Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: merrill on October 09, 2007, 11:44:24
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well, I am out of ideas,
66 230 sl rebuilt motor etc, new ign parts, inj pump and injectors etc....
when I first put the car back together it ran great, no pinging.
torqued the head, adjusted the valves, adjusted the inj pump via the richness test, now it pings during acceleration.
the distro is the 051 with vacuum retard, all seems to work ok.
I have actually backed the timing off, so now it is at 26 deg btcd at 3000 rpm.
Hans at H&R is out of ideas as am I.
Thoughts, Ideas?
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
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I gotta ask:
Did you check compression to see if one or more cylinders is too high?
Did you use the same crank? Was it checked for tolerances?
How about cooling? Are you running hot? Could you do something to run cooler?
Have you tried a cooler spark plug?
How is the intake manifold gasket? leaking?
1967 230SL Havana Brown Auto with A/C
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A couple of things come to mind.
Cutting the head on these older high compression engines can raise the compression enough to make it unrunnable on available fuel. I know some people on this board will think less of me but when I rebuilt my head I didn't let my machinist even measure it for warp because I refused to cut it below stock. I figured it was sealed when it came off and the cam didn't bind so I decided to leave it as is.
It could be that when you leaned it down you might have raised combustion temperature enough to start the pinging. If you have not tried Sunoco 94 and it's available in your area try it. I find it the most consistent of all the fuels I have tried. If not try some octane booster.
I find wild variations in octane from fuels that are supposedly the same octane. I tuned my car to run on Sunoco 94 and it pings on anything less. A few times after buying "93" octane along the interstate the quality was so low I have had to pull over retime my engine to not ping.
When an engine "pings" it disturbs the airflow across the piston and more importantly the boundary layer or thin layer of air that adheres to the piston top. What this all boils down to is that the temperature of the piston top can soar to three times normal. So in short PING = BAD.
If all else fails keep dialing the timing back until it no longer pings.
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guys
thanks for the replies,
regarding cutting the head, metric motors rebuilt the entire motor
the head had a minimal cut when resurfacing.
distro has been backed off to 26 btcd at 3000, s/b 30 deg at 3000
I did add some octane boost which did not make any difference
compression - I have not checked since the rebuild
used original crank - metric did the rebuild assume it was checked
temp is solid at 80 c
tried 2 different sets of plugs ngk bp6e's and bosch wrd9's
last time i checked the for leaks I did not find any leaks
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
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Try locating TDC by some other means(dowel in the spark plug hole and GENTLY turning it to find where the piston travel is at the top) and compare it against what the timing marks are telling you where TDC is. I don't remember how the front hub is keyed to the crank but something could have slipped.
In other words what you see on the marks may not be right.
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Time it by feel, turn the dist. until it runs good. Do some zero to 60 performance runs ans compare. Some engines just don't time well with a timing light.
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Matt
it is possible that one of the springs has fallen off of the centrifugal advance weights. this will casue the timing to advance too early in the rpm range.
I know that Benz Dr. Dan will cringe at this, but when I rebuild these distributors I cut one coil off of the springs to increase the tension and slow down the advance curve.
I have never needed to use any fuel other than regular.
Good Luck
Al Lieffring
66 230Sl
New blue top just arrived
new gas tank on order
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My compression is 195 psi and i'm running regular Costco gas. Timing is set to the book but I have reworked the stops on the distributor flyweights to give me 33 degree of advance @ 3,000 rpm. No change to the springs. Pistons are Mahle and flat. Flush with the deck. Head is new and not machined. Cam is 08 with 09 waiting to be installed. The small space under the intake valves promotes even combustion without pre-detonation. Honda did a lot of research about that. Pinging is very bad! Don't drive it! Inspect ignition timing at 3,000 rpm and verify that it comes up gradually from idle. Check plugs for heat range. check valve timing & compression. Check intake valve clearance at 5 deg btdc. Look at the book for that procedure. Don't assume that the engine has been properly rebuilt.
