Head & head gasket questions

[hayd3n]

ok so im drilling out my 10mm threads on my POS xl250 and fitting 12mm head bolts

what is the safest way to make the head gasket holes bigger to fit the bigger bolts??

the head gasket is made of 3 layers of some kind of steel with a teflon?? coating,
i have had a play with the old gasket and tried using a die grinder to make the hole bigger but it just makes a mess of the hole

also i will have to remove the locating pins between the head and barrel to fit the bigger bolts will this be a problem as they wont be going back on??

there must be a way with out damaging the gasket, other wise can i make my own gasket out of something???

[Drew]

The two head stud holes in the gasket, that used to have dowels should accept M12 bolts. Drill and tap those two first, then bolt the head to the barrel, and do the other two.

Not putting dowels in with the new bolts, will be an interesting way to fuck a motor. Good luck with that.

[FJRider]

Have you actually tried putting a 12 mm bolt through the bolt hole in the gasket ??

[Akzle]

hole pnch dude. with a short taper, and probably on hard wood.

else if you were gang$ta with a twist drill...

[hayd3n]

the head and barrel will accept the new bolts but the gasket wont yet

[bogan]

Step drill would be my first try; anything else is going to be tricky to line up right.

Dowels, I agree with Drew on that one.

[hayd3n]

if i have to i can make new dowels just a little more work to do with the radial drill

[scumdog]

if i have to i can make new dowels just a little more work to do with the radial drill

Check your PMs

[Virago]

I regularly drill perfectly neat holes in paper, using a standard twist bit in a drill press. I would think it should work okay on a gasket.

Sandwich it between two bits of wood, the top piece pre-drilled with your 12mm hole. This will provide perfect support under and around the hole as you drill it.

[hayd3n]

will have a play tomorrow

[FJRider]

I regularly drill perfectly neat holes in paper, using a standard twist bit in a drill press. I would think it should work okay on a gasket.

Sandwich it between two bits of wood, the top piece pre-drilled with your 12mm hole. This will provide perfect support under and around the hole as you drill it.

Pre-drilled with 10 mm holes in the wood .. would be easier to center the holes.

Or get stepped 12 / 10 mm stud bolts.

[hayd3n]

Pre-drilled with 10 mm holes in the wood .. would be easier to center the holes.

Or get stepped 12 / 10 mm stud bolts.

cant see how this would work ??

[bogan]

I regularly drill perfectly neat holes in paper, using a standard twist bit in a drill press. I would think it should work okay on a gasket.

Sandwich it between two bits of wood, the top piece pre-drilled with your 12mm hole. This will provide perfect support under and around the hole as you drill it.

That'll work cos the paper is softer than the wood, try it with steel between wood and I expect you'll make a mess. Sandwiching it between steel or aluminium is more likely to work I think. ut bear in mind a twist dril from 10-12mm is going to have a lot of 'bite' you might want to adjust the cutting angle a bit first.

[Drew]

Do the studs not go right into the casings?

[Virago]

...bear in mind a twist dril from 10-12mm is going to have a lot of 'bite'....

Yup. That's why it's important to use a drill press - that way you can finely control the feed. Do it with a hand-drill and it will rip things to shreds.