A sideways glance into the mind of filsmyth (previously Phil Smith), author of Virtual Dreamer.

Thursday, December 16, 2004

Gaussing and Guessing


I TEND to think it was an accident. A vandal would not be likely to wipe years of algae growth away to see how much damage was done (time that could have been spent busting out another section).



AARRGH
Posted by Hello

THERE WAS, however, no note -- so either it was blown away in recent brisk winds, or it was never composed, never left. Which level of carelessness was it? No way to know, and besides, I'll be trolling the junkyard for parts anyway. I may even find an intact pair of taillights from a slightly newer model, and decide I like them better...

YES I finally have my project/getaway car legal and on the road, but yes, it still has the problematic starter which sidelined it half a decade ago.

WHICH IS why I travel with a hammer. The remedy, you see, for a starter with a stuck solenoid is to tap the housing -- fortunately Toyota starters of that era are mounted high enough to be reached from above the engine (but be careful with that claw when you pull the hammer back out).

BUT WHY does this work? Personally, I didn't see why it would, even after a few successful whacks -- that is, until I noticed a magnetic attraction between the housing and my hammer...

A SOLENOID is a very simple electrical device that uses an electromagnetic field to move a steel core in one direction, usually with a spring to push it back (this is the mechanism in a standard doorbell). Somehow, my starter's housing is becoming magnetized, and this interferes with the function of the solenoid (which moves a gear into contact with the flywheel, so that the starter motor can turn the engine over). Whacking the housing with a hammer doesn't physically unstick the solenoid -- rather it degausses (nullifies the magnetic field of) the housing. With the interfering magnetic field removed, the solenoid can function as it was intended to.

A REBUILD of this starter will not solve the problem. Oh, it might behave fine for a while, but sooner or later the magnetic field would generate again. A replacement starter may behave in the exact same way -- as past replacements seem to have done on this car...

THIS SORT of thing isn't covered in the Haynes manual I picked up today, but my limited knowledge of electromagnetics gives me some clues. Though it wasn't meant to, the starter solenoid is generating excess magnetism, temporarily magnetizing the housing. The housing's field degenerates over time (or abruptly, through judicious use of the hammer), but not at a predictable rate (variables such as temperature and humidity are factors). There may be a low amperage short somewhere, giving the solenoid enough charge to slowly build a larger and larger magnetic field, until the housing becomes gaussed enough to keep the solenoid from functioning.

THAT SHORT, if it exists, will be tracked down and corrected. If one cannot be found, the solution will be to rig up some kind of anti-gaussing device -- perhaps an induction coil...

THE MECHANIC who nursed this Cressida back to life reported a short (which he could not locate) that drained the battery over a few days, but something tells me the key was left in the 'on' position during that time -- it did not drain a second time when left to sit again. If there is indeed a short in the starting system, that was likely the culprit -- not the glovebox light, which is on only when parking lights and/or headlights are on. Then again, it might have been indicator lights in the instrument panel...

"BUT HOW does it drive?" you ask. Well, it goes really well, and stops just fine, and the ride and handling aren't bad either. For now, at least, there doesn't appear to be anything mechanically wrong with it -- except, of course, the starter.

DON'T GET me wrong -- there are plenty of problems, but none of them get in the way of getting down the road (once it's been started). Power windows, doorhandles and locks, rear armrests, and the glovebox door will all need attention, as will the fuel guage...

OH, AND the steering column surround is cracked -- leading me to believe that someone, at some point, tried to steal (or succeeded in stealing) this Toyota sports sedan.

IT HAS more wrong with it than I thought, but nothing that can't be taken care of, certainly nothing that will make me regret spending what I did to get it going again.

THE SHAKESPEARE play? I tried, but could not slog through the flowery dialogue, and found nothing to support the idea of the title characters -- either Troilus or Cressida -- being ghosts, beyond one line with a reference to India... Oh, never mind. I skimmed over the Cliff notes. BFD (yawn).

AS WITH any project car, this one may never be 'completed'. However, it could theoretically be driven coast-to-coast as it is now. Seriously -- it is that solid.

FUTURE ENTRIES here will be from the road...




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