Leaking flywheel… AGAIN!
Posted: Wed Jul 01, 2015 9:02 pm
by mike.smith
So this weekend I am about to take my AeroVee engine off my plane for the THIRD time in as many weeks. I have been following the AeroVee installation instructions to the letter. The flywheel assembly is brand new (if you followed my post about the self destructing flywheel and alternator you know why). I put in a new rear seal. I used RTV on the hub and 8 pins holding the flywheel. Last time this happened (only a week ago), when I removed the flywheel I found the rear seal 100% intact, with no sign of even a drop of oil getting by. But the area of the 8 pins holding the flywheel was leaking heavily. We cleaned up everything down to bare metal. We lubed the rear seal. We put RTV on the flywheel hub and the 8 pins. We torqued the gland nut per specs.
There was no oil for the first couple of hours on the engine. After flying for an hour yesterday the back of the engine is a mess. There was so much oil that it filled the bottom of the air cleaner, and had half filled all the pores of the air filter. It’s a wonder the engine was still breathing.
So I ask, WHAT THE HECK CAN I DO DIFFERENTLY SO THIS DOESN’T HAPPEN AGAIN!!! I have the AeroVee manual open through the entire process and follow every instruction. Why is it leaking!?
Re: Leaking flywheel… AGAIN!
Posted: Wed Jul 01, 2015 9:19 pm
by merle reppert
Make sure the oil drain passage in the case is not blocked by sealant ??
Re: Leaking flywheel… AGAIN!
Posted: Thu Jul 02, 2015 12:30 am
by mike.smith
merle reppert wrote:Make sure the oil drain passage in the case is not blocked by sealant ??
I ran a pipe cleaner into them to make sure they were clear. Oil pressure is the same as it’s been for the last 80 hours, so no sign there is a problem with oil flow.
Re: Leaking flywheel… AGAIN!
Posted: Thu Jul 02, 2015 10:49 am
by vwglenn
Well I don’t know about the Aerovee flywheel but the regular flywheel on a VW has an O ring on it…
Usually when the main seal isn’t leaking, the cam plug can be the culprit. Drips down, hits the flywheel and throws oil all over the place.
Re: Leaking flywheel… AGAIN!
Posted: Thu Jul 02, 2015 10:32 pm
by mike.smith
vwglenn wrote:Well I don’t know about the Aerovee flywheel but the regular flywheel on a VW has an O ring on it…
[/img]Usually when the main seal isn’t leaking, the cam plug can be the culprit. Drips down, hits the flywheel and throws oil all over the place.
The AeroVee does not use the O-ring. It relies solely on the RTV sealant throughout that area. I did look at the camp plug, and I didn’t see any evidence of oil coming from there. I’ll be re-doing the back of the engine again tomorrow, so I’ll report back on what I find. I’m just not sure I’ll be any closer to figuring out “why.”
Re: Leaking flywheel… AGAIN!
Posted: Thu Jul 02, 2015 10:48 pm
by SonexN76ET
Mike,
I would still be suspicious of your rear main seal. You have to handle those things very delicately. You have to evenly and gently tap them into place and go no farther than flush with the case, maybe not even that far. Once in, you can not adjust it or re use it.
I don’t remember for surer, but double check that their is not supposed to be an o ring on the flywheel. I just don’t recall.
Also, when you pack on the RTV into the dowel pins make sure you give it plenty of time to dry before you add any oil!
Good luck! Happy Fourth of July!
Jake
Re: Leaking flywheel… AGAIN!
Posted: Thu Jul 02, 2015 10:56 pm
by mike.smith
SonexN76ET wrote:Mike,
I don’t remember for surer, but double check that their is not supposed to be an o ring on the flywheel. I just don’t recall.
The manual says specifically that the O-ring has been omitted from the construction. I don’t know why, but that’s how they tell us to build it. As for the rear seal, I replaced it with a new one, and it was flush with the case; no further. When I re-do the work tomorrow I plan to replace the seal once again. Luckily I ordered an extra last time!
Re: Leaking flywheel… AGAIN!
