The downside to my six-car collection is that sometimes the cars can sit around for long periods of time while I tinker with the others, and the Dirty Dart is no exception. In fact, when I retrieved it from the storage barn last Tuesday, it still had some winter gas in the tank; therefore, the obvious thing to do was replace the differential with an unknown quality used one and leave for a 400-mile road trip “up north.” A few risks make life more rewarding, right?
Eric Clapton and Duane Allman’s awesome remake of “Key to the Highway” has been playing in my head for weeks, and it really sets the tone for a discussion regarding the benefits and drawbacks of hitting the road in a slant-six powered junkyard refugee. I love hitting the highway in an old car, having spent most of my formative years behind the wheel of a ’65 Mustang with an interstate stretching out before me. And although almost anything I own is a better choice than the Dirty Dart for a long trip, it carries a bike rack well, so it got the nod.
Before our departure for my mother-in-law’s northern retreat, my first order of business was to replace the howling differential. I first pounded out the old axles with an old 13-inch wheel and a sledgehammer (7.25 axles are glued in by some extraterrestrial slime, according to my experiences), replaced the axle seals, and then got to work on the pinion seal. It’s torqued to a Herculean 240 ft. lbs., so I punched a mark on the nut and pinion to make sure I torqued it the right amount without the use of the proper He-Man torque wrench. I reused the axles from the old rear end, because I had already replaced the bearings.
I also had to weld on a couple of brake line clips that I didn’t notice were missing until the last minute. Luckily, the Dirty Dart is so dirt and manure crusted underneath that a base-level cleaning of any part is all you need. There’s no reason for a Pebble Beach level of detailing for a car that probably has seen more fields than roads.
It only took a couple of hours to swap rear end housings and move on to the next project, but this picture is an opportunity to show the clean Idaho and Oregon by way of Arkansas subframes underneath the Dirty Dart. Somewhere under the bondo and rivets, alternatively, are some not so clean quarter panels, but who cares?
My next project was to disassemble the 1974-model electronic distributor and install this neat mechanical advance limiter plate. I’d never disassembled a Mopar distributor before, so I had a good time learning how to do it, and now I can set my initial advance way up to 13* and avoid the “too much total timing” trap. It’s a great part. The only downside is that I have a little high-gear slow-speed ping, so I’m bringing the vacuum advance in a little slower, a little at a time, via a small allen screw inside the canister: tweaking and tuning 101.
Next, I had to get inside the door and bend the lock lever that is actuated by the door handle button, because opening the passenger door was a two-thumbed test of strength and annoyance. It works much better now, although my new aftermarket weatherstripping seems to keep all the doors under too much tension when they’re closed, even two years after installation.
Before patching the door up, I used some drop cloths to replace parts of the tattered plastic splash shield. Yes, that’s duct tape you see — what of it?
With that, a spare orange box, fuel filter, ballast resistor, and a lot of tools, it was time to hit the highway. I made sure to drive about 25 local miles before leaving for our short trip, just to shake out any potential bugs.
The real reason for our taking the Dart was to carry our bikes on the back. The Cheboygan/Indian River area of northern Michigan has an extensive rail trail system that offered something for me to do, as I have a hard time sitting still and I get stir-crazy easily. We hung two of our less valuable bikes on the back in case they fell off: mine is a rare but home-painted by some guy 1962 Schwinn “Straight-Bar” Typhoon, and hers is a JCPenney three-speed, probably made by Huffy.
Much has been said here about how awesome the slant six is, and I’ve tempered that love a little by wishing the Dart had a small-block Mopar. Northern Michigan is hilly, and with 3.23 gears, the 225 is probably turning 3100 RPM at 70, and it takes some pedal to maintain that speed on long, steep inclines. I know you can make a slant go, go, go; but stock, it’s no great shakes. Sorry. All cars have a comfortable cruising speed, and the Dart’s is 65. I drove 70 the whole trip, but if I let my attention wander, I ended up at 65 again.
From this view, you can see the gas gauge that I haven’t fixed yet, and my unplugged temperature gauge (it pegs). My aftermarket temp gauge read 190-195 the whole trip, which is perfectly acceptable on a hot summer drive. The Dart mostly ran well and the differential was acceptably quiet, so we’ll call it money well spent for now.
For some reason, more people want to approach me to talk about the Dart than any other car I own other than my ’53 Special. The grins and thumbs up from other passengers were countless, and I talked to two groups of people at a rest area where I stopped to check the bike rack; in fact, I think the old bikes on the back added to the general ambiance of the scene. People just love this old beater.
Needless to say, we made it to our destination with little drama other than a little vapor lock. The next day, I drove the 25 mile round trip into Cheboygan and bought some fuel hose, steel line, and a tubing cutter, and installed a version of our own Daniel Stern’s fuel line modification. Beforehand, I could see fuel boiling in the plastic filter (sorry, I know it should have a metal one), and afterward, it didn’t. Thanks Dan!
Other than that, our trip was fun and uneventful, other than a little neck sunburn for me. Fittingly, as we pulled into the driveway, a piece of detritus must have made its way into the idle circuit and it died at the garage door. I had a good laugh out of that one, but it started back up after we unpacked and it ran fine.
The problems: First, fuel mileage is not awesome. I filled it up twice, once when we got to our destination and once when we got home, and it’s only getting 16 or 17 MPG, which is only as good as my V8 cars typically get on the highway. I think I’d push 20 MPG if I drove closer to 60 than 70. Second, it leaks and uses oil at high speeds. I think the rear main seal is a little leaky and my oil pan gaskets didn’t take when I swapped oil pans to fit this engine into the Dart. Slant sixes use a mix of rubber and cork gaskets to seal the oil pan, and I probably did not use enough (or the right kind) of sealer where they meet, because the front corner is where it’s leaking the worst.
Either way, it probably used a third of a quart on the way up and almost none on the way back; perhaps it found a level where it didn’t leak or burn. I probably shouldn’t expect much more from an engine I bought off the floor of a machine shop where it had been sitting for at least five years. On the plus side, I could still see cross hatching in the bores when I replaced the pan, so it’s not totally worn out.
These are minor problems, however, in the scheme of things. I’m in no hurry to crawl under this thing and replace a rear main seal, and long highway trips in the Dart are going to be few and far between. If Jason Shafer and I have done anything to sway your opinion of driving old cars long distances, put your tool box in the back and get out there. Driving with the windows down at 70 mph and hearing all the noises of the road is a more engaging way to see the world, and a sense of adventure keeps one from feeling too old.