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Broken oil seal mating face in crankcase

Submitted by tony_wood on Sat, 04/05/2019
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Heavy Twins

Hi,

I’m working my way into my barn find Domi 99. I’ve now pulled the left-hand crankcase half off the engine. The crankshaft oil seal on the drive side looked well fitted from the outside of the case and was indeed very tight in its bore. However, when I looked at the seal from the inside of the crankcase half I could see that part of the crankcase area that supports the seal is broken away (photo attached). Do you think the case will be ok to use? As I mentioned, the seal fits really tightly into the bore and pushes home against the part of the crankcase that’s still there, but will that missing area affect the seal around the crankshaft nose? If it’s an issue, could I make a shim to put into the crankcase before putting the seal in, that way, the shim would cover over the broken area.

Any advice gratefully accepted.

Regards

Tony

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Submitted by mark_savage on Sat, 04/05/2019

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I'd have it fixed whilst it was apart. Easy for someone who knows what they are doing and have the right equipment. Where abouts are you?

Hi Steve, 

I’m in north Bucks/south Northants. So do you think someone would be able to bridge that broken area and then mill It all square on both sides and accurately bore the crankshaft nose hole? Sounds like I need a very competent engineer -any ideas who is a good person to do it?

Thanks

Tony

Submitted by mark_savage on Sat, 04/05/2019

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I've pm'd you a number of someone Pete Lovell recommended when I needed some repairs and modifications to my Commando crankcases.

Submitted by robert_tuck on Sat, 04/05/2019

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I can't see how that would affect the sealing at all. For peace of mind,nice to get it fixed. Not simple or needed though.

Submitted by chas_goupillot on Sun, 05/05/2019

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Trying to repair that thin section by alloy welding, even by a competent welder, could lead to a whole world of pain and expense.

If the oil seal fits tightly into the recess, it is well capable of doing the job. I would be tempted to tidy things up a bit by enlarging the hole to the diameter of the damaged area. To a large extent you would be removing redundant metal.

Your call.

Best regard,

Chas

 

Submitted by ian_soady on Sun, 05/05/2019

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I'd leave it alone as the seal is around the edge of the oil seal. I would fit it with a light coat of wellseal around the periphery.

As said, it's not structural.

 


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