Brand new Oil seal leak help

[Vintage Engine Repairs]

Permatex grey dissolves when fuel contacts it.
Threebond smells really good, which is great for huffing, but dries brittle.

Yamabond #4 will dern near stick to oil. Won't dissove in fuel, and stays semi-pliable when dry. Which is good for vibrating high RPM engines.
It's da bomb.

Great stuff, thanks! I’ll get some on order

 

[Justin Taylor]

Permatex grey dissolves when fuel contacts it.
Threebond smells really good, which is great for huffing, but dries brittle.

Yamabond #4 will dern near stick to oil. Won't dissove in fuel, and stays semi-pliable when dry. Which is good for vibrating high RPM engines.
It's da bomb.

Might have to change sealant but I’ve been using it for years and never had a problem

 

[trains]

been using threebond 1104 for years, never had it go brittle.
great for gearbox, engine, etc

 

[rogue60]

been using threebond 1104 for years, never had it go brittle.
great for gearbox, engine, etc

Same threebond for the win it's good stuff.

 

[Conquistador3]

It doesn't look like any Stihl seal I've seen before, with a seemingly molded in reinforcement ring.
View attachment 792997
It may not be all the way in against the case housing.
If I see that right, it looks like it doesn't clear the flywheel taper, maybe? It still shouldn't leak under pressure though, as that's the inner lips' job. Maybe that's a bodgy Chinesium seal aye?

No, wait. It's upside down. (down there in Austria).....

I know I will probably sound like an ignorant children in a room full of university professor but... why the engine sealant around the oil seals? It will make removing them a veritable pain when their time comes. If the workshop manual calls for any sealant why not use something like Loctite 638?
Just curious.

 

[rogue60]

I know I will probably sound like an ignorant children in a room full of university professor but... why the engine sealant around the oil seals? It will make removing them a veritable pain when their time comes. If the workshop manual calls for any sealant why not use something like Loctite 638?
Just curious.

It's a clamshell engine. In general anyone working on one pulls the engine out of the saw chassis then takes the bottom pan off. The crank and piston basically just fall out then.
From the factory they are done the same way with gasket sealant on all mating surfaces and around the seals to help stop any air leaks.

 

[alexcagle]

Green Loctite 638 is designed for applications such as retaining a bearing on a shaft, or a bearing pocket to prevent movement.

Dirko and Yamabond #4 sealants are for sealing two metal surfaces together, without gaskets, and is somewhat pliable, or gives a bit after it's cured. Engine parts that have constant heating and cooling cycles need a seal that can flex with the metal expansion and contraction without being brittle or loosing adhesion.

 

[Justin Taylor]

Green Loctite 638 is designed for applications such as retaining a bearing on a shaft, or a bearing pocket to prevent movement.

Dirko and Yamabond #4 sealants are for sealing two metal surfaces together, without gaskets, and is somewhat pliable, or gives a bit after it's cured. Engine parts that have constant heating and cooling cycles need a seal that can flex with the metal expansion and contraction without being brittle or loosing adhesion.

Are you saying that you shouldn’t use dirko and yamabond?

 

[Totembear]

Are you saying that you shouldn’t use dirko and yamabond?

 

[Conquistador3]

It's a clamshell engine. In general anyone working on one pulls the engine out of the saw chassis then takes the bottom pan off. The crank and piston basically just fall out then.
From the factory they are done the same way with gasket sealant on all mating surfaces and around the seals to help stop any air leaks.
View attachment 793615

Ah, yes clamshell. I have one and as much as I like it it will fly into the scrap metal heap without a second thought the moment it needs any engine work. Less hassle buying a new one.

 

[Vintage Engine Repairs]

Ah, yes clamshell. I have one and as much as I like it it will fly into the scrap metal heap without a second thought the moment it needs any engine work. Less hassle buying a new one.

And cheaper !

 

[TheTone]

I know I will probably sound like an ignorant children in a room full of university professor but... why the engine sealant around the oil seals? It will make removing them a veritable pain when their time comes. If the workshop manual calls for any sealant why not use something like Loctite 638?
Just curious.

Why sealant? I would say (1) because it fills a space that could possibly leak and (2) it acts as a lubricant, helping the seal go in easier. Dirko is not really a "tough" sealant and will allow pulling the seal without much trouble. I don't use Yamabond 4 on seals because I once had to re-do a clamshell I had sealed a few days prior. From the effort it took to get the bottom pan off, I learned two things : I will always use Yamabond 4 to seal clamshells, and I will never let Yamabond 4 anywhere near an oil seal.

 

[Applehead]

Wanted to add the Permatex ULTIMATE grey, not the silicone based ultra grey to acceptable sealants for crankcases. Been using on sleds and saws with no problems.

 

[mike-s]

Hylomar Blue.

 

[lone wolf]

Thanks for the suggestion mate just had a look but doesn’t say anything about it being able to come into contact with fuel? Been stung with this before with another sealant that’s all. Set time of 1 hour sounds absolutely wonderful though!!

Yes you can use Yamabond there.

 

[SteveSr]

Took it out with the engine together will fit another. Notice where it’s leaking, it’s from the bloody gap in the metal ring area. When I pushed the ring around, the air leak moved inline with it every time. anyway, going to tap a new one in and go from there.

what sealant gives you a longer working time than dirko? This stuf is a pain in the arse. It skins up so quickly it’s infuriating.

Use the other seal type next time... the one made for engine disassembly.

The key with Dirko is to use the winding key on the tube and a small hole in the nozzle and a vice or Workmate to hold the engine in place. Run one small (1/16") bead around and clamp it together. Flattening the bead will expose enough fresh Dirko to seal everything well.