Posted: Fri Jul 03, 2015 1:00 am
by nwyooper
Red RTV is not the answer in my humble opinion. I used 1211 Sealant that I got from Amazon for about 25.00 for a 3.5 oz tube. My friend tried RTV 3 times and finally went tried my 1211 and it stopped his flywheel leak. Do need to make sure the drain hole is open
Re: Leaking flywheel… AGAIN!
Posted: Sat Jul 04, 2015 5:56 pm
by rizzz
Mike,
Check out this post on the legendary Bob Hoover VW blog:
http://bobhooversblog.blogspot.com.au/2 … -seal.html
It might explain some things.
Re: Leaking flywheel… AGAIN!
Posted: Sat Jul 04, 2015 8:23 pm
by mike.smith
rizzz wrote:Mike,
Check out this post on the legendary Bob Hoover VW blog:
http://bobhooversblog.blogspot.com.au/2 … -seal.html
It might explain some things.
Sounds like the AeroVee manual would benefit from some of these tidbits of wisdom!
I know my oil return hole is clear. I check that every time with a long pipe cleaner. As for installing the rear seal, pretty much everyone I know has done it with a rubber mallet or a mallet and a block of wood. I’ve removed 2 seals, and in both cases there was no damage, no nicks, no cuts and no sign of leaks coming from the seal. There was evidence of leaks coming from around the 8 pins that hold the flywheel. I’m letting the RTV set up for at least 36 hours (instructions say 24 hours) before trying the engine again.
By the way, for all us male type individuals, did you know there are “instructions” on the tube of RTV? And did you know that after applying RTV you are supposed to wait a full hour before tightening the parts and torquing them? This guy explains it pretty much like the instructions do:
https://www.youtube.com/watch?v=21CvanhKILA
I found the video made by the makers of RTV and Right Stuff to be pretty interesting, too, though if they say their Right Stuff is the best product to use, I’m not sure why they make all the other products:
https://www.youtube.com/watch?v=h_y9FTicNnM
Re: Leaking flywheel… AGAIN!
Posted: Sun Jul 05, 2015 6:34 am
by rizzz
mike.smith wrote:
rizzz wrote:Mike,
Check out this post on the legendary Bob Hoover VW blog:
http://bobhooversblog.blogspot.com.au/2 … -seal.html
It might explain some things.Sounds like the AeroVee manual would benefit from some of these tidbits of wisdom!
I know my oil return hole is clear. I check that every time with a long pipe cleaner. As for installing the rear seal, pretty much everyone I know has done it with a rubber mallet or a mallet and a block of wood. I’ve removed 2 seals, and in both cases there was no damage, no nicks, no cuts and no sign of leaks coming from the seal. There was evidence of leaks coming from around the 8 pins that hold the flywheel. I’m letting the RTV set up for at least 36 hours (instructions say 24 hours) before trying the engine again.
By the way, for all us male type individuals, did you know there are “instructions” on the tube of RTV? And did you know that after applying RTV you are supposed to wait a full hour before tightening the parts and torquing them? This guy explains it pretty much like the instructions do:
https://www.youtube.com/watch?v=21CvanhKILAI found the video made by the makers of RTV and Right Stuff to be pretty interesting, too, though if they say their Right Stuff is the best product to use, I’m not sure why they make all the other products:
https://www.youtube.com/watch?v=h_y9FTicNnM
Yeah…
As usual John Monnett and Bob Hoover don’t quite see eye to eye on this one.
Both are considered to experts by many and I’m certainly not one, so I can’t say whether one is overly perfectionist or the other is overly relaxed in their recommendations. Each of us mere mortals have to make our choice.
However if your problem persists and you’'re just not able to find what’s actually causing the problem in the first place, maybe try something different is all I’m saying. You can buy a seal installing tool on amazon for $10 if you would want to try Bob’s method next time.
That said, none of this matters if the seal installation is not the problem and the oil leak is around the dowel pins.
Re: Leaking flywheel… AGAIN!
Posted: Mon Jul 06, 2015 9:59 pm
by mike.smith
Since I started the thread, I’ll perhaps complete it. With all my practice I am now able to single handedly remove an AeroVee, rebuild the entire back side from the fly wheel out (while still hanging from the hoist), reinstall the engine, and wire tie everything back up in 6 hours flat. I feel like an Indy 500 pit crew!
