Author Topic: 1926 EW350 Crankshaft Dismantling  (Read 1071 times)

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Offline SteveTea

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1926 EW350 Crankshaft Dismantling
« on: 28 Aug 2020 at 16:58 »
As you may have seen from an earlier posting I made (https://www.douglasmotorcycles.net/index.php?topic=8293.0), I am having trouble clearing the oilways in the crank of my EW.  I have stripped the crank to its component parts as shown in the first picture but I canít clear the oilways in the central web as shown in the second picture.  Iíve tried all the suggestions given to date but no luck so far.
I suspect it should be possible to dismantle the central web a little further to expose the oilways, possibly by removing the bigend bearing sleeve (assuming it is a sleeve).  So, my question is, can the central web be dismantled further and if so how?






[Attachments converted to linked images. 25Nov21 -Doug, Admin]
« Last Edit: 27 Nov 2021 at 03:20 by Doug »

Offline EW-Ron

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Re: 1926 EW350 Crankshaft Dismantling
« Reply #1 on: 28 Aug 2020 at 22:55 »
It is getting down to basics, isn't it. !
That whole crankpin would have to be pressed into there, wouldn't it ?
If its not all manufactured in one piece, and the bearing surface machined into it.

You can't poke through there with say a good strong bit of wire ?
Or a rotary bit of bowden cable with the ends initially flared out just a bit ?

You'd wonder that cranks shouldn't get hot enough to burn fresh clean oil coming through,
its not like constant loss oiling systems recirculate old used oil or anything.
« Last Edit: 28 Aug 2020 at 23:03 by EW-Ron »

Offline Doug

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Re: 1926 EW350 Crankshaft Dismantling
« Reply #2 on: 29 Aug 2020 at 04:05 »
The bearing race is removable, though they can be a challenge. Generally with the EW you just have two small notches at 180 degrees to let the oil out from behind the race.



Behind that is the hole that connects to the cross-drilling in the web. In theory the orientation of the notches should not matter as the oil can get around via the annular gap left by the very large chamfer on the inside of the bearing race.



It is likely the hole or the gap that is clogged up. Since removing the race can be such a difficult job, you might want to try to track down someone with an ultrasonic cleaner and give that a try first to see if it will unclog it.

The half-round cut-outs on your bearing races I associate with the later spray bar type oiling system (no internal drilling in the camshaft). So they may have been replace once, or perhaps they made the change earlier than I thought. You could try to make a puller. But what I have had luck with is using a collet in a lather to grip the outer diameter of the race and working it off by tapping the center web clockwise and counter clockwise to ease it off. They tend to be tightest when passing over where the location pins were drilled.

Some other pics in this post here:

https://www.douglasmotorcycles.net/index.php?topic=3518.msg12813#msg12813

-Doug


Offline Dads bike

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Re: 1926 EW350 Crankshaft Dismantling
« Reply #3 on: 29 Aug 2020 at 12:21 »
Blind bearings are fiddly to get off.
In a past life I would Have used a hand held induction heater to locally warm the bearing and allow it to slide off or pry far enough to get a small three legged puller behind it.
Google Btex iDuctor thatís the type thing I am talking of.
Do you have a friendly local garage or tool hire shop?
If things do go very wrong I can recommend Alpha bearings to reproduce the journal

Regards
    Steve

Offline SteveTea

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Re: 1926 EW350 Crankshaft Dismantling
« Reply #4 on: 30 Aug 2020 at 15:13 »
Doug and Dad's Bike, thanks for the information and suggestions.  I think I'm going to have to remove the bearing rings to clear the oilways but also, as I've just found out, the company that refurbished the crank ground away most of the case hardening on the crank pins so they are effectively useless!

Offline EW-Ron

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Re: 1926 EW350 Crankshaft Dismantling
« Reply #5 on: 31 Aug 2020 at 01:07 »
Could they be case hardened again though ?
I've seen folks putting parts into a tin of that 'casenite' stuff after heating to red heat.

They might need a bit more grinding after.
And checking for size/fit.  ??

Offline Doug

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Re: 1926 EW350 Crankshaft Dismantling
« Reply #6 on: 31 Aug 2020 at 05:43 »
There are a few issues with re-hardening.

(1) If already reground and then ground again after re-hardening, they will be well undersized. That has to be made up by larger rollers or a smaller race i.d. in the conrod.

(2) Besides roasting the outside of the race and requiring re-grinding, it will also impact the surface finish of the i.d. where it is a light press fit on the crank pin. Not to mention what distortion will occur on the i.d. You cannot hone it true, as that would then make it slack on the crank pin.

(3) Compounds like Kasinite are intended to impart a superficial depth of case hardening of about 0.005-0.010". The case depth for surfaces supporting rolling elements ought to be at least 0.040" and better if over 0.060" deep. That is why the carburizing process take many hours in a furnace, to diffuse the carbon that deep into the sub-surface. Granted, there will be some case left from previously and you might be thinking one just needs to 'top up' the carbon content at the surface. But you still need to have a high carbon content below that to a certain minimum depth to support the case, gradually tapering off to the carbon content of the core. If you don't, the thin, hard surface layer will flake off the softer substrate. Particularly if the transition between the case and core is abrupt. Also known as Brinelling. To get the carbon that deep, needs a long soak in a carburizing environment.

It is simpler I think just to make a new race. An additional advantage is you can make it so the final diameter is oversized, in order to use standard diameter rollers since oversized rollers are getting so difficult to purchase cost effectively. If making both a new crank pin and conrod race, then that does not matter so much; you can stick with the original dimensions.

In this application, there is really no reason for the race to be made of carburizing steel. It could just as well be made from through-hardening steel like a ball bearing race is. Avoids the costly carburizing step. And no risk of Brinelling. Douglas probably used a carburizing steel as the cost for carburizing steel is less than for through-hardening steel. And they were running the carburizing furnaces every workday anyway. 

-Doug

 

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