AMR Wetsumping Mod Installation Video

NickZ

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I discussed this previously here: https://www.accessnorton.com/NortonCommando/amr-nortec-mod.32150/

So here's the full video if you'd like more detail on installing the mods and the theory behind it.
It's been a few months and so far I can't detect any wetsumping at all.

Thanks to @Mike T for putting this on his channel.
Great video.
Do you know if the AMR oil pump modification includes putting a seal in the top end plate for the driving shaft as well? I see pumps with a lot of leakage from that source, especially while running.
 
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Great video.
Do you know if the AMR oil pump modification includes putting a seal in the top end plate for the driving shaft as well? I see pumps with a lot of leakage from that source, especially while running.
No they do not do that mod.
 
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Is Norton more prone to wet sumping than other makes? it’s not been an issue with my Trident or my ‘oil in frame ’ T140’.
I wonder if the Honda CB 750 also had wet slumping issues. I haven’t heard of it as an issue, not that I’ve had much to do with them.
regards
al
 
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Tridents have a rotary pump similar to a Commando. They will wet sump. However, they do have an internal check ball similar to the AMR mod in concept that slows it down. T140's and all Triumph twins have a plunger pump that is much more resistant to wet sumping than the rotary style pump that both Norton and BSA used.
 

MichaelB

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Not really a side track to the thread, more of a small detour....
What's the Informed Opinion about what to do when the motor has wet-sumped enough to expose the gauze inlet filter? I have a reed valve installed on the crankcase (my own version, I'm not really happy with the detail, but it works), and in the same way as the JS & JC valves, it will clear the flooded sump in a few seconds.

JS, you seem to think that there's no harm in starting the engine, even though the oil pump will be sucking air for a short while, am I correct?
It's always good to hear from the blokes who have knowledge of this, rather than the theorising that I tend to do...
In the past when the gauze was exposed, I would drain the sump, pour it back in the oil bag and fire away.
Now with the reed valve, I'll kick it slowly a few times, ignition off, to push some of the oil out fo the CC.
You can feel the engine freeing up. Then fire away.
My thinking is this..
1. Less chance of blowing seals.
2. Easier to give a healthy kick.
3. Best reason of all, JC recommends it.
 
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Sorry to bring this thread back up. It's got a lot of mileage on it. However, there is discussion regarding breathers in here, so...

Has anyone with a Norton engine without machine work for the breather at the rear of the crank case or a timed breather cam installed a CNW/Comstock breather off the timing chest and had success doing it?

I know it is not designed to work there, but want to know if it works as well as any other timing chest breather solution people have tried. I'm going to try it and find out for myself, but still it would be interesting to see what others that have done it think.
 

Fast Eddie

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Sorry to bring this thread back up. It's got a lot of mileage on it. However, there is discussion regarding breathers in here, so...

Has anyone with a Norton engine without machine work for the breather at the rear of the crank case or a timed breather cam installed a CNW/Comstock breather off the timing chest and had success doing it?

I know it is not designed to work there, but want to know if it works as well as any other timing chest breather solution people have tried. I'm going to try it and find out for myself, but still it would be interesting to see what others that have done it think.
It will work as a breather for sure. Not quite as good as doing it ‘properly’ but most likely good enough not to notice any deficit.

But it won’t work as a wet sump oil return route (not that that is of interest to you I know).
 
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It will work as a breather for sure. Not quite as good as doing it ‘properly’ but most likely good enough not to notice any deficit.

But it won’t work as a wet sump oil return route (not that that is of interest to you I know).

That first sentence echoes what Matt says. I expect the reed valve will do a better job than the shade tree engineered breather setup I'm using now. The CNW/Comstock breather is really small and will be a lot cleaner install than what I have, so not a waste of my time or money.

The reed valve should open easier and would probably help reduce crank case pressure enough to allow a Norton with a moderately wet sump to start without blowing out any seals. Not sure though. I never have blown a main seal out. I have cut one on the woodruff key slot installing it in a hurry though. Might as well have been blown out.

I plan to make a mounting plate for it that is ported like a mini 2 stroke reed cage. Mad science. Probably won't make a fart in a wind storm worth of difference, but it will be entertaining.
 
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That first sentence echoes what Matt says. I expect the reed valve will do a better job than the shade tree engineered breather setup I'm using now. The CNW/Comstock breather is really small and will be a lot cleaner install than what I have, so not a waste of my time or money.

