COPs and Pulleys
by Pat Goss
Times change, cars change, parts that go in them change. And, we have with us today our parts guru, Tom Taylor. Tom, welcome back to Goss’ Garage.
Tom Taylor: Thanks for having me back, Pat.
Pat: You know, I can remember back in the day, like that old Falcon sitting behind us, where all cars, had sparkplug wires.
Tom: Right, you’d have one ignition coil that would send current through multiple sparkplug wires, a sparkplug wire for each sparkplug. And that’s pretty much gone away. You’ll have separate ignition coils for each cylinder with little boots that go down to the sparkplug. And what people may not realize is these boots should be replaced as part of routine maintenance like they used to replace the sparkplug wires.
Pat: Yeah, these uh are subjected to oil, fumes and all kinds of things and uh you know they do deteriorate with use.
Tom: If you look at them, their inside is a little conductor coil-wire and the outside is an insulator, very similar to a sparkplug wire. Replacing a whole set of these costs the same as replacing one ignition coil and its boots. So if you’re replacing these all as part of routine maintenance, you may never get and error code or a misfire or something that might occur if the boots were bad.
Pat: Ok, So good advice there. Now everything is electrical on modern cars, that brings us to where we get that electricity from, the alternator.
Tom: Yes, over the years, we have a lot more electrical accessories, heated seats and that sort of thing. The output of the alternators has jumped from averaging 65 amps to over 200 amps on a lot of cars and the rotating mass on the alternator has increased a lot though to reduce the jerking of the serpentine belt system that drives the alternator. Pulleys now have what’s called a de-coupler or a clutch, a flexible material that absorbs that tension when the alternator cycles on and off.
Pat: Yeah, and the problem is that some of these will physically look the same and may bolt up but they don’t work right.
Tom: Right, these are both off and fed a Ford 4.6-liter, but this is off an older engine that required less amps. It’s a conventional pulley and you can’t mix and match the two. If you put this on the car on the car that needs this, you’ll get the jerking as the system cycles on and off or you might even get a check engine light because the whole serpentine belt system is not working like it was designed to.
Pat Goss: Gotcha, Tom, thank you. And if you have a question or comment, drop me a line, right here at Motorweek .