Starting to do DFL (Dry Film Coating)
http://en.wikipedia.org/wiki/Dry_lubricant

Ever pull apart an engine and you look at the bearings and say to yourself "those look good, I bet I could reuse them..." but you don't because the are stained or have the odd speck in them?
Well these puppies are getting expensive and some are hard to find.

For the most part you don't need expensive measuring tools to figure this out, you just need eyeballs and fingernails.
If it has obvious physical damage, wear through, pitting, material missing or large scratches you can catch your fingernails on, then sorry you need new bearings. Minor scratches down the middle that you barely catch a nail on may be OK.
Also look at the backs, loose bearings will "walk" scoring the back. Again stains are OK, physical damage is not. Also when you remove the bearing does it just fall out (not good) or does it still hold itself in the saddle (good sign) and you have to wiggle it out.

On Porsche 911 I'd say 9 out of 10 of the #8 bearings can be reprocessed.

Used main bearing set



New full bearing set



used intemediate bearings before

after


3.2 set before, minor scratches, 3 deeper scratches but still within spec.
before

after

Close up pic's of the 3 worst from that set


Not offering this on type 4 bearings (except I will do the steel backed split middle) at this time.
This may change once I test a process.

Piston skirts and ceramic piston coatings coming soon.


Inspect and process full 911 engine bearings set (main, #8, rod and intermediate bearings, new or used) $175
Turn around 2-3 days.

Reprocessed #8 bearings, two are 3.0- and one is a 2.0-2.7
One of the 3.0 was within spec, but IMO a hair loose, the DFL slightly tightened up the tolerance. The DFL at the most adds .0005 (0.01mm) and this can reduced by polishing with a soft cloth. This takes a quite while to do, but is safer than using a green scotch bright pad.

Top set of rod bearings are used 3.2 and the middle set are used 2.7

Pistons with DFL skirts and ceramic tops.

Theses have a fair bit of prep labour.

Very interesting Mark,

Do these "wear in" and eliminate piston slap? This looks like it might be applied via power coating? One of my designers @ work has a neighbor who is supposedly powercoating superchargers for Eaton with a wear in low friction coating.

Thanks

David

I s sort of like powder coating but you don't need the electrical charge on the part. It is a baked finish.

It can increase the tolerance slightly, but by burnishing you can make it very sight.
It won't eliminate piston slap from a part with excessive tolerances, It will help the skirt slip in the bore better.

The coatings, besides being a dry film lube, wick the oil or grease to the face of it's surface.

What is the additional thickness of the film? I just tore down a -6 and bearings look very good.

When burnished I have a hard time reading it, literature says .0002 To be safe on a bearing I'll say since it's double about .0005" or .01mm.
You can easily burnish it more if needed but the coating is getting pretty thin.
On a used bearing and crank the extra .0005 is probably a good thing.

BTW my 3.0 crank is good used standard, rods were done to the tight end of the spec and I only very lightly burnished the bearings with a soft cotton cloth. The bearings feel smooth as silk.

Did you use Calico Coatings to do the work?