best way to pull a clutch ???

[scottr]

Impact Wrench

The mechanical shock and ringing that impact wrenches create are high , why risk the damage to the electronic ignition module ? Scott

 

[jokers]

Stumper,

I just noticed the MLK quote in your signature. How true!

Russ

 

[jokers]

The mechanical shock and ringing that impact wrenches create are high , why risk the damage to the electronic ignition module ? Scott

I dunno Scott? Can`t say as I`ve ever had an ignition failure tied to a clutch removal. Have you seen evidence of this? This is a sincere question.

Turning the pressure to the wrench down lowers the BPMs as well as the ultimate torque, every technique of disassembly has some measure of wear associated.

Russ

 

[scottr]

Failures

I have only replaced one clutch drum and I used the cotton rope and 3/8" breaker bar method . Experience with mechanical shock and vibration of electronic components shows me that it can and does cause failures and stress . If it is not necessary why do it ? How much longer does it take to use a breaker bar on a clutch ? Scott

 

[jokers]

Hi Scott,

I`m not saying that there is no effect on any component of the saw from the vibrations or that because the ignitions are made to work in a harsh environment, the impact is not damaging. Simply that I am not aware of any pattern. If you could be a fly on the wall in most shops you would see the technicians using impact wrenches for clutch removal.

Given the huge number of electronic ignitions in service on chainsaws with the extremely low failure rate, I don`t see any correlation between ignition failure and clutch removal using an impact wrench.

To borrow a statement from your previous reply, "If it is not necessary why do it?", I could hold the same view regarding the application of the breaker bar to the end of the crankshaft.

Whether you use rope or a solid locking device, at some point the piston truly becomes locked. The rope will compress enough to become solid as opposed to the alternating pressure of the impact wrench. Reducing the pressure of the wrench which in turn lengthens the pressure/no pressure cycle, or alternately shortens the pressure application period, allows some rebounding of the rope and crank assembly which then requires more energy to overcome it`s inertia counter to the direction of applied force from the wrench, atleast by my spud farmer logic, which ultimately puts less angular momentum on the crank and it`s associated components.

Whew, I`m out of breath and feeling dizzy......

Get my point? LOL!

Russ

 

[rupedoggy]

No offense Scottr but you have taken off one, and now you are giving advise. It does seem to be a human trait that we want others to do as we do. When a new member addresses the forum with a "what kind of saw should I get?" question, I notice several will encourage him to get the kind they have, even though it is the only saw they have ever owned. I have removed hundreds of clutches and used an impact each time. I don't turn it down and I don't put anything in the cylinder. Inertia and compression does the trick. I have broken no cranks nor experienced any ignition failures. If vibration caused ignitions to fail they wouldn't last an hour on a running saw. I hate to agree with Cahoon on this but I do. Mike

 

[Molecule]

impact wrench & flywheel keys ... ?

for the generic case of 60cc (say X.mm bore by 35.mm stroke with 55.mm rod), stopping the piston at around 1/2" either side of TDC should roughly place the rod and crank offset at about a 90 degree angle, which would seemingly minimize stress to the two bearings

I like the rope stopper with impact wrench, per jokers explanation ... the sponginess of the rope would shift most of the impact into the two largest inertials in the system, the flywheel and crankshaft. It works ... if the flywheel is on tight, and the flywheel key and the two slots it sits in don't get nicked by the intertia of the flywheel. (And that might be a big if on some of the new one ... I don't know.) If it is, then an impact wrench on low setting gives the lower bearing the best protection possible, and the upper bearing and wrist pin are additionally protected by the inertials of the rod.

So, jokers you want to cook this board up a little ...

For Stumper, love that MLKJr quote ... he is unstoppably becoming the man for the 21st Century, no doubt about it. Being as astronomy is one of my favorite topics, may I add, as a student of MLKJr, that God is still writing his gospel in our hearts and in our minds, that we might know the whole of mankind as his creation, that we might then never trade down the immortality of his most precious gift, our compassion, our intellect, and our power of choice. From the mountain top to ... might it be that the immortality of the human soul, is His only son, and His highest creation? It remains only that we help the blind to see. ... Thanks Stumper ... no tellin how quotes from MLKJr seem to bring me right up

 

[jokers]

Inertia and compression does the trick. Mike

Whew! You jump right in with both feet Mike! I wasn`t even going to suggest this because I thought too many guys would disagree, lol.

Russ

 

[Fish]

Which one is Cahoon?

