12mm block studs and bolts / 10mm cylinder head holes

[cozzoi]

I'm rebuilding a 1500 engine block with 12mm studs & bolts.
The euro cylinder head I'm using has 10mm holes
Is it OK to bore out the head to accept 12mm bolts and studs?
any risk involved?
Thank you
George:italia:

 

[Steve Hoelscher]

Nope.

I have done this myself to be able to fit an FI 1500 head on a 1300 block. works fine but you must take great care in setting it up on the drill press to ensure the bore is true.

 

[cozzoi]

Thanks god I 'll be able to use it

I mean thanks Steve

 

[Rupunzell]

A 1/2" diameter drill will get this done. If possible, set the head up on a mill and drill out the holes on the mill. The holes will be nicer and straight if a sharp drill bit and rigidly held in place. Enlarging holes by drilling them out can result in the drill bit getting caught in the material which can ruin your whole day and what is being worked on.

Do use cutting fluid for aluminum while drilling out the holes, this will go a long ways to producing a nicer hole finish and prevent problems while drilling.

Yes, I have drilled out M10 cylinder heads to M12 bolts/studs before with no problems.. You will discover block side of the cylinder head will almost clear M12 and the other end of the hole is where this hole is smaller to fit the M10 hardware..

Bernice

I'm rebuilding a 1500 engine block with 12mm studs & bolts.
The euro cylinder head I'm using has 10mm holes
Is it OK to bore out the head to accept 12mm bolts and studs?
any risk involved?
Thank you
George:italia:

 

[cozzoi]

Bolts / Studs replacement

Should I replace the 12mm bolts and studs for new ones?

 

[paul]

For my 1300 I'm using an euro 1500 head and also had to enlarge the holes from m10 to m12, no problem.
I'm not planning to replace the hardware.
Depends a little bit if the old head will come off easily and how the studs look.
How much have you skimmed the head George?

 

[cozzoi]

Cylinder head pics

Paul, I don't know how much it was skimmed but these pics can give you some idea.:italia

 

[cozzoi]

thank you Bernice

for sharing your knowledge with me.:brow:

 

[Rupunzell]

Thanks.. :happy:

Bernice

for sharing your knowledge with me.:brow:

 

[Rupunzell]

On every engine I put together, every nut, bolt and fastener is replaced with equal or better. All old hardware is tossed.
Think of this as low cost insurance that can easily prevent problems in the future.

As a rule, cylinder head studs/nuts, main studs/nuts, con rod (There is little reason not to use SCAT con rods for a 1500) are always replaced with proper ARP bits.

Many failures and problems can be traced back to fastener failures, or improper assembly. Every detail needs to be attended to down to the nat's eye brow.

Bernice

Bernice

Should I replace the 12mm bolts and studs for new ones?