A strange thing happened!!

[fmen3366]

Boy, did I just do something dreadful to my engine? This afternoon, I tried adjusting my valves and re-torqueing my head bolts (70 280 sl).

Opened my computer to the wiki site for Joe A’s step by step valve-adjustment procedures. Followed every step until I reached the part where I had to crank the engine to get the correct cam lobe position. I first cranked the engine but realized I still have the fuel pump running so I took out the #4 fuel pump fuse. After the second or third crank, the craziest thing happened. When I turned the key to the off position, the starter remained engaged. I took out the key and still the engine continued cranking.
 
Panic started to set in.  With the darn valve cover out, the spark plugs removed and oil spewing all over the %3@ place, I thought the engine was toast. (No kidding but I could feel the oil pressure coming out of the spark plug holes) It may have a been a couple of minutes but it might as well have been hours as it felt like it. I finally found a wrench to get the battery ground terminal off to stop the mayhem.

Never finished adjusting the valves needless to say. I wanted to make sure that the engine still is OK so I put the valve cover on and replaced the spark plugs. Now every time I connect the battery cable, (still without the key in the ignition) the starter may not be engaging the crankshaft BUT a loud whirring sound is coming out of the starter motor. Again, all this without the key in the ignition!

Whew…Well first and the most obvious question is-- did I hurt the engine? I hope not but If so, how bad? (BTW, this is a new Metric Motors rebuild. Also I checked the oil level after the incident and it was a quart low.) And secondly, what caused the continued cranking? Do I have a bad ignition switch? A bad solenoid in my starter, maybe?

Tomorrow I will remove the starter motor and check its condition. Meantime, folks, what just happened?

Andy

[SteveK]

Andy, the good news is I would be surprised if this hurt anything. Being a quart down is no big deal, particulary since the engine was not running.  If oil was flopping all over the place, good distribution was occuring.  Too bad it happened in an uncontrolled mode, it's kind of fun to watch how the oil comes out of the cam distribution pipe.  

It sounds like a stuck ignition swithch, but I'm not sure how that happens.  I'd start with a good forum search.

[ejboyd5]

It sounds as if your ignition switch chose that moment to stop playing nicely in the sand box.  Can't imagine that any damage was done to the engine.  Disconnect the ignition switch and run a hotwire test to see if it starts normally.

[waqas]

Was your door ajar when this happened? Is you brake fluid low?

If so, then your issue is the result of a common quirk in the later cars related to the brake fluid warning and door ajar circuits, causing the car to continue running even after the ignition is switched off.

Here are some threads which touch on the issue:
http://www.sl113.org/forums/index.php?topic=3222.0
http://www.sl113.org/forums/index.php?topic=4019.0
http://www.sl113.org/forums/index.php?topic=10282.0

[fmen3366]

Hi SteveK and ejboyd5,

When sanity finally overcame panic, my idea of “fun to watch” was pressurized oil molecules hitting me smack in the face like bits of metal shavings. It was a scary sight. Fortunately, it was just oil.

Wagas, thanks for the forum links. My brake reservoir is full. I suppose it is my ignition switch which I’ll be disconnecting shortly.

More importantly, 3-0 (plus my mechanic friend) consensus from you folks that no harm was done to the engine.

Andy

[Anfinn]

"My brake reservoir is full"
Just a small point; If one of your reservoir floats has developed a leak, (mine had) it will sink, and the effect is the same as if the fluid level is low. A sunken float is difficult to spot.

All the same, my first suspect would also be the ignition switch, I had to change that as well. Quite a job.

[Ron]

Hi Anfinn, I'd start by taking both wires off the starter, the large and small.  See if the small gets 12v when key is off and battery connected.  Then go after issues with switch, door light thing, etc.  If key turns 12v on and off, then go into starter.  It may have a stuck plunger in the solenoid.  (I have not had one apart, so that's a guess.)  Ron

PS I had this happen on a 1984 Ford diesel, on the first camping trip with the thing.  In Redding, CA, late Sat. afternoon, 100+ degrees in a gas station after fueling, I started it and the starter stuck on.  Key had no effect.  Tools buried in cab over camper.  Two batteries to disconnect.  Starter was smoking by the time I got it stopped.  Tried reconnecting battery, starter still ran.  Lucky to find a dealer open, only a salesman there.  He says: "just go under with hammer and hit the side of the starter."  That did it!  Rest of trip with battery wrench under my feet, but it never happened again.  Ford replaced complete starter/solenoid (design like our cars) under warranty upon return home.

[ctaylor738]

This exact situation happened to me when I went to start my (ex) 280SL after rebuilding the head.  It turned out the be the starter solenoid sticking and continuing the power to the motor after the key was released.  I had to disconnect the battery to get it to stop.  A rebuilt starter fixed the problem.

[ja17]

Hello Andy,

Quite an unlucky circumstance! When working on a car, having a battery cable loosened and ready to take off is always a good safety precaution. Electrical shorts, runaway starters, can be dealt with quickly in this way.

There is hardly any chance that any damage occurred to the engine. You would have to pump all the oil out and continue cranking for a very long time in order to cause any possible engine problems. Even then, a cranking engine, without combustion, does not develop much heat, load, or friction from just cranking. You have a mess to clean up and need to find the root of the problem. The starter sounds like a good place to start. Keep the battery unhooked while removing the starter.

The small wire on the starter is the wire from the ignition switch . If it stays hot (energized), the ignition switch or an electrical issue is most likely the cause. If not hot (not energized), and the starter still stays engaged, then the starter is the most likely culprit.

[glenn]

All's well that ends well.  !!  Great story, as long as it's not (me).   It's a great oil shower with the valve cover off, eh?  Video?  Did it once, just to see it..... ..  How about turning engine with a socket and bar?  Couple of turns and done. 1-5-3-6-2-4 interlaced with 1-5-3-6-2-4.

   And, does the starter/solenoid tend to stick, if the engine doesn't start thereby overspeeding the starter?

[fmen3366]

Gents,

Appreciate all the responses. Found the culprit--my starter. After banging on it a couple of times, got the solenoid unstuck.

Just finished adjusting the valves and test drove the car. Very happy with the result. This FORUM is just a fantastic source of info and help!!!Carry on guys.

Andy

PS   Reason I didn't use a wrench to turn the crank manually to begin with is because the shop that installed my motor replaced the crank veeplulley bolt from the standard 27mm (70 280sl) to ? With the a very tight space to work under, it was a challenge just finding the correct size wrench that fits. I'll save that for another day.

[ejboyd5]

A solenoid that stuck once will stick again.