checked that the linkage was adjusted to the right length. I opened up the carb linkage all the way and tried to reconnect the linkage. It wouldn't fit even with the loud pedal all the way to the floor. So, something to adjust when it all goes back together.

When I opened up the throttle it sprayed a bunch of fuel through the carb. Removing the carb revealed a lot of fuel had seeped past the gasket. Hopefully this is just a leaky gasket and not a leaky carb. You can also see that I have an open spacer on top of the Edelbrock dual-plane manifold. It should really be a 4-hole spacer that keeps the two sides of the plenum separate.

Step three: Remove the intake. Starting at the rear, I disconnected the water temp wire, the power booster vacuum hose, the heater hose, and lastly the thermostat housing. After removing the 12 bolts the manifold lifted off with very little prying.

Flipping the manifold over I saw that the front cork gasket was out of position. This cutout is right behind the distributor and someone had applied a lot of sealant from the outside in an attempt to seal this area. Needless to say, I will not be using the replacement cork end gaskets.

When I looked down in the lifter valley of the engine I was a little surprised. The block casting says "HECHO EN MEXICO." Obviously this is not the original block. When Ford stopped making the 289 in 1968 they started up production of a replacement block down in Mexico. This new block was designed as a 302 with a heavier casting and beefier main bearing caps like the Hi-Po 289. So it's possible I actually have a 302 instead of a 289--depends on what crankshaft I have. The only way to know for sure is to pull a head and measure the stroke.

There is what I assume to be a partial VIN on the rear of the block which looks to be 2K526084. I think the K means it was assembled in Kansas City but that's all I can figure out for now.

Two things in the above shot. First, it pays not to skimp on antifreeze. This car had been sitting for a long time and desperately needs a flush. Second, the old gasket cutouts looked a little big for the intake ports. Sure enough, when I checked the old gasket it measured 2.067". Then I moved the calipers over to the new gasket. 

The new gasket is the correct 2.00" so you can see the difference. In an ideal world I'd have the heads and intake ported to match the gasket, but that would involve removing the heads.

Step four: Reinstall the intake manifold. Whoa, not so fast. All mounting surfaces must be prepped first. This is the most time consuming aspect of the whole deal. If the surfaces of the heads and intake aren't clean then the gaskets won't seal. I was a little disappointed that I couldn't pinpoint the exact area the manifold was leaking, but it was probably leaking in multiple places since the surfaces were wet in many places. So I definitely need to take the time and get the surfaces as clean as possible.

While I have the manifold off I wanted to address the paint.

Someone painted the manifold a nice silver (I hope it wasn't Edelbrock), but obviously didn't prep it right so the paint bubbled badly. I'll see what I can do to smooth things out before painting it a nice Ford blue.

Well it's not perfect, but it's definitely better. I followed the directions for the paint and sprayed on three coats, waiting 10 minutes between each one. The can says for the paint to fully cure you need to place the manifold in an oven for an hour at 200 degrees. Since my wife will probably read this I didn't do that. I swear. I'll let the engine heat cure it when I fire it back up.

I went to dry fit the gaskets and check the clearance under the manifold when I ran into a snag. The gaskets I ordered from Amazon were Fel-Pro 1250S-3. They are listed on Amazon and the Fel-Pro website as fitting a stock head 289. Lies I say.

The opening for the water jacket is so big it overlaps the edge of the head.

How does a big company screw this up? Luckily, the local Autozone had a different Fel-Pro gasket MS90103-1 in stock that was supposed to fit my engine. This new gasket fit way better but it had the heat riser cutout which the other gasket didn't have. Living in Florida I definitely don't need hot exhaust gases heating up the manifold.

Amazingly the black 1250S-3 gaskets came with block-off plates even though there wasn't a hole to block. That was very fortunate since the blue MS90103-1 didn't come with any. I had to use my Dremel to cut the block-off to fit.

Here a shot to show the differences in the water jackets of the two gaskets. While I was prepping the heads I found more characters "1M9L" stamped in the block by the distributor.

One of these days I'll have to pull the starter so I can read the casting numbers and finally figure out where the block came from. With the headers on the way it'll be a bear of a job reaching the starter.

Here's the spruced up manifold in place with a new 4-hole spacer on top. I finished putting everything back together and the engine fired right up--yeah, dream on. So far in this project, whenever I've taken something apart and put it back together the same way I've run into hidden problems.

The first snag was reinstalling the distributor. I knew this was going to be a beyatch from past experience. The problem is re-aligning the oil pump driveshaft with the end of the distributor. Since my distributor wasn't oriented correctly when I removed it I needed to rotate it clockwise 20-30 degrees so the hex end of the shaft was never going to been lined up. If that wasn't bad enough, the bottom of the shaft is attached to the oil pump, but the top end is free to wobble around side to side. When I looked down the hole for the distributor the driveshaft was always leaning to one side.

An easy trick to getting things to line up is to drop the distributor in place until it hits the top of the driveshaft and then turn the crankshaft, which rotates the distributor, until the shaft lines up and the distributor drops down. Tried that. Didn't work. I rotated the engine a full 360 while pushing down on the distributor and it still wouldn't drop into position. And now my rotor was a full 180 out of whack. I didn't want to continue rotating back to TDC just yet because I wanted to static time the engine later on.

