black oxide vs either 18-8ss or 316ss ???

[wholehog]

I need to replace the cap screws in the oil filter mount for an HD oil cooler....the OEM was gr 8 hex head with a torx socket because it was too close to get a thin wall socket on the head (the OEM screw is proprietary and no longer available from HD)

my idea is to replace them with either a 12 pt Ferry bolt or a socket cap screw.....the OEM hex heads were held by a lockplate so that makes me lean towards a hex socket drilled for some safety wire.....

I don't want to end up with galled threads in the engine case but I don't want corrosion either.....

Do I go with black oxide or stainless?  I need grade 8.

[rbabos]

I need to replace the cap screws in the oil filter mount for an HD oil cooler....the OEM was gr 8 hex head with a torx socket because it was too close to get a thin wall socket on the head (the OEM screw is proprietary and no longer available from HD)

my idea is to replace them with either a 12 pt Ferry bolt or a socket cap screw.....the OEM hex heads were held by a lockplate so that makes me lean towards a hex socket drilled for some safety wire.....

I don't want to end up with galled threads in the engine case but I don't want corrosion either.....

Do I go with black oxide or stainless?  I need grade 8.

If you plan on safety wire , anti-seize the threads for protection as well as any face contact points.
For that matter, even loctite offers protection from galvanic corrosion since it forms a barrier between the two metals. A combination of both will work too. I would paint the black oxide since it offers little in the rust prevention.
Ron

[Admiral Akbar]

I use ARP 6 point stainless flange bolts, Cross drill the head with 1/16 inch cobalt bit.. Install with blue LT and 0.031 stainless safety wire.

Max

[wholehog]

thanks guys......the ARP 6 pt looks nice....I can wrench it with with a 5/16 so that fixes my clearance problem and just use the lockplate instead of safety wire...

I'm assuming loctite on the entire thread length to prevent galling, or am I better off with antiseize since I now have the lockplate?

why the hell didn't HD do this in the first place

[Admiral Akbar]

Just the usual amount of LT is fine... With ARPs you won't get any galling when sunk into aluminium even without the LT.. Threads have a real smooth finish on them and they are pretty tough.. Cheap 18-8 is where you need to worry.  What causes galling in SS is when you use a SS nut on a SS bolt..

Max

[koko3052]