Which 2 strokes have a ringed piston ?
03-25-2010 | 08:39 AM
#26
Senior Member
My Feedback: (14)
RE: Which 2 strokes have a ringed piston ?
ORIGINAL: Hobbsy
Hey Mikester, Fox made a few engines that came in both ringed and non ringed. I don't have any non ringed fourstrokes, just Saitos, Enyas and the LASER .70. I sold my OS .52 a few weeks ago.
Since this is kind of about engine piston to cylinder seal, my PAWs are steel in steel and my Fox .25 is Meehanite in steel, the PAWs might be too. None have rings. On the PAWs and the Fox 25, you could hold them against compression all day and they will not leak down.
Hey Mikester, Fox made a few engines that came in both ringed and non ringed. I don't have any non ringed fourstrokes, just Saitos, Enyas and the LASER .70. I sold my OS .52 a few weeks ago.
Since this is kind of about engine piston to cylinder seal, my PAWs are steel in steel and my Fox .25 is Meehanite in steel, the PAWs might be too. None have rings. On the PAWs and the Fox 25, you could hold them against compression all day and they will not leak down.
Stand down, Hobbsy. We're not fighting the civil war of model engines!!!
I just bought a pair of Magnum .52 RFS (four-stroke engines - so much for thread drift) at their low price. I'm planning on building a few multis. Four-strokes have their own sound in that particular mode.
However, I'm still buying two-strokes too. I miss ringed two-stroke .40 sized engines (or thereabout), but the ringless Enya .40 & .45 CX engines that I have are holding up amazingly well.
Maybe I'll get the NIB .50 & .61 CX engines running this year. Maybe...
Ed Cregger
03-25-2010 | 01:17 PM
#27
Thread Starter
RE: Which 2 strokes have a ringed piston ?
What exactly is a needle bearing ?
I am referring to ball bearings,like the two of them that support the crankshaft of many glow engines.
Is there any manufacturer that uses instead of a bronze bushing ,to connect the crankshaft to the connecting rod, a ball bearing ?
I am referring to ball bearings,like the two of them that support the crankshaft of many glow engines.
Is there any manufacturer that uses instead of a bronze bushing ,to connect the crankshaft to the connecting rod, a ball bearing ?
03-25-2010 | 02:12 PM
#28
Senior Member
RE: Which 2 strokes have a ringed piston ?
I now understand you Kostas, but manufacturers don`t use BALL bearings in those places, but rather NEEDLE bearings. As a general rule only gas engines has bearings in those places (both ends/holes of the con-rod) There`s some exeptions and as mentioned some MVVS glow engines also utilize needle bearings in the rod. Just google and you will find out just what a needle bearing looks like
03-25-2010 | 04:18 PM
#29
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RE: Which 2 strokes have a ringed piston ?
ORIGINAL: Kostas1
What exactly is a needle bearing ?
What exactly is a needle bearing ?
03-25-2010 | 06:54 PM
#30
My Feedback: (20)
RE: Which 2 strokes have a ringed piston ?
ORIGINAL: Kostas1
What exactly is a needle bearing ?
I am referring to ball bearings,like the two of them that support the crankshaft of many glow engines.
Is there any manufacturer that uses instead of a bronze bushing ,to connect the crankshaft to the connecting rod, a ball bearing ?
What exactly is a needle bearing ?
I am referring to ball bearings,like the two of them that support the crankshaft of many glow engines.
Is there any manufacturer that uses instead of a bronze bushing ,to connect the crankshaft to the connecting rod, a ball bearing ?
03-26-2010 | 07:20 AM
#31
My Feedback: (102)
RE: Which 2 strokes have a ringed piston ?
I have a Webra .61 SilverLine that has a needle bearing at the top end of the rod. The needles in it are not caged but are loose fitting so it looks like there is room for one more needle. I assume that is deliberate so they won't crowd each other.
My OPS 30 Maxi had a needle bearing on both ends of the rod and could be run on 10% or less oil.
My OPS 30 Maxi had a needle bearing on both ends of the rod and could be run on 10% or less oil.
03-26-2010 | 07:59 AM
#32
Thread Starter
RE: Which 2 strokes have a ringed piston ?
ORIGINAL: asmund
I now understand you Kostas, but manufacturers don`t use BALL bearings in those places, but rather NEEDLE bearings. As a general rule only gas engines has bearings in those places (both ends/holes of the con-rod) There`s some exeptions and as mentioned some MVVS glow engines also utilize needle bearings in the rod. Just google and you will find out just what a needle bearing looks like
I now understand you Kostas, but manufacturers don`t use BALL bearings in those places, but rather NEEDLE bearings. As a general rule only gas engines has bearings in those places (both ends/holes of the con-rod) There`s some exeptions and as mentioned some MVVS glow engines also utilize needle bearings in the rod. Just google and you will find out just what a needle bearing looks like
Asmund now i got it!
So the part that provides this friction-free ,spin, is not a ball but needle-shaped part.
Why these needle-bearings in such areas as the conrod,
are used only by few manufacturers.
I don't think it is the cost of parts.
And that assembly could give far better operation and smothness.
03-26-2010 | 08:04 AM
#33
My Feedback: (102)
RE: Which 2 strokes have a ringed piston ?
Kostas, the crank pin has to be very hard or have a hardened sleeve to risist wear when using needle or roller bearings. C&H Electronics used to do work like that to convert glow engines to gas but I think gave it up as too expensive.