Again I found the leak was coming from the 8 pins holding the flywheel to the hub. The rear seal was 100% intact, but I replaced it anyway. Couldn’t hurt, right? The previous sealant at the 8 pins and hub was nearly non-existent. As I had surmised, by tightening up the gland nut while the RTV was still fully wet, apparently that let it ooze out so that there was very little left to stop the oil. So this time I follwed the (red) RTV instructions to the letter, only putting on the gland nut finger tight, and then waiting for a full hour before tightening down the nut and torquing it. I then let the sealant set up for 36 hours before starting the engine.
I took the plane on a 2 hour flight and no leaks! If that changes I’ll be sure to let you know.
Re: Leaking flywheel… AGAIN!
Posted: Wed Jul 08, 2015 9:50 am
by Klimek
There is caution given about using RTV under the cylinders on the AeroVee and certified engines. Theoretically the ultra thin layer remaining can cause cylinder movement and later failure. Is there the same possibility of flywheel to crank movement and failure? Why is there no o-ring in the flywheel? How much red goo do I use?
I really disliked taking my engine back off. I was very proud of the way all the wiring was routed and secured. Just hope I haven’t gotten too old to do it again.
Frank
ONEX090
Re: Leaking flywheel… AGAIN!
Posted: Wed Jul 08, 2015 10:20 pm
by mike.smith
Klimek wrote:There is caution given about using RTV under the cylinders on the AeroVee and certified engines. Theoretically the ultra thin layer remaining can cause cylinder movement and later failure. Is there the same possibility of flywheel to crank movement and failure?
That’s what I have wondered. Plus, since you can’t measure for the rear shims with the sealant in place, you have to do it dry. Now you add the RTV and you’ve added thickness back there that is not taken up by the shims, so all the end play measurements are for naught. Sounds like a really bad deal. I think a good O-ring would be a much better solution than using the RTV.
Klimek wrote:How much red goo do I use?
Good question, with no good answer.
Re: Leaking flywheel… AGAIN!
Posted: Wed Jul 08, 2015 10:48 pm
by Gripdana
I was told that RTV on cylinders and case halves is a bad idea because any excess on the inside of the case will end up in the case and in the oil to potentially clog the oil passages.
Re: Leaking flywheel… AGAIN!
Posted: Thu Jul 09, 2015 12:44 am
by mike.smith
Right, but we’re talking here about the flywheel and hub, not cylinders and cases. Sonex does not call for RTV at cylinders or cases. They use Permatex.
Re: Leaking flywheel… AGAIN!
Posted: Thu Jul 09, 2015 1:00 am
by wlarson861
Klimek
You don’t need to take the entire engine off the mount. Leave the accessory plate (red anodized) attached to the motor mount and just remove the engine section. This leaves all the wires attached to the plane and gives access to the flywheel. The only wires that need to be removed are the spark plug wires.
Re: Leaking flywheel… AGAIN!
Posted: Thu Jul 09, 2015 8:25 am
by Sonex541
I have been using hondabond or yamabond instead of rtv for years i used it to re seal my cylinders and it has been great , its what they use on Honda , Yamaha’s motorcycles from the factory. , you can buy it online or any motorcycle dealer ,
Adam Simmons
Sonex
541sx
Re: Leaking flywheel… AGAIN!
Posted: Tue Jan 30, 2024 3:31 pm
by Bryan Cotton
Hey flywheel experts,
I’m about to pull the engine off the airplane. I’m in the middle of annual, and one thing I have to do is to re-shim the engine as it has sagged a little bit. While I have it off, I want to address the biggest oil leak in my collection, which seems to be coming from the back of the engine. I’m thinking it is the seal.
I’ve been reading the threads, looking at the manual, and watching some of Joe Norris’s Aerovee videos. It seems like my best bet would be to do this sequence:
- Unbolt the engine from the accessory plate and remove it, with the accessory plate still on the engine mount.
- Remove the trigger shaft for the secondary ignition
- Remove the exhaust so I can lay the engine on the bench
- Remove the flywheel
- Replace the seal
- Replace the flywheel, allowing time for RTV to cure before torquing the gland nut.
