051 Dizzy Timing Help!

[vande17941]

I remember from these Forums being told that a  66 230sl with a 051 distributor needs to have 30deg + 10deg BTDC for reasons which were explained and made sense.

I'm running California at gas (91 octane) and I'm at about 36 BTDC still getting ping and running hot on the freeway. At 30 BTDC the thing was sputtering out at high RPMs.

Any ideas? Is it the crappy gas why I can't run as much advance? Should I just back of 2 deg at a time?

[rgafitanu@gmail.com]

Yes, back it 2-4 degrees at a time. Try also premium gas, made a huge difference to me.

[vande17941]

Premium gas in California is only 91!

Doesn't most of the country get to have 93?

[Benz Dr.]

Your distributor needs to be rebuilt. Sounds like it's advancing too quickly because your engine should never ping if it's working right.

[vande17941]

Here's the thing. I could see it pinging prior to 3000 rpms if it advanced to quickly....but its pinging under heavy load, high gear, 4000 rpm and above. After messing with it tonight, it appeared that it was set at 37-38 degrees on 91 gas. Reducing it to 34-35 degrees resulted in sputtering at 5200 rpm+ on 91 gas.

Car has 56k miles on it verified.

Does that still indicate bad distributor. Also it is NOT on the hotter NGK's everyone recommends it's on the normal NGK that is one cooler so plugs aren't making it worse.

If it's needs a rebuild...who does it, how long how much? Thank you!

[Cees Klumper]

Get  it rebuilt, put it in the trunk as a backup, and install a 123 electronic unit. I had a rebuilt distributor in my car but when I swapped it for a 123 unit I could really tell the difference.

[vande17941]

What's a 123? I have a Pertonix ignition inside the distributor. I didn't think about it, but has anyone heard of the electronic ignition causing probs?

[Benz Dr.]

Trying to point to just one cause can be fraught with problems. Everything that is part of ignition should be looked at including timing, fuel ratios, throttle linkage, IP problems and all ignition related parts. Pinging at high RPM's might be more about fuel than it would be ignition. Regardless of cause, running any engine while pining under heavy load is going to do damage.

What does it do under light or gradual throttle up to 4,000?

[vande17941]

Throttle linkage was checked/set again yesterday and it's perfect. However, awhile back I did replace the dash pot and progressive linkage to the manifold with an idle step-up motor and bracket so my ac would idle correctly. At that time, the linkage rod to the intake manifold fit exactly onto the new step-up motor bracket ball with zero rod adjustment required. Thought I would mention just to be thorough.

 I ended up at 34-35deg and the car definitely was down big on power compared to 2 degrees more advance. In both situations it ran fine until high RPM...with the ignition retarded at 34-35 it sputters (definitely  ignition sputter). At 37-38 it seemed to run fine and have a LOT of power.

I've wondered if its pinging on the freeway under heavy load at 4000+ because the car runs so warm. The car does run hot, but all of them I have ever been in run too hot for my. My plan before this was to recore the radiator either way. The car running hot can't be helping the situation.

How would it be possible to check fuel ratios at high rpm in a car like this without removing the injection pump? I've taken out the injectors to check operation and flow pattern and they were all good.

[ja17]

Check your engine compression. If your cylinder head has been over-machined, your compression could be too high on some cylinders causing your pinging problem.

[vande17941]

Will do. If the head was over-machined, I would be seriously screwed

[mbzse]

.../.... If the head was over-machined.../...

I suppose you know the minimum allowed measurement is 84.0 mm
See attached for example of measuring.
I guess you can do the corresponding measurement also on a mounted head

[vande17941]

I just looked at the test results I did after I did the valve job a couple years ago. I got about 160 across the board on a hot motor. Compression is probably fine.

[vande17941]

Benz Dr.
Will u please look at my post about three posts back and see if it gives you any clues? Thank you, sir.

[ja17]

160 is a bit high for a 230, but still should be OK. You might want to check it again in case it has a carbon build up. Typically, a warped head which is machined, has higher compression on the end cylinders (#1 & #6) mostly.

[Benz Dr.]

I've seen 230SL's produce anywhere from 150 to 165 PSI, and all were fresh engines. The third version with stepped pistons will give you the lower end and first and second version will give you higher readings. I'd be very happy to find 160 PSI. 

Your question:
 First of all, how hot is hot? 190 or maybe 195F is up there a bit but should be safe; 210F or higher is not a good idea. Some of the later US cars have a 100C degree switch ( 212F ) to advance ignition timing but I feel that's it's kind of useless. Useful if it comes on and works, useless in that your engine might already be so hot that it wouldn't cool down quickly enough to prevent any damage because once you get one that hot, the temp gauge will only go higher. So, lets determine how hot you are actually running. You could have two conditions; too hot and too lean. If you already know that you're running too hot fix that first. If the condition persists then look at your IP. If your pump is OK then we really do have a '' who done it. ''

If you are too lean at full load that can be adjusted out but it's not something that should be taken lightly. Too lean, too rich, too hot......... none are good for your engine. Believe me, removing the pump now for testing, if that is what the problem is, will be less work and cost than burning up your engine. Pinging at high speed ( 4,000 ) is asking for trouble.

I don't want to be an alarmist but you have something very wrong. 

