i wondered about that first o-ringed one too, it wasn't something i've ever seen like that.

head cc'd means the head is taken off and the combustion chambers filled with a liquid to see their volume, to calculate the compression ratio.

the thing with the pistons is the hyperwhatever ones expand less when hot so they can be closer to the size of the bore and slop less and seal better.

Standard cast pistons are usually Hypoeutectic, which means that the silicone content is less than 12%
Higher strength Hypereutectic pistons have a silicone content of 12% or more.

From my source material.
(Quote)This higher silicone content gives these pistons greater strength and the ability to operate at higher temperatures without scuffing when compared to standard pistons.
Cast Hypereutectic pistons fall between ordinary cast pistons & forgings in both strength and expense, making them an excellent option for those building a mild engine on a budget. (Unquote)

Quote:
in aircraft they do plenty of checks for cracks:
"die pen" fluid that high lights cracks when put under UV light
"magnitic partical" the item in question has a huge magnetic feild ut through it an a fluid with particals in it is poured over it an the particals align on cracks
"ultra sound" ....pretty obvious

O.k - There's 4 standard types of NDT (non-destructive testing).

2 volumetric - Meaning they check the entire volume of the material for discontinuities (cracks, tears, porosity, inclusions etc).

2 surface oriented - Check for discontinuities on the surface (or just below the surface) only.

Volumetric: -

Radiography - X-Ray... Any discontinuities will show up on the film

Ultrasonic - Passes high frequency sound through the material.
Any discontinuities will disrupt the sound & change the reading at the receiver

Surface Oriented: -

Dye Penetrant - Soak the mat'l in dye, then wipe off & spray with a paint type substance.
If there's any porosity / cracks etc, they will soak up the fluid, it will then leak out & show up on the paint.

Mag Particle - You spray the surface with an indicator fluid (another paint like substance), allow to dry, then spray with a fluid that has ferrite (iron) particles.
You then apply a magnetic field & the iron filings will form around any cracks etc.

Shot Peening uses intersitiual substitution to harden the surface (down to about 1.5mm).
Basically if you look at the atomic structure of a material as a lattice, blasting the surface of this material with another substance (usually lead) forces this substance between the spaces in the lattice preventing inter planar slip.

In laymans terms, shot peening makes the outer 1 - 2mm surface of a material harder.

Nitriding, Case Hardening, Induction hardening, carburizing etc. etc. etc.

Quote:

knife edgeing has something to do with removing mass from the cranks counter weights. i'm not sure how this is done but apparantly it lightens your crank by about 1kg and this helps your engine rev.
i would have though removing weight from the counterweights would throw the balance of the bottom end out....

dont hold me to this though.

Sorry to dig up an old thread but i have been searching for the answer that ronald asked an carnt find much.
Do you need to lighten the pistions and con rod to match the lighten crank? Thanks

Lemonheads knife edged crank.

wow that looks soooo much lighter I bet it would be heaps more responsive at light throttle touches hey?
Can someone tell me what it means to have the crank "offset ground"?

Your crank can also cut through the oil with less resistance when it's knife edged.

I believe when a crank has been offset ground, it's been modified so the crank offers a longer stroke. Not sure exactly what's involved.

Correct me if I'm wrong.

lemonheads crank is extreme knife edging, having just done the research and seen my brother just knife edge a crank, what lemonhead has done is alot more of lightening than convetional knife edging

i was shown a performance crank for a 350 chev the other day, and the factories version of knife edgin is simply rounding the front edge of the counter weight(front as in the egde that is spinng forwards if that makes sence) so that if it does some how come in contact with oil is glides through it smoother

not really alot to it, just radious all the counter weights on the crank and it will be knife egded(they should really call it spoon edging ), but you cant get too carried away with lightening if you are on a budget as the lighter it is the more expensive it is to balance