Which type of fuel should I use>>

[Andrew Mitchell]

I have come across a mint 1985 Merc W123 230TE. Red in colour with a full service history of only 80,00 miles since new. I am going to buy it but need advice. How the present owner uses unleaded with a small amount of fuel additive. Can these four pots be run on normal unleaded without additive or can you adjust the ignition or do you have to have a special head conversion.

Any idea's anyone? I know your out there....

Andrew

 

[mlc]

I'm no expert on this particular model, however the usual check is to look on the inside of the fuel filler cover, the fuel type is normally mentioned on cars that can handle unleaded.
Alternatively search the forum on the word "unleaded", this is a very popular subject and I'm sure has been answered before many times.

 

[sclass]

Put anything in it after all it is an old car near the end of its day If you burn the valves out not a big deel plenty more old cars out there. Hope you find this helpfull.

 

[mattsavage]

A little education...
older cars that run only on 4 star use the lead in the petrol to lubricate the valve seats. Also leaded petrol has a higher octane rating and burnes quicker.
Unleaded petrol will not lubricate the valve seats as much as leaded and the octane rating is lower, therefore burning slower.
Cheap cars like all old Britich Layland cars, old Fords etc all have valve seats that need 4 star, they need the lubricant. With these cars it is best to use an adative. If you don't, the fuel will knacker the valve seats and burn out the valves, but it will take ages.. unless you thrash it!
However, more expencive cars and hi performance cars will have hardened valve seats anyway. So it is not a problem. The only thing that may need to be altered is the ignition timing, as the unleaded burnes a little slower, so the timing has to be advanced a little.

Having said all that I would think the car you're talking about will be set up for unleaded anyway!

Hope that helps a little,
Matt Savage

 

[sclass]

A little education...
older cars that run only on 4 star use the lead in the petrol to lubricate the valve seats. Also leaded petrol has a higher octane rating and burnes quicker.
Unleaded petrol will not lubricate the valve seats as much as leaded and the octane rating is lower, therefore burning slower.
Cheap cars like all old Britich Layland cars, old Fords etc all have valve seats that need 4 star, they need the lubricant. With these cars it is best to use an adative. If you don't, the fuel will knacker the valve seats and burn out the valves, but it will take ages.. unless you thrash it!
However, more expencive cars and hi performance cars will have hardened valve seats anyway. So it is not a problem. The only thing that may need to be altered is the ignition timing, as the unleaded burnes a little slower, so the timing has to be advanced a little.

Having said all that I would think the car you're talking about will be set up for unleaded anyway!

Hope that helps a little,
Matt Savage

My exact sentiment!

 

[landover]

Dont see any problem running your car on unleaded fuel Fill it up go for a run and enjoy it . :wink:

 

[peterchurch]

Hi,
well done on your find. Hope you enjoy it why dont you try a simple method of elimination ?

one at a time try £10 of fuel of various types from each provider, which ever gives you the best ride stick with it at the end of the day if the engine sounds sweet and the performance is pleasing then I doubt that is can be doing anything bad to the car, on the other had if it starts to sound like a bag of bolts...

 

[mlc]

Correction to the "education"

I always love it when "education" is offered.

Whilst I agree with much of mattsavage's comments about older engines he got the comments about speed of burning and adjusting the timing the wrong way around!

Unleaded has a lower octane rating than good old 4 star. Octane rating is a measure of energy content, 95 Octane petrol when burnt has 95%
of the energy value of pure octane, HOWEVER lower octane fuel actually burns quicker - a fact well known to all the older drivers on here because we can all remember "pinking" or more correctly pre-detonation which you used to get when you used cheap petrol! The solution is simple - since its important that the burning process is completed at the correct moment, rather than when it starts - is to delay the iginition, by retarding the timing a little. Those old Fords that mattsavage loves so much used to need a 4 degree reduction from memory.

Mark.
1972 350SL
1997 230SLK
and a (not old) Mondeo Ghia X for the real world

 

[mattsavage]

ahh yes well. That's what I meant!! Anyway, it was the hardend valve seat deal I was trying to get accross more...
As for liking old Fords.. I used to have (about 16 years ago) an old Ford Granada 3.0 V6 (just like the Sweany!!) It was fantastic. but it lasted about 4 weeks. It blew up going south on the M1 just before the Leicester Forest East service station!! Nice car, but couldn't handle 85mph for a long period. I then had the MKII 2.8 which was OK, but not as cool! Those were the last Fords I ever had. I have 'normal' boring cars now!
Cheers,
Matt