engine oil leaking into the primary

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JimC and Sawsall,

Worth considering, thanks. I want to approach this in that new Commandos didn't require any PCV type of help and my '72 ran without PCV or leaks for at least 8 years after the restoration. I'll consider blow by although the rings were renewed last year and the engine develops 185psi per cylinder. The all rubber crankshaft seal has cured the primary leak, so my belief is poor quality seals, will know more once I get another source for points seal.
 
I'm glad you mentioned the different styles of seals because that was my problem. I had oil leaking past the seal no matter what i did to it . It would start in tight but became loose as it was fitted into place indicating a worn bore. The first two seals i tried had a metal outer edge . I re-ordered more and the next batch were rubber coated . New seal fits very snug without the aid of any adhesive. No problems in the last 7000 miles.
 
I'm thinking the crank end float may be disrupting the seal...any comments on that?

Thanks,

David[/quote]
How many shims did it take to get the correct crank end play after installing the superblends 4 or 5? I was told 3 thousanths is what you shoot for. End play will do a number on a seal after a while.
 
Recommended crankshaft end float (with Superblends) is 10 to 30 thousandths. I measured mine between 10 and 15 thousandths - no issue there. Again switching to all rubber crankshaft seal replacing the type with metal outer part cured that leak. Before I go chasing positive crankcase or blow by, I'm going to replace the points seal from a different source. If this works it will end all my issues...for now. Oh, except I have two oil tanks with broken rear mounts. Will take those to the local welder tomorrow. No I don't use two oil tanks, have a back.
 
A reed type PCV valve will increase horsepower. That's been known for a long time. If you want, consider no more oil leaks a side benefit. No doubt, now that CNW is offering a PCV valve, more Norton owners will discover it's benefits.
 
Hi Jim,

OK I spent $16 for the reed valve and installed it. The points seal still leaks, so I think my initial assessment of poor quality or expired seal is correct. I cured the crankshaft seal before adding the reed valve by using an all rubber seal instead of the type with metal surround. This doesn't mean I'm going to remove the reed valve, though. Also can't confirm power increase, but then with this modern fuel I can't completely use the power anyway due to detonation. Lucas RITA ignition set at 26degrees full advance helps, but doesn't completely eliminate the pinging.
 
David,

I've "cured " the crankshaft seal leak many times by replacing the seal, only to have it re-appear after a 1000 miles or so. As for the timing seal, looks like a replacement is due. I don't know if you've been plagued with other leaks, like the tach drive, head, rocker covers, but if so you should see a marked reduction of those with the XS 650 PCV valve. As for an increase in HP, some have reported a detectable increase. I can't say I've actually felt any increase. I believe it was Jim Comstock who developed the PCV valve for CNW and showed a power increase on the dyno. In any case, the $16 was well spent.
 
debby said:
I do notice the ATF looks brown whenever I change it so I suspect I'm getting some leakage too.
Debby
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Debby, doesn't the primary lube always turn icky (technical term) fairly quickly? Mine does, and not just in the Norton. I've always assumed that friction material from the clutch plates is the culprit. Not to say you might not have a leak, also, but I would think this would happen even without one.

Then again, what do I know?

Best - BrianK
 
That could be. I do not see any increase in oil volume, so perhaps it's not leaking after all.

I came up with a solution so that I no longer have an issue with ATF turning brown: I changed to 10W/40 engine oil in the primary! Seems to work just fine and it's already brown! :)

Debby
 
JimC said:
You might try the Chicago Rawhide #12343 crankshaft seal. It has a long life lip. I noticed some improvement with this. Once I installed the XS breather valve I had no more leaks. I had tried the Motormite brake check valve with poor results. IMO, the Norton needs a reed valve. Automotive PCV valves don't work either. The XS is very inexpensive, $16.
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Thats the one to fit, I fitted one and was very surprised at the total absence of irritating oil leaks .(Especially the tacho drive that I never got around to modifying for the seal upgrade...fixed straightaway.)
 
illf8ed said:
I agree regarding the reed valve and may go that way. However this engine didn't leak at all for the first 7-8 years after the rebuild even with no one way system. I'm ruling out wet sumping blowing the seal since I drain off the sump before starting. I don't understand why a new stock seal won't work, must be something else going on. I'm thinking the crank end float may be disrupting the seal...any comments on that?

The three bolts holding the inner primary to the crankcase are tight and have new tabs.
I'm not getting gear oil from the gearbox in the primary - have Dyno Dave's seal already. The oil getting in is definitely engine oil and the primary gets too full then leaks out the gearbox shaft felt seal (not really a seal) from the spray of oil getting into the primary chain. I don't use ATF in the primary.

Thanks,

David
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Thats a lot of Oil ! how much riding from emptying the primary to the oil emerging from the gearbox shaft 'seal' ?
 
debby said:
That could be. I do not see any increase in oil volume, so perhaps it's not leaking after all.

I came up with a solution so that I no longer have an issue with ATF turning brown: I changed to 10W/40 engine oil in the primary! Seems to work just fine and it's already brown! :)

Debby
Click to expand...
I fitted a belt drive so no oil brown or otherwise :D :D
 
JimC said:
David,

I've "cured " the crankshaft seal leak many times by replacing the seal, only to have it re-appear after a 1000 miles or so. As for the timing seal, looks like a replacement is due. I don't know if you've been plagued with other leaks, like the tach drive, head, rocker covers, but if so you should see a marked reduction of those with the XS 650 PCV valve. As for an increase in HP, some have reported a detectable increase. I can't say I've actually felt any increase. I believe it was Jim Comstock who developed the PCV valve for CNW and showed a power increase on the dyno. In any case, the $16 was well spent.
Click to expand...

Hi Jim,

If the XS650 part helps any of the leaks it's worth the $16. Yes the front valve covers leak also. I was hoping the reed valve would cure the timing seal so I don't have to go in there again. The seal was replace and has maybe 500 miles on it, but still leaks (even after the reed valve installed).

On the engine detonation issue, I went to 240 mains from stock 230 and will try 260 next (because I have some 260s). If I can get rid of the leaks and detonation, I won't have anything left to do on this combat except to abuse it.
 
Was the timing seal installed correctly? Was the timing cover installation tool used?
 
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