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CS Hartzell throwing fine mist of grease

jeffw@sc47

Well Known Member
My Hartzell (on IO-390) is throwing a fine mist of grease mostly onto the right side my wind screen during even a short (1 hour) local fly-about tour at 60-65% power. The airplane has been flying for a year (66 hr TT) and I noticed the fine mist early but I think that it is throwing a little more and is more consistent. Grease in the prop is #6 (not #5) as that is how it came to me (I doubt that makes a difference).

I will call Harzell and see what my options are and whether it's still under any warranty. (? Prop shops near Greenville SC ?)

Any comments / suggestions appreciated as I don't know much about CS props.
 
My Hartzell (on IO-390) is throwing a fine mist of grease mostly onto the right side my wind screen during even a short (1 hour) local fly-about tour at 60-65% power. The airplane has been flying for a year (66 hr TT) and I noticed the fine mist early but I think that it is throwing a little more and is more consistent. Grease in the prop is #6 (not #5) as that is how it came to me (I doubt that makes a difference).

I will call Harzell and see what my options are and whether it's still under any warranty. (? Prop shops near Greenville SC ?)

Any comments / suggestions appreciated as I don't know much about CS props.

Mornin' Jeff,

Re-torque the long prop hub bolts which are shared by the spinner backplate.
 
I had a similar issue when my prop was new. First make sure all the bolts were torqued to the proper spec. The hub bolts that hold the spinner back plate not being torqued properly can cause leakage issues.
I flew to Hartzell in OH for service. My issue turned out to be a bad seal between the hub halves which they repaired under warranty while I waited.
Good luck.
 
I had / have this problem. Somewhere around 2018, aeroshell reformulated the #6 grease and the new version has a serious separation issue (oil part separates from the clay part). WHile grease cannot get past the seals at the roots, the separated oil can, as it is thin. Very large centrifugal forces here and this brings the separated oil out to the seals.

After about a year of customer complaints, Hartzell changed to a different grease supplier to end the problem. Hartzell told me to switch to #5 (can be mixed with #6) and eventually the weeping would stop. Just need to be a bit cautious as the lower temp limit of #5 is higher than #6. The new grease cannot be mixed with aeroshell, so a tear down is required if you want to switch.

At 250 hours, the amount of oil slinging on to my windscreen has reduced a good bit, but not fully gone. It is worse in warm weather. Eventually it will separate as much as it wants to and will stop slinging. The key is to not keeping put more #6 into it, as this creates new material to separate out.

Larry
 
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I had a problem early on with the same set up as yours. I found a glob of grease on the inside of the spinner as well as fine grease mist on the windshield. I never was able to see where it was coming from on the prop however after cleaning the inside of the spinner several times it finally stoped. I greased the prop after a couple of hours of flight per the manual. Perhaps it did not need as much grease as I gave it.
 
#5 compatible with #6 ??

Thanks to all for the advice.

Both Tom and Larry do mention that #5 can be mixed with #6, but as Tom adds both 5 and 6 are not compatible with Nyco GN3058. I do have a tube of #5 but was under the impression that I could not use #5 until prop was disassemble and filled with #5, but if I was to disassemble I would opt to go with the Nyco GN3058. If #5 is OK to mix with #6 I can do that.

I remember once reading somewhere that #5 was NOT compatible with #6.

I'll make a call to Hatzell this week to clarify. Again Thank You all.
 
Thanks to all for the advice.

Both Tom and Larry do mention that #5 can be mixed with #6, but as Tom adds both 5 and 6 are not compatible with Nyco GN3058. I do have a tube of #5 but was under the impression that I could not use #5 until prop was disassemble and filled with #5, but if I was to disassemble I would opt to go with the Nyco GN3058. If #5 is OK to mix with #6 I can do that.

I remember once reading somewhere that #5 was NOT compatible with #6.

I'll make a call to Hatzell this week to clarify. Again Thank You all.

