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Feb 26, 2020, 01:11 PM
GloBroz PowerLab
1QwkSport2.5r's Avatar
Quote:
Originally Posted by Sam Ehab
If I remember correctly, an OPS engineer left OPS and started Picco.

The case looks beautiful on the outside, but at the exhaust port, the casting is a little rough and has some casting edges that I may grind down to smooth out that area. Will not effect any timing.

The bearings are fully open, no shields, I will replace with shielded ones. I hate leaky engines!

Once I get a header for it and new bearings, it'll go on the chop block for some Italian Music!
The bearing shields do NOT seal the crankcase - the oil film between the crankshaft and crankcase makes the seal. I have engines with shielded bearings that will weep oil just as open bearings will. That said, Iíll order open bearings for the rear and rubber shielded for the front and remove one shield and face that to the rear of the engine. But the shield isnít going to stop leakage from sitting.
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Feb 26, 2020, 01:13 PM
GloBroz PowerLab
1QwkSport2.5r's Avatar
Quote:
Originally Posted by SeismicCWave
Do you know the history of Picco? I think it has to do with part of the Rossi family. Also related to OPS?
Scott is right - one of the designers from OPS was one of the Picco brothers. Picco makes truck engines only now, which are phenomenal. REDS engines are made by Picco as well and Mario Rossi is the designer behind the REDS lineup.
Feb 26, 2020, 01:59 PM
Registered User
Thread OP
Quote:
Originally Posted by 1QwkSport2.5r
The bearing shields do NOT seal the crankcase - the oil film between the crankshaft and crankcase makes the seal. I have engines with shielded bearings that will weep oil just as open bearings will. That said, Iíll order open bearings for the rear and rubber shielded for the front and remove one shield and face that to the rear of the engine. But the shield isnít going to stop leakage from sitting.
Leakage from running not sitting is what I am after. I am experimenting with full shields for both bearings and one shield for front bearing on them Rossi's 40.
Feb 26, 2020, 05:58 PM
Still gassin' it.
Quote:
Originally Posted by 1QwkSport2.5r
I have engines with shielded bearings that will weep oil just as open bearings will.
Then it is just a poor shield (if it is a rubber shield).

Good quality bearings are able to keep a lot in, provided the prop or flywheel is properly balanced.
My OS FX 46 leaked around the nose when I bought it used with only 1,5 gallon through it. Replaced for an SKF 2RS bearing, kept both seals in and the engine has been bone dry ever since (well over 4 years).
Same for a .30 fourstroke that not even has a crankshaft/case fit that would allow for an oil film, the case pressure is hitting the front bearing unrestricted. Leaked fairly significant straight from the box. SKF 2RS to the rescue, also bone dry ever since.

Those rubber shields, provided good quality and properly balanced prop or flywheel, hold in quite a lot on their own.

Metal shields never seal by the way
Feb 26, 2020, 06:07 PM
GloBroz PowerLab
1QwkSport2.5r's Avatar
Quote:
Originally Posted by Sam Ehab
Leakage from running not sitting is what I am after. I am experimenting with full shields for both bearings and one shield for front bearing on them Rossi's 40.
No ball bearing engine Iíve ever owned that had open bearings ever leaked when running. If you get leakage from the bearing when the engine is running, it is either sloppy stupid rich or the crankshaft/crankcase fit is compromised, or possibly too little oil in the case of some cheapie engines.
Feb 26, 2020, 06:15 PM
GloBroz PowerLab
1QwkSport2.5r's Avatar
Quote:
Originally Posted by 1967Brutus
Then it is just a poor shield (if it is a rubber shield).

Good quality bearings are able to keep a lot in, provided the prop or flywheel is properly balanced.
My OS FX 46 leaked around the nose when I bought it used with only 1,5 gallon through it. Replaced for an SKF 2RS bearing, kept both seals in and the engine has been bone dry ever since (well over 4 years).
Same for a .30 fourstroke that not even has a crankshaft/case fit that would allow for an oil film, the case pressure is hitting the front bearing unrestricted. Leaked fairly significant straight from the box. SKF 2RS to the rescue, also bone dry ever since.

