Citroen DS fuel?

danspooner

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Fellow Frogger
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Jan 15, 2011
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Sydney
Hi,

I am sure this is an old old subject that's been gone over a thousand times, but what petrol grade/type should I be using in a '72 DSpecial (21 I think, with the single choke Solex carb). When I bought it, the previous owner was using lead replacement fuel additive ("Valvemaster", phosphorus based). Is this strictly necessary - are the original valve seats the hardened type, or the type that relied on lead in the fuel?

Also, I get quite a bit of pinking when accelerating/pulling uphill. The timing is set via dwell meter and strobe, but should I be adjusting this a few degrees off standard settings (retarding?) to cope with modern fuels?

And, is it worth buying the expensive "high octane super" type fuel, or is standard unleaded adequate?

And finally, what about 10% ethanol fuel? French cars were always designed to run on petrol watered down with cheap vin de table, weren't they? It was certainly one of the design criteria for the 2CV, along with the basket of eggs over the ploughed field. This I am quite sure of.

Cheers,

Dan
 
No need for lead replacement additive in any Dee, as the head is alloy and the valve seats are hardened.

I think later short stroke Dees like yours need 95 octane fuel. Are you running it on 91? That might explain the pinging. Use the money you save on additive to pay for the fancier fuel.

I find dwell meters OK for setting the points but strobes useless for setting timing in old cars. Modern fuels have different characteristics from old fuels, and the engine is not the same as it was when new. I set timing by ear nowadays. Advance it until it starts to ping, then retard it until it doesn't ping. This needs to be done by road testing, so just keep the distributor spanner in the car with you. A strobe is OK for obtaining a basic setting to get the engine going, but it is just as easy to set the timing statically with a dwell meter.

In any case, don't adjust anything until you are running in on 95. And if you can get only 91 and 98, because some places don't offer 95, you can always mix a shandy by putting in half a tank of 91 and half a tank of 98.

Early Dees with long stroke motors run fine on 91 octane fuel. I tried putting E10 ethanol fuel in one once and it ran like crap. Never again. I have no experience of putting ethanol fuel in a later Dee and I don't want to try it.

Roger
 
That later 21's (especially the injected cars) run a high'ish compression ratio, I'd suggest 98octane if you can find it (it would be the closest to the old "super" fuel).

The only time I've ever used an ethanol blend was years and year ago when we went to Queensland.... And the fuel pressure regulator died on the way home..... I've avoided the stuff ever since (even though it's likely the ethanol has nothing to do with it).

Don't worry about lead replacments... no-one else does :) they have been using straight ULP for years longer than us in the US with no problems too. DS's & CX's seem to have very hard valve seats from the factory.

seeya,
Shane L.
 
95 or 98, no octane booster stuff.

Get the timing sorted once you have flushed that 91 crap out by running at least one tank of decent stuff through it.
 
95 or 98, no octane booster stuff.

Get the timing sorted once you have flushed that 91 crap out by running at least one tank of decent stuff through it.

I've been running Celine (DS 23 Safari) on Premium Unleaded for the past three years.

Seems to be running really well.

Should I abandon Premium and go to 95?

Regards Graham
 
Apparantly the aromatics in fuel that increase the octane rating boil off very quickly if the tank of petrol isn't used. So if your going to put 95/98 into the DS ....... Put in only as much as you need, then add more fuel next time you use it (this is if the car isn't used regually).

I've found modern fuels go stale incredibly quickly if left sitting in lawm mower/brush cutter/small engines too.

seeya
Shane L.
 
Apparantly the aromatics in fuel that increase the octane rating boil off very quickly if the tank of petrol isn't used. So if your going to put 95/98 into the DS ....... Put in only as much as you need, then add more fuel next time you use it (this is if the car isn't used regually).

I've found modern fuels go stale incredibly quickly if left sitting in lawm mower/brush cutter/small engines too.

seeya
Shane L.

I'll try some 95 in her. I am not sure what the octane rating of Premium Unleaded is but it sure is expensive.

Now that I have had her air-conditioned I will be driving her a lot more.

Regards Graham
 
I've found modern fuels go stale incredibly quickly if left sitting in lawm mower/brush cutter/small engines too.

My wife's triumph is on historic rego so gets used infrequently. The father in law has told her to keep it filled because his concern is crap in the fuel tank but I prefer to keep it low because of the stale fuel issue. One morning after not being used for a fortnight or so the car was running really rough. A quarter of a tank of 98 and it instantly starting running as sweet as a nut so I'm a big believer in 'modern fuels go stale quickly' theory.
 
My CX has carburettor and conventional points. I generally run it on premium unleaded cos it doesn't like the 91 octane stuff. It actually runs better on E10 than on the standard Unleaded. But I am a bit wary (for no genuine reason) of running E10 so it is 2nd choice after 98 octane.

I have used unleaded ever since lead replacement petrol disappeared. No addatives and no problems so far. My car has just hit 300,000 km and the compression is the same as the day I bought it about 10 years and 150,000 km ago.

I don't worry too much about the cost of fuel. It is an emotive issue because it hurts the hip pocket every week and because the price fluctuates a lot. The real cost of running cars is depreciation, rego, insurance and maintenance in that order. When you do the sums the cost of fuel is relatively small. And the cost difference between small economical cars and big thirsty ones isn't all that much. Because depreciation is zero and it is reasonably reliable (and what needs fixing is generally cheap by new car standards) the CX is probably the cheapest car I have ever owned. And it I still love driving it - most of the time.

So don't skimp on fuel for your pride and joy. Feed it what it needs.
 
I run all my cars on Premium (badged as) 98.
I only use a upper cylinder head lubricant on the '65 Mini. It probably wont save the engine , but what can you do??

My D's have run without issue on PULP since Super was discontinued.

On the cars that dont get regular use (Mini and Dspecial) I keep the tanks at 1/2 or under so "fresh" fuel from the nearest Petrol Station can be added before any long drives.
 
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