right.... both heads are on nice and tight, the valve clearances are set at 0.20mm inlet and 0.25mm outlet, tappet adjusted with a screwdriver and a spanner round the locknut etc etc.. did the valve clearances going by my haynes.. rotate engine untill 1 valve is fully compressed then adjust for the coresponding valve on the oposite cylinder head etc... did all that, put the rocker covers on... all i've got is very loud tapping noises... and theres definately oil being pumped round the head! for once i know what im doing but the tapping i dont understand! the old cylinder head was fine and i've done nothing differently!

i wont be able to get any photos untill tomorrow, that's if i get a chance to go upto the workshop before work!

Who ''invented'' this theory ignoring Citroens specifications of 0.20 mm for both valves. I'm yet to be convinced by anybody that 0.25 mm on the exhaust will benefit the engine at all. I have never set the exhaust to 0.25 mm, even down under in extreme heat driving for days with a brick on the pedal, no overheating? Please explain

Did you feel if the tip of the push rod head is not loose?

2cv racers

COVERS!

you cant ajust the tappets then fit the rockers

my bad sean

Yes I know but why? Do they overheat on 0.20 mm unlikely?

No its got more than just heat dissipation going on

Not just 2CV racers, but also owners of classic Jaguars, it seems...


Due to economic forces, it is inevitable that leaded petrol will not be freely available within the next five years or before.
Aftermarket fuel additives need to be carefully matched to the fuel to which they are to be added.
The quality of the construction of Jaguar engines, even including the cast iron units from the pre-war period, is such that, if carefully maintained and driven, catastrophic engine failure should NOT occur.
The use of unleaded fuel will induce higher running temperatures.
Unleaded fuel, generally being of lower octane rating, will render the car more susceptible to detonation or pinking from sources not directly attributable to the fuel, like oil dilution of the petrol, localised overheating, etc.
The American experience is such that the often talked about valve seat recession will not be a problem with Jaguar engines.
Maintaining a relatively low engine cruising speed is important.
RECOMMENDATIONS

Don't panic! - the process of valve seat recession or erosion of the cylinder head material, even if it were to occur, would take place over many tens of thousands of miles. With the low mileage that many of these cars are subjected to, any potential problems would probably not occur for 5 to 10 years assuming the engine is in a reasonably good condition to start with.

If it ain't broke, don't fix it! - if you have no reason to remove the cylinder head or carry out an overhaul at this stage in time then the introduction of lead free fuel is not reason enough in itself to go to the expense of overhauling your engine. It must be stressed however, that the valve clearances need to be checked and re-set if necessary. Ideally 0.001in to 0.002in wider than the nominal 0.004in or 0.006in setting recommended for the earlier engines. This may make the valve gear slightly noisier but will reward the owner with a more reliable engine.

Any damage that may be caused due to running on unleaded fuel would be gradual and, if the engine is maintained correctly and the car driven sympathetically, then as the engine degrades, a loss in performance would be noted before it would actually break down and a plan could subsequently be drawn up to rebuild it at a convenient time.

If an engine is to be rebuilt then certainly the fitment of lead free valves is to be recommended.

On pre 1975 engines, if they are to be rebuilt. then the fitment of lead free valve seats is certainly worth further investigation at that stage. The decision would be taken dependent upon the condition of the existing seats and cylinder head material (eg, is the aluminium eroded from previous detonation or water ingress from head gasket failure?) and also the hardness of the seats which can be determined by standard procedures. Adjust the mixture so that the engine is running slightly richer particularly around the 2,500 to 3,000 rpm mark. This can be achieved by carefully selecting different grade needles and/or jets or possibly (with care) filing a needle locally at some point down its length. This would need to be carried out by someone experienced in the modification of such needles.

Ensure that the cooling system is correctly assembled and is functioning efficiently.
Post-1975 engines all had valve seats fitted to take into account the use of unleaded petrol and would not necessarily require replacement.

I may be a bit thick but sorry I fail to see how that has anything to do with a 2cv engine running the public road around the world. It still does not explain the benefit of changing the exhaust valve clearance from 0.20 mm to 0.25 mm on 2cv street cars