(Re) Coating Main Bearings

[Moyock13]

Who re-coats main bearings?

[Piledriver]

You can... but the bearing must still be a tight fit in the block or rod, if it was moving around this won't really help.
https://forums.pelicanparts.com/911-eng ... rings.html
(first hit from Google not AI)

Also mentions Calico, who would be the first company mentioned in the discussion, perhaps before 3M or Techline.
(The Techline stuff seems to be mostly moly powder or WS2/MoS2 blend, but I assure you it still sticks and attracts oil and provides protection, do not hesitate to put it on new bearings and journals)

I think I still have ~a kilo of .3-.5 micron WS2 somewhere around here...

This isn't a new thing in the least...
Folks have been doing this... a very, very long time, just not talking about it much...
Probably...likely during WW2... possibly well before, as oil (relatively) sucked until much later on..

I used Molykote exactly like this on a T1 at 16 or 17, suggested by my bosses who raced, as T1s tend to run out of oil occasionally when driven ...violently, unless you dry sump or deep sump it.(deep sumps have their own issues)
..... worked great for a very abused motor driven like a teenage idiot I was... (A dropped valve, pulled through a retainer got that motor, bearings/coatings still ~as installed 30K miles later)
I'm now in my early 60s.

It's also used a a coating for blower rotors, takes quite a few coats to build up... its a "secret" self clearancing coating, good to over 450F.(resin limit, the MoS2 or WS2 are refractory materials good well over 2000F)
Works peachy on piston skirts.

I have heard an airbrush and careful masking allows good control.... DO buff them out after curing and between layers.

If somebody started making awesome quality bearings again , I would still not hesitate to at least give them the dry buff coatings, even if they were multi-layer coated like the best Clevite 77s...

[Moyock13]

Yeah, I've got main bearings on order but they are back ordered. No telling when they'll be delivered.

Thanks for the tips. Push come to shove I may try coating.

[raygreenwood]

I will be doing a set of type 4 main, rod and cam bearings (maybe two) in a couple of weeks. with Techline DFL-1.

The biggest hurdle to doing this is actually getting acceptable grit size for grit blasting them to put a tooth on them. I found a source for medical grade aluminum oxide for cheap that is about 2X finer than Techline listed (their tech said it would work just fine)...for cheap. I use a cheap badger air grit gun (listed as a hobby sandblaster or air eraser).

I have a really good airbrush I will beusing but you can get any cheap with with a 1.0mm or finer needle for about $25 on Amazon.

If you have none of the stuff except a toaster oven to bake them in you are looking at about $50 for the coating, $25 for the airbrush, $35 for teh grit blaster and about $30 for five pounds of grit (you can buy a pound but its cheaper to get more). With shipping, call it $200. I will post a link to teh how to when I get it done. Ray

[Piledriver]

Looking forwards to your results, Ray.

I picked up several Mahle bearing sets from various sources before they finally disappeared, but honestly they all look horrible compared to old sets, so likely will get scuffed, sprayed and buffed before use.

[raygreenwood]

Looking forwards to your results, Ray.

I picked up several Mahle bearing sets from various sources before they finally disappeared, but honestly they all look horrible compared to old sets, so likely will get scuffed, sprayed and buffed before use.

While I have used DFL-1 in a couple of engines, I have never applied it myself. This will be my first time and it should be fun. I have been test grit blasting some old used bearings from dead engines with my badger grit blaster and some medical grade grit and they look great. I have a brand new super excellent airbrush I really like and this will be teh first industrial coating Ispray through it and in my new lighted/exhausted/filtered airbrush booth.

This is my new airbrush. Just outstanding. I have never seen atomization so fine.

https://www.gaahleri.com/products/ghac- ... pviOHcvcXb

One of the things I like about it from past experience is that it fills the fine scratches from the dial bore gauge...that while they look ugly do not actually hurt the bearing. But it does fill the scratches.

So I had another thought/question. Techline says that the buildup or thickness after drying, curing in the oven and buffing is typically about 0.0005" max to about 0.00025"-ish maybe less.

I am wondering if this material may help to make a set of something like Silverline bearings which can have some variation.....have LESS variation.

Months back when the news hit that Silverline was gone....I went ahead just for the hell of it and bought a set of Std/Std type 4 main bearings just to have a backup set even if they are poor.

Ray

[Piledriver]

They use something very similar to the 3M (and related) spray on roots and some modern screw blowers, it can actually be built up fairly thick as long as each layer is allowed to cure and you buff it out... it is basically self clearancing.sacrificial layer, and will assume the needed shape to make the tolerances essentially down to whatever is needed, and the abraded material is a fine lubricant good to ~450F once cured.

I actually picked up a gen5 M62 at a local scrap yard for $75. The only thing wrong with it was the teflon coating was peeling off the rotors... It has a looooong shaft on it, was originally a limited run for some japanese V6... it's probably going on my Cabby. Will be vapor blasting what I can then coating both rotors and housing interior..

The ~only difference between gen 5 & gen 6 Eaton blowers is gen 6 ditched the teflon rotor coating and used the abradeable/self clearancing coating.