hey feral can you help me on the choice of piston and rod that will allow me to run a longer rod and shorter compression length piston in an a14? I'll hopefuly find out about the compatability of the mitzi arp bolts in an a series tomorrow or the day after.

The process is commonly used on gearbox components and some engine components.

I just had some gears and shafts done for a 260Z box and it cost me $280 for the gears. Not bad I thought.

Yeah it's f*cken expensive . It changes th e martensite into austinite, wich makes the metal stronger and stuff like conrods much less prone to faiigue related failures. It does all this without causing brittleness the way heat anealing does. Its also suposed to make rings and bores wear out much slower , so it could well mean rebuilds are required less often, so it'd save money there. Scientest have found that this phenomenon is probably the reason why swiss clocks last so long. Their parts were stored in some cold mountainous place and led to the molecular realignment. This Also explains the theory behind weathering blocks prior to maching them (way way back) as low tempratures but not liquid nitrogen cold, over a longer time will have the same effect.
But it is only for people who have sh*t loads of $$$, If I ever build a really serious motor (v8 hemi or the like) then Id consider it.

That's really funny to read ...

it changes the m-something-cite into s-somthing-cite - if you understand that.

when metal is cast, there are tiny bits of cocky #### in it (you know, the #### you have to chip off your fresh welds before painting).

anyways, cryogenics re-aligns the grains in this very fragile metal, and it becomes 4x as strong, actually changing into another form of fragile metal.

either way, the metal as a whole doubles in strength roughly, but the little bits of cocky #### in the casting have quadrupled in strength, and actually 'bonds' itself to the supreior metal around it during the compression process involved in cryogenics.

and to those who say it doesn't work - pull your head out of your ar5e.

ok, I rang the company and had a chat and basicly its real expencive and doesnt replace heat treatment but takes the process further. It costs $1350 per run ( you have to rent the machine for 4 days) and they use liquide nitrogen to take the metal down to -160c slowly. The guy said there are people still looking into the benifits and the changes in the metal (theyre not sure what happens?!) but basicly it gives better stress load and heat disipation, as to how much they dont know yet. Sounds like something you would do if your building a 100k drag motor and dont mind chucking $$ arround. I think I'll stick to shot penning and polishing.

how does the cyogenic anealing work and how is it better, or should i ask the company? I take it (from what little science background i have) that it involves freezing the metal which will aneal it ( make it stick or bond?). Sounds interesting, who's done it?

Hey Quinn, If your motor is going to be hard core, you might be well advised to talk cryo solutions in auckland about getting some of your bottom end cryogeniclly anealed. From what I've read about it, it's meant to be the shiznit for making motors resistant to terminal failures.

bump

Cheers Feral and dattoman ( a second set could come in handy as im also building a second motor)
I have been ringing arround and have found a company that has 8mm arp bolts (part no 107-6002) that are for a Mitzi 4G63 motor, they come in 4 cylinder sets but Im not sure what thread they are but the have them in stock so I'll check them out tomorrow, The Datsun bolts are a fine metric right? Length shouldn't be a problem because they can be machined to size. At the moment Im also looking at pistons and I have found a realy helpful guy at ACL in auckland who said if i can provide the compression size ( mesured from the middle of the pin to the top face of the piston) and pin size, does anyone know the standard mesurements? I am trying to find a piston that has the shortest compression size and a matching rod (longer to keep the final piston travel hight the same) as this will keep the piston at top dead centre for longer and change the rod movements and create less load on the rods. Anyone have any experence with this?