Hi Guys,
I recently bought a 1999 1.6 silvertop with 68k, although she ran fine, she blows blue smoke and drinks oil like theres no tomorrow. I am fairly competent with spanners so heres my question. Does anybody know the piston to bore clearance for this engine, as Haines doesnt give / or know .
The engine has suffered a belt breakage at some time with some inlet valves being changed. The bore ovality is 0.0006 but the pistons are showing 0.013 ovality measured at the oil ring rails, 0.003 at the second ring and the same at the top ring. All the oil rings were gummed , so although compressions were 150 on all four pots,she was always going to drink oil. The engine has no leaks and no evidence of head gasket failure.
The gap between a new standard class 2 piston and my bore measurements would indicate a piston to bore clearance of 0.0013,
hence my need for the correct clearance figure.
One reason for the failure may have been that although the water temperature gauge always sat in the middle, the thermostat was closed.
Sorry about the long story, thanks for any replies in advance.
Focusbob2

 

If they are ford pistons or another decent make they have a steel casting within the alloy piston itself, they are known as "restricted growth" pistons, and as such 2-3 thou bore clearance is normal, race zetecs are down to 1 1/2 thou.
tabetha

 

Thanks Tabetha,
why is this engine specification such a mystery, I understand about not releasing the mains etc, but there are occasions when new rings can be a cure.
Haines dont specify valve stem diameters either.
A good low mileage secondhand motor would be ideal, but that represents a risk too.
On a slightly different note, can I fit a blacktop lump in,and what do I need to make it fit.
Thanks again
Focusbob2

 

I haven't had much to do with zetecs swapping around bits wise so don't know.
Often when the info is not there, it is because ford did not give it to haynes when they did the manual for the car.
tabetha