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[Scalyback]

Hi All, Tornado is about to get sealed bearings in his 4 speed albion type gearbox. What suggestions are there for lubricant? Somebody suggested SAE50, but what do our experts reckon?

[Scalyback]

Forgot to add, I'm using the 90118 kit from our hosts which comes with all the gaskets, etc. YAY!



Well I had to get him something for Xmas even if i bought it last year!

[Presto]

The Bullet gearbox is a very lowly stressed unit and lubrication is not critical – hence their survival and flourishing with grease as a lub. Normal recommendation for gearbox oil would be a 80-90 grade gear oil (which approximates to about 40-50 engine oil). It'd be perfectly OK to use 20W/50 engine oil – as recommended for Crusaders for instance. Of course unit construction engines use engine oil (rather than ‘dedicated’ gear oil) and a modern multigrade will give perfectly satisfactory protection. However – other opinions are bound to be given on this subject!

[PeteF]

This 'box is an old design and back then it was usual to just use engine oil. Gear oil is possibly better but it really doesn't matter what grade you use. 80/90 is probably the most common so it will be the cheapest. Having said that, I have a can of sae 150 gear oil which I use in the Cub and a big mower - works fine.

[Gwilly]

I use GEAR oil because thats what it says on the tin..

I think its better than Grease in the northern climate as it doesn't thicken in the cold, plus by removing the level plug its easy to know exactly how much lube is in the box when topping up..

Only my opinion of course which is often suspect anyway..

PS don't you dare ask if the inner seals should be removed or i'll send the boys round

[simon]

Straight 50 will be fine if it doesnt leak out. It will make the change quicker and will be more than adequate lubrication for straight cut cogs.

[JTL]

I'm about to do the same conversion; just recieved the # 90118 kit today. I have previously been topping up with some Castrol SAE 140 and intend to use the rest of the bottle for the first oil change. It's very thick, so I might end up using some lighter gear oil. But gear oil it will be. As Gwilly says: it's what is written on the product. Since Scalyback is not allowed to ask about this thing with removing one of the seals in the sealed bearing, I will, because I have been wondering about bying sealed bearing just to remove the seals. Something is not that logic to me. Pete Snidals manual says to remove the inner side sealing for better lubrication, but shouldn't sealed bearing be up to the job since they are contructed as sealed bearing? He also metion to drill a 2 mm gearbox vent hole close to the filler hole? What's that all about? (Scalyback, hope it's ok to ask additional questions in your thread)... regards Jacob

[Leon Novello]

JTL: 140 gear oil is good. Drill a vent hole to release pressure inside a sealed gearbox by removing the fill plug and drilling a small hole from the bottom, nearly to the top, but not right through, then drill a hole through one of the flat sides of the plug to meet with the vertical hole, check before drilling through the flat that the hole will be facing backwards when the plug is screwed down, to stop water entering. This is also called a breather.

[Scalyback]

JTL, you're welcome mate, and I would like to know about some of the things you have brought up too!

[JTL]

Scalyback, good to know since I'm right in the midle of the same job. Leon, the vent hole Snidal advocates for is made almost in top of "filler funnel" in the inner cover and vents into the outer cover. Because the outer cover is not sealed all pressure is releaved (and no water comming in). In a spanish made Bullet restoration video on Youtube (https://www.youtube.com/watch?v=UTY-IgdEPN8 at 6:15) I have seen it done as well. Maybe a thing to do to improve the gearbox environment?