>I still have my original starter on my '79 MGB which has 115k miles on it. I
>am amazed that the starter has lasted this long. The problem is that sometime
>swhen I turn the Key, The starter will not engage. What I assume is happening
>is that the solenoid is not engaing the gear to the flywhell to crank the
>engine. I was so bold as to turn the key with the car still in gear and
>nothing happened. I can hear the starter turning but the engine doesn't crank.
> Has anyone else had this problem?
I've had similar problems. I have a '77 MGB with about 80K miles on it
and twice in the last five years I've had to deal with starting problems.
The first time it turned out to be the ignition switch itself. You can
figure this out easily by just checking that the ignition relay is being
activated when the key is turned. If the relay doesn't click then the
problem is somewhere between the relay and the ignition switch.
The second time was more closely related to what you describe. When I
turned the ignition key, nothing would happen even though the relay was
turning on and supplying voltage to the starter. The solution to this
was to clean the contacts inside the solenoid that engages the starter.
This solenoid also acts as a relay. It works like this: You turn the
ignition switch on; that turns a relay on; that relay supplies power to
the solenoid which engages the starter motors gear to the engine -and-
the solenoid also closes some heavy duty relay contacts that supply
LOTS of current to the starter motor. If the starter is turning then
the solenoid is working (or else the starter wouldn't get any current)
and since the solenoid also engages the starter to the engine, the
engine should turn. This says that the something has happened to the
gears there. There are gears on the starter motor, gears on the
solenoid shaft and gears on the flywheel that turns the engine. One
possibility is that some teeth have broken off one of those gears.
Another possibility is that the starter or flywheel gear has broken
loose from it's shaft (unlikely I hope in the case of the flywheel
gear since that probably means opening up the front of the engine.)
The solenoid gear is supposed to spin, and (I think) may be able to
slide on its shaft also with a spring to push it out to the end of the
shaft (this is to make the engagement smoother.) That spring may have
broken so that the gear never reaches the correct position.
In any case, it is fairly easy to remove the starter and solenoid.
For safety, don't wear any rings or jewelry that might conduct
electricity and disconnect the battery. Remove the nuts that hold
the electrical leads to the starter (here's where you start thinking
"those battery leads couldn't have slipped back into place could they?"
It's only 12 volts but thats a lot of amps.) Then remove the wires (noting
where they go so you can put them back.) If there is a plastic hood
over the starter you may have to work it back at some point to get
access to bolts. There are a few bolts that hold the starter on
and when they are removed you should be able to pull the starter
out. Do NOT be under the starter when you loosen these bolts.
It is heavy and you don't want it to fall on you! Once you have
the starter out the solenoid is easily removed and disassembled
(you might as well check the electrical contacts inside while
you're at it--I think there's some nuts you remove and some leads
you unsolder and then the back pulls off) and you can also inspect
the gears to check for missing teeth, free spinning, or broken spring.
>From there, the solution should be obvious. If you need more
details on these procedures I can look them up for you in my
repair manuals (the standard repair manuals will tell you how
to pull the starter. One of the restoration guides tells how
to rebuild the solenoid.)
I was just wondering yesterday if there was any sort of freeware
expert system AI software that the archives of this mailing list
could be loaded into. Sounds like a business opportunity to me.
Ron
ron@vicorp.com or uunet!vicorp!ron
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