turning the engine by hand

[n/a]

Attempting to turn the engine by hand can be a challenge.  There is very little room between the front pulley and the radiator.  Turning the engine by means of the starter motor is hit or miss.

While perusing the MB Ponton site (yes, it was part of my quest to find answers to my electronic ignition problem), I found a post with a great technique for turning the engine by hand.  Here it is:

1.  Chock the wheels securely.
2.  Put the car in 4th gear and release the hand brake.
3.  Jack up the left rear wheel.
4.  Turn the wheel in the direction of motion.

I tried it and it works.  I guess this doesn't help you folks with automatic transmissions.  I thought I would share my discovery.

Happy motoring,
Don
Cleveland, OH
71 280sl

[knirk]

When I adjust the valve clearance I remove the spark plugs and then use the camshaft sprocket bolt to turn the engine. I think I read somewhere that this should not be done. Is this true, and if so -anybody knows why?

Per G. Birkeland
69 280 sl

[Cees Klumper]

Hi Per - all experts stress that moving the engine by turning the camshaft sprocket is a no-no. I don't know why, but I can imagine there's a risk of the chain jumping and/or too much strain on the camshaft towers?

Anyway what I do (automatic transmission, Don - thanks anyway!), after removing the spark plugs, is I slip the proper size socket onto the crankshaft bolt (27 mm I believe) and with the short extension on a 1/2 inch drive, it fits in there quite well. I move the engine from below the car which makes it a bit difficult to rotate the engine spot-on. A lot of standing up and getting back down.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello,
Yes Cees, the right combination of rachet and 27mm  socket works on turning the engine. 1/2" drive ratchet handle is a must. Don't forget to remove it when finished!
Removal of the spark plugs  always helps. I believe the earliest 230-SLs used a 22mm crankshaft bolt?

On automatics I like to use a remote starter switch. If you unplug the four prong plug at the nuetral safety switch on the engine  firewall, one connector activates the starter. I hook the other end  to the positive battery post.

Knirk, the danger with using the cam bolt is that the chain tensioner may relax enough during the process to allow chain slack to bunch up and jamb the chain. The cam sprocket may also jump links if the chain has enough slack.  Removal of the spark plugs does help and be sure to allow the chain tensioner to take up slack by moving your wrench back and forth during rotation. This will keep the chain tight and the tensioner pumped up. It is not an advisable method, but if you have gained a feel for it, use caution.



Joe Alexander
Blacklick, Ohio

[hands_aus]

Hey Joe,

What size socket would be needed on the early 250SL?

Which of the four connectors on the neutral safety switch plug activates the starter?


Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Naj ✝︎]

Bob,
Should be 27mm. My '65 230sl uses that.
Re: Wiring - Sorry, mine are manual.
naj

65 230SL
68 280SL

[Cees Klumper]

Bob - I will find out which of the four pins 'handles' the starter and post it here when I do.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello Cees,
Thanks I am not sure which one I use.  I am thinking lower right?  One wire is ground find it with a test light hooked up to  positive battery terminal. It is safe to touch all the others with a hot wire once you have identified ground. Caution make sure the car is in park. It will start in drive gears if you accidentally leave the ignition on.
Of coarse if you have the ignition disabled (spark plugs out coil wire off etc) you are safe.

I made a nice remote starer switch from an used transmission kick down switch and a couple of wire leads.

Joe Alexander
Blacklick, Ohio

[knirk]

Hi Joe,

When using the remote starter switch, are you able to turn the engine in small steps, or is it the "try and see where it stops - and then try again" method. What about wear on the starter drive pinion and starter ring.

Per G. Birkeland
69 280 sl aut 834
Norway

[ja17]

Hello knirk,
With the spark plugs out, the remote switch can be very quick and precise. In addition I make a diagram of which valves are adjusted so none are missed. Valve adjustment is done only at 12,000 mile intervals,  with the plugs out and no compression, I consider starter wear neglegable.


Joe Alexander
Blacklick, Ohio

[hands_aus]

Hi Naj, Cees and Joe,

Thanks for the info.
I just flicked the starter when I was teaching myself how to install new points.
It was very hit or miss.
Fortunately now, I have replaced the points with electronics.
I tried to rotate the engine by hand but there was not enough room for my arm from above and doing it from below seemed to be very hit or miss too.

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto