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Malte · Lowered Joined: 11 Dec 2007 Posts: 534 Location: Germany

does somebody have a list of all engine types of the a modells?

i need information about the engine:

am2 a , the sticker is purple , its an akadyane.

thanks.
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Olli · Posted: Mon Jun 02, 2008 11:48 pm Post subject:

how 'bout this? http://www.cats-citroen.net/citroen_atypes/enginegearbox.html

-Olli
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Malte · Lowered Joined: 11 Dec 2007 Posts: 534 Location: Germany

thanks olli.

but what does the color of the "sticker" say?

don't know the date of the car...
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Olli · Posted: Mon Jun 02, 2008 11:56 pm Post subject:

Malte · Lowered Joined: 11 Dec 2007 Posts: 534 Location: Germany

ok, that's possible...

i've heard that the color says something about the type of fuel.. leaded / unleaded and so on...

but i'm also not shure...
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Matt Black · Snailer Joined: 11 Oct 2008 Posts: 25 Location: Holland

yep, red plate is normally leaded fuel, black plate is unleaded fuell, but only if the numbers are printed on it (80's models). If they are punched numbers (70's models), a black plate can be leaded... So don't just look at the color, but check the enginecode itself.. AM2, AM2A, A06/635, A06/664, etc... you can find the complete list on Cats' website..
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backfire · Posted: Sun Oct 12, 2008 12:13 pm Post subject:

little correction needed, citroen did not change the head since the 1970's, only tested for unleaded in the 80's. So officially in the 80's unleaded version was marketed by citroen, but since the parts are exactly the same as in the 70's ones, they can run unleaded without problems. The ONLY important item is that the 70's begin 80's engines require octane 98 and the late 80's so called S6 can run on octane 95. But strange enough I have a user manual from 1978 and according to this manual the engine from 1978 can run on octane 94-98. But with a remark, that if the engine starts knocking you should switch to higher octane fuel. This info can be found on cats site and 2cv.nl site
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Kustombart · Posted: Sun Oct 12, 2008 12:42 pm Post subject:

I ran an AM2A engine in the woody for two years and it is one of the best 602's I've driven. Especially fitted with the "power tube" forced cool air inlet, it runs very nice. I ran 95 in it always and have had no troubles. It does run a little better on 98, though.

I had the carbs rejetted (second stage one step bigger, can't remember the numbers) and came up with an extra horse. I believe 32,5 at the wheels with electronic ignition and the rest standard. Carbs, especially in the 80's were set to minimalize emissions but that means most of the time that it doesn't perform as well as it could. Changing those can make a big difference.

I now have an AM2, where compression is slightly higher but I can't find a noticable difference in performance. Agian, I run 95 all the time with no problems but it runs better on 98.

Oh yeah, and I always fill it up with unleaded. All 602's I've driven so far and I haven't noticed any excessive valve wear.
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Matt Black · Snailer Joined: 11 Oct 2008 Posts: 25 Location: Holland

backfire · Posted: Mon Oct 13, 2008 9:25 pm Post subject:

What also is confussing, my motorbike a honda from 1976 runs great on octane 95 en stil has compression of 1:9, tested my bike with german v-power and of course octane 98. I did not test for top power, but for smooth running and fuel consumption. As you may have noticed, octane level also depends on the way you drive the car. I am a smooth driver so 95 is good for me, and when you keep pedal to the metal I would use 98 too, and also use bit larger jets, to give extra cooling.

Fortunately an air cooled engine is much more tolerant to abuse.
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Kustombart · Posted: Mon Oct 13, 2008 9:51 pm Post subject:

Wise words, backfire. The main reason to use a high octane fuel is to prevent knocking. Knocking happens when the gas/air mixture in the cylinder ignites before the piston is in top dead center and the sparkplug sparks. The force of the explosion works against the movement of the engine and it can cause major engine damage.

This only occurs under full load so if you go easy on the gaspedal, it may not be a problem. Raising the compression of an engine makes it more likely that knocking occurs, so you need a higher octane number. Octane is an "anti knocking dope" and the higher the octane number, the more resistance there is against knocking.
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dyanut · Posted: Mon Oct 13, 2008 11:10 pm Post subject:

Kustombart,
it looks as though you've been reading that 'ignition masterclass' stuff and failing to spot some of the deliberate mistakes... ;o)

The thing is that the mixture is _always_ ignited before TDC, at approx 8 degrees BTDC at tickover, advancing to 'somewhere around' 30 to 35 degrees at full ignition advance, depending on the compression ratio of the engine.
Combustion of the mixture should be a controlled burn, _never_ an explosion.

It's also worth recognising the difference between 'detonation' / 'les cligueitis' and 'pre-ignition'/ 'auto allumage'.
The former occurs when the pressure rise in the cylinder is too great, for a variety of reasons, so that the remaining mixture spontaneously ignites. Possible causes include too much ignition advance, too low octane fuel, weak mixture or the engine running too hot.

The latter occurs when there are hot spots in the engine which ignite the mixture before the spark plug has fired.

< http://fr.wikipedia.org/wiki/Cliquetis > gives more detail en francais.

Ken.
( I have a suspicion that the AO6/635 red labels commenced in 1978 with the introduction of the twin choke carb on 2CVs. As other folk have already pointed out, they have nothing whatsoever to do with leaded or unleaded fuel. There are about 50 engines stored here, so I could probably work out when the change from black label to red label did take place, but there certainly was an overlap because the M28 engines still had black labels into the 1980's. )

Kustombart · Posted: Tue Oct 14, 2008 9:13 am Post subject:

@ Dyanut: I know all this, I am an automotive engineer. However, most of the people here are not. For the sake of explaining the octane discussion, I simplified things a little. I have to say I also don't really know some of the correct terms in english. Embarassed

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JoZeF · Grave Digger Joined: 25 May 2007 Posts: 1734

"Lead additive" is bullshit on any engine with steel valve seats in aluminium heads.

The benzine contained in moden fuels requires replacement of most rubber parts (carb and fuel pump diaphragm, and hoses)

Wink

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Matt Black · Snailer Joined: 11 Oct 2008 Posts: 25 Location: Holland

but as i said, lead additive doesn't only protect your valves..
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