Author Topic: Crankshaft oil gallery flush  (Read 1228 times)

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Offline Dstep

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Crankshaft oil gallery flush
« on: October 08, 2016, 03:11:07 pm »
Simple way to make sure your crankshaft oil gallery is clean and not blocked if the unit has not been used for awhile. Mine had been sitting for a decade and I wanted to clean it before assembling.
Two feet of 1" hose, a couple of hose clamps, a suitable plug, and a gallon of diesel. Attach the hose to the crank, fill with diesel, put in the plug, and apply air. Repeat.
David
'52 BSA C11
'50 BSA B34
'67 MGB Roadster
'00 Kawasaki W650

Offline ginantonik

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Re: Crankshaft oil gallery flush
« Reply #1 on: November 09, 2016, 07:55:53 pm »
I found it was easier to remove the screw in the crank-pin (impact screw driver) - then i could drill out the deposit of ?????

i am sorry but have found, no amount of flushing will remove the virtually solid deposits found in crank centrifugal dirt traps.

Offline Dstep

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Re: Crankshaft oil gallery flush
« Reply #2 on: November 10, 2016, 03:39:05 pm »
I agree with you that would be the better method to use, if the crank-pin has a screw fitted. This was a refurbished one without a screw, so this was the only method I could use. Even if you clean out the crank-pin by removing the screw, you should still flush the oil gallery out as there may be some blockage between the inlet on the journal where I am applying the fluid and the entrance to the crank-pin.

It was just a suggestion for a simple method to forcefully pass a large amount of fluid through the oil passages to make sure they weren't blocked.

David
'52 BSA C11
'50 BSA B34
'67 MGB Roadster
'00 Kawasaki W650

Offline camman3

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Re: Crankshaft oil gallery flush
« Reply #3 on: November 10, 2016, 07:01:17 pm »
Yes David, a bit like flushing a coolant system or boiler.....its alwags surprising how much fluid you pump through before it stops flushing crud out ???
Would agree it best to remove the bulk of crud physically if possible, but flushing is still required.....cleanliness is next godliness  :D
Graham
1957 C12
In sunny (sometimes) Christchurch, Dorset, UK

Offline ginantonik

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Re: Crankshaft oil gallery flush
« Reply #4 on: November 10, 2016, 08:10:55 pm »
Yes flushing is better than nothing, but one problem is that unless the crank is split, any particles dislodged follow the line of flow into the big-end - i have recently converted a nice smooth crank into a cement mixer by flushing it via the oil-feed (yes i have now split it!)

Really you could do with flushing from the big-end towards the oil feed - not really practical, i know.

I have always been surprised how hard any deposit becomes, after many years of centrifugal force, I find that a twist drill is invariably required - in fact when i started on engines, i often mistook these deposits as being part of the engine !!??

I have recently been using is a very strong detergent or even a caustic bath - this has cleaned up an couple of recent cranks dramatically, also attacking/removing any rust and having an inhibiting effect to prevent corrosion - my cement mixer crank happened after this treatment, then flushing ....................

I've even boiled up a crank in an old pan, on a camping gas stove - again using a strong detergent or caustic solution.

Nowadays i simply bite the bullet and split the crank - particularly when I'm being paid for an rebuild.

Offline ianinglis

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Re: Crankshaft oil gallery flush
« Reply #5 on: November 10, 2016, 09:36:22 pm »
i used to work in a big iron foundry and we had a very large very caustic tank permanently on the boil for cleaning resin coated parts (some very very large)
we used to do bike frames oven shelves etc - very useful
one guy hung and old ally cylinder head over the side and came back 6 hours later to find only the valve seat on the end of the wire hanger :-\



ian
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Online hampshirebiker

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Re: Crankshaft oil gallery flush
« Reply #6 on: November 10, 2016, 11:40:09 pm »
How many people's lungs disolved?
Postal - Liphook Hants - But just into West Sussex.

Offline Dstep

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Re: Crankshaft oil gallery flush
« Reply #7 on: November 11, 2016, 04:22:49 am »
Actually Dave, the fumes are not harmful, as I worked around them quite a bit when I was younger. I used to put nasty piston and rod assemblies in at night and come back and just have the rods and pin left in the morning, which was easier than trying to disassemble them. ;D

Crank is now apart, and sludge cleaned from trap, but pin has no clean-out, just a pin pressed into the end. It is hardened, but am resisting the idea that I need to drill it out and clean it. What do you guys think? Yes/No??? :-\

David

'52 BSA C11
'50 BSA B34
'67 MGB Roadster
'00 Kawasaki W650

Offline Owen

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Re: Crankshaft oil gallery flush
« Reply #8 on: November 11, 2016, 06:25:11 am »
I would imagine it does not have the large void of the ones woth the plug. So soaking it and poking the drillings should be enough.
Another area that could have crud is the oil way behind the plain bearing. Where it is pressed into the RHS casing. I have I the past taken the bush out and cleaned the oil way but not found much. But that may be a step too far?
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11
Anyone want a B20 in need of a lot of tlc

Offline ginantonik

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Re: Crankshaft oil gallery flush
« Reply #9 on: November 11, 2016, 10:04:07 am »
Yes its a difficult one to clean well - the hard steel plug is probably a tapered plug to seal and help lock the pin in the crank.
I've seen a ball-bearing swagged into a recess to do the same job - god knows how you are supposed to remove to clean?

Most engines have a proper removable plug to catch particles and allow later cleaning, i suspect the C10/11 being a 'cheap' runabout cast savings have been made.

As Owen says, poking with a wire + flush +perhaps something like caustic is all you can do.

My current favorite is undiluted RTC (Road traffic Cleaner) - judging by what it did to my rocker-box and my hands, that is mildly caustic, good to clean ali but don't leave it in for more than 24 hours otherwise it ends up an interesting grey (titanium finish I've been told?)

As i said, flushing via the feed end turned my spare 3HW crank from smooth to cement-mixer as crude was carried into the b.e bearing - should have simply done a proper job in the 1st place, but as its for my spare engine, though i could cut corners......

Offline c11jim

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Re: Crankshaft oil gallery flush
« Reply #10 on: November 11, 2016, 10:35:40 am »
Hi everyone,
I've been following this forum for about a year but this is my first post. It is a great source of information and I really appreciate all the effort that goes into it.
I recently re-built a C11 crank and it had a plug in the crankpin like the one pictured but it was brass and easily drilled out. After removing a lot of crud I made a new brass plug (slightly tapered) and hammered it back in.

Jim

Offline Owen

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Re: Crankshaft oil gallery flush
« Reply #11 on: November 11, 2016, 12:37:51 pm »
I must have been lucky with my 45c 11. I managed to unscrew the plug without too much effort. It's quit clean inside. Probably because it's sat in oil for 30+ years. I will be screwing it back in and punching a couple of indents in the thread section to stop it undoing.
Having used some Screwfix budget degreaser on the rest of the bike and seeing how it takes off the crud, paint and oil stains. I will be dunking it in for a few days/weeks to make sure it's clean.
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11
Anyone want a B20 in need of a lot of tlc