Crank seals

[mike031]

Hey guys I was thinking of ideas to test cranks seal. If I made a metal plate with a rubber gasket that could bolt to the block where the cylinder is bolted onto and applied a vacuum pump to a brass nipple that would be threaded into the plat.

how much vacuum in inches? any ideas

 

[thompson1600]

I believe it would depend on the saw. Most of the Stihl stuff I work on uses .4 to .6 BAR, which would be 5.8 to 8.7 PSI (I believe).

Tom

 

[TonyM]

One way is to simply buy some gasket material, and make a gasket for the carb and muffler without a hole in the center. Then take an old spark plug, and break out the porcelan, leaving just the metal nut. Then you can braze or weld a nipple or pipe fitting to the plug. I've had difficulty getting the muffler to seal well with this method sometimes, so buy some thicker rubber gasket material with a lot of give to it.

 

[Molecule]

In their plumbing dept, Home Depot has 4"x4" rubber seals, for seating toilet bowls. They're dark red in color, about 1/16" thick, and cut and drill easily --- that might work.

But, do you test the crankshaft seals under vacuum or under pressure ? In other threads, I've seen the idea of coating the outsides of the seals with gas fitter's soap, or just detergent, and look for bubbles on the compression downstroke ?

Also, being as another of us has his lower end opened up, once it looks like the crank seals are OK, then is there a good way to clean the inside of the crankcase ? will gas mixed with a little extra oil hurt the seals-? or bearings-? I was concerned that might also strip the grease packing-? in the bearings. What about kerosene and oil-?

 

[glens]

But, do you test the crankshaft seals under vacuum or under pressure ?

Yes, both.  The crankcase encounters both situations every time the crank cycles.

 

[sperho]

Also, being as another of us has his lower end opened up, once it looks like the crank seals are OK, then is there a good way to clean the inside of the crankcase ? will gas mixed with a little extra oil hurt the seals-? or bearings-? I was concerned that might also strip the grease packing-? in the bearings. What about kerosene and oil-?

Apologies for the blast from the past, but I just wanted to show that the search engine works, only to not answer my question...

Anyone care to chime in here to make this thread whole? :biggrinbounce2:

 

[Lakeside53]

What's to be said?


Maybe try your newly aquired search powers to find the one that answers your needs :help:

 

[Goat]

http://www.arboristsite.com/showthread.php?p=706097#post706097

Run through this thread, it's covered w/ pictures.