Ceramic Needle cage Bearings

[philski]

HI all

i started blueprinting my engine today and the clearance on the small end of the rod is insane

The gudgeon pin is 10mm and the id of the factory bearing is 10.64mm
outer is even 13.5mm and should be 14mm
so i have over 1mm of free play in the piston in all directions, and the roller thats in it is already starting to show signs of fatigue from being smashed into by the loose piston, and it makes port timing impossible.

I was just wondering if anyone here knows where i can get some 10mm x 14mm x12.5mm ceramic needle cage bearings? I know its overkill, but they weigh half as much and are twice as strong and are rated at approx 75000 rpm and are used in F1 etc and i wanted to go full ceramic anyway. once i measured up the internals

Ive tried google etc and a few european bearing makers. but so far have not had any joy. apart from one way sealed needle bearings. There everywhere,, but not in open cage design?

im more than happy to oversize the rod to make it fit ie: 14.5mm -15mm or 16mm if that helps..

any assistance is most appreciated..

Kindest Regards
Phillip

 

[HeadSmess]

hmmmmm...why the obsession with overpriced ceramic coated mumbo jumbo?

do you realise that in drag racing harleys, they actuallly remove the OEM roller bearings, replacing with straight brass/bronze bushes?

the clearance/play can be reduced to the quality of your surface finish....mmm, reamers at +.001 oversize.... the pressure is spread across a wider area. theyll take more pressure before failing....
they do add some minor friction yes. yet theyre used a lot in lubrication free areas too...like fan motors, alternators, etc...

and.... when they do fail you dont get an engine full of hardened steel chunks....

 

[DougC]

HI all

i started blueprinting my engine today and the clearance on the small end of the rod is insane
.....
I was just wondering if anyone here knows where i can get some 10mm x 14mm x12.5mm ceramic needle cage bearings?

I don't think I have ever seen any ceramic needle bearings, all I've seen are chrome or stainless.

VXB shows a 10x14x12mm needle cage bearing for ten bucks. htXXXtp://www.vxb.com/page/bearings/PROD/kit945 (chrome steel, that is) ,,,,, Just putting in new (chrome-steel) bearings and snugging up all the loose fit would probably do quite a bit for the engine.

---------

Among bearings, chrome-steel is the lowest material type, stainless is better, hybrids are better than that (hybrids are stainless races with ceramic balls) and full-ceramics are the best,,,,, but in most uses, there's not really and advantage in full-ceramic bearings. ....Full-ceramics are somewhat more durable than the metals, but their lower rotating friction is not going to be an advantage unless the bearing drag is the main limitation left on RPMS (in a bicycle motor it's not) and unless the RPMs are fairly high, like 20,000+.

In a 400K RPM air grinder, full-ceramic bearings are a great idea.
In a motor-bicycle engine, they're probably a waste of money (if you can even find any at all).

Most full-ceramics are ball bearings anyway. If you do find ceramics later you could always swap them in, but don't hold your breath.
~

 

[philski]

HI

i contacted the biggest bearing companys in Europe and Japan and they dont make any ceramic needle bearings as small as i need. They said "because the rollers/pins are small they will fail/crack under load" So,,,, i got 15x10 stainless ceramic hybrids ball rollers. RC Hobby shop, Their oversize, But because i have large 2mm squish band. I am oversizing/raising my conrod little end 1mm to raise both my capacity and compression. A stroked 72.5cc!

I realise traditional bushes/ bearing are used in racing and every normal daily driver. However they are in an oil fed system. you need oil in between them under pressure at all time or they will gall up and fail. Bronze has some inbuilt lubrication propertys, But again, needs to be oil fed, under pressure or it will fail and has way more drag.

the benefit in ceramic in a 2 stroke is less oil. 200-1 oil ratio, longer lasting, less resistance and lower weight. 3 of them weigh as much as 1 normal bearing, so i will cut and grind out my piston to get ballance. an impossible task when the piston slops about.
The Horsepower released in other small engines using ceramic bearings is 1/4 - 1/2 HP gain.

Prices are wildly different. i got 2 sets for under $10 or i could have got 1 for $80

The ceramic bearings arrived today too! yeeehaa! including a set of genuing stihl 029 50k rpm rollers, so i will get some results up for you when i get it all reassembled.

Kindest Regards
Phillip

 

[spad4me]

Hello.
I can only find the places that sell ceramic bearings for $80.00 dollars.
Please post the address of the business that sold you two sets of ceramic bearings for under $10.00


You posted
Prices are wildly different. i got 2 sets for under $10 or i could have got 1 for $80

The ceramic bearings arrived today too! yeeehaa! including a set of genuing stihl 029 50k rpm rollers, so i will get some results up for you when i get it all reassembled.

Kindest Regards
Phillip