Newer Mopar engines - experiences

Besides my 65 Dart and 65 Newport, we have a 96 Voyager 2.4L and 02 Town & Country 3.8L. I relate some experiences since some relates to A-body builders who "upgrade" their engines.

The 3.8L appears a direct descendant of my 273 SB, less 2 cylinders. It has a traditional cam w/ roller lifters (like Magnum). It stranded us on a road trip when the plastic power steering pulley failed. Auto parts list for $10, but always "not in warehouse". The shop drove 30 miles to a dealer and cost $56.

Failure was probably my fault since I cracked the pulley a bit when I beat it off the pump 6 months ago, after trying a torch (thought aluminum until I saw the surface bubbling). I first tried a pulley puller but just broke off the plastic grooves. I reused the pulley since, as you guess, nobody had it. Fun removing the pump on a sideways engine when you can barely get 2 fingers on the bolts and keep dropping things.

I can manage w/o power steering, but the serpentine belt drives everything. I got 10 miles to San Clemente by tying a nylon rope around the other pulleys, but apparently the alternator slipped too much. The battery runs down amazingly fast in new cars (fuel pump, injectors, etc). My Dart can run all day on a full battery. Interesting things happen at 7.5 V. As I rolled to a stop, the anti-lock brakes pulsed on their own, the electronic transmission selector went crazy, and the wipers came on and off. I see people retrofitting serpentine belts on classic engines. Perhaps a bad idea.

Cost $330 w/ towing (would have bought nice things for my Dart), but I now face a bigger problem. The strange metallic rattles I heard last winter when cold appears to be a cracked flexplate, which is common. The "toner ring" is welded to it, with slots for the crank sensor. When it or the flexplate cracks get big enough, the crank sensor starts missing. It used to stumble a bit at idle, now does so on the highway when accelerating. Interesting thing is no matter how bad it misses, it sets no codes. Removing a front drive tranny is @**!.

I think Magnum engines are similar. My engine has 156K, which is beyond the fatigue life other people have experienced. The Hemi engine has a different crank pickup. I read it has a "toner ring" integral to the crankshaft. Many truck owners who "upgraded" to under-drive pulleys have quickly experienced toner ring failure. Vibrational resonance is suspected. Is that why Chrysler engineers termed it "toner" (joke). I read there is a better Hemi crank that shatters toner rings less often. Speaking of cracks, if you go to a Magnum engine or heads, they regularly crack between the intake and exhaust valves since Chysler induction hardened the metal around the seats (not hardened inserts).

The 2.4L engine is a more modern design with DOHC. The power steering pulley uses a separate belt (yeah) and the water pump drives off the timing belt. Still, without the alternator I found you won't get far down the road. The original head gasket design was bad - it leaked oil to the outside, starting at 39K in mine (just after 36K warranty), but the new MLS design fixes that. While a rubber timing belt seems unreliable, it broke twice, not from the belt, but the timing idler bearing (~40K) and tensioner bearing (~130K). They have 4 tensioner designs over the years and you must pull it apart to see which you have. It missed at WOT until I lowered the spark gap from 0.060" to 0.050", as Chrysler recommends for the PT Cruiser turbo (higher cylinder pressure = harder to spark), so the ignition system probably weakens over time. Same trick didn't work on my 3.8L. Amazingly, the tiny bicycle-type chain that drives the 2 balance shafts underneath the crankshaft hasn't broken yet at 160K. I think my 3.8L has a similar setup. Also, the 3-spd tranny wouldn't reverse, which turned out to be the rubber seal on a piston. It looks just like the 904/727 inside, other than the differential add-on and maybe cheaper parts.

I try to carry enough parts to avoid getting stuck far from home, since that can be expensive and puts you at other's mercy. I can fix most anything in my garage. I have only required a tow 3 times in 35 years. I once got my 69 Dart down the road after a wheel bearing failure using a big washer I found on the side. I carry points to swap in if my electron ignitions fail, a carb to swap for my Holley Projection, and a timing set for my 2.4L. If I only had that stupid pulley (ordered one). If my wife would just agree to using the Newport or Dart for trips we would be set.

It is hard to know what you are getting into when you lay down big money in a showroom. Nobody knows for sure what surprises await at >100K during the first years of a new engine, but I wish Chrysler had cared more about >36K miles when they designed mine. Anyway, study much before you upgrade your A body and make sure not a downgrade.