Wpc - Cryo - Shot Peen Treat For More Strength ?

[cobrAA]

I want to strengthen some of my tranny component and I'm looking for feedback or opinion on this.

1) Anyone tried one of these process ? should I only do one process or can I do 2 or 3 of them ?

2) which part should I think about treating ? gear + synchro ? Anything else ? Should I try to treat other component of my engine rebuild ( valve- valve spring - camshaft - piston etc.)

Thanks guy

[sucram]

Shot peening and cryo seemed to help on a diff. Never tried WPC

Some gearsets come peened and cryo from factory, i.e albins

Also heat can make shit expand, a pinion heated up to 80 deg c gained 2mm in length which changes

the contact patch, if your running on the brink of failure for 20+ mins in competition you want to

look into additional capacity, additional fins or even pumps and coolers

Wouldn't bother doing it to an aftermarket gearset, most are peened already if helical.

valve springs are already peened, would not bother cryo

Would not bother with cam either, snapping cams you have other issues

I have cryo'd a crank before, but that was when it was new and still cheap.

[warps]

a pinion heated up to 80 deg c gained 2mm in length

2mm? Really?

What was it made of - Uberexpandium?

[Ben C34]

Surely .2 mm?

[warps]

Closer to .02mm

Given that steel has a thermal coefficient of expansion of about 12x10^-6 m/m K, a 50mm diameter pinion will grow approximately 0.033mm when heated from 25 deg C to 80 deg C.

On the heavy mining equipment we run the gearboxes with .5mm to 1.5mm backlash, and those pinions are about 300mm diameter, with gears about 1.5m diameter. The change in backlash is negligible when they are at full operating temperature. Scaling that down to an automotive gearbox running 0.1 - 0.2mm (?) backlash, I would think that any expansion beyond 0.1mm (combined between the pinion and gear) would be catastrophic.

[sucram]

Nope, it was 2mm, pinion in particular was from a Subaru front. It is very long

and part of the layshaft so box temp is the same as front diff. An R200 is about

half the length.

Peened, cryo, backlash set for higher temps, gearbox oil cooler and pump

solved the problem

[turboedsloth]

how did you get in there to measure the 2mm difference?

[sucram]

Dial gauge on the end, pinion in vice, oxy on low heat, IR thermometer

[cobrAA]

Anyone else tried cryo and/or WPC, REM finish, shot-peening on a stock gearset, input shaft and synchro set ? Really tempting to open my box and do that, but not sure of which process I should go for.

[GTSBoy]

My local auto trans specialist friends swear by cryo for auto gearbox components in big HP drag cars. They used to smash input shafts on Ford autos all the time. Haven't smashed one on those (several) cars since they cryo'd them. Seems convincing enough.

[Piggaz]

Didn't "Tricstar" try this in his own stock gear set and smash it to bits the first event?

[tricstar]

Yep. True story.

Altho that clutch also saw off a couple OS gear sets too. I think someone needs to try it with a friendlier clutch, for a better test.

But my gearbox guy cryo's high hp 4WD autos with really good results also. ?!?!

[GTRPSI]

Autos force shock impact will always be less than that of a manuals shock impact.

Many are Cryo treating Auto parts with great sucess, manuals are more a mixed bag of results with more manual components failing.

Those breaking manual boxes and drivelines on launch (only) have learnt that loading up the driveline with some clutch grab to take up the driveline slack before launching violently have had reduced breakages just by changing to that technique.

Most breakages are from sudden shock impact loading.

[tricstar]

Never broken anything on a launch.

Mostly third, couple of seconds and snapped an input shaft clean off.

The cryoed one just striped third like most of the others.

[MrStabby]

tric - any oiling mods in your gearboxes? I hear that Award Diff and Gearbox here in Sydney do *something*. Might also be worth trying something like Liqui Moly Mos2 gear oil additive as a hack as it should help if there's any starvation causing the gears to fall out of sliding hydrodynamic into boundary lubrication.

Edit: are your failures as you just start to gun it in the gear, or after you've been gunning it in the gear for a while?

[tricstar]

Thanks Stabby. I have since sold the GTR with a new OS box and coppermix clutch. I did put a lot of the breakages down to brutal R3C OS clutch. Most breakages were on the shift or just after. And quite a few were towards the end of track work or sprints so I definately think a cooler would help. But this is all getting a bit off topic, so I still couldn't definitively rule out Cryo being an option with a nice sprung centre clutch.

[cobrAA]

alreayd bought my coppermix so hopefully it can take away some slack like other said.. and shift a bit more kindly than smashing gear.