'69 280SL,Signal Red,Automatic,retired engineer, West-Seattle,WA (http://www.sl113.org/forums/uploaded/theengineer/20051219121123_Drehstern.gif)
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all
so how would I inspect the distro weight springs?
the engineer,
this is a new issue. I put 600 km on the car with out pinging.
something has changed.
Plugs are new, same type as the ones I started with.
the only real change is torque hear and adjust valves (snug)
leaned out inj pump via the richness test.
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
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I agree that you not run this engine if it pings. You could ruin it very quickly.
If a spring broke inside the distributor it would advance too quickly. I've seen this a few times but it's rare. It should be 30 degrees at or before 3,000 RPM. The actual spot can vary somewhat but most engines will reach max advance before 3,000 so I can't imagine it's a problem with fuel or too high compression ratio. My engine is around 180 PSI and it seems to run fine on anything but regular. I can run it on 91 but it has more power using 94.
So, it would seem to me that you should look closely at the distributor advance. An engine is most likely to ping ( where you can really hear it ) if you have too much timing advance.
Dan Caron's
SL Barn
benzbarn@ebtech.net
slbarn.mbz.org
1 877 661 6061
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When you put the engine together,did you tighten the clamp that keeps the distributor from turning? Get a timing light and verify the timing: At idle, it should be about 3 deg. after top dead center and as you speed up the engine, (have a person on the throttle & read the rpm's)the timing should advance smoothly to about 30 deg before top center at about 3000 rpm. This test is with vacuum connected. It is much easier to see when you remove the hood. Test the vacuum advance mechanism: Using a vacuum tester, pull a vacuum on the retard mechanism and observe rotation of the distributor plate clockwise. There should be no vacuum leak. If you can, exchange distributors.
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Any carbon in the combustion chambers can raise the compression ratio. Any chance that the rich mixture may have built up some carbon?
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I use decarbonizing aerosol in my engine at each oil change. You get it at a marine dealer, OMC makes one, Yamaha makes one, these are primarily for outboard boat engines. The stuff cleans carbon like nothing else. I spray it in the intake then into each spark plug hole and let it sit overnight. Run the engine, then change the oil. There is also a fuel additive I use every so often to help with decarbonizing made by OMC. The aerosol is great for parts cleaning also. This may not help the pinging, but it is great regular maintenance. I use it in all my gas engines. In the early 80's the fuel companies took the dispersants out of fuel and this resulted in older engines getting carbon buildup, thus the advent of the 2 stroke TCW-3 oil, it has the dispersants in it. The end result if not used in high performance 2 strokes is a ring of carbon on the head and the top piston ring and cracks the rings, a condition called ring jacking.
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so, here is an update and a correction.
I have the 009 distro not the 051, I know the 009 replaced the 051
I checked the retard vacuum at idle, hooked up a vacuum gage in line so I could check it live. At idle there was at least 10 hg/mm then when I inceased rpms the vacuum dropped to zero.
I re installed the old condenser I had
Set the timing at exactly 30 deg btdc at 3000 rpm
at idle the timing is about 3 atdc
car started right up, got the idle rpm's set to 850 rpm
did the richness test, seems ok
took it for a drive, still seemed to ping a little, just a tad.
? are the points for the 051 and 009 the same?
shoud I check the valves? Since I set them snug maybe set them not as snug?
thanks for the feedback
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
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Matt,
quote:
? are the points for the 051 and 009 the same?
No, Have a look here under Maintenance, Service parts table:
http://www.sl113.org/wiki/pmwiki.php?n=Electrical.Distributor
naj
68 280SL
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No, the points for the 009 are different:For the 051 it's Bosch P/N 1 237 013 027 for the 009 it's 1 237 013 112. The 009 has an alu housing and replaces the 051
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well, that is not it, I have the correct points installed.
I may check the valve adjustment, I did make them snug last time.
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
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What do you mean by "snug" ? You ever heard of "specifications" There's a reason why things have to be adjusted to "specifications" Such as pinging which will destroy your engine.