From an earlier version of the Hartzell Propeller Owner's Manual No. 115N (61-00-15), Rev 23, Feb 2018 (prior to the introduction of Nyco GN3058 grease):

WARNING:

WHEN MIXING AEROSHELL GREASES 5 AND 6, AEROSHELL GREASE 5 MUST BE INDICATED ON THE LABEL (HARTZELL PROPELLER
INC. P/N A-3594) AND THE AIRCRAFT MUST BE PLACARDED TO INDICATE THAT FLIGHT IS PROHIBITED IF THE OUTSIDE AIR TEMPERATURE IS LESS THAN -40°F (-40°C).

CAUTION:

USE HARTZELL PROPELLER INC. APPROVED GREASE ONLY. EXCEPT IN THE CASE OF AEROSHELL GREASES 5 AND 6, DO NOT
MIX DIFFERENT SPECIFICATIONS AND/OR BRANDS OF GREASE.

(6) Aeroshell greases 5 and 6 both have a mineral oil base and have the same thickening agent; therefore, mixing of these two greases is acceptable in Hartzell propellers.
 
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How about a simple fix!

Had this exact problem with my Hartzell CS propeller after a condition inspection. I had greased the prop according to guidelines but it seems my grease gun had a little dirt on the end. It deposited a few grains of dirt into the grease fitting on the hub - just enough to keep the little ball from seating.

Look inside your prop spinner for a small glob of grease near the grease zert. That’s confirmation it’s leaking through the zert. Remove zert, clean with solvent and re-grease the hub. You’ll probably find problem solved.
 
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Mornin' Jeff,

Re-torque the long prop hub bolts which are shared by the spinner backplate.

May not be the OP's issue, but DanH offered this advice many years ago and saved me an unneeded reseal on my previous RV-8's Hartzell prop. Worked like a charm. Here is a pic:

i-GSQhpDV-L.jpg
 
I had prop grease escaping the seals. It manifested as grease near the prop hub on the blades. That was cured by retorquing the prop hub bolts as described above.

I also had a fine mist mostly onto the right side my wind screen. That turned out to be a leaking front crank seal.
 
I had the same grease slinging issue and ended up sending the prop back to hartzell under warranty at around 100 hrs. for a reseal.

No way was I going to tolerate a new prop throwing grease all over the plane. The prop came back with new orange seals on the blades and the newer Nyco greese.
 
What torque spec does one use on these bolts?

Attached below is an earlier version of the Hartzell Propeller Owner's Manual No. 115N (61-00-15), Rev 23, Feb 2018 (prior to the introduction of Nyco GN3058 grease).

- Table 3-1 on page 3-7 lists the torques values. "Hub clamping bolts/spinner mtg. nuts 20-22 ft-lbs (28-29 N•m)”.

- See Figure 3 on page 3-10, which shows the hub clamping bolts, like the picture I included in my VAF post. Obviously, the other 6 bolts that actually hold the hub together should not be disturbed.

- Page 3-11 through 3-13 talks about metal spinner bulkhead installation using those bolts.

- Figure 3-4 on page 3-12 shows the spinner mounting bolts and the spinner bulkhead spacer and stack up, just like on my airplane.

Check to make sure all that makes sense, as it’s been awhile since I did it.
 

Attachments

  • 115N-0000-R23-WA.pdf
    3.3 MB · Views: 79
Read twice; torque once

Be careful to look up the correct hub model and the correct bolts. I was pretty sure that I had somehow grabbed the wrong torque spec when installing the spinner plate to my Hartzell and over-torqued said bolts. To be safe, I opted not to trust my recall and replaced those bolts with new.

If memory serves, the torque spec is different for the bolts that hold the hub together and those that hold the blade cup portions together and attach the spinner plate. Lots of model numbers for Hartzell CS hubs and lots of resultant variation in bolt size and torque specs.
 
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