Oil pipe banjo bolts are 8mm.

Is this a repair when the 7mm bolt has been lost or damaged.
Both cylinder heads, that had the severe pinking, are like this.

Do the bolts have the correct small holes in them. This would not cause the damage within the heads but could oil starve the rocker shafts etc...

Valve gear lubricated all ok.
Bolt has 2mm hole through is centre with one 1mm outlet near the bolt head.

Should be allright then.... can't be the problem (pinking).... pinking takes only place when ignition comes to early..... Pinking because of little unburned particles inside the cilinders doesn't happen at a 2cv...... does it still run( a little) when you put the ignition off thats mostly a sign when the ignition is to early (all my opinion)

History of engine.
Purchased as unknown from a Dedicated/restorer/hoarder of 2cvs
Had it running see 4x4 video.
Now new barrels/pistons.
Used some other heads as the pinking ones are dubious.
When putting the heads back on found oil union bolts did not fit!!!

Sounds like they have been rethreaded at some time - cant think that oil starvation will cause pinking - overheating and seized valves etc maybe - but pinking is usually caused either by poor carburation or timing is it not?

Nels,
primarily over-advanced timing, although a lean mixture, plugs too hot, etc. will also play their part in causing detonation.

@ ipgo,
when there's as much carbon on the piston crown and on the cylinder head as in the attached photograph, that will cause detonation or even pre-ignition and 'running on', since the carbon will act as a glow plug.
Not one of mine, btw, just another of those little jobs of clearing up the mess made by someone else...




piston with heavy coating of carbon by slcchassis, on Flickr