

| Subject: | Re: Trying to understand starter stuff |
| From: | John Rodgers |
| Date: | Tue, 23 Dec 2014 11:57:10 -0600 |
I have one of Jay Browns starter relays on both of my vans. Recently I discovered that I could pull the relay cover and actuate the relay by hand, thus making it work as a remote start switch when working onthe engine. Very handy. John On Dec 23, 2014 10:49 AM, "Stuart MacMillan" <stuartmacm@gmail.com> wrote: > Here is a nice relay setup: > http://www.thesamba.com/vw/classifieds/detail.php?id=1119534 (Won't work > with an automatic with factory cruise control for some reason though.) > > Stuart > > -----Original Message----- > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of > David Beierl > Sent: Monday, December 22, 2014 9:46 PM > To: vanagon@GERRY.VANAGON.COM > Subject: Re: Trying to understand starter stuff > > At 11:03 PM 12/22/2014, Marc Perdue wrote: > >Hi all, > > Excellent! I now have three verified cases of a starter control lead > coming > off without causing a hard start failure: your Van, my '89 2.1l, and my > '71 > Fiat 128. I solved that one after running out of gas in an uphill line to > buy gas somwehere in upstate New York, when it became clear that the motor > would crank if it were torqued slightly sideways. > > Starters have some challenging necessities. They have to have big cables > direct to the battery; a heavy switch that can switch them on and off under > load without burning up quickly; a means of engaging the pinion into the > flywheel ring gear; and a positive means of disengaging it when the motor > starts, so the starter doesn't burst from overspeed. > > Back when the world was new the electrical switching was done by a > heavy-duty relay that would today be called a contactor but was commonly > known as a solenoid. It was mounted somewhere between battery and starter, > and a light wire from the starter button or key switch used to activate it. > For testing you could use a screwdriver to jumper between the big battery > cable connection and the control terminal. Starter "solenoids" were a > commonly available FLAPS part and no doubt still are; as they regularly > failed in use. Last one I bought cost three or four dollars. Excellent > for > switching a couple hundred amps DC but not rated for continuous duty. > They're meant for starting cars, once per trip segment, plenty of time to > cool in between. > > Engaging and disengaging the pinion was accomplished by a clever invention > called a Bendix drive. The pinion was mounted on the starter shaft and > engaged a pair of helical slots in the shaft. It was kept wound down to > the > bottoms of the slots by a light spring that pressed it away from the end of > the shaft. When you hit the button, the shaft would spin violently and > hurl > the pinion into engagement during the first few revolutions. And when the > motor started, the ring gear would spin the pinion back down the track out > of engagement. It worked a treat, so long as you kept it clean and not > gucked up with oik or grease. The Bendix Corporation waxed fat and happy. > > Came the day that someone thought it would be better to combine actions. > If > the contactor were mounted on the starter it would simplify wiring, and it > could be used as a real solenoid, to physically throw the pinion into > engagement as well. Or rather a solenoid could be thus used, and with some > contacts added could perform the contactor function as well. An > overrunning > clutch would handle decoupling the starter from the engine, leaving the > pinion in engagement but not forcing the starter to keep up with it. Full > disengagement would happen when the key was released. Over a decade or two > this method largely took over for starting cars, and that's how Bosch did > it > on our starters. > > The big cable goes direct from battery to starter, where it meets the > thinner wire from the alternator that supplies charge. That connection is > subject to corrosion. The ground connection through the starter, bell > housing, transmission ground strap may be defective. The solenoid itself > wears and gets crudded up; you have to take the starter apart to clean it > up. Non-A/T versions of this starter have no bearing at the pinion end; > the > shaft inserts into a sleeve bearing that's in turn inserted into the bell > housing of the engine. That wears and needs renewal. And the solenoid > gets > its operating power not from that fat cable but from battery to panel to > ignition switch and back to the starter. It only needs two or three amps, > but it's a long trip. It's easy to see if a relay could help it -- just > jumper the alternator B+ post to the starter control terminal. You can > reach it by reaching your hand over the top of the bell housing, quite a > way > forward and then to the right. There's probably a spare terminal to latch > on to. If it cranks snappily that way and listlessly by the key, add a > relay. If it makes no difference, neither will the relay. > > Yours, > David >
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