[vande17941]

I think being alarmed in this situation is the correct think to do. So, thank you.

 I would say at highway speeds, pushing over 215 deg easy or more at 70mph on the California coast when it's only 75 deg ambient air temp. Seems to run cool enough around town though the needle will slowly creep up and stop at a drive-thru. It has a recent fan clutch that is working fine.

I'm going  through the ignition components again tomorrow and change the thermostat out (think I did the thermostat last year, but it's cheap).

Ivm also planning on a radiator rod-out or recore...though I have paperwork from the precious owner showing it was done 6 years ago.

Also, I contacted a guy who specifically works on these Bosch IPs and can rebuild or adjust on a dyno as needed.

So, ignition and cooling. Then, IP....and in the meantime, taking it easy.

[vande17941]

1. Took out the thermostat...it didn't start opening until 200 degrees...and slowly. Replaced it. Car runs 190 driving easy and 205 driving the crap out of it.
2. Replaced the spark plugs with the same NGK plugs...the miss at 5000+ rpm is gone.

Haven't had a chance to get it on the freeway but will do soon and report back.

[Benz Dr.]

Which thermostat did you use? I think the coolest is 79C. Bad plugs will cause a miss but more often at lower engine speeds. Getting the heat level down will clearly help.


You might want to try a bottle of water wetter. 

[vande17941]

I used a 79c, 174f, which is what it had in it before. However, when testing the old one in a pan of water, it didn't even start to open until 190 and was over 200 before 90% open. Plus it had wax leaking out. Of course, the old one was original MB from the local MB stealer only 2.5 years ago.

I'm pretty convinced I had a bad plug. It's happened to me two times prior when I was racing years ago,. For inexplicable reasons, a plug just wouldn't work correctly. The plugs would appear perfect, but just wouldn't run right.

I'm going ro drive it all day today and will report back.

[vande17941]

How does this radiator look? It was rebuilt in '13, so I don't have much reason to suspect it would be clogged.

[vande17941]

After changing the thermostat and the plugs, I drove it all day today in about 78-80deg weather.

This is what I got. 
1. Around town with AC on, moving stop-and-go then 25-45mph, then stopping for signals etc....about 195deg.
2. Sitting in line at a drive-thru restaurant not moving for 15min test with the AC on....about 215 deg
3. 85-90mph with the AC on....about 210 degrees.

Still a slight ping at high rpm in high gear. Need to check timing again...it's pulling strong and our timing light may be suspect. After checking timing, if it's still pinging, it's going on the dyno to check mixture.

[Benz Dr.]

That's still pretty hot for one of these engines. You may not hurt it in one drive but repeated hot cycles like this will warp the head. Did you add any water wetter yet?

 I realize it's your car, and no one else has asked, but do you usually drive your car hard like this? 

 It's the running hot that would concern me. Absent that, they're strong engines but they don't respond well to constant over heating.

[vande17941]

Where I live...Newport Beach, land of cars, you have areas where you hit traffic and then toll roads that make the autobahn look slow (exaggeratingn but you get the point). Every other car is a Ferrari, Benz, or Porsche.

The idea today was to test it after what we had done. And the temp reduced considerably. The ping too. I have never seen a w113 not run really hot...but I dont like it.

And yes, I have a race background but have never worn out a clutch in my life and never had a car need a bottom end or go less than 200,000. So, this temp & ping concerns me. My guess is scale in the radiator and engine, possible dizzy issue (unlikely), and too lean. I would like to have the engine in condition to be able to cruise 90-100mph for hours without concern. Since you are telling me that it still too hot...I will get on it and report back. Thank you sir!

[vande17941]

Side note...I drove a 280sl today and a 230sl. The 280sl was running so cool...so I took an infrared thermo to it and the guage was off by 30 degrees. The fresh 230sl motor without ac installed ran about 15 deg cooler than mine. So here we go....fun fun fun. But, it's a privilege to even have one of these vehicles to work on!

[vande17941]

Checked my temp gauge. It runs hot about 10 degrees until it gets in the upper range. The car runs absolutely fine on temperature until the air conditioner turned on. With the air conditioner turned on and the car idling, even with the fan clutch engaged, the car will just slowly heat up. An infrared gun shows no cool spots in the radiator indicating clogs. What's everyone's experience with what type of temperature increase you see running the air conditioner in idle situations and at highway speeds?

[vande17941]

After lots of research, reviewing shop manuals, etc, talking with two vintage Mercedes specialists (one who is ridiculously qualified and we'll known), and adjusting and driving three 230SLs it is clear to me that strobosonically setting with a timing gun a 051 distributor at 38 degrees BTDC at 3000rpm on a 230sl will turn the vehicle's motor into a grenade if the motor is driven hard to redline as it was designed. Works great until about 4000rpm or so then pings to the point that motor is going to blow holes in the pistons. This is on all three 230sl's tested.

In California, where we have 91 octane (which is about 3 below what Mercedes specified based on their 98 European octane rating), we must set timing to 28 (twenty eight) degrees BTDC MAXIMUM.  All three vehicles were used to experiment. At 91 octane.....28deg BTDC is it....38 would result in fireworks. There may be a misunderstanding between the various distributors which is is resulting in confusion.