Metal piston stop or rope?

[glennschumann]

I've always used rope to hold the piston when removing clutches, but I was wondering if the collective wisdom here has a preference... a length of clothesline or a metal piston stop, or ???

 

[Jonny Quest]

I've used the rope method before, but I now use the piston stop. I got mine from Bailey's for fairly cheap. I have heard accounts of pieces of rope being sheared off and causing problems in the cylinder / crank case.

"...always use the right tool for the right job..." still applies here.

JQ

 

[Lakeside53]

The screw-in metal piston stop should only be used (with care) if your sparkplug hole is perpendicular to your piston (old saws).. Sometimes, often because they were put on too loose, clutches need way more leverage, ft-ibs, brutality etc that a piston can hold on a point contact, and it will break though the top...

Use 3/8 poly rope... just make sure the piston is traveling in the right direction (up) and is above the exhaust port. And, take it out and re-insert before putting the clutch back on (direction revereses, rope falls in).


I do maybe 10-20 a week... and use rope almost every time now. I don't use the Stihl "spoon" tool now and then but it's way too fiddly to get in exactly the right spot (squish zone) on some saws.


BTW... according to Stihl, the "right tool" on all saws exact the old types (08, 041, 075 etc) is the "spoon", and definitely not the screw-in piston stop.

 

[superfire]

piston stop

me i read on another posting about using an impacted gun. i take the spark plug and muffler off for safety. then i use and impact gun. impact guns are faster and less likely to make a plethera of cusing from spilling forth

 

[Urbicide]

I normally use an impact wrench so I don't need a stop. A synthetic plastic one comes with Bailey's piston ring compressor set. One also came in the tool set with my MS-200T.

 

[Lakeside53]

careful... Impact wrenches on some saws can shear the flywheel key or break the crank. The 200T is one... I seen several over the years, and watched a guy do exactly that 30 seconds after I asked him not to...

Most of the "cast" key slot type on weeaters and small blowers will shear off - done a few of those myself..

 

[Crofter]

+1 on getting the piston on the upstroke for the direction you will wrench and top above all the ports! Stuff in as much rope as you can; it will do a better job of equalizing pressure and not be exerting force on maybe just one side of the squish zone. Also the closer to top dead centre toggle over the greater the stresses on the piston and bearings. The further down the bore the better the crank angle advantage is in your favor.

 

[Philbert]

Impact gun is something I am not likely to have in the field, like when changing a Husky sprocket. I've used the screw-in metal piston stop and the Stihl plastic thing (is this the 'spoon'?). Expect to use the rope sometime.

Philbert

 

[Edge & Engine]

I use both (rope or metal piston stop). 75% of the time I use the metal piston stop. I have never damaged anything by using it...however, like anything else, you need to use caution and moderation in the force that you apply.

 

[NDtreehugger]

I use them both

There simple to make.

I use an old spark plug drill and tap insert a bolt peen it down to keep them together and allow for removal grind round and smooth

 

[woodheater]

The "safest" way to lock up any engine for clutch or flywheel removal and installation is to hydraulically lock the engine with some light oil. Rotate the engine in the direction that you need it locked in until the piston is almost TDC and the fill the cylinder with oil through the spark plug hole. Re-install the plug and you can SAFELY put whatever torque is necessary to remove or install either side without worries. I am not saying this is the cleanest method but I promise you will never damage a piston like this because the load is evenly distributed over the entire surface of the piston deck. I have done this for years on everything from RC car engines to snowmobile engines and it works like a charm every time without the "pucker feeling".

 

[shawn022]

definatley rope

First post but have been reading for awhile.
I used a metal stop one time and it left a nice ding in the top of the piston ( luckily it was scored anyway). The stop wasn't rounded over on the end ,it was flat and had a edge that dug into the piston. Now I only use rope and haven't had any problems.

 

[Bill G]

The "safest" way to lock up any engine for clutch or flywheel removal and installation is to hydraulically lock the engine with some light oil. Rotate the engine in the direction that you need it locked in until the piston is almost TDC and the fill the cylinder with oil through the spark plug hole. Re-install the plug and you can SAFELY put whatever torque is necessary to remove or install either side without worries. I am not saying this is the cleanest method but I promise you will never damage a piston like this because the load is evenly distributed over the entire surface of the piston deck. I have done this for years on everything from RC car engines to snowmobile engines and it works like a charm every time without the "pucker feeling".

That sounds interesting. I would think you would need to be extremely careful not to allow the piston to drop back down and lose oil into the ports. Also I assume you are using a heavy oil so getting it back out needs flushing.

Bill

 

[woodheater]

That sounds interesting. I would think you would need to be extremely careful not to allow the piston to drop back down and lose oil into the ports. Also I assume you are using a heavy oil so getting it back out needs flushing.

Bill

I like to use a light oil like Marvels Mystery Oil or air tool oil. If it gets down in the engine through the ports I just hold the saw upside down with the plug out and give a few pulls. Again if you get the piston very close to TDC it doesn't take very much oil to lock it up.

 

[Mike Van]

Use what you feel most comfortable with - I don't see how the rope method can do any damage, the metal stop like Lakeside said can do damage if the hole is on an angle. An impact wrench in the wrong hands...... crankshafts are $$$$$$$$. I've seen a few studs snapped off axle hubs, lotta torque there.

 

[Mike PA]

Both work, with caveats.

Piston stop can poke hole in piston, as the top of the piston is weak.

Rope works well, but care must be taken to keep it out of ports/ exhaust. Insert rope when piston is near top to avoid this happening.

Another option is a squish wrench (not sure if this is the proper name). It is a curved rod that is inserted into plug hole and placed near the side of the piston (piston strongest at sides).

 

[glennschumann]

Recently, this thread came up... see for pictures of what a metal piston stop did to a piston. I'm going rope from now on.

http://www.arboristsite.com/showthread.php?t=75896

Oh, but this is what rope did...

http://www.arboristsite.com/showthread.php?t=75926

Lets just be careful out there...

 

[blsnelling]

Recently, this thread came up... see for pictures of what a metal piston stop did to a piston. I'm going rope from now on.

http://www.arboristsite.com/showthread.php?t=75896

Oh, but this is what rope did...

http://www.arboristsite.com/showthread.php?t=75926

Lets just be careful out there...

That was a plastic piston stop. Metal would probably even be worse. I'll never use anything but rope from now on.

 

[lesorubcheek]

Oh, but this is what rope did...

http://www.arboristsite.com/showthread.php?t=75926

Lets just be careful out there...

That was on one of those cheap little stihl saws though . Rope is the way to go.

Dan

 

[oldsaw]

never used anything but rope.

Mark