Author Topic: overheating EW600 - no oil to rear and failed bearings  (Read 1754 times)

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Offline geomellish

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Further to my earlier queries over my overheating 1927 EW600 (re compression and induction pipe) I have removed the engine and barrels for inspection.

The rear piston and connecting rod are bone dry of oil and completely cooked (hence virtually no compression). The small end of the rod is turning on its bronze bearing (rather than the bearing turning on the gudgeon pin). There is a large amount of movement in the big end roller bearing.  The (cast iron) rear piston and barrel seem surprisingly fine (with about 5-6 thou clearance).   The front barrel is apparently well-oiled with the rod in better condition and piston with maybe 3-4 thou clearance. I can feel some movement in the main crank bearings by lifting the flywheel up and down.

So next I have got to take the crank out to assess the full extent and cause of the damage - why was there no oil being splashed?.  I'm a bit of a newbie at this so I will take it slowly - any advice gratefully received. For a start I am going to purchase the club's flywheel puller... 

Regards, George


Offline geomellish

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Re: overheating EW600 - Crank timing gear removal
« Reply #1 on: 20 Nov 2017 at 11:58 »
I am struggling to remove the dog tooth and nut holding the timing gear onto the end of the crank. Any advice on this and the whole process of getting the crankshaft out?

Trawling through the forum I understand that the thread is a normal R/H and that once removed I might need a special puller to get the gear off the crank.

I am worried to apply excessive force as I don't want to break anything, not least the aluminium casing which splits vertically and will move apart c1 cm

Offline eddie

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #2 on: 20 Nov 2017 at 12:15 »
George,
             With the timing end of the crankshaft rotating clockwise, usual practice is to have a L/H thread (especially as the drive dog is part of the nut), so that normal rotation will tend to tighten the nut. Having established whether it is L or R/H, if you still can't shift it, take it to your local garage and ask them to shift it with an air impact wrench.

Regards,
               Eddie.

Offline geomellish

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #3 on: 20 Nov 2017 at 17:46 »
Thank you Eddie, it is indeed a L/H thread - armed with which info I was happier to use a 2lb lump hammer onto a socket bar to shift the nut.

It is now clear I will have to replace the flywheel side crank bearing race as well as renovating both big-end roller bearing arrangements and one of the bronze bush small-end bearings and gudgeon pin. 

The crankcase sections have no joint washer or gasket between them - which would explain why no oil was available to splash into the rear barrel and lubricate the bearings.  A layer of gritty metallic/oil gunge is congealed on the bottom of the two aluminium sections...

Also I am looking at my E28 spare parts list- it indicates there are two 'oil throwers' (part nos 7565 and 9368) . In the list photo they just look like flat washers.  Can anyone enlighten me otherwise and where they are positioned? These are missing from my engine.

Regards, George


Offline eddie

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #4 on: 20 Nov 2017 at 20:30 »
George,
             The oil throwers are probably just large thin washers that fit on the main journals to fling oil away from the main bearings (to prevent excessive leakage). If there was no oil in the bottom of the crankcase, you may find the joint faces have become distorted, in which case, you will need to file/scrape them back to get a good joint. Only use a thin paper gasket, don't be tempted to use a thick gasket - that will only cause more distortion. Also, some of these late 20's machines had a drive side main bearing that was 21mm wide or 2 bearings 10mm wide with a 1mm spacer between them. The  21mm wide bearing is no longer available, but you can use a 20mm wide main bearing from a postwar machine, with the 1mm spacer fitted into the bearing housing first.
  Hope this is of some help,
   Regards,
                 Eddie.

Offline Doug

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #5 on: 21 Nov 2017 at 13:49 »
Yes, the oil throwers are what we call in the States oil slingers. Thin washers to keep the larger bits out of the bearing and direct most of the oil away. It is only a felt seal on the drive side.

Drive side bearing is a 30x62x21mm double row self-aligning ball bearing. This was soon to be an obsolete size, so was made up of a 20mm wide unit and a 1mm shim. Or two 10mm wide radial bearings with a 1mm shim between.

Whether there was a joint washer present or not should not have determined if there was oil in the crankcase. It will leak either way! There ought to be enough turbulence in the crankcase to blow the oil mist about; I doubt it ever gets deep enough to really be splash lubrication from the crankcase sump.

