Wet sumping

texasSlick · Aug 18, 2014

I think FastEddie, Mike996, and I have treated this topic to exhaustion.

That is the beauty of this Forum....together, we get the whole picture.....

Slick

PS: One point I and others failed to mention....it was the clouds of blue smoke that first committed me to use a tapered plug valve in the oil line....that was waaay back in the '60s when no one offered the alternatives such as AMR. It was anathema to me to have some Harley guy watching when I cranked up.

texasSlick · Aug 18, 2014

Nortiboy said:
My real concern is, with modern electronic ignition, on more than one occasion, a cold and well tickled motor has fired up while I have been prodding it gently to TDC.
.

You do not want to reach TDC during the prod....that would put the engine past the trigger or points, and you would have to spin it nearly 360 more degrees before the next firing point. I suggest slowly rotating the engine to get the kick lever down, and it could fire as you say. It has never done this to me with a magneto, but if it were a concern, I could hold my thumb on the kill switch while prodding. With a Cdo, I suppose you could keep the switch off until ready for the big kick.

Slick

Hobot · Aug 18, 2014

Ideally and normally Cdo should start by shoving over TDC of one failed power stroke to get flywheel enough the other piston hits and starts before completing the lever swing through. Electronic spark'r may need a full cycle or more to prime their brains of course. ZADP is all the rage in flat tappet cam engines and is nano size stump like pads that are nano high/thick so easy rubbed off by metal contact. It does not form until surfaces it encounters heats oil over boiling hot. Cam break in occurs at 2000+ rpm. Takes a handful of seconds below red line rpm to refill crank shaft to spray oil out into sump slinging. Do your own math on most desirable conditions to start up on and shut down a long time.

bill · Aug 18, 2014

the issues IMHO with wetsumping is the possibility of the crank seal being pushed. another one is the large amount of oil that while in the sump the rings have to contend with. also the reduced air space to build higher than normal crankcase pressure to cause other oil leaks. worst case is starting with the oil level below the pickup in the tank and starving the rods of oil till enough oil is returned from the flooded sump.

Hobot · Aug 18, 2014

Huh, my silly mind thinks the few blown seals and extra smoking starts are pre-exising faults being revealed by wet sumping not that wet dumping causing them. Of course could be just me rationalizing away my lazy ways, though my Combats are made to make short work of wet sump starts, which is another point in their favor to me above other versions. Wes and I must just be lucky so far.

MikeM · Aug 18, 2014

I look in the oil tank. If its 3/4 full, I am kicking it.
Yes?
If not, Im draining the sump.
Dammit, Im a newbie.

1up3down · Aug 18, 2014

though my Combats are made to make short work of wet sump starts, which is another point in their favor to me above other versions.

ok hobot, you got me stumped on this one

how exactly is a Combat specification motor able to "make short work of wet sump starts" any differently than non Combat Norton motors?

a Combat motor has a little higher compression and a bit higher lift cam in addition to a 19 tooth sprocket, how do these things make that motor handle wet sumping any better?

I won't bother asking you to defend your opinion that the Combat motor is at minimum equal to or somehow " better" than other Commando motors because I doubt anyone here cares but I am interested in your wet sumping Combat superiority theory

MikeM · Aug 18, 2014

Ball valves. I get the concept. I get the risks. Where exactly would it be placed? Photos? Again, I get the risk.
Seems like it would be an acceptable solution. FWIW, my HD Fatboy does the same thing after it sits for the winter.
First start I let it idle for a couple of minutes and it doesnt seem to cause an issue.

bill · Aug 18, 2014

the 72 and 73 750 crankcases have the vent @ the bottom rear of the sump. the early rmotors have a timed breather on the end of the camshaft and the 850's vent through the timing chest. so with it @ the bottom rear of the sump vs all others the wet sump oil has a direct path back to the oil tank from crankcase pressure.

1up3down said:
how exactly is a Combat specification motor able to "make short work of wet sump starts" any differently than non Combat Norton motors?

bill · Aug 18, 2014

it is NOT pre exesting faults but the systems of wet sumping. think of the sump full of oil as adding high compression pistons but on the sump side, crankcase pressure can go WAY up till the sump is cleared and all that oil is flooding the rings and over loading them also.

hobot said:
Huh, my silly mind thinks the few blown seals and extra smoking starts are pre-exising faults being revealed by wet sumping not that wet dumping causing them. versions. Wes and I must just be lucky so

Hobot · Aug 18, 2014

Ugh, some do some don't and some its just as well. In my Cdo camp and Wes's, a normal intact crank seal in cold contracted cases is more than up to a wet sump cold oil slashing leaks a long time, as well as in heated expanded cases with hot thin oil jetting around. So summary is some think its normal for wet sump to eventually blow past crank seal into primary or is the cause of smoking starts, others don't. Experiences differ to guide our views is all.

JimC · Aug 19, 2014

Wet sumping; What's the worst case? A blown crankshaft seal. The fix; An inline valve, with the possibility of a blown engine. Or, remove the timing case and oil pump, send it and $70 to AMR. No more wet sumping and no more worries about oil starvation and no ugly valves, switches, tags, chains , etc hanging off your Commando. Seems like an easy choice, to me, anyway. KISS!

texasSlick · Aug 19, 2014

MikeM said:
Ball valves. I get the concept. I get the risks. Where exactly would it be placed? Photos? Again, I get the risk.
Seems like it would be an acceptable solution. FWIW, my HD Fatboy does the same thing after it sits for the winter.
First start I let it idle for a couple of minutes and it doesnt seem to cause an issue.

The outside line is the oil feed from tank to engine. I would place it nearest the oil tank, giving a longer flex line to dampen the engine movement. For a 750 engine, a 1/4 orifice valve is adequate. An 850 needs 5/16 but next common size is 3/8. Before deciding to go with AMR mod., I used a tapered plug gas cock rather than a ball valve.

Slick

Hobot · Aug 19, 2014

Ok many ways to skin a wet sump kitten or just let it alone. How about thinking out loud on a Commando pre oiler? Of course makes as much common sense as owning a road worthy Commando.

Wet sumping

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