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I'd make sure the engine is stone cold and readjust the valves. I've never done my SL's But on my Triumph you had to use a feeler gage to get the right distance. Torque wrenches are great too.
1967 230SL Havana Brown Auto with A/C
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Why would anyone think valve adjustment has anything to do with an engine that pings? It doesn't.
However, set the valves because it can't hurt to have them right.
Look at timing.
Dan Caron's
SL Barn
benzbarn@ebtech.net
slbarn.mbz.org
1 877 661 6061
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As far as I know the main causes for pinging are too much heat or too much compression (for the octane rating).
contributing factors to these include:
too-lean fuel/air mixture (not enough gas for the air present)
incorrect valve timing
engine cooling system inadequacy
faulty exhaust gas recirculation (EGR) valve
high intake-air temperature
excessive carbon deposits
poor combustion chamber design/shape
wrong spark plug
But if the valves were adjusted wrong, it couldn't hurt to get them right.
1967 230SL Havana Brown Auto with A/C
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I was thinking about valve clearences today and if there was a way they could contribute to pinging (contrary to Benz Doc's opinion).
I know it can make a car run hotter. I dug around the internet for corraboration. I found this on a valve company's website.
"Too little valve clearance throws valves out of time. Valves open too early and close too late. This causes the valves to overheat due to hot combustion gases rushing past valves when out of time. Overheating lengthens valve stems which prevents proper seating of valves. The valves seat so briefly or poorly that normal heat transfer into the cooling system does not have time to take place, causing burned valves and low power."
As I was saying in an earlier post. One of the things that can cause ping is excess heat. The question is if the hot valve would be enough of a hot spot to create a secondary ignition.
Knocking and pinging result when the fuel/air mixture self-ignites somewhere else in the cylinder, away from the spark plug. In these cases, the combustion from each source burns toward the other until their leading edges — called the flame fronts — literally collide, causing the ping or knock sound.
1967 230SL Havana Brown Auto with A/C
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well, checked the valves today and most were tight, so I ended up doing the valves.
checked the dwell and timing which were spot on
did a richness test, the car barely increased in idle, so I increased the mixture x2 clicks.
took the car for a drive, I could still hear something but maybe not pinging any more.
I have a local indy I am going to take the car to. maybe they can figure it out.
matt
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
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I had an engine that lost compression and was smoking a little bit. After I took it apart I found two cylinders slightly scored and one piston and its rings slightly scuffed.
Unpon further inspection I found a loose valve guide and some worn valves which were letting engine oil get into the cylinders. In this case the extra oil getting into the cylinders was causing the engine to run hot similar to a lean condition. The carbs were working properly ( 190SL engine ) and the coolant temps never went above 180F. I heard no pinging during driving yet it was still gamaged. Engine used a liter of oil in about 400 miles.
Is your engine smoking or using oil? Does it ping when cold or only when hot? Does it ping under light throttle up or heavy?
Adjusting the valves will make it run better but I still don't think that's the main problem. What is your compression readings?
Dan Caron's
SL Barn
benzbarn@ebtech.net
slbarn.mbz.org
1 877 661 6061
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Dan,
the motor is only 800km since a rebuild at metric motors
1. exhaust does not smoke
2. I notice the pinging sound when cold and hot
3. it only seems to ping when under heavy load, once I get up to 60 mph I have a hard time hearing the sound.
4. I have not verified the compression since the motor is new
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
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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
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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
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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
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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
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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
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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
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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
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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.
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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
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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
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Hello Matt,
Very interesting, so where was the pinging noise originating from, the injection pump itself or engine pre-ignition pinging?
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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
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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
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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.
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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
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Matt,
is this the shut off screw?
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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.
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No. That screw that holds the assembly in place.
??? Hmm .. then which one is it? ???
Matt, can you post a picture please?
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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.
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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.
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Thanks Matt!
A picture is worth more .... :)