Valve clearances..stuopid question

[alzmoore]

I have finally got round to checking valve clearances and have the following measurements (in old money..thou)

Inlet (5,3) (4,7) (3,3) (3,3)  Manual states 5-7

Ex.  (5,7) (9,7) (8,8) (6,5)  manual states 10-12

So these are well out of spec, but all smaller... What I can't understand is why as things wear, the gaps have got smaller, or could they have been wrong from the start?

Sorry if its a stupid question but I wanted to get it straight in my head before I start taking the cams off.

 

Thanks

Alan

[andydclements]

Not all wear causes the gaps to open, any wear on the faces of the valves or valve seats would cause the gaps to close. That's not saying that's what's happened, it could have been wrong from the last time somebody set them.

[CHANGES]

As they are so far out ,  I would go for set wrong on last build .   Experience will show it is rare for a valve or valve seat to ware significantly without there being an underlying  issue ..  The most common ware point is the valve stem into the shim .  This can be seen on the shim and can cause valve clearances to increase by 3 to 4 thou , although in most cases  just 1 or 2 thou.