The reed valve should open easier and would probably help reduce crank case pressure enough to allow a Norton with a moderately wet sump to start without blowing out any seals. Not sure though. I never have blown a main seal out. I have cut one on the woodruff key slot installing it in a hurry though. Might as well have been blown out.

I plan to make a mounting plate for it that is ported like a mini 2 stroke reed cage. Mad science. Probably won't make a fart in a wind storm worth of difference, but it will be entertaining.
Why not get the sump breather from NYCN and get the best of both worlds?
 
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Why not get the sump breather from NYCN and get the best of both worlds?
That would be great, except I have a frame cross member in the way, and my 2:1 exhaust runs under the sump drain plug.

I know what I'm doing will work, I just wanted some feedback from others that have tried it. Looks like not many have, or they are ashamed to admit it. LOL Maybe I'm asking in the wrong forum.

Being as out of touch as I am about what has been happening with Nortons for the last 40 years, I just learned today that a version of the 850 cases had a breather off rear of the timing side. This is essentially exactly what I am doing. How well did that work on the 850, or is that why Comstock came up with the sump breather?

In the end it doesn't matter much. I'll make the CNW breather work. I guess all I'm really accomplishing by posting the query is burning up bandwidth. Nothing new.
 

MichaelB

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The CNW is a fine piece.
There is another, little more compact.
 
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That would be great, except I have a frame cross member in the way, and my 2:1 exhaust runs under the sump drain plug.

I know what I'm doing will work, I just wanted some feedback from others that have tried it. Looks like not many have, or they are ashamed to admit it. LOL Maybe I'm asking in the wrong forum.

Being as out of touch as I am about what has been happening with Nortons for the last 40 years, I just learned today that a version of the 850 cases had a breather off rear of the timing side. This is essentially exactly what I am doing. How well did that work on the 850, or is that why Comstock came up with the sump breather?

In the end it doesn't matter much. I'll make the CNW breather work. I guess all I'm really accomplishing by posting the query is burning up bandwidth. Nothing new.
I don't think you comprehend how much bandwidth has been consumed in discussing breathers on the forum. I suspect @Jerry Doe would be a retired wealthy man by now if we didn't yap about it endlessly.

Short answer is that thanks to Comstock's research the most efficient breather is one directly on the crankcase, as that's the volume you are trying to evacuate. As you move away from the crankcase space you will be less and less efficient. The timing case typically doesn't share very well with the crankcase so it's less efficient.

So it all comes down to how efficient you want your breathing system to be vs. cost/effort. But only you can answer that equation.
 
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The CNW is a fine piece.
There is another, little more compact.
I considered the JS breather without the short nipple for the Maney case, but I like the design of the CNW product, and I got a considerably better deal on it, because I don't need the base piece designed for the 72 Commando.

I don't think you comprehend how much bandwidth has been consumed in discussing breathers on the forum. I suspect @Jerry Doe would be a retired wealthy man by now if we didn't yap about it endlessly.

Short answer is that thanks to Comstock's research the most efficient breather is one directly on the crankcase, as that's the volume you are trying to evacuate. As you move away from the crankcase space you will be less and less efficient. The timing case typically doesn't share very well with the crankcase so it's less efficient.

So it all comes down to how efficient you want your breathing system to be vs. cost/effort. But only you can answer that equation.
I would imagine "breather" is right up there with "wet sumping and Amal carburetor problems" on the forum bandwidth consumption meter. I tried a search before asking if anyone has tried what I am doing. None of the hits were from anyone that has tried what I plan to do. Nothing special about what I am doing. It's just that most Commando owners can fit the better solution, or use what the factory came up with.

I got the word from Matt on the crank case pressure relief being less efficient from the timing chest, but I gotta do what I gotta do. I enlarged those two holes and added another one through the timing chest into the crank case when I installed the Combat cam. It'll all work about as well as it did for the 850, which apparently wasn't that great?
 
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MichaelB

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Start a new thread with pictures when you do it!
 
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Start a new thread with pictures when you do it!
I'll post a new thread in the P11 forum. I don't plan to take the timing cover off, so that part of the case mod will be missing in the pics, but I'll document the mounting plate I'm making, the rest of the install, and my impression of how it works. I might have an old piece of paper in my Norton P11 folder that shows what I did in the timing chest. If I can find it, I'll take a pic of it.
 
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