Oil pump scavenge

[roadkingdresser]

What are the signs of the oil pump scavenge going bad?

[kd]

What are the signs of the oil pump scavenge going bad?

Loss of power and more engine heat are the most common first signs.  Measuring the amount of oil you can drain from the crankcase is the way to confirm it. 

[aswracing]

And heavy engine braking. I once rode a wet-sumping bike that would chirp the rear tire and try to throw you over the bars when you chopped the throttle. Tech had screwed up installing an o-ring. That's all it took.

After fixing the misplaced o-ring, the bike also picked up 30hp on the dyno. Literally.

[roadkingdresser]

Will it throw oil out the head breathers? If you pull the dipstick while it's running does it sound like an air compressor inside?

[RoadKingKohn]

What are the signs of the oil pump scavenge going bad?

The easiest way to check it is to pull the sump drain plug and measure the amount of oil that comes out. If you have more than 6 ounces you need a new oil pump. If you need one get either the Feuling or S&S with their camplates. I have the S&S on my 2005 Road King Classic. I drained the sump and had over a quart of oil come out. Since I put in the S&S I get 4 to 6 ounces.

[ziggy24]

Why do you need a new oil pump, if it's just a pinched scavenge o-ring?

[Thermodyne]

Easiest way to check a twin cam for sumping is to just dead rev it.  If its running hot and pissy, and you suspect its sumped, just whack the throttle open.  If it bounces off the limiter its not sumped.  If it loads up around 4000 and doesn't want to go higher, its sumped.

Past that, pushing oil out the head breathers is what twin cams do as they age.  Most can be fixed by modifying the rocker supports.

[JSD]

Thermo do you mean drilling bigger holes in oil drains in supports ? 

[Mi Infidel]

Thermo do you mean drilling bigger holes in oil drains in supports

Under the area where the umbrella seals are there's a small drain hole. I drilled mine out to 1/8".

If you forget to align your oil pump it can cause sumping and if it's bad enough it will coat the side of the bike from the breather bolts. Learned that the hard way lol. And like mentioned above it didn't want to rev and when it did it pissed oil!

[60Gunner]

Sumping and puking oil aren't necessarily related. Puking oil is the result of crankcase pressure is the result of blowby usually due to poor ring seal. Puking out the breather bolts can also be because of crankcase pressure caused by the breather valves(umbrella valves) not working properly.
Drilling out the hole in the rocker support plates helps oil drain from the heads so it's not as easily carried out by the breathers.
Sumping is oil sitting in the sunp due to poor scavenging for a number of reasons. A 3 stage pump improves scavenging with 2 scavenge ports scavenging oil from the cam chest and crank side.
Personally I like and run the Dan Thayer 3 Stage Pump. Oil pressure can be adjusted with the turn of a screw in the cam plate. I believe mine came adjusted to 43psi as I recall.

Note: You must check crank runout and it can't be more than .0003 at most if even that. It might even be .0001.
Crankshaft runout can cause scoring of the gerators and plate. So does debri in the oil pumped thru it.

 

[kd]

Sumping and puking oil aren't necessarily related. Puking oil is the result of crankcase pressure is the result of blowby usually due to poor ring seal. Puking out the breather bolts can also be because of crankcase pressure caused by the breather valves(umbrella valves) not working properly.
Drilling out the hole in the rocker support plates helps oil drain from the heads so it's not as easily carried out by the breathers.
Sumping is oil sitting in the sunp due to poor scavenging for a number of reasons. A 3 stage pump improves scavenging with 2 scavenge ports scavenging oil from the cam chest and crank side.
Personally I like and run the Dan Thayer 3 Stage Pump. Oil pressure can be adjusted with the turn of a screw in the cam plate. I believe mine came adjusted to 43psi as I recall.

Note: You must check crank runout and it can't be more than .0003 at most if even that. It might even be .0001.
Crankshaft runout can cause scoring of the gerators and plate. So does debri in the oil pumped thru it.

 

That's a pretty hard standard to meet.  That's 2 points less than 1/2 thou.  Do you actually mean .003?

[60Gunner]

Sorry. .003. Actually I think it's .001. In any case, crankshaft runout just makes poor scavenging even worse as it wears the gerators and cam plate. If you notice in the pic of the DT pump there's also an oring that seals it to the cam plate. The cam plate helps maintain a steady vacuum according to them and the patent it holds.
Crank run out also causes the stock cam plate to flex.
Every oil pump revision harley has done is to improve scavenging, not oil pressure. You would think they would just do a 3 stage pump like this. But what do I know. I just know I have no oil left in my sump when riding. Even at sustained high rpm.
Being a softail and not having the spring plate in the gerators in will sump when sitting tho. But it quickly returns to the tank once it's running.

The stock cam plate and pump might be adequate for a stock motor but start building these for performance and/or running higher rpm I wouldn't run anything but a 3 stage but that's me. I didn't stick $5000 in this build to have it sump. But I run consistently higher rpm with the 30 tooth solid primary.
 I did do an S&S crank to address the runout.  The moco's tolerance of .012 is over the top. This was raised because of all the warranty issues with crank run out when the tolerance was lower. My stock wasn't bad at .003 but it's sitting in the attic now anyway.
I highly suggest checking run out and either balancing/truing/welding the stock crank or better yet replace it with an S&S.

[roadkingdresser]

Finally found out what was going on with this bike. Even though it had 160 psi in each cylinder. when I pulled the heads off, the rear cylinder was oil soaked and the front looked normal. after further investigation found the groove between the top ring and the second had broken away from the piston in the front. There was just enough lip on that section that the rings held it in place and didn't explode the piston and cylinder. Never seen this before.

[Ohio HD]

That would do it. If those rings are not retained by the ring lands you can see blow by and loss of oil control. The second ring is really more oil control than compression assist. Compression will leak behind the top ring if there's an opening due to the piston being damaged. And oil will go past them to the combustion chamber.

[60Gunner]

I'd be worried where that piece of the piston that broke away is.

[kd]

I'd be worried where that piece of the piston that broke away is.

I'd be worried where that piece of the piston that broke away is.

Finally found out what was going on with this bike. Even though it had 160 psi in each cylinder. when I pulled the heads off, the rear cylinder was oil soaked and the front looked normal. after further investigation found the groove between the top ring and the second had broken away from the piston in the front. There was just enough lip on that section that the rings held it in place and didn't explode the piston and cylinder. Never seen this before.

The answer was in the OP's previous post #13.