So on to trick #2. I removed the distributor (remembering to keep it 180 degrees from normal) and used a small socket on a long extension to reach down the distributor hole and rotated the driveshaft in small increments until things eventually lined up. And I didn't drop the socket inside the engine.

With the distributor in place I needed to static time the engine. The vacuum advance was now pointing at the radiator like it should, instead of the driver's headlight. First, I rotate the crankshaft another 360 to bring cylinder #1 back to TDC. But I stopped with the balancer pointer at 9 degrees before TDC. Then I rotated the distributor until the points opened (that's when the coil would fire). With my multimeter checking continuity across the points this was fairly easy to do. But I noticed something peculiar that should have raised a red flag. Normally my meter will read "1" for an open circuit and "0" when you touch the terminals together. When I checked the points, however, the meter still read "0.4" when the points were closed. I was still able to static time the distributor but I failed to see any problem with the points. Apparently, when I had checked to gap on the points with my oily feeler gauge I contaminated the contacts.

So of course, when I tried to fire the engine, no go. I suspected the ignition right off so I checked for a spark. I pulled the coil wire from the distributor and placed the end near a ground and cranked the starter. No spark. Now I'm suspecting the MSD box. Maybe I fried something, maybe a fuse blew, maybe a wire came loose... I wasted several hours tracing wires, checking voltages, and still couldn't find a problem. I looked up how to test the MSD. Simple. Disconnect the only lead running to the distributor and touch it to ground. Spark! So the MSD is working but the spark isn't getting through the distributor. It finally dawned on me that the points were probably the culprit so I went online to see if the local Autozone had a replacement in stock. They did, although when I picked them up the counter guy thought they were for a tractor.

With the new points installed the engine fired right up--but it still wouldn't idle below 1100 rpm. I'm pretty certain I did a decent job of sealing the intake manifold so it's time to move on to the carb.

Clutch Play

I'm still waiting for my intake manifold gaskets--taking a little longer to arrive due to hurricane Matthew. Looking on my todo list I decided to finish up the clutch and brake pedals.

For the brake pedal I installed a new brake switch (the old one had a loose terminal) along with new bushings for the master cylinder pushrod. It was a real bear getting the retaining pin in place--definitely a lot easier working under the dash without the pedals and steering column in the way. After plugging in the new switch I spent some time organizing the wires that were hanging down under the dash. As much as I hated to, I even remounted the stock 5-circuit fuse block. Someday...

On the clutch pedal side I installed new bushings on the clutch rod and attached it to the clutch pedal. The z-bar had about 1/2" of side-play so I moved the end mounting bracket over, reducing the play to 1/8". Then came the hard part. When the headers were installed they interfered with the end of the clutch fork so someone hacked an inch off the end of the fork to provide clearance. The downside is that was where the spring for the equalizer rod attached. Without that spring the clutch fork can ride against the throw-out bearing, and even worse, the equalizer rod can fall out leaving the car undrivable. I attempted to drill a new hole for the spring, but the clutch fork is pretty beefy and there isn't much room to get a drill in the right place. The way the fork is stamped you can just hook the spring over the edge but I was afraid that it would slide off the end. So I whipped out my Dremel and ground a notch on the backside of the fork so the spring would have someplace to seat and wouldn't shift around. It's always under tension so I'm pretty certain it can't fall off. The spring seemed a little short to reach the z-bar and I felt like I was over-stretching it so I added in a stainless S-hook I had laying around. I also had to cut a slit for the end of the spring in the rubber boot covering the fork. The full-length fork would have extended through a slit in the end of the boot.

There's just under 1/4" clearance between the spring and the header so we'll see how it goes. If it rubs I'll have to grind another notch in the fork closer to the transmission. Before I put the spring on I adjusted the equalizer rod to have about 1/8" of play which gave me 7/8" play at the pedal. Cool.

I Thought Brake Fluid Was Clear

While I'm waiting for my intake manifold gaskets to arrive I decided to take a look inside the brake master cylinder. When I was driving it home on day one I could tell the brakes needed some work. The power boost was nonexistent and the pedal felt like I was trying to crush a brick. I can see that the master cylinder and booster are new, as well as all the brake lines. There are new disc brakes on all 4 corners, of what origin is yet to be determined.

Now I know the booster won't work with the 6" of vacuum that I currently have but that fix is on the way. And I've eliminated the brake pedal binding caused by the worn support bracket. So the only thing left to do is flush the brake lines and bleed the brakes. Although the brake components are "new" they were probably installed between 6 and 9 years ago. Since that time the car has been driven less than 1500 miles.

Yuck! This is pretty nasty stuff. I hooked up my little vacuum pump and siphoned out as much as I could.

The bottom of the reservoirs looked even worse. I was worried that all the brown stuff was corrosion but it came out pretty clean.

Time to go buy some Dot 3 brake fluid and flush out the lines. Stay tuned...