Crank rehardening after offset grind

[cinquecento]

Building a 4.8 by offset grinding a 4.6 RV8 crank..is it essential to reharden the crank after .185" are removed from the big ends?

Thanks in advance.

[DVandrews]

Was the crank originally tufftrided or induction hardened?

[cinquecento]

Good question..TBH, I'm not sure...
It's a standard 4.6 crank

[Starfighter]

The case hardening you had is gone and you are on core material which may be tough but not hard so it will not resist wear.

Rehardening will depend on the material use. Induction hardening can be done on some materials but some will need to be carburised and then hardened. If the later then you will need to remachine the surface after heat treatment

[19Dogger87]

If it was tufftrided it will be black, however, re-processing cannot be done locally. When grinding you would usually aim for bottom tolerance before tufftriding as you will see a slight increase on diameter. So any areas you haven't ground, with tight tolerances, might end up over/under size.

If it was induction hardened, it's easy to re harden the diameter followed by a low temperature tempering treatment.

If it was carburised, you run the risk of significant distortion and also having an undesirable over carburised structure in other areas which weren't ground to remove the "case". Carburising is almost exclusively done prior to finish grinding.

[paintman]

What advice did the company doing the grind give you?

[Boosted LS1]

If you tuftride it you may find the thrust to be a bit tight. Ask me how I know ;-) I've done a few but lack enthusiasm.

[Boosted LS1]

DVandrews said:

Was the crank originally tufftrided or induction hardened?

They're not tuftrided on rovers. So, something else?