Front crank Seal

[pa20]

Re: Crankcase seal leaking

Good advice but I can’t remember the last time I saw a good way to heat water in a hangar unless something like a camp stove or hot plate was brought from home. A microwave could be used to heat the water too but I don’t keep any of those things in the hangar. Or even my shop at the house for that matter.

I use an electric kettle to heat water for my coffee. That would work well in the hangar, and you can also make coffee for the time waiting for the seal to soften! You can thank me later!

 

[ysifly2]

Well, the revival of this thread with recent activity is timely... started my condition inspection and noticed front seal on mine is leaking. And as described, running down the case seam and dripping on the muffler. Guess I will be changing mine out too.


Bryan


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[Steve Pierce]

Got the tool back today, can send it up to you if you would like to use it Bryan.

 

[ysifly2]

Got the tool back today, can send it up to you if you would like to use it Bryan.

Thanks Steve... I would like to take you up on that

Bryan


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[Steve Pierce]

PM me the address you would like it sent to and I will get it in the mail to you.

 

[Glen Geller]

Correct crankshaft seal for O-320 (no dash)?

Hi floks,
Crankshaft seal questions: Is the O-320 (no dash) a small bore crankcase? It's difficult to measure the bore with the leaky seal still installed, best I can tell is ~3.30" measuring with a dial calipers.
Seal is still installed and has SL-76940 molded in, I think that's a split seal, correct?
IA wants me to order a solid stretch over seal.
I think that is LW-13792, is that correct?
Lycoming SI-1324C shows bore size for oversized bores but not factory original.
There was a two-piece retainer clamp over the seal, only four holes in the nose (not six as described in Lycoming parts manual.)
The seals listed in AC Spruce catalog/website are not very clear on correct part for this engine, so I hope you experts can help me out.

And what is the preferred method for removing the seal from the nose of the crankcase.
My IA knows how, but I like to look smart to him.
Thanks,
Glen in Oregon


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[Steve Pierce]

Re: Correct crankshaft seal for O-320 (no dash)?

Glen, Did you look up the part in the O-320 prts manual? I merged your thread with another on the subject. On page 3 of this thread Rex list a different seal than what you posted. Don't have my parts manual handy but will check.

 

[Steve Pierce]

Re: Correct crankshaft seal for O-320 (no dash)?

Here is the 6 bolt flange that calls for the 76940 seal. I think the L13792 is the one you want and most common.


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[Steve Pierce]

Re: Correct crankshaft seal for O-320 (no dash)?

I use the cotter pin puller or radiator hose tool to stick into the old seal and pry it out.


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[ysifly2]

if you are a subscriber or can find a hardcopy, it was timely for me that Kitplanes had a write up in the June 2018 issue that really supplemented the Lycoming SI1324C - Crankshaft Oil Seals really well...

http://www.kitplanes.com/issues/35_...e-Matters-Crank-seal-replacement_22111-1.html



Bryan

 

[Glen Geller]

Re: Correct crankshaft seal for O-320 (no dash)?

Here is the 6 bolt flange that calls for the 76940 seal. I think the L13792 is the one you want and most common.
View attachment 14058

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Thanks everyone for the replies. This is certainly a helpful group. And thanks Steve for merging the thread, great info.
My engine nose has four threaded holes and the split keeper shares the 12:00 & 6:00 bolts. Photo is after I removed the keepers but you can see the holes. I suspect this was an aftermarket kit but not sure. Wish I had asked the Lycoming rep I met at a fly-in this weekend.
Anyway, I did refer to the Lycoming parts catalog, it specified 76940 for cases with six holes, and mine has four but I think it means with the keeper.
I'll order the LW-13792.
But... This seal has a lip on the outer face.
Can I or should I reinstall the keeper over the new seal?

Thanks,
GG

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[Glen Geller]

Re: Correct crankshaft seal for O-320 (no dash)?

And I found the same Lycoming PN74034 Seal Retaining Kit that is installed on 14P, available on Ebay.
So I now see that this was a retrofit for older engines like mine. Kinda spendy...
https://www.ebay.com/p/Lycoming-74034-Crankshaft-Oil-Seal-Retaining-Plate-Tool-Kit/785941216

GG

 

[Pacerfgoe]

Re: Correct crankshaft seal for O-320 (no dash)?

Thanks everyone for the replies. This is certainly a helpful group. And thanks Steve for merging the thread, great info.
My engine nose has four threaded holes and the split keeper shares the 12:00 & 6:00 bolts. Photo is after I removed the keepers but you can see the holes. I suspect this was an aftermarket kit but not sure. Wish I had asked the Lycoming rep I met at a fly-in this weekend.
Anyway, I did refer to the Lycoming parts catalog, it specified 76940 for cases with six holes, and mine has four but I think it means with the keeper.
I'll order the LW-13792.
But... This seal has a lip on the outer face.
Can I or should I reinstall the keeper over the new seal?

Thanks,
GG View attachment 14060

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Glen I think someone modified your case to accept some sort of seal retainer. The pic you have looks just like my 320-no suffix, and I don't have any of the holes you have. Here is an exploded view of Steves pic of what the case should look like if it has a retainer plate for the seal. (notice the casting lugs for the bolt holes)

View attachment Lycoming case.pdf

 

[Glen Geller]

Re: Correct crankshaft seal for O-320 (no dash)?

