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What fuel to use?

Started by Dazbot99, 14 May 2017, 06:21 AM

Dazbot99

Hi all, I'm new to this, so appreciate your help. What's the correct fuel to use in 1977 280se in Australia? Do I have to add any additives along with fuel? I'm in Australia. Thanks for any advice.

ptashek

Quote from: Dazbot99 on 14 May 2017, 06:21 AM
Hi all, I'm new to this, so appreciate your help. What's the correct fuel to use in 1977 280se in Australia? Do I have to add any additives along with fuel? I'm in Australia. Thanks for any advice.

Unleaded, 98 octane. No lead replacement additives required.

Avoid any fuel blends with more than 5% ethanol (I think you guys have E10 and E85 at the pump in some places).
It's causing serious issues in the supply/injection system - increased fuel tank and supply line corrosion, vapour lock injector side etc.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

mrkozzy

re:  Unleaded, 98 octane. No lead replacement additives required.  Have found this to be correct.

Thru my Experience I recommend


My preference is the Shell Optimax or the BP Ultimate, in that order.

Do not use United. Apart from the ethanol, there is a good reason why its cheaper per litre. Definitely do not use the (at some stations) United brand 100% octane.

I don't bother with the Caltex.

MrKozzy

UTn_boy

By 1977 weren't the M-110 engines designed to run on regular unleaded, or 87 octane?  I can't find any literature that makes mention of using high octane fuel whether the engine is high compression or low compression.  Everything I have states that regular unleaded 87 octane is sufficient.  Anyone else have experiences with one or the other?
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

ptashek

Quote from: UTn_boy on 14 May 2017, 04:36 PM
By 1977 weren't the M-110 engines designed to run on regular unleaded, or 87 octane?  I can't find any literature that makes mention of using high octane fuel whether the engine is high compression or low compression.  Everything I have states that regular unleaded 87 octane is sufficient.  Anyone else have experiences with one or the other?

My 1979 owners manual states on the very last page, that the required fuel should be "minimum 98 RON / 88 MON". It doesn't make much sense really, since 88 MON = 96 RON.
Is it likely, that back in those days 98 RON / 90 MON was not available in the US?

Per the "Tabellenbuch" from 01/1981, if lesser fuels are used in the V8s, ignition needs to be retarded by 1deg per octane below 98 RON.
I personally drive on 95 RON with a 5% ethanol content, as that's the only petrol grade we have in Ireland.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

beagle2022

I only ever used 98RON on my 1979 280sel.  Crazy expensive but the car ran beautifully.  When stuck I sometimes had to use 95RON.  Slight loss in power but no knocking. It all provides incentives to keep your K jet in good condition.  The system runs rich in warm up cycle, so AAV, WUR should be checked so that it moves through that stage efficiently.  Also look at replacing the injectors and seals.  They are cheap and easy to replace.
Sydney, Australia

UTn_boy

Quote from: ptashek on 14 May 2017, 05:38 PM
Quote from: UTn_boy on 14 May 2017, 04:36 PM
By 1977 weren't the M-110 engines designed to run on regular unleaded, or 87 octane?  I can't find any literature that makes mention of using high octane fuel whether the engine is high compression or low compression.  Everything I have states that regular unleaded 87 octane is sufficient.  Anyone else have experiences with one or the other?

My 1979 owners manual states on the very last page, that the required fuel should be "minimum 98 RON / 88 MON". It doesn't make much sense really, since 88 MON = 96 RON.
Is it likely, that back in those days 98 RON / 90 MON was not available in the US?

Per the "Tabellenbuch" from 01/1981, if lesser fuels are used in the V8s, ignition needs to be retarded by 1deg per octane below 98 RON.
I personally drive on 95 RON with a 5% ethanol content, as that's the only petrol grade we have in Ireland.


At the time, we had different grades of fuel available from 90 octane all the way up to 105 octane.  It literally says in the books that 87 octane is what was required.  Then again. all U.S. cars were low compression to meet the strangulating emissions requirements, so that may have something to do with it.
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

Dazbot99

Thanks all for your advice. Being a 1977 vintage, leaded was around , however I purchased the vehicle from its original owner and it had been sitting in his garage for 5 years , with about 15 litres of fuel. I drained the tank and I have never smelt fuel like it in my life!! It was putrid!! I took the tank out, flushed all lines, purchased new fuel filter, pump and that other contraption near the fuel pump and renewed the petrol filter that you unscrew in from the tank. I cleaned all the metal fuel injection pipes and have purchased new injectors. I just wanted to make sure she is fed the best food possible for this beautiful vehicle .

s class

My 1980 280se is euro spec with high compression pistons.  In the 350 000km that I drove it, I found it to be quite sensitive,  and was included to ping on lower octane fuels, especially at coastal altitude.  Here in Johannesburg (1600m elevation) it was less of an issue.


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

djenka018

Quote from: s class on 19 May 2017, 12:39 PM
My 1980 280se is euro spec with high compression pistons.  In the 350 000km that I drove it, I found it to be quite sensitive,  and was included to ping on lower octane fuels, especially at coastal altitude.  Here in Johannesburg (1600m elevation) it was less of an issue.

High altitude makes less air (and fuel) enter the engine hence you can have lower octane fuel as there will be less to compress.
Hence you can advance it more.
Such setup in coastal town would need top octane fuel.

I still remember howmy car drove soooo nice in Durban and it was more than perception.
Vitamin C for SL... the SLC

entresz

On my ex UK 1975 280SE it specifically states that 98RON is required. I

Previous owner of 30+ years used to put "flashlube" additive in. I don't think it's really necessary but I have continued using it (has a vacuum feed in the engine bay). It's not harming anything. I never put any fuel with ethanol added in. Not good for old cars.

Have had to use 95 on occasion and didn't notice any ill effects, but did not load the motor heavily either.

On a side note - I have driven an "australian" w116 280SE (1977) and mine feels noticeably more responsive. Not sure why that is. I know my car doesn't have any emissions gear on it being ex UK. Perhaps that's the reason?
1975 Mercedes-Benz 280SE
1981 Mercedes-Benz 300D
Previous cars:
1979 Mercedes-Benz 450SE
1982 Mercedes-Benz 280E