Does that sound right?
Thankfully, Northern Illinois weather in January SUCKS!
Re: Leaking flywheel… AGAIN!
Posted: Thu Feb 01, 2024 10:59 am
by pappas
I was never able to get my Aerovee to stop leaking completely. The back of the engine was always weeping to some degree. But, another possible remedy that might help to keep some oil inside is this.
I had a leak at the prop flange that would not go away. The oil slinger just wasn’t sufficient to keep the oil inside the engine. I also had a pretty good leak at the rear seal. I purchased the Anti-Splat oil separator and installed it with the drain kit plumbed to the exhaust per instructions. It creates a small vacuum inside the engine case, reducing the internal crankcase pressure and the front oil leak stopped completely and immediately. The rear engine seep was considerably reduced as well.
I also went through the process of installing several rear seals, using different sealers, waiting 24 -36 hours for it to set up before final tightening, etc, etc, etc. I am a pretty good mechanic but keeping the Aerovee dry was certainly frustrating for me. There must be a better way. I haven’t found it.
Re: Leaking flywheel… AGAIN!
Posted: Thu Feb 01, 2024 11:50 pm
by Bryan Cotton
We removed our flywheel and replaced the seal. Old seal:
Screenshot_20240201-213007-249.png (633 KiB) Viewed 2493 times
Check out our nifty new prop. Watch out Lonnie! Another competitor.
Screenshot_20240201-212947-234.png (584.2 KiB) Viewed 2493 times
Somewhere I saw a post from Randy down at Area 51 in Florida. He mentioned the poor surface finish of the flywheel part that rides on the seal. I polished it up with scotchbrite as best as I could. There was definitely a bevel in the corner of the old seal.
Screenshot_20240201-212930-671.png (625.45 KiB) Viewed 2493 times
Lou, I had tried adding a check valve to my air-oil separator. That worked poorly. Good to know the anti-splat system works better. I’ll see how this seal replacement goes.
Re: Leaking flywheel… AGAIN!
Posted: Fri Feb 02, 2024 12:02 am
by BRS
Interesting topic even though mine is a Revmaster. I too have the Anti-Splat exhaust vacuum kit (but not the separator). My engine seems to be dry in flight but after it sits a few hours something in the back leaks and there is like a tablespoon of oil on the floor in the morning. One day I’ll probably pull the engine to see what is going on. Don’t know if the R2300 is built like the Aerovee in that area since I’ve not seen either of them apart. Sure would like to figure it out. Annual starts next week but the leak is not pesky enough, yet, for me to deal with it.
Re: Leaking flywheel… AGAIN!
Posted: Fri Feb 02, 2024 12:04 am
by BRS
Bryan, you literally posted that while I was typing. Thanks for the pictures. Now if I could get a picture like that for the R2300.
Re: Leaking flywheel… AGAIN!
Posted: Fri Feb 02, 2024 9:40 am
by Bryan Cotton
BRS wrote:Bryan, you literally posted that while I was typing. Thanks for the pictures. Now if I could get a picture like that for the R2300.
Sonex has an Aerovee manual you can download. They also have a YouTube series on building the Aerovee starring Joe Norris. They are really well done.
Re: Leaking flywheel… AGAIN!
Posted: Fri Feb 02, 2024 6:22 pm
by BRS
Made my last post on the wrong thread. It was meant for this one, see…
viewtopic.php?f=9&p=57451#p57451
Re: Leaking flywheel… AGAIN!
Posted: Sat Feb 03, 2024 1:25 pm
by Bryan Cotton
I decided to take that hub polishing a little further. I am a polishing guy after all. I mounted it in the lathe:
flywheel in lathe.png (555.57 KiB) Viewed 2291 times
I ran it at 240 RPM and started with maroon scotch brite. Then I stepped through 1000, 2000, and 3000 grit sandpaper.
polished flywheel hub.png (540.61 KiB) Viewed 2291 times
I think that is a pretty seal friendly surface. The RTV as another 45 minutes to cure and then we will loctite & torque the gland nut.