"Glen I think someone modified your case to accept some sort of seal retainer. The pic you have looks just like my 320-no suffix, and I don't have any of the holes you have."
Thanks Forrest. The photo I posted is the nose with the retainer halves removed, showing the threaded holes.
It has a Lycoming 74034 Oil Seal Retaining Kit which was installed sometime after the aircraft was delivered in 1955, likely during an overhaul. The mechanic has to drill and tap the four holes and the two clamps share the top and bottom screws.

https://www.ebay.com/p/Lycoming-74034-Crankshaft-Oil-Seal-Retaining-Plate-Tool-Kit/785941216
You can buy this one for the paltry sum of $250 and install it on your engine!

And the fixture referenced in the instructions can be found here on page 20, ST-105:
https://www.lycoming.com/sites/default/files/SSP-384 2nd Edition.pdf

And damned if the same guy doesn't have that kit available too for $209!
https://www.ebay.com/p/Lycoming-740...ing-Plate-Tool-Kit/785941216?iid=142888543873

Hey Steve Pierce, have you ever seen this before?

Anyway, I think its completely legal and once again, One For Papa has a weird thing nobody has seen since Pug Piper was in knee pants.

Cheers,
GG

 

[ysifly2]

Mine has the seal retainer as well.


Bryan


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[Steve Pierce]

I have seen the retainer you pictured but did not realize it was a service kit installed in the field. Interesting.

 

[Pacerfgoe]

Yes Glen, that's pretty neat, I didn't realize there was a kit to do that, I thought it was only on the ones with the lugs in the case like Steve's picture.

 

[Glen Geller]

Kinda cool that we keep discovering new stuff about our ~60 year old aircraft and engines.

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[Joeman434]

Toss the split seal and put a solid one on it. If you have fresh 3M weather stripping, use it on the outer surface. Clean the inner seal bore with MEK or ?? first. Let the adhesive cure for a day.

 

[Glen Geller]

Toss the split seal and put a solid one on it. If you have fresh 3M weather stripping, use it on the outer surface. Clean the inner seal bore with MEK or ?? first. Let the adhesive cure for a day.

We did use a solid (non-split) seal, cleaned and used the Dow 737 as described in the Lycoming SI. Looks good, put a couple hours on it Tuesday and Thursday and no new evidence of leaks.
Thanks all for your advice.
GG

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[Will K]

We did use a solid (non-split) seal, cleaned and used the Dow 737 as described in the Lycoming SI. Looks good, put a couple hours on it Tuesday and Thursday and no new evidence of leaks.
Thanks all for your advice.
GG

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Glen,
I'm curious how your seal is holding up. I just replaced my crankshaft seal the other day and my engine also had the retainer installed. Upon further discussion with Lycoming builders, the retainer ring was used on cases that didn't have the groove cut to hold the seal in place. This means that the solid seal with an outer ridge is the incorrect part. However, you said yours was good after a few hours. I've heard installing the retainer ring with the solid seal will deform it and cause it to leak. Debating pulling the whole think on my O235 and reinstalling the split seal without the outer ridge but also thinking that using a washer between the case and retainer ring at each of the four bolts "could" work as well. But wanted to hear your long-term experience. I prefer the idea of a solid seal, but only if it'll work with my case.

 

[Glen Geller]

Glen,
I'm curious how your seal is holding up. I just replaced my crankshaft seal the other day and my engine also had the retainer installed. Upon further discussion with Lycoming builders, the retainer ring was used on cases that didn't have the groove cut to hold the seal in place. This means that the solid seal with an outer ridge is the incorrect part. However, you said yours was good after a few hours. I've heard installing the retainer ring with the solid seal will deform it and cause it to leak. Debating pulling the whole think on my O235 and reinstalling the split seal without the outer ridge but also thinking that using a washer between the case and retainer ring at each of the four bolts "could" work as well. But wanted to hear your long-term experience. I prefer the idea of a solid seal, but only if it'll work with my case.

Hi Will,
Funny you should mention that...
It's been six years and perhaps 250 hours since I replaced that seal and it is leaking again.
Took two three-hour trips last weekend and after each three hour leg there was an uncomfortable amount of oil on the windscreen, and the path was through the right hood hinge up by the nose bowl. I checked the dipstick before each leg and there was NOT a noticeable loss, but obviously the leak not going to heal itself over time, so I think it's time to repeat that pleasant exercise and replace the main seal again.
At least this thread has all the PN's and BKMs available so I don't have to do a bunch of research.

GG

 

[Will K]

GG, thanks for the reply! I did end up pulling the solid seal I installed as it was the incorrect part for my engine case. Installed the correct split seal and used pliobond at the recommendation from some Lycoming builders and crossing my fingers that I won't have to dig into it anytime soon. The good thing is its not a difficult job, especially with the split seal. But in the grand scheme of things if it takes 6 years for the seal to leak again I'm not going to be terribly upset about it. Now if it leaks in a month, I'll be slightly irritated.