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CS Prop Seal Oil Leak?

bkervaski

Hellloooooooo!
Testing
I think I have the (in)famous CS Prop Seal Oil Leak issue.

As I understand it (please correct me if I'm wrong) a new prop will leak oil until the seal "seats".

My question is, how long does that typically take and how much oil leaks?

I just finished my 6th flight. There is about 3 flight hours worth of "leaked oil" from that area. If I could make a guess, it's somewhere in the range of 2-3 ounces of oil that ended up on the inside of the bottom cowl and (very lightly) sprayed on the canopy.

I have the cowl off, if I need to swap that seal or re-install the prop would like to do it over the next few rainy days.

Any advice appreciated!
 
The prop seal should not leak after you put it on. I don?t by it will leak a little till it seats! That is bogus BS. Pull the prop clean lube and reinstall with new seal. You will be glad you did.
 
Are you throwing oil at the blade/hub or hub/crank? The hub/crank should be dry from day one. If not, it was probably cut on installation.
 
It's collecting inside the flywheel.

Okay, I'll take the prop off and see if the seal was damage, sounds like in any case it has to come off.

Thanks all, please keep the advice coming :)
 
If it's collecting oil on the inside of the flywheel, I"d say it's the front seal of the engine leaking.

I too call BS on props leaking for a few hours after installation.
 
Bill, I really doubt with that Thunderbolt engine you have a leaking nose seal. Check the o ring inside the prop hub.

Vic
 
As there is no "seal" between the ring gear carrier and crank, it's possible that oil is working out of the crank/hub seal and slinging to the inside, but normally it stays in front. The nose seal is certainly a prime suspect, regardless of who assembled it.
 
As there is no "seal" between the ring gear carrier and crank, it's possible that oil is working out of the crank/hub seal and slinging to the inside, but normally it stays in front. The nose seal is certainly a prime suspect, regardless of who assembled it.

Michael makes a good point, but look carefully for even traces of oil on the forward face of the flywheel or inside the cowl ahead of the flywheel, as this would pretty much confirm the source is the crank to prop seal. There is also no seal between the prop and the forward face of the flywheel, so unlikely that ALL oil would divert to the aft side of the flywheel if from the prop O-ring. If the new prop is the only new change on an engine that had been flying recently, then it is the natural suspect.
 
No Leak Initially

My Hartnell CS had no leaks at all on initial and subsequent re-installation when I converted to EFII (about 150 hours ago). Now at 200 hours I am getting a little (very small drop) of oil on the engine casing that can be traced back to the CS hub.

In my investigation, I'm finding it difficult to source the Hartnell C-3317-228 O'Ring. Searching ACS gets zero results. I can find them on a couple of websites with an RFQ for pricing.

Anyone got a good source?
 
Update: Removed prop, a few tiny "hair" like pieces of aluminum collected in/on/around the prop seal. Most about 1/8 long, one about 2 inches long.

I'm wondering if this material was there before or perhaps it was shaved off the hub during the prop install.

At any rate, new seal will be here Tuesday, I'll get it installed and update again!
 
Thanks

Thanks fo the link. I tried several different searches resulting in zero finds.
You must have a secret decoder ring.
 
Well, chased this one around a bit.

This issue was the prop governor gasket leaking .. the bolts weren't torqued to spec.

A small amount of oil apparently goes a long way when it's leaking. It would collect underneath the flywheel and then slung all over the place.

Seems to be resolved, a few more flights to be sure.
 
I?m pretty sure every suggestion you?ve received here is on target. However I will relate an experience I encountered last year after my condition inspection. On my second flight post inspection, I took off from ADM flying back to home base. My wife asked me what that film was growing across the front of the canopy. I thought uh oh!

I closely monitored my oil pressure (rock steady) and continued back home since I was close to mid way. After a quick landing and parking, I pulled the cowling, checked my oil level, and and looked for an oil leak around my prop and forward part of the engine. Nada! In fact there was no oil anywhere! Everything was clean and dry. Examined the canopy further and noticed how thick the ?oil? was. Pulled the prop hub and there was just a little grease build up at one point inside the hub. But from that little build up lots of oily film quickly accumulated and was spread to the canopy by the centrifugal force of the prop.

Further investigation yielded the fact that the hub grease lined up perfectly with a prop grease zerk. It seems the little ball inside the zerk had not returned to fully seated position because of a piece dirt lodged in it (I suspect from a dirty grease gun nozzle used by my A&P during the inspection).

Lessons learned: always make sure the grease gun tip is cleaned before use. Don?t assume the oily film growing on the canopy is always oil. Always assume the worse and land ASAP! Finally, when investigating a problem be sure to completely identify the cause before deciding on a fix.

Replaced the zerk with a new Hartzel zerk, re-greased the prop and no reoccurrence.
 
Well, chased this one around a bit.

This issue was the prop governor gasket leaking .. the bolts weren't torqued to spec.

A small amount of oil apparently goes a long way when it's leaking. It would collect underneath the flywheel and then slung all over the place.

Seems to be resolved, a few more flights to be sure.

No doubt a frustrating chase. Glad you seemed to have found it. For reference, the 9/32" hex cap head screws must be torqued to 21-25 in-lbs per the manual (HC-SL-61-277 Rev. 3 D(1)(b)g).

I had a prop governor leak too. In my case it was due to a damaged gasket, as I explained here.

IMG_20171119_113612.jpg


Damaged gasket on left. New gasket on right.

IMG_9327.JPG
 
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