Crankcase mods and build update

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swooshdave

swooshdave

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Just about everything I know about Nortons (well, almost everything) I’ve learned from the people here.

This isn’t a comprehensive report, just an update. Posting it here because half of you will go “good job”, half will go “your an idiot” and the other half will go “huh?”

:)
 
Nice post Dave.
What would be the optimum depth of milling if one wants to retain the rear breather?
Anyone out there with real world experience of this scraper mod and keeping the rear breather?
 
MichaelB said:
Nice post Dave.
What would be the optimum depth of milling if one wants to retain the rear breather?
Anyone out there with real world experience of this scraper mod and keeping the rear breather?
Click to expand...

Technically you just need to remove enough to expose the oil pickup (although some people just relocate the oil pickup hole further back, which does the same thing).

I'm still not sure why Fred removed the entire oil scraper (windage thing) because that means you have to blank off the rear breather.

http://www.oldbritts.com/n_c_case.html

And I'm not sure why removed any of the oil scraper other than I had someone who could. And we only removed 1/2in. so no oil should be thrown into the breather.
 
I'm not a fan of my ad lib narration of the crankcase mods. We'll do another episode in which I go into more detail and I'm a little bit more accurate. Which means I'll go off a script.
 
MichaelB said:
Nice post Dave.
What would be the optimum depth of milling if one wants to retain the rear breather?
Anyone out there with real world experience of this scraper mod and keeping the rear breather?
Click to expand...

You are best off to leave as much of the baffle as you can. I just remove enough to open a passage into the passage as Dave pointed out. Then use a reed valve to replace the original open breather and you will be in good shape. Jim
 
comnoz said:
You are best off to leave as much of the baffle as you can. I just remove enough to open a passage into the passage as Dave pointed out. Then use a reed valve to replace the original open breather and you will be in good shape. Jim
Click to expand...

Thanks Jim,
Looking at my crankcase and pondering how much more beneficial to mod the scraper vs. boring a hole at the rear of the line.
Makes sense that it gets a little lower and below the breather more by modding the scraper.
Now, how much? Should be at least equal to or greater than the bore. Bore + 50%??
Anyone have a magic number?
Crankcase mods and build update
 
What I do is bore a hole where I have marked it and plug the old hole. I don't remove any of the baffle. The baffle allows air to get to the breather but prevents some oil from getting there.

Crankcase mods and build update
 
comnoz said:
What I do is bore a hole where I have marked it and plug the old hole. I don't remove any of the baffle. The baffle allows air to get to the breather but prevents some oil from getting there.

View attachment 10341
Click to expand...

There are two options for moving the pickup to the rear. One involves removing removing enough baffle to expose the pickup hole (if you remove too much you have to deal with oil in the breather) and the other involves drilling a new pickup hole (per Jim's picture above). Both require plugging the old front pickup hole.

There are advantages and disadvantages to each. I feel the advantages and disadvantages are pretty minor and either method should result in the same solution, moving the oil pickup to the back of the case.

The other option is to remove all of the baffle per Old Britts but then you should blank off the breather and move it to the timing case. If you follow Jim's research breathing through the timing case is the less desirable option.

At least this is what I have learned so far from people way smarter than me.
 
comnoz said:
What I do is bore a hole where I have marked it and plug the old hole. I don't remove any of the baffle. The baffle allows air to get to the breather but prevents some oil from getting there.

View attachment 10341
Click to expand...


I like this idea, as I want to go with a Reed breather at the rear.
Might as well ask what size hole you bore?

Another option for the breather is at the tach, as I am going electronic on the tach.

Crankcase mods and build update


Don't know if one is better than the other. Not so sure I like the looks of the breather hanging off the
front with hose running around the side the tank.

I kind of like the breather at the rear as it pumps the wet sump back in the tank.
I'm leaning this way.

BTW, thanks for starting this thread Dave. Very timely on my end.
 
Just curious, what does the inside of a Maney case look like with rear breather?
I assume it has a baffle. How's the oil pick up done?
 
MichaelB said:
Just curious, what does the inside of a Maney case look like with rear breather?
I assume it has a baffle. How's the oil pick up done?
Click to expand...

No baffle in the Maney case. It breathes [rather poorly] out of the timing chest like a late model Commando.
 
Yeah Jim, but he also machines the rear of the case for the breather too.

My Maney cases have no breather holes to the timing chest (by request) and I have both of your breather designs on the shelf Jim, sump plug and rear of case.

Which one should I use ??


Crankcase mods and build update
 
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