Those rubber shields, provided good quality and properly balanced prop or flywheel, hold in quite a lot on their own.

Metal shields never seal by the way
While I agree that a rubber shield will hold a lot back, they are not a seal by true definition. I have had other people tell me that a brand new 2RS bearing cured their leaky front bearing problem too. While I donít doubt a new bearing can cure that trouble, it isnít to say the rubber shield is the sole reason it stopped leaking.. a mechanically sound bearing silk behave no different than a mechanically sound shielded bearing. I, as well as many other people, have engines with open, rubber shielded, and metal shielded bearings in their engines. I dare say putting the rubber shields from a new bearing into the old bearing would not change a thing.
Feb 26, 2020, 06:25 PM
Registered User
Thread OP
So my only concern with "fully shielded" front and rear bearings, is adequate lubrication while running (2 and 4 strokes). Will the bearings get proper oil from the fuel to keep them happy? I don't know the answer yet but my Rossi 40 I just rebuilt has full shields and its too early to make an observation.
Feb 26, 2020, 06:54 PM
GloBroz PowerLab
1QwkSport2.5r's Avatar
I remove one Shield from the front and face the shield out front. I don’t even think twice about it. It’s never ever failed me doing it this way. Oil WILL still find its way into a double shielded bearings whether you like it or not.
Feb 26, 2020, 10:04 PM
Registered User
Thread OP
Quote:
Originally Posted by 1QwkSport2.5r
I remove one Shield from the front and face the shield out front. I don’t even think twice about it. It’s never ever failed me doing it this way. Oil WILL still find its way into a double shielded bearings whether you like it or not.



That's exactly what I was hoping for, the fuel oil will go in and lube the balls...
Feb 27, 2020, 02:29 AM
GloBroz PowerLab
1QwkSport2.5r's Avatar
Quote:
Originally Posted by Sam Ehab
That's exactly what I was hoping for, the fuel oil will go in and lube the balls...
Itíll get in there easier without the shield on one side. If the OEM felt an open bearing is good....
Feb 27, 2020, 02:52 AM
Registered User
Thread OP
Quote:
Originally Posted by 1QwkSport2.5r
Itíll get in there easier without the shield on one side.
Sure. Agree.
Feb 27, 2020, 04:27 AM
Still gassin' it.
Quote:
Originally Posted by 1QwkSport2.5r
I dare say putting the rubber shields from a new bearing into the old bearing would not change a thing.
YeahÖ but that is because you can't remove a rubber shield without damaging it, let alone place it back in another bearingÖ

All I meant to say, is that there is a very distinct difference between lower and higher quality bearings WRT sealing capabilities.
Feb 27, 2020, 12:56 PM
GloBroz PowerLab
1QwkSport2.5r's Avatar
Quote:
Originally Posted by 1967Brutus
YeahÖ but that is because you can't remove a rubber shield without damaging it, let alone place it back in another bearingÖ
Iíve had great luck not damaging the seal, so I cannot agree here.
Quote:
All I meant to say, is that there is a very distinct difference between lower and higher quality bearings WRT sealing capabilities.
Here again, my experience is different. Iíve used $1 bearings and Iíve used $20 bearings and as far as leakage goes, I havenít found a difference. Again, I agree to disagree. YMMV.
Feb 27, 2020, 06:32 PM
Registered User
downunder's Avatar
I'm not sure if there's some confusion with terminology here but there's a big difference between shielded bearings and fully sealed bearings. Shielded bearings (rubber or metal, single or double sided) don't make contact with the inner race and are simply a means of keeping dirt away from the races. Fully sealed bearings though are pre-lubed with grease and are designed for use in dry, dusty environments. They can be used in model engines but are rated at somewhat lower revs than open/shielded bearings. I fitted a sealed bearing once in an engine that leaked horribly from the front bearing but first I removed one seal and thoroughly washed out the grease. That cured all the leaking.
Feb 28, 2020, 12:04 AM
Diesel Danny
danny mz's Avatar
Well, if fuel is leaking from the front bearing, at least one knows that the crankshaft is being lubricated

I seem to recall that some model engines had a reverse spiral machined on the crankshaft to fling oil back into the crankcase (not 100% sure though)


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