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Monday, June 4, 2012

Shovelhead Breather Timing with Space-N-Time Tool

The oil misting out the crankcase is just plain killing me at this point. I'm going to put the breather gear and breather gear timing to bed once and for all. I have friend that got a Delkron Time-N-Space Tool and I got a brand new S&S Breather Gear Kit.

Once you get the push rods and cam cover off, you put the this collar on the crank shaft. I'm leaving the old breather in the same spot(one tooth off mark) as an science experiment to see where it has been.

The cam jack goes on next.

Bolt it on with the gasket.

Now for the degree wheel. Oops. The front pipe needs to come off.

Pipe off and the wheel fits on the collar on the crank.

Find TDC on the front cylinder.

Make a point and adjust the wheel to zero, but don't turn the crank in the process.

You would think they would include a pointer with this tool kit, but a coat hanger bit works fine. EDIT: If you put pin that hole you don't need a hanger.

Now turn the motor with the primary front sprocket nut.

The basic spec is opening between 10 deg before TDC(BTDC) and 10 deg after TDC(ATDC). So let's go to 10 deg BTDC and take a look.

It is very difficult to get good pictures of the breather window with my photography skills and equipment, I but will include these pictures in this write-up to keep the processes documented even if the photos stink.

The screen is no where near the window at 10 deg BTDC.

Now over to 10 deg ATDC.

The screen is still nowhere near the window at 10 deg ATDC.

So where does the opening occur? All the way out at around at 60 deg ATDC.

The screen is coming into view.

At this point I pull out the old get and start over with the new S&S gear. As I suspected the new gear and old gear are different. 

This is the new gear screen aligns with mark.

Old gear. The screen is about one tooth clockwise from the mark.

Here's the new gear in place lined up with all the marks. (The red line is a digital edit to highlight the mark for documentation clarity.)

I checked the end play to get the proper end clearance. My choice seems to be too loose or too tight. So I'll go slightly loose and it a thicker spacer than was in there from before.

TDC had to be found and wheel properly placed once again.

Check at 10 BTDC.

No screen there 10 BTDC.


No screen at 10 ATDC

Where does it open?All the way out at around at 50 deg ATDC. Basically exactly where we were with the old gear aligned one tooth counterwise from the mark.

Trust me, the screen is starting into the window.

Pull off the tool and pull the breather gear. Reinstall the gear with the mark one tooth clockwise of the cam mark and we'll see how much that helps.

TDC has to be found and wheel properly placed.
Where does it open now? At around at 30 deg ATDC. So we are getting closer.

The screen is in the window.

Pull off the tool and pull the breather gear. Reinstall the gear with the mark one tooth clockwise of the cam mark and we'll see how much that helps.

TDC has to be found and wheel properly placed.
Looky, looky, at 7 deg ATDC and...

the screen in coming into the window! If I had put the old gear one tooth over the other way I bet it would have been correct.

We tried to check the closing, but we were slightly confused about what starting to close and closing meant and whether it was measured from TDC or BDC. We are going to assume the closing correct given the quality of the S&S breather gear and the Delkron case window.

A quick check on the cam end play. It's right were it needs to be.

I'm going to ahead put Harley-Davidson part number 25329-91 Air/Oil Seperator into the cam cover tube just in case.

Now I just have to put the cam cover back on. Look near the end of this post for how to do that.
The front exhaust and push rods needs to go back on, too. Read this post for that.

The misting seems better. I didn't get to run it much because I ran out of gas. The bike starts easier and doesn't seem to have the funny "catch" that it seem to have occasionally kicking through. I think that was pressure building up.


  1. I figured out I was running the wrong cone gasket and that the hole at 12 o-clock on the base plate to the tool should be used for a marker after this post.

  2. Are these marks right, I have no way to degree my S&S gear 33-4250

  3. Using a piston stop and rotating cw then ccw against it, half the distance between your 2 marks is exact tdc.

  4. can you check for valve operation with pushrods off? I'm wondering if a movement of the lifter on the cam will directly translate to valve movement?