What size reamer?

[bert]

I'm fitting some new valves in a xflow head and the valve stem is measuring a diameter of 0.314" or 7.976mm in new money.

What diameter reamer will I need to source for this? Will 8mm be too big a hole?

Thanks
Darren

 

[doubleboost]

I'm fitting some new valves in a xflow head and the valve stem is measuring a diameter of 0.314" or 7.976mm in new money.

What diameter reamer will I need to source for this? Will 8mm be too big a hole?

Thanks
Darren

you need a bit of clearance 8 mm should be good
that is way less than a fannys hair clearance

 

[Pete.]

That's just about a thou clearance. Pretty much the minimum you'd ever want, might be tight for the exhaust valves.

 

[Rannsachair]

Its a very long time ago I last worked on a cross flow. though I thought you could run tight clearances with bronze guides and needed to open them up a bit with cast iron. This may help: http://www.partinfo.co.uk/files/SI 1080.pdf

 

[Parm]

you need a bit of clearance 8 mm should be good
that is way less than a fannys hair clearance

I like that, proper old school engineering measurement expression

 

[Fazerruss]

Around the these parts any measurement that small is referred to as a Gnats c**k

 

[RWD3M]

I'm fitting some new valves in a xflow head and the valve stem is measuring a diameter of 0.314" or 7.976mm in new money.

What diameter reamer will I need to source for this? Will 8mm be too big a hole?

Thanks
Darren

Hi Darren,

Have you fitted new guides too?

The Ford crossflow head being of the imperial variety, I would guess that the valve stems are 5/16" diameter.

 

[bert]

No not yet, the new valves don't fit the current holes which are 5/16" , the valves should be 7.88mm or 5/16 but they are slightly thicker stemmed.

 

[RWD3M]

No not yet, the new valves don't fit the current holes which are 5/16" , the valves should be 7.88mm or 5/16 but they are slightly thicker stemmed.

Ah, ok.

Then I'll leave it for the machining experts to advise a suitable clearance.

Good luck!