crazyjay
ArboristSite Member
im just going to get a piston stop, i have a couple other saws that need work. to have the right stuff makles it easier.
my first top end rebuild on a 066 has some issues
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KTM640
ArboristSite Operative
Crazyjay, I thought I've seen some posts on people using the metal thread in type (spark plug hole) that only provides a point load on the piston that have cracked the piston. Therefore, may I recommend a decent 3/8 inch hank of rope or the hard rubber piston stop (sold by some of the sponsors) as your best option for this. I've used the rope and can say that I've never had any damage other than what was stated by the others in getting it pinched in the exhaust port. Just my 2 cents.
crazyjay
ArboristSite Member
where is the best place to get bearings from. around here
Dan_IN_MN
Addicted to ArboristSite
crazyjay
ArboristSite Member
got her apart, both bearings are shot, while taking it apart i noticed a crack in the case.
im thinking im just going to find a good used case and crank thats all together.
im thinking im just going to find a good used case and crank thats all together.
Regarding the use of a pull rope as a piston stop:
1. Double up a section of rope, so that NO frayed ends are inserted into the piston. This effectively prevents trapping the piston rings with loose strands.
2. Push LOTS of string into the cylinder. You don't want to stop the piston at the top of the stroke; ideally, you would prefer to stop the piston at half-stroke, or 90 degrees, so that the stress on the piston and bearings is reduced. Obviously, you won't get to 90 degrees without opening up the exhaust port, so just be real liberal with how much you stuff into the spark plug hole.
3. Don't use an impact on this system, you are likely to create a damaging condition that you won't detect in time to stop.
You want to use an impact? No problem. Just hold the flywheel with your hand (or some other non metallic binding method), and let 'er rip. Just be sure that you know what you are doing, because going the wrong way is probably going to screw up some really expensive parts. 3/8ths drive impact is pretty safe; a big 600 ft.lb. Ingersol-Rand 1/2" drive...well...you can be sure that the nut will either strip or come off, no matter which way you turn it.
1. Double up a section of rope, so that NO frayed ends are inserted into the piston. This effectively prevents trapping the piston rings with loose strands.
2. Push LOTS of string into the cylinder. You don't want to stop the piston at the top of the stroke; ideally, you would prefer to stop the piston at half-stroke, or 90 degrees, so that the stress on the piston and bearings is reduced. Obviously, you won't get to 90 degrees without opening up the exhaust port, so just be real liberal with how much you stuff into the spark plug hole.
3. Don't use an impact on this system, you are likely to create a damaging condition that you won't detect in time to stop.
You want to use an impact? No problem. Just hold the flywheel with your hand (or some other non metallic binding method), and let 'er rip. Just be sure that you know what you are doing, because going the wrong way is probably going to screw up some really expensive parts. 3/8ths drive impact is pretty safe; a big 600 ft.lb. Ingersol-Rand 1/2" drive...well...you can be sure that the nut will either strip or come off, no matter which way you turn it.
crazyjay
ArboristSite Member
its already stripped
Ooops. Did you strip it?
If you did, don't think of it as an unnecessary expense. Think of it as money well spent on education and training. That's what I do, every time one of my guys destroys some of my equipment.
It helps. A little bit.
If you did, don't think of it as an unnecessary expense. Think of it as money well spent on education and training. That's what I do, every time one of my guys destroys some of my equipment.
It helps. A little bit.
A crack in the case, if it is not too "structural" can be sealed up pretty well with JB weld.
I'm curious; did you make the crack, or did you find it? Cracked cases are kind of unusual, except for abuse by dropping, running over with trucks, etc.
I'm curious; did you make the crack, or did you find it? Cracked cases are kind of unusual, except for abuse by dropping, running over with trucks, etc.
crazyjay
ArboristSite Member
it was easy taking it apart, i have not yet cracked the case, still debaiting if i should find a good lower end, or get mine repaired and a new fly wheel side case. i have a 12 volt dewalt impact worked great for everything
crazyjay
ArboristSite Member
when i got the saw there was some jb weld in front of the saw. the guy told me the gasket went out and he didnt feel like repairing it. i chipped it off and it was pushed in a bit has a couple of cracks.
crazyjay
ArboristSite Member
one lesson learned already, make sure there is no oil in before splitting a case. i ended up just pulling the the cases apart. it wore a grove on the crank,(is it still usable) . ihave pics of the grove and what is left of the bearing. View attachment 224570View attachment 224571
KTM640
ArboristSite Operative
Jason, if you can repair the case that might be your best option... There have been some on here that have been lucky enough to mix and match case halves on Stihl's and all is good. I have tried a few and they were off just enough to bind the crank. It'll be a crap shoot. Also note that there are 2 different style of the 066/660 crankcase. There is a shorter version on earlier 066 and 064's and then a longer one that you might have since you have the poly FW. Make sure you bring the case with you when you order the gasket kit.
As for the crank, if the lower rod bearing is still good, clean it up and reuse it that is unless the FW nut is stripped and you have no way of rebuilding the threads..
Jon
As for the crank, if the lower rod bearing is still good, clean it up and reuse it that is unless the FW nut is stripped and you have no way of rebuilding the threads..
Jon
sefh3
Addicted to ArboristSite
Post a picture of the crack in the case. JB weld can fix that. If you decide to spilt your case, here is a picture of the builder I made. You need a 2 jaw puller to place on the end of the crank.
crazyjay
ArboristSite Member
the case isnt that bad, i can repair it . and for the case splitting. i used a punch put it on the center of the crank hit it with hammer and come right apart. the bearing was totally gone on the clutch side. cant believe it didnt ruin the new piston and cylinder.
