View Single Post
  #39  
Old 24th October 2019
Hippysmack's Avatar
Hippysmack Hippysmack is offline
XL FORUM TEAM MEMBER
 
Join Date: Jul 2014
Posts: 6,025
Reputation: 5839052
Hippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond repute
Default

The hard part about this subject is that the whole pressure system has to be taken into account at the same time.
We also speak of blowby as in compression getting past the rings and into the crankcase.
But that can also work in reverse especially on engines with worn rings which is another factor.

I kind of think of it more of a closed system with an intake air leak (blowby).
You are right, the changes are small when things are going good.
And truthfully, this is all a talking point until problems occur.
As with the op with oil puking out the oil tank;
Knowing what should be happening inside sometimes clues to why it happened and how to diagnose and fix it.
I believe you can pull up too much oil in suspension which is compounded on the next cycle and it gets ugly after that.
So as long as everything is percolating, changes are small.

I believe it is 91-03 engines with the largest splash holes in the cam wall (91-99 in particular).

They blocked those off with the piston squirters in 04 which bottled up the CC leaving the pinion bearing as the only vent port to the cam chest.
They closed off the top end otherwise including moving the heads drains to the cam chest.
But they also have the flywheels with the cups cut into the ends for the crank sensor.
So the wheels are no longer slick on the end which is bound to pick up more windage.
Think about it, they didn't have to cup the wheels. They could have installed a trigger on the face with a horizontal pickup.

I don't believe upstroke picks up raw oil but rather oil mist.
The wheels can pick up mist from the sump which compounds around the wheels which is the reason for windage trays.
The fluctuations pulse air/oil mist that is picked up by all the moving parts.
So upstroke play does a part in lubrication however slight.

On a separate note, I am working on a homemade slack tube.
Made the fitting and got a hose. Just have make a backplate.
__________________
Reference the XLFORUM'S Sportsterpedia for additional technical information & advice

In Search of Fuel, Sunshine and a Steady Idle.
Reply With Quote