Rebuilt engine seized

[GregMcN]

My rebuilt engine has seized on me.

I had done about 50 miles in 10 mile trips but the seizure occurred after about a mile from starting from cold. On pulling the engine apart the starter sprocket was seized and in trying to remove it I actually pulled it off leaving the brass bush attached to the crank. On a full dismantle the rhs crank bearing has also seized.

To say I am gutted is an understatement but I need to try and understand why and what I can do about it. There is a small hole above it in the crankcase which I assume is an oil feed to the bearing? When I got it this was blocked but I did clear out the sealant. Now it is blocked at the bottom with what looks possibly like aluminium but more like melted than swarf.

Are new crank bearings available or am I trying to find a good replacement crank?

Any thoughts on cause and trait appreciated. I will try and post photos but last night I could not get to load for some reason.

Greg

[GregMcN]

Should have read any thoughts on cause or way forward.
Still can not upload pictures - says I am trying to upload an empty file - what am I doing wrong as have not had problems before?

[Seadog]

I wish I could help with your crank bearing problem, but I’m just not knowledgeable enough. It sounds like the right side wasn’t getting lubricant. I just don’t know whether you’ll need a new crank. Is it out of the engine now? If so, how are the other 3 bearings? The outer bearings are available.

The forum photo option has been down for months and I don’t believe it’s coming back soon. If you want to post pictures, you’ll have to use a photo hosting site like Flickr.

[GregMcN]

Have stripped it down now and all the other bearings are ok so it is just the oil feedto the rhs bearing and starter sprocket. No idea why at the moment. Where can you get replacement bearings from?

Greg

[AlanW]

Sorry to hear about that Greg, when I build an engine I always make sure that small feed hole is clear. The process I use is to wash it through with thinners then blow it through with the air line. When that is done put a bit of turps or white spirit in the indent and it should flow freely through to the bearing. The bush seizing indicates no oil from its feed and that's a bit worrying. Has the crank been stripped and oil ways cleaned?
Best of luck with it mate,
Al.

[Seadog]

Greg, try CMS and David Silver Spares for new bearings.

[G-Man]

Hi Greg

What type of bearing was fitted to RHS? Ball race or roller? If a ball race is fitted to an engine which used a roller bearing, the oil feed to the bearing is blocked unless you cut a little channel in the crankcase.

This is the early type designed for a ball-race.



This is the later type designed for a roller bearing.



This is a 'universal' case I picked up which does both.



I may be able to help with a bearing or, at least, help you get the correct one in there.

How is the crank?


G

My rebuilt engine has seized on me.

I had done about 50 miles in 10 mile trips but the seizure occurred after about a mile from starting from cold. On pulling the engine apart the starter sprocket was seized and in trying to remove it I actually pulled it off leaving the brass bush attached to the crank. On a full dismantle the rhs crank bearing has also seized.

To say I am gutted is an understatement but I need to try and understand why and what I can do about it. There is a small hole above it in the crankcase which I assume is an oil feed to the bearing? When I got it this was blocked but I did clear out the sealant. Now it is blocked at the bottom with what looks possibly like aluminium but more like melted than swarf.

Are new crank bearings available or am I trying to find a good replacement crank?

Any thoughts on cause and trait appreciated. I will try and post photos but last night I could not get to load for some reason.

Greg