Sumping?

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Dec 1, 2017 | 08:33 PM

#11

Mattbastard

Grand HDF Member

Joined: Nov 2009

Posts: 4,315

Likes: 1,663

From: Tampa

My rule of thumb is do all things oil when the motor is warm. Change it, check it, etc... on a hot motor. This way there's no inconsistencies.

Especially change hot oil. This way all the crap is suspended in solution when it runs out, versus settling on the bottom of your oil pan to be recirculated next time around into the fresh oil.

Dec 1, 2017 | 08:37 PM

#12

hollandhunter

Road Captain

Joined: Oct 2016

Posts: 638

Likes: 127

From: Kentucky

Quote:

Originally Posted by Max Headflow

No difference between today oils and yesterdays as far as coefficient of volumetric expansion.. The difference between it and aluminum is about 0.00033 / degree F. That would account for about 1/4 to 1/3 qt.. The other part could be from general oil viscosity and it clingy-ness to internal parts in the motor.

I keep my m8 half way up dots on the cold side of the stick. Halfway between add a qt and full while cold. When i ride it and get it hot then check it it may rise a dot or 2 but not much from what i have seen. I will add my m8 only has 3k miles on it but i have had to add about a qt to keep it where i want it during those 3k miles total. In a nut shell i uses a little oil.

Dec 1, 2017 | 09:07 PM

#13

Max Headflow

Seasoned HDF Member

Joined: Dec 2005

Posts: 19,830

Likes: 7,968

From: poway

Quote:

Originally Posted by hollandhunter

Well 2 1/2 dots should be 1/4 qt.. Need to know oil temps..

Another issue is oil cooled is that the oil in the heads / cooled can drain out while sitting. The filter oil might drain forward or back (not supposed to drain back but some of the filters are not perfect).

FWIW, as long as the oil is in the good zones of the dipstick, don't sweat it.. A little too high might blow some into the intake.. Check it hot. If too high suck a little out.. The rest of the time be happy...

If you are driving down the road and motor feels sluggish. Pull over and check the oil.. If oil off the dipstick, worry.. Let it cool off a little then start and let idle for a minute. Oil back, you got sumping.

Dec 2, 2017 | 08:12 AM

#14

Harttoo

Thread Starter

Road Master

Joined: Feb 2014

Posts: 1,240

Likes: 170

From: Wisconsin

This is My 7th Harley,so I have changed plenty of oil.Not until the M8 have I changed oil and filter and found too much oil days later.So I started this thread to try to understand sumping in the M8.What I get is instructions in oil changing and cracks about overfilling and discussions about oil viscosity.

I can solve My issue easily by filling only to one quart low after oil change.

The question is:

Can the M8 keep a half quart of oil sumped away during an oil and filter change?

Can it appear after levels have been checked and driven for say 50 miles?

Did the Tech Who installed the cam create a problem with oil jets?

Do I need an upgraded oil pump?

Dec 2, 2017 | 11:32 AM

#15

harleytuner

Outstanding HDF Member

Joined: Mar 2009

Posts: 3,253

Likes: 222

From: Fredericksburg, Va.

Quote:

Originally Posted by Harttoo

This is My 7th Harley,so I have changed plenty of oil.Not until the M8 have I changed oil and filter and found too much oil days later.So I started this thread to try to understand sumping in the M8.What I get is instructions in oil changing and cracks about overfilling and discussions about oil viscosity.

I can solve My issue easily by filling only to one quart low after oil change.

The question is:

Can the M8 keep a half quart of oil sumped away during an oil and filter change? YES

Can it appear after levels have been checked and driven for say 50 miles? YES

Did the Tech Who installed the cam create a problem with oil jets? NO, oil jets are in the crankcase below the cylinders

Do I need an upgraded oil pump?

Wouldn't hurt

Answers in red above. The oil pump has the ability to scavenge the "sumped" oil from the case if you let it idle long enough. So when you are checking you oil it can appear to be low if you shut the bike off and check it without extended idle time.

Dec 2, 2017 | 11:40 AM

#16

cosarguy

Intermediate

Joined: Jun 2010

Posts: 31

Likes: 1

From: Western Montana

Quote:

Originally Posted by Harttoo

I’ve owned a few twin cams and now a 2017 UltraLimited. I do my own services. Twin cams were spot on…add the recommended amountof oil, start bike, let run for a couple minutes, turn off, let sit for a few minutes, check level. Halfway up on the stick….good to go. Fast forward to my M8; add recommended amount of oil, run for a couple of minutes, let sit a few, check level and nothing showing on the stick, scratch head and assume I missedjudged by a quart or so, add a quart and now shows midway on stick, smile and go for short fifteen minute ride, let bike sit for a few minutes, check oil level….way over the mark, remove one quart to arrive at proper level. I have done two oil changes on the bike so for and had the same oil level issue. So now when I change the oil, put in the amount I think it needs and go for a 20ish minute ride before I check final level. Seems kinda "basacwards" to me. This has prompted me to periodically check the oil while riding; I find it varies by 1/4 to 1/2 of a quart fairly consistently on the stick. Now in all fairness, I did not check any of my twin cams like I have my M8, so perhaps they did the same thing when riding, though I doubt it. My conclusion, and what many have stated on here, is the oil pumps in the M8 definitely has issues that may be somewhat masked in stock, or near stock, form and in some cases, are exacerbated by heaver mods. Also, since new, my bike has been a stage 2 (torque cam) with dealer installed aftermarket exhaust and heavy breather intake. I am eager to see how Harley handles this when/if many M8 motors start going south and this becomes much more public than a few forums. Final note, I like this bike….A LOT!

Last edited by cosarguy; Dec 2, 2017 at 02:26 PM.