Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Pioneer => Topic started by: Bob on June 03, 2014, 09:36:01 am

Title: p 41 flywheel
Post by: Bob on June 03, 2014, 09:36:01 am
Hi cannot get the flywheel off the saw tried a puller and tapping & prying with a hammer it will not budge. Leary of using air tools do not to damage the crank.
Any suggestions
Thank You
Title: Re: p 41 flywheel
Post by: Warped5 on June 03, 2014, 09:40:52 am
Hi Bob - I'd try some penetrating oil around the crank after installing a puller with light pressure.  Come back the next day and apply a little heat to the flywheel right around the crank and tap the end.  Be sure to use a spare nut on the crank end so you don't booger the crank threads.
Title: Re: p 41 flywheel
Post by: KilliansRedLeo on June 03, 2014, 09:42:30 am
+1 on the oil and heat!
Title: Re: p 41 flywheel
Post by: Bob on June 03, 2014, 09:50:26 am
Thank You
I soaked with pen oil last night and left the puller on I will try the heat today.
Thanks again
Title: Re: p 41 flywheel
Post by: fossil on June 03, 2014, 10:03:46 am
Those are well known to stick. I had a heck of a time with mine. I left the puller on under tension for about two weeks and it popped right off with a smack.
Title: Re: p 41 flywheel
Post by: KilliansRedLeo on June 03, 2014, 11:36:46 am
Don't remember how long it took me to get the last P-41 I did took me but I had to resort to some heat. I had the same sort of problem with a 3120XP ended up using 50/50 mix of ATF and acetone, puller and heat to get the bugger off!
Title: Re: p 41 flywheel
Post by: Bob on June 03, 2014, 09:47:47 pm
Thanks for the tips everyone, finally decided to use the air wrench on the puller and it popped off. However I may have put the rings on the piston up side down not paying attention does it matter if the notch in the rings were it rest against the pin is facing up or down?
 
The circlips have a 90 degree bend were the opening is it ok that it faces toward the cylinder wall?
Thank you
Title: Re: p 41 flywheel
Post by: KilliansRedLeo on June 04, 2014, 07:06:53 am
The rings MUST be aligned correctly with the locating pin! Most pistons have the locating pin toward the top of the ring groove. The ring must be put on such that the rounded cutout on either end of the ring is aligned with the locating pin.

Not getting what you are saying about the circlip however Nothing should protrude outside the piston toward the cylinder wall. There is a groove inside the piston pin boss where the circlip goes, position the opening in the clip at the 12 or 6 o'clock position.

Here is an article on how to do the clips, is for a motorcycle engine but the process is the same
 http://juicemotoparts.com/bearings  (http://juicemotoparts.com/bearings)
Title: Re: p 41 flywheel
Post by: Bob on June 04, 2014, 09:06:11 pm
Thank you, here are some images of the ring & circlip.
With regards to the ring the notch in the end by the opening of the ring that goes on the piston pin does it face towards the top of the piston or towards the bottom of the piston or does it matter?
The circlips with the prongs were it is open I assume the prongs face outward towards the cylinder wall?
Sorry for the confusion hope this helps.
Thanks

                                           
Title: Re: p 41 flywheel
Post by: KilliansRedLeo on June 05, 2014, 06:59:31 am
There is a very small pin in the ring groove of the piston this in the locating pin for the piston ring.
The locating pin is most often mounted close to the top of the groove but could also be at the bottom.
The little rounded notch in the end of the ring faces which ever side of the groove the locating pin is on.
When the ring is compressed into the groove the notch will wrap round the locating pin.

I don't think you are getting what I told you about the clips. If you look closely at your piston, where the piston pin goes. You will see a groove machined into the piston, this is where the clip goes. No part of the clip should be outside the body of the piston!

Look at the attached picture
Title: Re: p 41 flywheel
Post by: KilliansRedLeo on June 05, 2014, 12:42:22 pm
OK Bob, here you go!

The first two pictures are of the piston circlip installed in the piston correctly, the second picture clearly shows the groove in the piston pin boss where the circlip goes.
The third picture is the piston ring installed correctly

If you click on the pictures they will enlarge so that you can see them clearly.

KRL
Title: Re: p 41 flywheel
Post by: Bob on June 05, 2014, 07:21:10 pm
Thanks Killian
The pictures are great I have the rings on the piston and the saw reassembled but I don't remember if  the little notch on the ring that goes against the pin is facing up as in your picture or if I have it facing down, does it matter as long as the ring is in the groove and up against the pin?
The circlips are in the groove but unlike the ones in your picture, mine were the clip ends meet stick out at a 90 degree angle it is not protruding past the piston but is close were as yours curl up.The clips came with the piston I see no way of installing them with 90 degree prongs facing into the piston.
Thank you for all your help.
Title: Re: p 41 flywheel
Post by: 660magnum on June 05, 2014, 07:23:04 pm
Everything must be made to look like in the pictures.
Title: Re: p 41 flywheel
Post by: Bob on June 05, 2014, 07:53:55 pm
Thanks 660
I will have take the cylinder head off and recheck. Should have better paid attention the first time.
Thanks for all the help.
Title: Re: p 41 flywheel
Post by: 660magnum on June 05, 2014, 08:01:58 pm
I doubt the piston would have fit up in the cylinder unless you did it correctly?  But it is best to check.
Title: Re: p 41 flywheel
Post by: KilliansRedLeo on June 05, 2014, 08:49:36 pm
OK, Bob, now I understand! Those type of clips were used a long time ago on motorcycles (Ossa, Bultaco and Montessa) the little 90 bends on the ends were an attempt at 'locking' the clip in the groove. You basically grabbed the clip with bent nose pliers, compressed it very gently, inserted the bottom of the clip in the groove and then compressed it a tiny bit more so that the top of the clip could be pushed into the groove with a small punch. IIRC, the Spanish bikes used a very thin walled piston pin that would aid in this.

Your saw is from the time period when this method was common so, I can understand from where your frustration comes.

Tim