What is sumping?

hdmarsh77 said:

From what I understand it's when the oil pump doesn't pull enough oil out of the bottom end(crank case) and it fills with oil. The fly-wheel has to spin in there and with excess oil it's like trying to run in water. It really slows things down, hence the loss of HP. Normally there's not too much oil in it. Just enough to lube the bottom and splash up under the pistons. I think.

I'm not sure what causes it or how to determine if you have that problem.

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That's correct and it's probably the major cause of "wet-sumping". The scavenge side of the oil pump can get a cracked rotor or excessive wear due to particles in the engine and will then fall behind, causing excess oil to collect in the case. This causes oil burning, excess drag and generally too much oil in the wrong places.

Another cause, usually more common in the older engines like Knuckleheads, Panheads and Shovelheads, was leakage in the check valve ball in the oil pump feed for the oil tank. It lets oil flood the bottom end when parked and then when the engine is started it comes out of the open breather pipe and, before you realize it will make a puddle just large enough so that you can't step out of it. Ha.

Most T.C.'s won't wet sump since they added the wavy washer in between the gerotors. This was to prevent internal leakage into the crankcase. This was meaningful for the softails that have the high oil tank but really is of little value in the other bikes with the oil tank under the tranny.

If an E.G. or Dyna is wet sumping, it's usually a sign that the oil pump is damaged.

Current Build

My build is 95" BB, SE Performance Heads, TC1 cams, Vance and Hines 2 into 1 Pro Pipe, Big Sucker air cleaner, CV40 with Yost Kit, 48 low and 195 main jets, stock ignition. My neighbors have the TC1's in their bikes with the exact same set up as I do. Both dynoed the same within one or two points one way or the other. 90 to 92 torque and 80 to 82 HP. My bike after installing the SE heads and dynoed on the same dyno only came to 95 Torque and 79.5 HP. It was 92 torque and 80 HP before I added the heads. I only gained 3 ft. lbs. of torque. We all did the same modifications at the same time and all got about the same results. I received a message from Mike Roland who designed the cams after I had asked about if the heads were too much for the cams. His reply was absolutely not that I should have had about what I was expecting and suggested a sumping or tuning problem. My plugs are burning a light tan and I am checking the CCP tonight. I will also see how much oil is in the crankcase. I asked the HD shop if a module or SE Race tuner would help but they could not insure me the 10 HP I was looking for. According to the builds that I based this on I should be at nearly 100 torque and 88 to 90 HP. I have a problem but have not found it yet. Thanks for any help you all can offer.