hi fellas, ive got a saito 180 that is causing a bit of trouble, when its on the ground it really has got some pull but when its in the air it seams to go limp. It has also just starting making a kind of ratteling nosie when on the ground and in the air, if you put your hand on the propeller blade and move it from side to side you can see and feel the cranksaft moving, is this normal? we have been told it know as a slip bearing? or do you feel the bearings need replacing? The engine is running on 10% nitro has always been kept rich plus after run oil is always used, the engine has about 15 flights on it.

thanks flyjunkie

Bearings must be bad?

hey w8ye thanks for the reply, i think you might be right there, the only thing is, is when the prop is turned over theres no crunchy feel, like one of the balls has gone e.t.c
anyways thanks again Flyjunkie

You won't always feel or hear things crunching around when the bearings are going.

I had the same symptom with my Saito 180 although almost new.

Internal ball bearing was fully rusted with its inner ring tolerating a lot.

You can destroy everything if you don't change it immediately.

Stelios

Hi Fellas

Flyjunkie and I removed the bearings from the Saito and the rear bearing is completely shot. Red rusty and very rough when turning. The front bearing doesn't seem too bad. This is the second set of Saito bearings we've had to change in low hours motors, both having run less than 10 hours. New ceramic bearings with stainless steel cases are on the way from Paul at RC bearings.com, unbelievably reasonable prices, £22 ($41) delivered to the UK.

The motor showed signs of debris inside with some pitting in the machined area of the crankase where the crank and conrod revolve. We also found one of the tappets was sticking, debris again. After lots of careful cleaning and polishing everything is clean and smooth again, just need the bearings to start reassembly.

Having thought it through I think we've hit problems because the engines are inverted so when we put after-run oil in if we turn the aircraft the right way up the oil goes into the cylinder rather than the bearings. Also we keep the aircraft in a heated shed, inside a garage but in the UKs damp climate rust is a real issue. We've used Irvine formula fuel which uses synthetic oil. This has produced plenty of power but with our problems so far we're going to go back to a fuel with castor, not a reflection on the fuel just our hope it will provide better protection.

We'll let you know how the rebuild goes when back together.

Davesdad