ET: Engine (Twin) Series ‘D’ Breather

Cyborg

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Me too! In my die cast C motor 10545. Bush seized onto the spindle, well tight! Had to split it longitudinally with a hacksaw blade. Polished the spindle & fitted the the pinion from my '48 B motor which has what appears to be a cast iron? sleeve. The inside of that sleeve had plenty of natural lubrication grooves, it gave the distinct impression of having been drilled in manufacture, not bored, and certainly never honed!
So is there a preference for sleeve material?
I need to make a new bush to replace the alloy one, I am leaning towards cast iron, an old sash window weight could be good?

There is a note in Instruction sheet 6 "The Timing Gear" page 3 under breather valves. It says the one piece cast iron type ET141/1 was found to be unsatisfactory under racing conditions and if fitted, should be replaced with one or the other of the composite pattern ET141/1AS which has a bronze sleeve or ET141/3AS which has a cast iron or light alloy sleeve.
Not sure why the one with the cast iron sleeve is preferable to the one piece cast iron one.

Mine has a bronze bushing and the gear is stamped ET49/1, so a !/@ time pinion, but no keyways.
 

Pushrod Twin

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yes, when I first got my hands on them, I was admiring the new and improved casting. Less chance of my gearbox and case turning into chutney.
So did your castings have any porosities in them? My die cast cases look like volcanic rock, more holes than alloy, around the mains bearings. I had to sleeve the bearing bores to rectify the wear & mis-alignment anyway, so have good seats for the bearings. Then they mysteriously leaked oil from below the rear barrel. Fixed that by riding until it was hot, laying it on it's side, and my son laid into it with the TIG until it stopped bubbling!
 

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Bill Thomas

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I found the spindle, I just wondered if the pinion was wider, But I think it's a half time pinion,
The photos can mislead you ?.
Was trying to see what the tube was made of, They also say the "C" one was for a Comet, But I think it's the same for a Twin ?. All too tricky for me !.
 

Pushrod Twin

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There is a note in Instruction sheet 6 "The Timing Gear" page 3 under breather valves. It says the one piece cast iron type ET141/1 was found to be unsatisfactory under racing conditions and if fitted, should be replaced with one or the other of the composite pattern ET141/1AS which has a bronze sleeve or ET141/3AS which has a cast iron or light alloy sleeve.
Not sure why the one with the cast iron sleeve is preferable to the one piece cast iron one.

Mine has a bronze bushing and the gear is stamped ET49/1, so a !/@ time pinion, but no keyways.
Thanks Cyborg, I had forgotten about the bronze sleeve version, clearly that's the best option.

Here is a pic of the leak stopping weld. There is a lot of metal in that part of the case so I was not concerned about distortion of the barrel throat.
 

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Cyborg

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The only porosity I have found is on the timing side case where the front cylinder liner resides and it doesn't look like it would cause any problems. There is one other tiny spot around where a push rod tube ET104 seal would sit, but it too is minor and a pinhead sized drop or two of Devcon would seal it and not be visible. They look like very nice cases, so barring any surprises as they get assembled...... like perhaps finding out why a set of NOS cases were sitting on the shelf collecting dust for 65 yrs.
 

Cyborg

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I found the spindle, I just wondered if the pinion was wider, But I think it's a half time pinion,
The photos can mislead you ?.
Was trying to see what the tube was made of, They also say the "C" one was for a Comet, But I think it's the same for a Twin ?. All too tricky for me !.

Yes its a 1/2 time pinion. I've seen them with and without the keyways.
 

John Cone

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On the VOC Spares site, the photo of the D spindle part number ET159/1 (or the later parts book MO13) shows the flat. I have an NOS one here in the photo, but didn't want to use it due to some pitting from corrosion, although the pits might help hold oil.
Based on your responses (thank you) I decided to go dig out the idler that mounts on it and there are two oil holes in the bush that line up with the flat, so now it becomes obvious that they put the flat there to hold whatever oil mist should find its way in. I recall looking at this pinion previously and wondering if it was OEM or something that was just made up by someone.... but now looking at a later (D era) MO13, it shows the oil hole in the bushing. As for indexing, I'm assuming the flat should be towards the top in order to hold more oil while hopefully keep it away from the cam and mag pinions because of the aforementioned reduced bearing area. If anyone can confirm my assumption on the indexing, it would be appreciated.
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Not long ago i had to remove my timing side for some thing else and found a nut laying in the bottom of the timing chest. This had the end off the spindle still in the nut. I notice that it had sheared off the Idler spindle that drove the distributor gear. After taking the steady plate off i found that the idler was seized to the spindle which in turn had been spinning in the crankcase. I replaced the spindle, slightly oversized, supplied by Maughans and fitted it with the flat upper most hoping that oil would get into the new idler bush.
 

Pushrod Twin

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The only porosity I have found is on the timing side case where the front cylinder liner resides and it doesn't look like it would cause any problems. There is one other tiny spot around where a push rod tube ET104 seal would sit, but it too is minor and a pinhead sized drop or two of Devcon would seal it and not be visible. They look like very nice cases, so barring any surprises as they get assembled...... like perhaps finding out why a set of NOS cases were sitting on the shelf collecting dust for 65 yrs.
Lucky! I guess they improved as the foundrymen improved their techniques. The push rod tube seats on mine are riddled with porosities, needed plenty of RTV sealant around them.:)
 

Pushrod Twin

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Not long ago i had to remove my timing side for some thing else and found a nut laying in the bottom of the timing chest. This had the end off the spindle still in the nut. I notice that it had sheared off the Idler spindle that drove the distributor gear. After taking the steady plate off i found that the idler was seized to the spindle which in turn had been spinning in the crankcase. I replaced the spindle, slightly oversized, supplied by Maughans and fitted it with the flat upper most hoping that oil would get into the new idler bush.
Was the idler bush aluminium?
 

Cyborg

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VOC Member
Lucky! I guess they improved as the foundrymen improved their techniques. The push rod tube seats on mine are riddled with porosities, needed plenty of RTV sealant around them.:)

I am debating whether or not to paint the cases and suppose porosity would be a good argument (supported by the factory according to that bannanaman) for doing so.
 
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