1959 Mercedes 220S,1971 Mercedes 220, fuel questions?

Question

We have a small collection of old Mercedes. 1959 220S, 1971 220 and 1974 240D. The question is about the fuel for the gas models. Todays fuel is so different than what was available in 1959 and 1971. Is there anything you can do to make the fuel right for the old cars?

Answer 1

The biggest difference is that various chemicals are used in place of tetraethyl lead. Contrary to the mythology that lead "lubricates" valves, it does nothing of the sort. What it does do is build up deposits on the valves (especially the exhaust valve), providing some insulation. Without lead, it's like a blacksmith pounding on a red hot horseshoe: the overheated valve seat can recess into the head. This is only really a problem with cast iron heads operating at high RPM, because cast iron is a poor thermal conductior. I believe all of your cars have aluminum heads with steel seats, these should be resistant to the problem. And vintage cars are rarely driven at the limits, so the valve seats won't get as hot. You should be fine. I have several vintage cars and have never worried about unleaded fuel.

However, ethanol can be a problem. If possible, you want to avoid using ethanol enhanced fuels in older cars. The reason is that older hoses and pump diaphagms tend to degrade rapidly in ethanol. If your fuel lines, carbs, and fuel pump have been redone in the last 20 years, the probability is that you're fine. But if your fuel system still has vintage rubber anywhere, beware of ethanol.

I almost forgot the 240D. I've always used Mercedes Diesels as daily drivers. Most of them go hundreds of thousands of miles without a fuel related problem (as long as the fuel doesn't get contaminated with water and you change your filters regularly). Recently, the US went to ultra low sulfur Diesel. In raw form, ULSD has less lubricity than the old stuff, so it has the potential to cause pump failure. But the refiners (at least in the northeast) have been mixing a little biodiesel in with it. This not only increases the lubricity, it raises cetane a couple of points. So far, I've found it works better than the old stuff. We'll see if there's any impact on durability.

Answer 2

Your best source of information is the Mercedes-Benz Classic Center in Stuttgart, they have a website also fax [phone].

Valve seat recession is over-rated as a source of engine failure but it is worth finding out about in older Benz cars. It's quite possible that these cars have hardened valve seats.

Obviously the 240D will not have a problem with unleaded fuel since Diesel fuel has never been leaded.

Quote the engine number, body number and country of first sale when you enquire, as they made have made different versions of the same engine for different countries.

As someone else noted be careful with ethanol fuels. They appear to make the fuel pumps on my '83 W126 noisy, even with only 10% EtOH so I don't use them.

Answer 3

there are compounds that you can add to the fuel to take the place of the lead , some are called top end lube , others are called lead substitute , pick up a copy of hemmings and you will find many suppliers , also check around your local area for car clubs or restoration shops that may know of a local supply . good luck

Answer 4

those year cars ran leaded gasiline,and one of leads functions was that it acted as a lubricant for the valves,since lead is no longer available,since 1974, when unleaded gasiline came on the scene. they make engine valves and valve guides out of a much harder material now [stelite] you can have a competent auto machine shop retrofit the heads with new valves and seats ,[valve job] and run the cars on unleaded fuel

Answer 5

the automobile's no longer worth something incredibly in that circumstance. Junk expenses. sorry yet that's the industry and you asked. Can that is fixed? advantageous. could you? No. you will come across those sparkling and working for under the in all probability value of those maintenance. i'd additionally enjoyed to function that I truthfully have by no ability seen a Benz timing chain "snap" in my complete existence. i ask your self what's certainly incorrect right here? i think of this tale is amazingly atypical.