Ball Bearing V Neele Bearing

Glow/Nitro and gas engines, propellers, fuel and other stuff associated with making lots of noise and thrust.

Ball Bearing V Neele Bearing

Postby spitfire2010 » Mon Nov 08, 2010 2:20 am

Hi ALl,

Looking to convert the asp 61ar to either petrol or a 50/50 mix of nitro fuel and petrol.

This seems to work very well from my readings but the "HOW TO" is a bit harder to find.

My questiong relates to oils etc and the amount required. If you have needle bearings you can have less oil as opposed to a bushed engine.

My motor has ball bearings so where does that fit into the equation??? Can i run less oil ....if not why? what else is the oil doing in the engine.

Ian
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Re: Ball Bearing V Neele Bearing

Postby jeffie8696 » Tue Nov 09, 2010 12:19 am

I think the problem you are going to run into is not the crankshaft bearings but the connecting rod bearing. You would probably get away with a lower oil content if the connecting rod bearing were a needle bearing but I have no experience with such.
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Re: Ball Bearing V Neele Bearing

Postby RCModelReviews » Tue Nov 09, 2010 9:25 am

Jeffie is right.

The ball bearings on the crankshaft aren't the issue - it's the crankpin and wristpin (conrod) bearings that is why our model engines need so much oil.

These bearings are just plain bushings on virtually all glow-plug engines so you need sufficient oil to create the film that allows them to slide smoothly rather than galling.

I run 12% high-quality oil in my glow engines and you could probably drop that to 10% if you were running petrol because petrol in itself has a higher lubricity than methanol - which is very "dry".
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Re: Ball Bearing V Neele Bearing

Postby TMKits » Wed Nov 10, 2010 8:18 pm

I sent you a messge on the HK forum....Hope you got it.
It's the big end (Bush) of the rod that requires all the oil.Whats needed is boring out the rod and fitting a "Drawn cup needle roller bearing" and fitting a hardened pin, replacing the crank journal, as it is too soft for the bearing rollers to run on.
Fits of the bearing in rod, and pin in crank are critical.
You can keep the original bush with petrol but keep the oil mix high. Normal petrol RC engines generally run 30/1 to 50/1 mix because all the bearings are ball/roller type.
You will also need:
An ignition system (RCEXL). You will need to decide if you want to use a 1/4 x 32 plug or machine (tap) your head to the more common cm-6 10mm plug (if it wil fit).
A magnet mounted to the propdriver and a mount for the hall sensor. Static timing should be around 26/28 degrees BTDC to start with.
A carb adapter to use a walbro type carb is recommended as the nitro carbs can flow too much fuel. Walbro carbs have a built in pump so you can mount the fuel tank anywhere.
The engine will run hotter with petrol so cooling is important.
Hope that helped......
Regards
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Re: Ball Bearing V Neele Bearing

Postby spitfire2010 » Sun May 01, 2011 9:04 am

sorry for the late reply. I didnt get a msg on HK btw.

I have the appropriate machines and tooling required to peform the task excluding the tap for 1/4 x 32 and the spark plug to suite.

RCModelreviews, I had previously asked you about synthetic ester based oils as i cant remember or find the post but were you for or against.
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