can't stop this pinging,.....

[merrill]

well,
thought I was on to something, I ready joe's reply to a question on re torquing the head and making sure the standoffs for the valve cover do not twist and cause tapping.

no such luck, checked them yesterday and there were no clearance issues.

then I noticed something else, maybe joe was correct in his earlier post about this being an ignition problem.  I have a volt meter connected at all times and when accelerating voltage goes up to 17 and the red light in the dash comes on a little and the pinging occures.

I thought maybe I mis connected the new alternator, so I connected a volt meter to both of the lugs on the alt, started the car and they both put out the same voltage - dang.

could I have mis wired the 3 prong connector that plugs into the back of the alt?

I currently have the old volt regulator connected, using this unit the only time the red light comes on in the dash is when the voltage goes up over 16v.

I also have a new voltage regulator, when I plug that one in the red light comes on all the time?

I need to put a voltage meter after the ballast resistor and see if the voltage getting to the ignition system is too high!

Would that cause pinging???

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[merrill]

so, found the D+ and DF connection on the alt were backwards.
corrected the wiring, then the voltage at the ballast was stable.

took the car for a spin, still pinged a little,  timing at just around 27 deg btdc at 3000 rpm, dwell right at 39, did richness test
and the rpm's went up to about 1100 but not too high.

off to the mechanic on wed, maybe they can figutre it out

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[merrill]

well, took the car to the indi shop, drove around for a while and he said the noise was coming from the fluid coupler or the disk on the motor that the coupler attacheds to.

went back to work and with a friend,  put the car in gear, brakes on and foot on brake pedal, pushed on the gas pedal a little and sure enough you could hear the noise.

called the tranny rebuilder, he said to check the 4 bolts that secure the coupler to the motor to make sure they are tight and if so, then with the motor running, have someone put the car in gear and see if the coupler is running straight.

more work for the weekend.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[ja17]

Hello Matt,

Sometimes these bolts are tight but are too long and bottom out so they never secure the flex plate.  Make sure you have both washers under each bolt head also (springy washer with flat washer).

Joe Alexander
Blacklick, Ohio

[merrill]

joe,
checked the 4 bolts that connect the flex plate to the fluid coupler.
the tourque setting should be 25 ft lbs, tourqued them to 27.
all needed a little tightening.

drove the car, no change.

I thought I would try something.  with the brakes set, running, put the car in gear (reverse and drive) opened the hood, then increased
the rpm till I heard the pinging.  still heard it.  It seemed to be coming from within the valve cover.  I walked around the engine bay both sides doing this test, the sound sure seemed to come from the valve cover.

Put the car in neutral, did the same test no sound,  So this only occures when the car is in gear and their is tension in the system.

I may take the car somewhere I can get it on a lift and do the same test.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[Benz Dr.]

Try this:
Start the car and let it warm up. Turn the key off and then back on again just before it stops running. If you miss it try again and repeat this a few times until you can keep the engine running. If you hear nothing when you do this test that's a good thing. If you hear a click or knocking sound that's bad.


Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[merrill]

dan,
did the test,  I did not hear anything....

the motor just kicked back on, no problem

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[Ben]

I hate to say this but you could be hearing piston slap !

I know 230SL's suffered from this even when new, Mercedes replaced a lot of motors under warranty. There were numerous redesigns of the 230SL pistons but according to the late Roger Edwards (RIP), who worked on W113's since they were new, they never really cured it and it happened particularly on No.1 cylinder.

You could test by going for a quick drive with no.1 plug lead disconnected and taped up !

I hope thats not it but I have the same noise on a rebuilt 230SL motor and I've checked everything you have !!

Regards,
Ben in Ireland.
'64 230SL 4sp.

[merrill]

I had a breakthru today,  after thinking about the affect of the idle adjustment and linkage agjustment on the mixture I figure the pinging was due to one being out of spec.

so,  went to the garage, warmed up the car, then opened the tb ever so slightly till the idle increased.  and set if there with the 10 mm set screw.

then, lowered the idle using the idle adjuster screw.
took the car for a drive and yikes the pinging was worse.  HA, so the car was lean causing the pinging.

put the tb back to the original setting, corrected the idle, then adjusted the tb linkage so the linkage was at the shortest throw without affecting the cross linkage.

took the car for a drive,  no pinging...

next step will be to make sure the inj linkage is at its max setting
when in the closed position.  Then check the co2 at 1500 rpm.

per the mb tech manual at 1500 rpm the co2 should be 4 - 6%
when I checked it today it only got up to 3.8 maybe 3.9%

I think I am close to having this resolved.

thanks everyone for their input
matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[merrill]

Well, it appears the problem is solved.

After trying everything that was suggested and replacing the distro I ended up pulling
the inj pump and this time I sent it to Gus at Pacific.

