Try it, the car just feels that bit more responsive.

Just remember... a slappy tappet is a happy tappet

Ooh had a big reply all typed out and then lost broadband and telly so had to sort that out!

So we all stick to factory settings and citroen never changed anything since first inception?

what about coconut cowlings, rubber fans, reduced primary main jet? all of which were introduced due to possible implimentation of legislation.

why not take on board stuff that others have found to work?-cross fertalisation of ideas from other disciplines isnt a bad thing, wasnt Maserati a big influence when it was absorbed? wasnt Walter Breccia a designer of aircraft engines before he came up with our little jem of an engine?

sure choosing to set up an engine one way or the other is a matter of taste i run bigger valve lash, ive gone up to 0.30 but have mellowed and use a bit less.

to just outright say "it wont work" on a 2cv is just ignorant, and to deny any principals that govern any internal combustion engine "un applicable " to a 2cv engine is particularly so.

anyway its all to do with the changing formula of modern fuel, after the Big change from lead all the main companies have been slowly changing to leaner greener fuels its an ongoing change, Texaco had its big campaign with Ferrari, Esso now doing "Extra litre for free" as aparently you go farther on each tankfull now.
Ok so a 602cc aircooled engine may not utilise the potential the way a computer controlled Ztec and the rest can( constantly monitored ignition timing might,lamda sensor ajusting the mixture- some moderns have Variable valve timing, some performance cars have valves in exhust to tune that too-if thats possible- is it....no?) but the formula and the way it burns isnt changed because of the tank its been put in.

so when we all have to go over to E95 the factory settings will be ok? if so why is there an advance curve for it on some 123 and why is there variable jets available?

sorry your thread well and truly Hijacked GJ

did you disturb the lower rocker shaft bolts, the flat sided ones, when they are loose it clatters something terrible.

No Worries Sean, i dont mind reading all these heated debates about valve settings etc, i did actually go for something a little bigger myself, i had inlets at 0.25 and my outlets at 0.30, going from 0.15 and 0.20 to 0.20 and 0.25 made a huge difference so i thought why not, and you wouldnt believe the difference, i cant remember my car feeling so "on the button" the key turned, and on the first turn she fired up into a very respectable cold tickover! after a test drive you wouldnt believe the extra power and the compression! however the larger settings do obviously make your tappets a little happier, and a little louder, so i went back to kens settings, which for me, still give perfect running!

Viking, why not live a little, try experimenting? what have you got to loose? valve settings are hardly something thats unchangable? try a different setting, see what you think? if you dont like it, then you can go back to factory standard!

anyways! Sean - i dont remember touching them at all, although one thing i did notice earlier was that on the nearside head the left one is "in line" and the right one isnt? would this be part of my problem, i'll have the rocker covers off again tomorrow, check them for scoring marks and i'll check the shaft bolts!

seenas i've been awake for well over a day now.. (night shift last night...)

hopefully i'll have some decent results in the morning!

thanks for everyones diagnostic help

Joe

Joe,
whilst we're (temporarily?) back on topic, there's no need for a torque wrench when tightening the nuts holding the rocker covers , but I'd advise using '2 full turns from finger tight' rather than 1/2 a turn.

ken

0.25 0.30, yes you can expect it to clatter now and it sounds like a real deep in the guts hammering

Unless you do most of your driving at full speed on the motorway reducing to 0.20 and 0.25 will make life quieter

dont worrry if the bolts dont line up they never do. you never check the alignment of any other bolt do you (unles you have one of those "disorders")?
Sean

Why re-invent the wheel I simply don't believe it. All cars I service are set at Citroens specification at 0.20 mm and I never had any problems.

It doesn't sound like anything short of direct personal experience will convince you - and yet you seem unwilling to try that.

Can I convince someone as stubborn as I to move away from 0.25 mm to 0.20 mm, doubt it

Should ad, prove it and I will try. Don't believe in old wife's tales

Hey Ken, we are now officially old wives. We should start a club.

This really isn't hard to understand. In a production car the manufacturer wants the valves to be quiet. However there has to be a valve clearance; the valve expands as the engine heats up and running too small a clearance would burn out the valve, the seat or both.

The camshaft in a production engine has a quieting ramp; before the lobe on the camshaft fully opens or closes the valve it lifts or closes very slowly. Because of the minimal lift no meaningful gas flow can occur. However because of the minimal lift the valve isn't sealing. The engine can only compress or burn the mixture when the valve is either fully open or fully closed. In an ideal world we want valves that open or close instantaneously and a camshaft by its very nature can't do that.

Therefore because of the marginally open valve the effective induction, compression, power and exhaust strokes are actually shortened by running tight valve clearances. It may be counter intuitive, but the efficiency of the engine is increased by increasing the valve clearance slightly, at the possible expense of slightly increased valve noise.