Leaks
Cruiser
Joined: Nov 2025
Posts: 189
Likes: 81
From: Long Island, New York
When I took apart my FLT that's the way mine was. Spring facing you. I've seen/read varying things on this. Not sure how it is with other years, but the FLT pulls a pretty deep vacuum on that primary case. Normally on a seal you want to put the spring towards the side with the fluid you're trying to seal. On my bike you're trying to seal the vacuum from sucking the oil out of the engine, though, either way if it leaks oil, I doubt you're going to know it because it'll get sucked right back into the cam case. Am I thinking wrong? I usually am when it comes to Harleys. I feel like most of my 35 years of auto repair experience goes out the window when I work on these things sometimes. Lol
I would think if you're running a manually oiled or open primary you'd want to put the seal spring towards the engine. With my bike I'm not sure how the vacuum might play into the direction of the seal.
I would think if you're running a manually oiled or open primary you'd want to put the seal spring towards the engine. With my bike I'm not sure how the vacuum might play into the direction of the seal.
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Road Master
Joined: Oct 2022
Posts: 960
Likes: 668
From: USA
In looking at sectional prints of the shovel engine it looks like the seal is spring away from the crank on the shovel. But looking at the EVO engine the seal is the other way around so I guess that would be backwards on the shovel engine. The EVO engine has a very similar lower end and that engine is supposed to be improved. The engine huffs and puffs in the crank case so so pressure and vacuum alternate. I still do not know which way I would install that seal yet. I am hoping for more input on this topic.
Seasoned HDF Member
Joined: Nov 2006
Posts: 12,878
Likes: 5,449
From: la la land jerzey
Sometime 35 40 years ago so self impressed ^sshole turn the seal around on line and said he was right everyone else was wrong -
never took a shovel original piece some ^ss hole did not make it his own yet - the seal spring faced the right side - panhead before the seal was invented had the reverse winders groove in the insert and the oil groove was to the right not the left - then they invented the rubber seal and it came with the outer housing and it cant be install with the spring facing the left only goes to the right inside facing — but it’s yours and i dont have any more to say on this subject
never took a shovel original piece some ^ss hole did not make it his own yet - the seal spring faced the right side - panhead before the seal was invented had the reverse winders groove in the insert and the oil groove was to the right not the left - then they invented the rubber seal and it came with the outer housing and it cant be install with the spring facing the left only goes to the right inside facing — but it’s yours and i dont have any more to say on this subject
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Road Master
Joined: Oct 2022
Posts: 960
Likes: 668
From: USA
Hey John, thanks for your input on these engines. I would love to get out in the garage and get started but I have a few things holding me back from doing so right now. But... I do now have a plan on how I will be doing this project, I like have a plan before starting.
Cruiser
Joined: Nov 2025
Posts: 189
Likes: 81
From: Long Island, New York
I had a plan and it went out the window as soon as I started taking it apart. Lol. I should have my cylinders back by the end of next week, so this was great info. Thanks fellas.
Seasoned HDF Member
Joined: Jul 2014
Posts: 8,590
Likes: 3,360
From: Cental, MI
In looking at sectional prints of the shovel engine it looks like the seal is spring away from the crank on the shovel. But looking at the EVO engine the seal is the other way around so I guess that would be backwards on the shovel engine. The EVO engine has a very similar lower end and that engine is supposed to be improved. The engine huffs and puffs in the crank case so so pressure and vacuum alternate. I still do not know which way I would install that seal yet. I am hoping for more input on this topic.
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Road Master
Joined: Oct 2022
Posts: 960
Likes: 668
From: USA
One thing for certain.. nothing is for certain.
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