Bubblehead

Bubblehead

Well Known Member
Tonight I will be installing a new front oil seal on my Lyc IO-360. I've read the service bulletin, walked through it a couple of times, cleaned the seal area and flange with Acetone, and have a new tube of Pliobond. The spring is removed from the seal, and a pot of water is on the camp stove ready for heating up to make the seal pliable.

My major concern has to do with the Pliobond. In reading technical literature on it, getting even coats on both surfaces is important to getting a good bond. Any tips and suggestions on how to get an even coat of Pliobond on the crankcase where the seal goes?

The literature also says there needs to be a path for the solvent to evaporate so the glue bonds properly. I do not see any reasonable path for the solvent to evaporate. Perhaps if I keep some mild heat on the area for a couple of days the solvent will evaporate sufficiently. It will probably be a couple of weeks before the engine is run so that will give extra time for the solvent too.

I'd appreciate any information on successful or unsuccessful installations, as well as any suggestions or on how to do a good job installing the seal. I don't want to have to do this a second time.

Thanks,

John
 
It looks harder than it actually is. You don't need to boil the seal. I've done it a half dozen times with 100% success. I just take some 1-1/2" masking tape and go around the crank with it, then oil it. I've used the special tool before, and don't like it because it scratches the flange. I just use a long prybar/screwdriver to pull it around and over the crank, and stick another phillips screwdriver in one of the lugs to pull the seal against. With the screwdriver there isn't any friction against the circumference of the flange, you just roll it around the flange with the screwdriver lengthwise. You can't get the pliobond inside the crank without making a mess, so just coat the seal once you get it on the crank and have given it some time to relax. Coat it 2-3 times with a minute or two between coats and you'll be good to go, it'll pop right in.
 
Bob - I have one question to make sure I understand things. Does the masking tape go on the crank or the flange?
 
oil seal

John,
I picked up a couple points from Bart at AeroSport on this subject.
Bart suggested shortening the spring about 1/8 inch to apply more pressure.
also there is a SB from Continental (good for Lycoming too)that pertains to sanding tiny scratches on the crankshaft flange in a angular pattern where the seal sets, to pull oil away from the seal as the crank spins.
Sorry I don't have the SB number available, but wanted to make you aware of it before you spend time replacing the seal.
also, if you use the split seal, do not apply contact cement to the ends as it actually creates a gap at the shaft the tiny thickness of the cement.
I used the one piece seal and heated it up in water and used the "tool" to slip it over the crankshaft flange.
I also applied glue to the crankcase area where the seal sits by using a small brush, hollow metal handle about half inch wide. I bent the metal handle 90 degrees and trimmed the bristles some to be able to get into the tight area.

There are lots of opinions on this subject for sure.
I installed three seals until I followed Barts lead and have been dry for 50 hours.
I hope somebody has the SB that speaks to this! Lots of good info.
Good Luck
 
Bob - You've used the Continental crankshaft "directional scratch" fix? Did it work for you? That's essentially a one-way mod to the crank surface - a last resort measure IMO. I've done it with unsuccessful results.

Protect the seal from the edges of the crank flange & threaded inserts with something (plastic, tape...).

Be sure to lube the ID of the new seal (I use STP). Don't contaminate the sealing surfaces with the lubricant.
 
worked for me

Low Pass said:
Bob - You've used the Continental crankshaft "directional scratch" fix? Did it work for you? That's essentially a one-way mod to the crank surface - a last resort measure IMO. I've done it with unsuccessful results.
Click to expand...

Well, it was my forth attempt and reached out for advice from Bart.
So far so good......don't know if it was the tightened spring or "directional scratch"........Bart recommended it......but maybe because I was having a problem.
Heck, it might start leaking tomorrow now that I was bragging on it :rolleyes:
 
My Aerosport 0-320 leaked at the split type seal from day one. Took it to an aircraft engine shop where they put in a new one piece seal. No improvement, so I took it back for a new seal and this time they shortened the spring by about 1/4". This worked 100%.

Fin
9A
 
Bob Martin said:
Well, it was my forth attempt and reached out for advice from Bart.
So far so good......don't know if it was the tightened spring or "directional scratch"........Bart recommended it......but maybe because I was having a problem.
Heck, it might start leaking tomorrow now that I was bragging on it :rolleyes:
Click to expand...
Excellent! Glad it worked for you. My 160-hp O-320-E2A has leaked for the last 1060+ hrs on 6 or so seals. I've never taken up on the spring though. I might just give it another go with that idea! Thanks Bob & Finley!
 
Low Pass said:
Bob - You've used the Continental crankshaft "directional scratch" fix? Did it work for you? That's essentially a one-way mod to the crank surface - a last resort measure IMO. I've done it with unsuccessful results.
Click to expand...

Not really, but I always clean up the crank with fine scotchbrite. They'll leak past the front seal if you have high crankcase pressure. You might want to try routing your breather outside the cowling. Tom Martin did some experiments a while back and measured the difference in crankcase pressures by rerouting the breather, and the results were pretty surprising. In a nutshell the best place for the end of the breather line is at least 4" or so aft of the cowl exit.
 
my $.02

1. Put a plastic sandwich bag over the crank flange.
2. Liberally coat the bag and with oil.
3. Stretch the seal over the flange using ROUND shaft screwdrivers. Verify proper seal orientation.
4. Remove the bag. Clean the seal. Allow it to shrink.
5. Install the seal spring.
6. Apply the Pliobond to the O.D. of the seal.
7. Slide the seal into the engine case.

Steve
 
<<You've used the Continental crankshaft "directional scratch" fix? Did it work for you?>>

I've probably done it to a half-dozen older Continentals (A-65's and the like, notorious leakers with split seals) and at least one Lyc. It's an old shaft seal trick with lots of applications outside the airplane world....and it works

I use fresh 600 grit glued to a flat stick about 1/4" wide. Very important to orient the scuff pattern correctly. Stand in front of the airplane's right seat and reach in from that side to work the top of the shaft. It doesn't take much, maybe two strokes, turn the shaft a little, two strokes...
 
Job is done

I tackled this today and everything went fine, just as everyone said. I appreciate all the tips and tricks and suggestions. It was not as bad as I thought it would be. The hot seal stretched fine, and getting it over the flange was pretty easy. I took the advice of one of the local guys and once the seal was over the flange, I connected the spring and then worked it into place on the seal. I also used Pliobond on both surfaces. Some people said to only apply on one but I followed the directions on the tube. I used an "acid brush" bent 90 degrees near the bristles to put the Pliobond on the crankcase.

I have a lot to do before I'll be able to fly and test the new seal. Four new cylinders to apply along with exhaust and intakes and prop, plus I'm installing an EIS-4000 and correcting some wiring that was not done as well as I would like. It may be Christmas or New Years before we're flying again but I think I will feel more confident with this plane then. The wiring is the part that concerns me the most but I will just take it one small step at a time.

I've learned a lot about RV-8's that other people built. If I ever go through this again I will take a much closer look at the wiring and I'll check for better engine records.

My thanks to everyone for their help. I have tackled a lot of things on this plane that I would not want to do if not for the help and guidance (and archives) here.
 
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