I pulled the pump because Hans at H&R had me make several adjustments on the pump and I was not sure IfI had the pump back to the starting point.

Gus found the pump to be calibrated correctly and the settings back to spec - good
Gus did find that the injection pump thermostat was working but not completely shutting
off the extra fuel.
I had Gus install a new thermostat, re check everything, (including thermostat function) and send the pump back to me.

Took the car for a 24 mile drive today and I did not hear a thing... the car ran great.

According to Gus the one way I could have checked the function of the thermostat was to
turn it off. 
If the pinging went away I could have discovered or eliminated the issue a long time  ago.


I need to send this tip to Joe Alexander so he can make a note in the injection pump tour.

thanks again everybody.
Matt

[ja17]

Hello Matt,

Very interesting, so where was the pinging noise originating from,   the injection pump itself or  engine pre-ignition pinging?

[merrill]

Joe,
It sounded like the noise was coming from the cylinders.
I took the car to a local indy mb mechanic with my friend and all 3 of us could hear the noise.
the noise was easiest to hear over an the intake side near the injectors.

I could re create the noise when the car was stopped, e brake on, put the car in drive then with the hood open give the car a little gas.

I would also notice the noise at speed.  (55 mph just cruising)

Since gus replace the IP thermostat the noise is gone

[jameshoward]

Matt,

I've been following this post with interest as I have a not dissimilar problem - I think.

Is there are relatively simple procedure that you can post in order to be able to eliminate the thermostat? i.e. what does one have to do to take it out of the equation and either identify it as a culprit or move on to something else? (I was hoping for a blow by blow account if you have one).

James

[merrill]

James,
on the 230 there is a way to eliminate the IP thermostat.

If you look at the IP, locate the thermostat.
look down to the base of the thermostat, just forward of the thermostat you will see a nut with
a "o" on it.

When this is turned 180 deg it shuts off the IP thermostat function. 
The thermostat still functions,  but the lever the thermostat pushes on is now pushed down
all the time.

you will not have the "extra" fuel on cold start that you had with the option on.
I guess one could get the car warm, then turn off the option then drive the car.

If you need I can find a photo and link it to this thread.

[jameshoward]

Matt,

Many thanks; I'll have a go. If you do happen across a photo, it'd be helpful. I can't think where you mean on the IP but I haven't ventured out to check the car. It may also be useful for the wiki or those that have a similar problem.

Thanks again.

James

[66andBlue]

Matt,
is this the shut off screw?

[Benz Dr.]

No. That screw that holds the assembly in place.

When we were having all these ' distributor ' problems I questioned how it could be the distributor if it wasn't going all the way to 30 degrees. Mixture ratios are critical on these cars and I was pretty sure it never was an ignition problem.

One of the many problems you can run into is called '' chain of ownership or command. ''  You remove the engine or have someone do it for you. Someone does the basic engine rebuild and you put it back together. Someone does the injection pump. Someone else does the cylinder head. Another shop does some ignition work. Even if one place does everything and all you do is the initial engine break in, you can still run into problems.
 
Now it comes time to put it all back together. Looks like you have a few things missing - not good. The plater lost a few pieces of hardware? Nope. Found them in the bottom of the box. Maybe a few things were done wrong or not well enough and now you have to figure out where the problem is. It's too far to send it back to the builder and sending it to a shop to let them figure it out could be very costly - but not always.

 Even though I do all of my own work in this area I still run into these problems sometimes. I can't expect it would be any easier for a novice and simply knowing that won't bring an answer over the phone or to this site. Like anyone else, I know my own work and can speak for that but I can't or usually won't speak for others.
 The starting and break in of the engine is as important as the rebuild. Fixing small problems before they turn into big problems and then dialing everything in takes some know how and experience. It's not for everyone but we can all learn from each other.

Let this be a small lesson learned for everyone who reads these posts ( including myself ) . Nothing is as simple as it seems and nothing is really that complicated either.

[66andBlue]

No. That screw that holds the assembly in place.

Hmm .. then which one is it? 
Matt, can you post a picture please?

[Benz Dr.]

Matt described the screw the way it should look and by location. I've found that some of these things have a small roll pin that holds everything in place and turning the screw can break things inside the housing or snap the screw off. I'd look at doing this as a last resort in any case.

[merrill]

Here are some photos of the bolt that turns off the inj pump thermostat

It is located on the front side opposite the thermostat air filter.

It can be kind of hard to find as  it is hidden below the 2 coolant lines that connect the the thermostat housing itself.

also, Dan is correct, mine has a cotter pin thru it, so make sure if you have one you remove it before trying to turn it.

[66andBlue]

Thanks Matt!
A picture is worth more ....