Installing new front seal on Lyc

Bubblehead · #1 11-26-2008, 07:02 AM

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

rocketbob · #2 11-26-2008, 07:25 AM

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.

Bubblehead · #3 11-26-2008, 10:32 AM

Bob - I have one question to make sure I understand things. Does the masking tape go on the crank or the flange?

Bob Martin · #4 11-26-2008, 11:44 AM

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

Low Pass · #5 11-26-2008, 12:19 PM

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.

Bob Martin · #6 11-26-2008, 12:37 PM

Quote:

Originally Posted by Low Pass

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.

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

Finley Atherton · #7 11-26-2008, 12:52 PM

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

Low Pass · #8 11-26-2008, 01:02 PM

Quote:

Originally Posted by Bob Martin

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

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!

rocketbob · #9 11-26-2008, 03:45 PM

Quote:

Originally Posted by Bubblehead

Bob - I have one question to make sure I understand things. Does the masking tape go on the crank or the flange?

Around the flange.

rocketbob · #10 11-26-2008, 03:54 PM

Quote:

Originally Posted by Low Pass

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.

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.