head bolt thread???

[Neal R19]

what fecking size is the head bolt thread on F-type engines?

M12 is too big and M11 goes in but rattles around, I'm pretty sure there's no M11.5 :lol:

 

[Chris H]

I don't have any bolts handy but I know my tap and die set has the right size.

I was sure it was M10 and 1.25, I'd need to check but not tonight.

 

[Neal R19]

it's deffo bigger than M11.

The M11 tap I have is 1.5 pitch and apart from being too small, threads in perfectly so I'm pretty sure the pitch is 1.5.

I only want to chase the threads out, think I'll just grind a couple of slots in an old head bolt and use that.

 

[Chris H]

I wouldn't even cut slots, just thread them in when it bottoms leave it a second and turn more and it will get any fluid out by capilarry actuion.

I haver yet to actrually see a bad threaded hole on a block aside from ally block ones.

 

[Neal R19]

bit of crap and slight corrosion in the threads thats all

not bothered about fluid, ill blow that out with the airline.

 

[maxiboy]

thought they were M12 x 1.5..iirc

 

[Neal R19]

I tried putting an M12 tap down a couple of them and it immediately felt like it was cutting rather than just dislodging grime... which says to me its too big...

 

[Chris H]

what make is your tap set? I have a few sets and the cheapo ones always cut the threads as they are wrong.

 

[maxiboy]

yeah pretty certain there M12x 1.5..get a quality cutter..