Crankcase sealant questions

[griffonks]

I am completely rebuilding my second Stihl TS400. I put this thread in chainsaw because it's almost like a chainsaw, but easier to rebuild, no brake and no oiler.

The first one I did went great, it runs well, but I am wondering if there might be a better sealant than the Dirko red that I have. I use the Dirko on Stihl clam shells.

The saws are old and bearings were trashed so I decided to seal the crankcase in addition to a new gasket. After extensive searching I looked into Motoseal, Yamabond, Hondabond, and Three Bond. The Yamabond and Three Bond have been replaced with new products because of hazardous potentials in the old brews. Someone posted that the new Yamabond 5 doesn't work- and now I'm wondering if the new Three Bond is in the same boat. So, I'm more confused that if I had just bought without researching.

My issue with the Dirko is that it sets up fast. I don't like to rush when I'm assembling the crankcase halves with new bearings and a new crankshaft.

Does anyone know which new sealants work well and setup slowly? I really don't want to waste a new Tecomec top-end because of a seal failure.

Thanks-

 

[jtracy1223]

bump. I would like to know as well. I split the case on an old poulan s25da last night. I have the paper gasket but the old gasket seemed to have some kind of sealer on it as well.

 

[Dan Forsh]

I can't speak with any experience on the Poulan, but the TS 400 is fine with just the dry gasket. If you want to use Dirko on it just smear a thin film onto the gasket itself and let it dry before installation. I think it's a silicone based sealant anyway so it will still work fine when cured.

On the Poulan, are you sure that it's not just that the old gasket has become oil soaked? Old paper gaskets do tend to look and feel a little rubbery because of this.

 

[Eccentric]

That Poulan would also be fine with a dry gasket. On either of them, do not omit the paper crankcase gasket. Use a thin skim of sealer on the gasket if you wish.

 

[rmh3481]

Loctite 515 or 518.

I use the 515, but I usually cut a brown paper gasket for the cases. You dont have to use the paper gasket if you dont want to. 515 cures a little slower than the 518 and I give them a day to set and then re-torque the bolts after the first run.

 

[rmh3481]

There is one other one in the family for High Temp environments. I cant remember what its number is. 515 is good to 300F. You can check them out here;
Loctite® Gasket Maker 515? - Henkel

 

[griffonks]

I can't speak with any experience on the Poulan, but the TS 400 is fine with just the dry gasket. If you want to use Dirko on it just smear a thin film onto the gasket itself and let it dry before installation. I think it's a silicone based sealant anyway so it will still work fine when cured.

On the Poulan, are you sure that it's not just that the old gasket has become oil soaked? Old paper gaskets do tend to look and feel a little rubbery because of this.

Thanks, you're probably right deeding only the gasket only. I decided to use the sealant as insurance, because the cut quick saws all overheated after the pto bearings started wobbling and the seals went out. I thought there might have been warping caused by heat. One of the pistons was destroyed by detonation. This was the first time I had ever seen it.

I had a marginal crankshaft, and decided to replace it too, it's important to just do it right and have reliable saws.

I need the saws for flood cleanup, cutting steel posts.

 

[griffonks]

There is one other one in the family for High Temp environments. I cant remember what its number is. 515 is good to 300F. You can check them out here;
Loctite® Gasket Maker 515? - Henkel

Thanks, I found the locktite 515 at a close autoparts store.

 

[Wrightington Saws]

I am completely rebuilding my second Stihl TS400. I put this thread in chainsaw because it's almost like a chainsaw, but easier to rebuild, no brake and no oiler.

The first one I did went great, it runs well, but I am wondering if there might be a better sealant than the Dirko red that I have. I use the Dirko on Stihl clam shells.

The saws are old and bearings were trashed so I decided to seal the crankcase in addition to a new gasket. After extensive searching I looked into Motoseal, Yamabond, Hondabond, and Three Bond. The Yamabond and Three Bond have been replaced with new products because of hazardous potentials in the old brews. Someone posted that the new Yamabond 5 doesn't work- and now I'm wondering if the new Three Bond is in the same boat. So, I'm more confused that if I had just bought without researching.

My issue with the Dirko is that it sets up fast. I don't like to rush when I'm assembling the crankcase halves with new bearings and a new crankshaft.

Does anyone know which new sealants work well and setup slowly? I really don't want to waste a new Tecomec top-end because of a seal failure.

Thanks-

 

[Wrightington Saws]

use Mylomar

 

[Huskybill]

I tested pro seal silicone on dirtbike cases. I fixed a tranny leak with pro seal on the case split line on the outside I had a drip leakage.

 

[grizz55chev]

You’re new here so I’ll give you a little hint, that thread is 6 yrs old. There are many posts that discuss this subject, at length. There are as many pinions on what to use as days in the month, do the research and pick what works for you.