lead free fuel

[knockmacool]

Hi

I have now done 1000miles on my 66 230sl, and while it is much louder than my long gone 58 220S convertible I am very happy with it. (Thanks Stick!). A couple of quick questions on fuel. In Ireland, all that is available is lead free 95 octane. Should I look at fuel additives? If so which ones do you recommend? Should I consider getting the work done to accommodate lead free fuel?

[dseretakis]

Your car does not require leaded fuel.

[JamesL]

And as such, will run on whatever you pump. My car has never been "converted" to run lead free and the view is that MB built the valves out of good enough material in the first place not to need harder materials to compensate for the loss of lead.

And if you search on here you'll see stuff about buying "premium" fuel. In general, US octane ratings are lower than we have so our standard (95) is likely the US premium. So don't start putting Shell Optimax in thinking your engine requires it.

[dseretakis]

94 octane is the highest we can get here in the US.

And as such, will run on whatever you pump. My car has never been "converted" to run lead free and the view is that MB built the valves out of good enough material in the first place not to need harder materials to compensate for the loss of lead.

And if you search on here you'll see stuff about buying "premium" fuel. In general, US octane ratings are lower than we have so our standard (95) is likely the US premium. So don't start putting Shell Optimax in thinking your engine requires it.

[Ziggy]

US Pagoda's (as well as other exports) have different timing as well as lower compression to compensate for the lower octane. I don't recall exactly from which year from the top off my head, but around 1969
Leaded fuel would be the best, but since this is outlawed just use unleaded without additives which would be bad for your injection pump.

[Benz Dr.]

Late US 280SL's have different engines which also include different valve timing. The compression ratio is the same at 9.5:1 as far as I've ever seen.

[Martijn]

I also struggled with the question: what is the best fuel for our cars? If I ask experts, I get different answers. Since leaded fuel isn't available anymore in Holland for many years, the only option is unleaded fuel of course. But which one? Here we can choose between unleaded 95 or 98. But there are also "special" fuels like Shell V-power and BP Ultimate.

One mechanic advised me to use BP Ultimate. This fuel has some cleaning qualities. They claim that this fuel cuts away deposits in the engine, especially in older cars. See http://www.bp.com/genericarticle.do?categoryId=9009378&contentId=7024182.
It sounded reasonable to me and last year I only bought BP Ultimate. My thought was: the extra cost for this fuel is always less than any repair to the engine.
The engine runs great on it. But I can't say that I have now a better engine performance or better mileage, that was not my objective. It's only the preservation of the engine and perhaps it also saves the injection pump.

Another mechanic advised me to use a unleaded fuel additive. I didn't use that so far, but I don't know if I should.

What are your thoughts?

Martijn

[graphic66]

All of the W113 cars have hardened valve seats. No need for the lead. Most have high compression pistons though, 9.5-1 or higher. That is what requires higher octane. Higher octane fuel burns cooler and wont preignite. if you don't get preignition with low octane it should be fine. Some low compression motors will have more power with low octane as it burns hotter.

[knockmacool]

Thanks to all, good to know fuel will only be an expense and not a problem! What mpg should I expect on what the Brits would call "B" roads?

[graphic66]

I get about 18 MPG with my 230SL. 

[ben.king]

morning group

aim just restoring my father in laws 1967 250sl and we are both wondering what fuel to use as in the UK we don't have unleaded fuel,will unleaded fuel be OK ?
also once the engine fires into life it will not rev,is this anything to do with the timing ?
kind regards

Ben

[dseretakis]

113 SLs do not require leaded fuel.  Doesn't matter if its a 230, 250 or 280SL.

morning group

aim just restoring my father in laws 1967 250sl and we are both wondering what fuel to use as in the UK we don't have unleaded fuel,will unleaded fuel be OK ?
also once the engine fires into life it will not rev,is this anything to do with the timing ?
kind regards

Ben

[Naj ✝︎]

morning group

aim just restoring my father in laws 1967 250sl
also once the engine fires into life it will not rev,is this anything to do with the timing ?
kind regards

Ben

If it fires up, the timing may be OK.

This thread may help if there is an air lock in the fuel injector pipes:

http://www.sl113.org/forums/index.php?topic=10188.0

naj

[JamesL]

Knock

I drive mine fairly hard (ask jameshoward) and I get about 21mpg. Imperial, not your poky teeny US version  (4.5l vs 3.87 IIRC)

20.7, to be precise. Mix of A roads and B roads. Very little sitting in traffic

[knockmacool]

Thanks. We'll see if I can match Tosh's 21mpg!

[Naj ✝︎]

Knock

I drive mine fairly hard (ask jameshoward) and I get about 21mpg. Imperial, not your poky teeny US version  (4.5l vs 3.87 IIRC)

20.7, to be precise. Mix of A roads and B roads. Very little sitting in traffic

That shud change now with the 3.46 

naj

[graphic66]

Knock

I drive mine fairly hard (ask jameshoward) and I get about 21mpg. Imperial, not your poky teeny US version  (4.5l vs 3.87 IIRC)

20.7, to be precise. Mix of A roads and B roads. Very little sitting in traffic

  What is an Imperial gallon? I remember them from going to Canada years ago. Is it the same thing? It was always so confusing, especially mixing oil in for my outboard boat motor.

[Jonny B]

One imperial gallon is 1.2009 us gallons

[graphic66]

I saw the 21MPG part and thought that was better mileage than I have heard from most, comes out to 17.5MPG US, about normal.