-Doug

Offline geomellish

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #6 on: 21 Nov 2017 at 17:32 »
Thanks both - crank is now apart and all bearings removed.

As suggested I will replace the very sloppy drive bearing with a 20mm wide 30x62 plus  1mm shim in place of the original 21mm obsolete one. However, I now think I should do the timing side bearing as well which is only 13mm wide 30x62 -  it does have some wear in it.  This also seems to be an obsolete size, the smallest width I can only find is 16mm (not even the 10mm mentioned above). Any ideas?

Turning to the big end roller bearings, most of the wear appears to be in the rollers: on the very worn rear end each roller diameter has reduced from 0.375 to 0.364 inches whilst on the front end only to about 0.372 inches. So multiply by the 13 rollers in each side this leaves a lot of play.  I seem to be able to get new 3/8 x 3/8 rollers so I will try these and see how they feel in place.

Regards, George

Offline Doug

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #7 on: 21 Nov 2017 at 18:15 »
Yes, 30 x 62 x 13 is obsolete. It is used in other Douglas models like the DT. I make them from the the 16mm wide ones. Tear out the seals or shields and grind 1.5mm off each side. This will just touch the face of the cage.

On the last batch I did - to avoid residual magnetism, grit, and to add the edge radius automatically - I have faced the bearings with a carbide insert in a lathe. You need one of the inserts grades intended for hard turning and you need a very, very rigid lathe. Even so, a little handwork with the polishing stone in the lathe is needed to finish the last tangent portion of the edge radius. If I had tool holders for inside and outside turning setup I wouldn't needed to bother. However I wanted to do everything with the same tool to ensure both inner and outer race were faced flush (it is not that critical, because you are going to shim the crank anyway to set the end float.) If you go to the trouble, you might as well use a premium maximum capacity bearing rather than the general radial ball bearing that has less balls.



The white stuff is oil based modeling clay. This was supposed to keep the swarf out of the bearing. That much less garbage to wash out latter. This worked fine with grinding, but when turning the heat just caused it to melt and catch fire!

Link to MP4 video of facing the bearing HERE (8Mb). 

As you can see, you can turn bearing steel.

-Doug

Offline cardan

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #8 on: 21 Nov 2017 at 20:14 »

Brilliant Doug. But even though I watched the video 5 times I didn't get to the bit where it caught fire!

I have a very modest lathe, and very modest machining skills, so modifying ball races is well beyond my capability. Great to see what the experts can do.

I think there's a lesson to be learned from George's experiences. Many old motors are really filthy inside. If you do score a bike that's been off the road for a long time, better to have a good look inside before you try to run it. Modern oils with detergents probably help to release old sediments and spread them around the motor. Yuk.

Some years ago there was a large collection of bikes and cars that came out of a huge shed in the US. The internet was alive with videos of a well-known motorcycling identity starting them up and revving them excitedly. Best to do some cleaning first!

Cheers

Leon

Offline Doug

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #9 on: 21 Nov 2017 at 20:55 »
Leon,

The full length (with pyrotechnics) was 280Mb, so I to prune it down.



-Doug

Offline cardan

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #10 on: 21 Nov 2017 at 22:55 »

Excellent flames Doug!

Now flames is something that I can do. Years ago I made some new valves for a veteran bike. I had a guy grind the stems to size, but when I went to cut them to length they were a bit tough for the hacksaw. No worries, I'll use an abrasive blade. Set up square, started to cut, pfoof! Sodium filled!!!! No movie unfortunately, but I still have the hollow-stem valve somewhere in the shed.

Cheers

Leon

Offline Doug

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Re: overheating EW600 - no oil to rear and failed bearings
« Reply #11 on: 23 Nov 2017 at 00:08 »
And just to reassure everyone, no bearings were harmed during filming!

Yes it got hot, but not that hot. Most of the heat was into the chips coming off, and when the liquefied clay got onto that it burst into flames. had the bearing itself gotten too hot it would have drawn the hardness out of it and rendered it useless. As it was, the face was just very warm to the touch, but not hot enough to burn your hand.

-Doug

 

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