L
Looked like an old type piston to me with the radial ribbing underneath the head of the piston. Specialloid?
E: Engine Damaged quill
- Thread starter everiman
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If it is, I run race clearance, 10 thou. Cheers Bill.
I'm with Greg on taking the chance to pump a bit of oil down the TS mainshaft and look for it appearing at the side of the big end while the opportunity is there.
Your quill is not quite the same as mine, the holes which pick up the oil from the gallery in the back of the timing cover are bigger on yours, which cant be a bad thing. Mine has 6 holes, KTB mentions these as 1/16" diam. The outer end of your oil return scroll looks a bit damaged, presume this is from the mainshaft? I gather exact clearance within the mainshaft is not too important but you mention yours seems bodged. An internally damaged mainshaft has the potential to damage a replacement quill just the same. I think most (?) quills must touch the sides of the mainshaft a bit, but probably not enough to make a mess of the quill. I dont think minor wear on the scrolls is an issue. I have always assumed the role of the scroll is just to move excess oil away from the big end to make room for more (low pressure) oil to arrive?
Your quill is not quite the same as mine, the holes which pick up the oil from the gallery in the back of the timing cover are bigger on yours, which cant be a bad thing. Mine has 6 holes, KTB mentions these as 1/16" diam. The outer end of your oil return scroll looks a bit damaged, presume this is from the mainshaft? I gather exact clearance within the mainshaft is not too important but you mention yours seems bodged. An internally damaged mainshaft has the potential to damage a replacement quill just the same. I think most (?) quills must touch the sides of the mainshaft a bit, but probably not enough to make a mess of the quill. I dont think minor wear on the scrolls is an issue. I have always assumed the role of the scroll is just to move excess oil away from the big end to make room for more (low pressure) oil to arrive?
Separated the muff and liner, see the pics. So what does it all mean? If the fit was correct, both liner and muff should be relatively clean and shiny?
Quill appears to have five holes about 1/8. The damage was at the point where the quill enters the mainshaft. It looks like the mainshaft may have been damaged by jamming stuff in there to mount a degree wheel.
There is oil on the crank wheels, in the bottom of the crankcase, the top end, plenty of it, but not too much based on other engines I have taken apart.
Quill appears to have five holes about 1/8. The damage was at the point where the quill enters the mainshaft. It looks like the mainshaft may have been damaged by jamming stuff in there to mount a degree wheel.
There is oil on the crank wheels, in the bottom of the crankcase, the top end, plenty of it, but not too much based on other engines I have taken apart.
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Your liner and muff look like major contributing factors to the spot overheating. The layer of carbon and burnt oil that found its way between the two parts provided some insulation preventing the heat of the piston from having a faster escape through the fins. Combine this with a high expansion piston and you have the perfect storm for this kind of problem.
When I was building street Vincents I would order pistons and barrels through Coventry. They would come fitted and all that you had to do was install them. I don't know if John still does that, but it was very convenient.
I would choose a solution that you can get done easily so you don't spend more time on repairs than necessary.
David
When I was building street Vincents I would order pistons and barrels through Coventry. They would come fitted and all that you had to do was install them. I don't know if John still does that, but it was very convenient.
I would choose a solution that you can get done easily so you don't spend more time on repairs than necessary.
David
I'm pretty sure Coventry will still supply all three parts fitted. When you consider getting it all machined and fitted locally, plus the chance of your machine shop erring in some way, Coventry usually is the cheapest route. The biggest problem I see is Canadian Customs. 
Sorry, I couldn't get the photos to come up, When you first sent them, I can now.
I wonder if someone damaged the main shaft hole, Fitting or removing a degree disc, When doing the timing ?.
Is the main shaft nut tight ?, Because it should be pin punched where the key way is ?.
Good Luck, Bill.
I wonder if someone damaged the main shaft hole, Fitting or removing a degree disc, When doing the timing ?.
Is the main shaft nut tight ?, Because it should be pin punched where the key way is ?.
Good Luck, Bill.
Bill, are you sure about that? In my motor there is a locking washer that prevents the 1/2 time pinion getting loose - no punch lock required.
Martyn
Morning Martyn, I am old school, And out of touch, It was punch locked at the factory, Always worked for me.
I can't see a lock washer on his ?.Cheers Bill.
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