I personally use an impact, but for the original poster I would recommend the rope
method. I have done plenty and never had any trouble.

 

[jokers]

So, jokers you want to cook this board up a little ...

Lively discussion has to be good for the forum, wouldn`t you say?

BTW, I don`t believe that I have previously welcomed You to the forum. Welcome aboard Molecule! What part of Virginia are you in? My brother is in Lynchburg and my sister lives in Arlington.

Russ

 

[jokers]

Hi Mike,

Slightly off topic and hugely controversial no doubt, but I know first hand that when MLK was travelling to speak, he had advance men who would first go to an area and get his fan base riled up, often leading to riots but also much notoriety.

None the less, the guy did have some profound thoughts and if we take them at face value rather than imparting ANY bias, we might become more Godly human beings. A modern reference might be taken from John Travolta`s statement in the movie Micheal, when questioned about his less than stereotypically angelic behavior. He stated something to the effect that "I`m not that kind of angel" suggesting that relevant messages and deeds come in many different vessels.

I believe that MLK Jr had a CHAINSAW.

Russ

 

[scottr]

best way to pull a clutch

Enviromental testing of electronic components is done at ambient , cold ,and hot temperatures . Vibration alone will not create the same failures that shock followed by vibration will cause . Sometimes shock then vibration will only show a failure at hot or cold and not ambient . I think the breaker bar on a clutch tool to turn the clutch is the least destructive method . This might not be the 'best way to pull a clutch' . Mike your experience with clutch removals is probably similar to my experience with electronic enviromental testing . Russ , I agree that the angular momentum of the crank is a dizzy subject . Scott

 

[glens]

To bad its not a Mac because they have a hole in the flywheel and a hole in the flywheel cover so you can lock it with a screwdriver But I gues that was old school now they want you to buy a tool or take it to your dealer

Those cranks were one-piece, right?  Don't you think that with the built-up cranks you'd run a real risk of twisting them out of alignment working one end against the other like that?  I'd suspect that likelihood whether physically stopping the flywheel or not stopping the piston and using an impact.  If you're going to stop the piston anyway (and you should), why use the impact?

Breaker bars (or cheated "regular" tools) should be used to produce gently-shaped rhythmic swells in torque, not mammoth amounts of steady torque.

Glen

 

[Fish]

Do not use a piston stop with the impact wrench.

AHEM!

 

[WRW]

I've got a couple questions.
If it takes 60 ft/lbs to free a nut and you use a 200 ft/lb rated impact wrench, do you really think that all 200 ft/lbs are imparted to the nut?
Isn't the ignition isolated from the clutch somewhat?
Did Fish really just say "AHEM"?

 

[glens]

He'd meant <i>AMEN</i> (he's religious).

Fish, what's the problem, are you afraid of making a convertible cylinder?

 

[jokers]

I've got a couple questions.......Did Fish really just say "AHEM"?

Ahhh, no, I said it for him.

Sorry Glen, I know that you don`t like that style of hack pruning but it seemed like the best action to take at the time.

Russ

 

[MacDaddy]

Just think a saw that produces maybe 10ftlbs of torque the cranksaft is rated to hold up to that with the piston creating the power So now put a stop on the piston and apply 60ftlbs or more to take the clutch off that cracksaft that is rated for 10ftlbs (something will be over stressed)Also most fatigue failers are due to harmonic vibrations that work harden the metal and then it gets brittle and cracks I have a friend that is a metalologist and he can tell you all about how this happens Does anybody know Rick Shell Team Yamaha motor builder for about 20 years If he builds a crank for you it comes with a pair of cotton gloves because the oil on your skin can cause a rod failure because it causes the metal to harden its self when it gets hot and then it get brittle I know some AS members know him and can back this up

 

[LJS]

Rupedoggy, removing old rusty clutches off those many clubs of yours should of made you an expert at this task. Glad you could agree with another expert. Now you just have to learn how to fell a tree! HaHaHa! LJS

 

[spacemule]

I have only replaced one clutch drum and I used the cotton rope and 3/8" breaker bar method . Experience with mechanical shock and vibration of electronic components shows me that it can and does cause failures and stress . If it is not necessary why do it ? How much longer does it take to use a breaker bar on a clutch ? Scott

Yes, but won't the mechanical shock from an impact be comparable to the mechanical shock and vibrations from a running engine? Try grabbing ahold of the engine part that is not isolated by dampers sometime on an idling engine.