Head & head gasket questions

[hayd3n]

Do the studs not go right into the casings?

the cylinder bolts to the crankcase via 4x 10mm headbolts and the head bolts to the cylinder via 4x 10mm headbolts,
the threads in the cylinder head are stripped and 2x have already been previously helicoiled (last year ) by a engine reconditioner
which lasted 10 kms

[Drew]

the cylinder bolts to the crankcase via 4x 10mm headbolts and the head bolts to the cylinder via 4x 10mm headbolts,
the threads in the cylinder head are stripped and 2x have already been previously helicoiled (last year ) by a engine reconditioner
which lasted 10 kms

Sweet. Clearer picture now.

The important thing is to sandwich the gasket between two things to drill it. I would use the head and barrel for the sake of making sure it all lines up in the end.

Things to remember. Without dowels, the head and gasket might twist. Piston hitting either of those will fuck it and maybe bend a rod and fuck a big end.

The holes on the barrel need to be smaller than the holes in the head, so there's material for the tap to cut away. If you do it my way, don't go too deep with the drill when going through the gasket. Drill press for the win.

If it had already been helicoiled and they stripped, those holes might already be oversize to cut a 12mm thread into. Check that out first methinks.

Others will come up with more warnings, wrap your head around it all before you start work. Many a workable solution has been botched, by impatience and eagerness.

[Akzle]

stepped bolt= shoulder bolt,
tap head *block for m12, have m12 stud turned down to m10 just below *mating* surface. Save fucking arnd with gasket.
Damn. Hate agreeing with figgy.

-edit-
sent from cellphone. you shoulda got whut i meant. (hell, he did...)

[hayd3n]

stepped bolt= shoulder bolt,
tap head for m12, have m12 stud turned down to m10 just below head surface. Save fucking arnd with gasket.
Damn. Hate agreeing with figgy.

i have to tap the barrel not the head
THE HEAD isint tapped

[FJRider]

i have to tap the barrel not the head
THE HEAD isint tapped

Do we have to draw you a picture .. ???

The stud has two different sized threads.

The 12 mm thread goes into the newly enlarged tapped holes in the barrel.

The 10 mm portion of the stud is what the head bolts attach to.

ANY half decent engineering workshop could make up the required number in less than an hour. You give them the required length of each thread ... and no issues.

[hayd3n]

Do we have to draw you a picture .. ???
.

would be a lot fuking easier lmao
is this what your referring to??

http://tnt-power.com/images/A1_STUDS.jpg



the ones i have look alot like this

http://www.peninsulardiesel.com/WP-P...es/6250504.jpg

[FJRider]

the ones i have look alot like this

And a reason not to change to the double sized studs would be ... ???

Quick and easy and you don't fuck gaskets.

[hayd3n]

And a reason not to change to the double sized studs would be ... ???

Quick and easy and you don't fuck gaskets.

hardened bolts are not that easy to thread
, and ive managed to sucessfully drill out the gasket now

[hayd3n]

Sweet. Clearer picture now.



Things to remember. Without dowels, the head and gasket might twist. Piston hitting either of those will fuck it and maybe bend a rod and fuck a big end.

.

the barrel dowels that attach to the crank will still be there ,
i cant see the head (with out dowels ) moving causing any piston problems apart from loss of compression,
+ the new bolts / holes have only slight clearance,
my foreman (engineer) is quite content that i should be fine with out the dowels in the head,
but i am looking into making new ones

[Akzle]

hardened bolts are not that easy to thread
, and ive managed to sucessfully drill out the gasket now

unharden them, machine them, re-harden them. sheeesh. blowtorch and lathe.

[bogan]

the barrel dowels that attach to the crank will still be there ,
i cant see the head (with out dowels ) moving causing any piston problems apart from loss of compression,
+ the new bolts / holes have only slight clearance,
my foreman (engineer) is quite content that i should be fine with out the dowels in the head,
but i am looking into making new ones

It won't be sliding around, but thermal expansion forces etc may cause bits to move. If you can get it lined up properly and dowels sized right there is not reason not to do it.

[Akzle]

It won't be sliding around, but thermal expansion forces etc may cause bits to move. If you can get it lined up properly and dowels sized right there is not reason not to do it.

stainless roll pin?

[Drew]

I've never pulled a motor down that didn't have locator dowells. I suspect the good folk who design motors all agree they should be there for some reason.

[hayd3n]

I've never pulled a motor down that didn't have locator dowells. I suspect the good folk who design motors all agree they should be there for some reason.

[FJRider]

If it had already been helicoiled and they stripped, those holes might already be oversize to cut a 12mm thread into. Check that out first methinks.

The difference between a 10 and 12 mm bolt is an extra one mm in the bolts radius.

Is that extra one mm enough safe steel to thread a bolt hole .. after a helicoil has been stripped from the same location ... ???