TC 117 Sumping
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3rd Gear
Joined: Sep 2018
Posts: 7
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From: Santa Barbara, CA
TC 117 Sumping
Hello, long time lurker, first time poster here.... I have a customer with a 2009 FXDC that is really stumping me. He changed his tired 103 to a built 117 from a local builder. It is mainly a Screamin Eagle 117 kit on a 103 bottom end with a straightened and welded crank. Shortly after getting it running and doing a break in it would start pushing huge amounts of oil out of the breathers into the air cleaner then all over the right side of the bike and rider. He consulted the builder numerous times and he said everything looked normal and to try a vented dipstick cap. Well he tried that ($500) with no change. Then he put a catch can system on it. It will fill up the catch can with oil then still puke over. Then he asked me to look at it, I have built quite a few of my own twin cams over the years but never had a sumping issue before. I checked the rocker arm drain back holes and they were not drilled so I did so to 1/8". Helped the issue take longer to happen (takes about an hour of riding now to do it vs doing it imediately) but still happens. Then we removed the crank plug after the engine was hot and saw barely 3-4 oz of oil come out so a Fueling OE+ oil pump was installed. Honestly I didnt find anything wrong with the stock pump that was in there but we already had the part and figured it was worth the $270 try.... well it still begins sumping after an hour or so. Ive compression tested and leakdown tested it and it is strong at 180 psi with no leak down even when hot. He is very frustrated with it as he spent good money on an engine that covers his bike, him and his passenger with hot oil every time he rides it. Has anyone else been through this before with a twin cam or a big cubic inch twin cam? I can't think of anything else that could be the issue and the engine builder has never had a problem like this before and says we have already covered everything that he would check.. any help is appreciated.
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3rd Gear
Joined: Sep 2018
Posts: 7
Likes: 0
From: Santa Barbara, CA
Yes it was installed on the stock pump and was in good shape. And a new O ring provided with the Fueling pump was installed when I changed the pump out.
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3rd Gear
Joined: Sep 2018
Posts: 7
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From: Santa Barbara, CA
I have not checked oil pressure with a mechanical gauge nor have I checked the piston oilers
only way to check those is to remove the cylinders correct? Being a dyna it doesnt have a factory gauge to go off of and I havnt thought about oil pressure being an issue. I will check it in the next day or two. It does have an Axtell bypass valve installed in the oem cam plate. Is there a possibility too high of sustained oil pressure is filling the crankcase faster than it can scavenge?
Road Warrior
Joined: May 2011
Posts: 1,956
Likes: 437
From: florida
Yes thats possible.
I would next want to look through the spark plug hole with a borescope and verify the condition of cylinder walls, carbon deposits, and spark plug condition. And take off the AC to see if any oil coming through. I know you say leak down was checked but Id want to look for signs there regardless
Grand HDF Member
Joined: Sep 2017
Posts: 4,359
Likes: 1,219
From: Dubuque, IA
Excessive oil and oi! pressure will do that. Piston oilers have been known to stick open and should be tested in any build.
That said, A 3 stage pump is way better at scavenging and oil pressure is adjustable. That feuling pump is child's play and not in the same league as the S&S or DT pump and plate.
People think they are saving money and the feuling is just as good. Dual scavenge ports should be oem imo. In a build, it's foo!ish not too. A sumping engine can burn it up. But that's me. I also replace the **** poor breather valves with inline reed valves. I don't care what anyone says, they reduce crankcase pressure. High crankcase pressure results in poor ring seal results in excessive blow by. It's a vicious circle.
That said, A 3 stage pump is way better at scavenging and oil pressure is adjustable. That feuling pump is child's play and not in the same league as the S&S or DT pump and plate.
People think they are saving money and the feuling is just as good. Dual scavenge ports should be oem imo. In a build, it's foo!ish not too. A sumping engine can burn it up. But that's me. I also replace the **** poor breather valves with inline reed valves. I don't care what anyone says, they reduce crankcase pressure. High crankcase pressure results in poor ring seal results in excessive blow by. It's a vicious circle.
Last edited by 60Gunner; Jan 30, 2024 at 04:06 AM.
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Seasoned HDF Member
Joined: Jun 2017
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From: Granville New York
One or both of the rocker gaskets are flipped and they're covering the breather passage way. Well that's my guess anyway.
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Grand HDF Member
Joined: Sep 2017
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From: Dubuque, IA
Good call...that'll do it.