Saw Modders...take a look at this!!

[Lakeside53]

LOL!!!!!!! Extemely High!!!!!



In two Hours???? you would have to put me in a wheel barrow and roll me about!!!! LOL !!!!!! And dump me on the sand bar!!!! under a shade tree Please!!!!!! (eerrr, well at one time!!!!)

Last I checked you were like that after one Mirror Pond. God only knows what would happen if you were fed Canadian beer..

 

[RiverRat2]

Last I checked you were like that after one Mirror Pond. God only knows what would happen if you were fed Canadian beer..

LOL!!!! You should have seen me after 3 Black Butte Porters!!!!! in a row!!!! :hmm3grin2orange: :help:

Oh hey SI Logger,,,, Run it and let us know how it does!!!!!

 

[sILlogger]

LOL!!!! You should have seen me after 3 Black Butte Porters!!!!! in a row!!!! :hmm3grin2orange: :help:

Oh hey SI Logger,,,, Run it and let us know how it does!!!!!

that is the plan...i'm gonna take a marginal cylinder that i have..port and mill it along with the piston and run it like a raped ape and see how long till i blow it sky high!!

 

[PES+]

that is the plan...i'm gonna take a marginal cylinder that i have..port and mill it along with the piston and run it like a raped ape and see how long till i blow it sky high!!

Can you explain what you mean by "marginal cylinder"?

 

[sILlogger]

i had a wrist pin clip snap on me a little over a year ago at about 12 grand...and the saw ate it...did a number on the piston(junk) and cut a groove or two in the cylinder..thinking about using it..but i'll have to look i've got a handful of 066 cylinders

 

[PES+]

If you can catch a nail easily in the grroves don't run it.......it will be pointless

Run it in in a good cylinder and se how it performs....then you can install the scored cylinder and you can cut the piston at the exhaust and the intake skirt to take it up in RPM till it blows.

If the piston does come apart in a "good" cylinder they rarely cause much damage but be careful with too high an RPM as rod breakage while quite spectacular and impressive is usually fatal to most if not all of the parts of the saw

 

[sILlogger]

the gouges are on the intake side at the base of the port..so the rings will never come in contact with the groove

 

[PES+]

You do what you gotta do but ........Marginal?

It won't run more than about 10 minutes if that ......you need to knock down the high spots to even have a chance.

Slight grooves and plating erosion are marginal....

 

[sILlogger]

It won't run more than about 10 minutes if that ......you need to knock down the high spots to even have a chance.

Slight grooves and plating erosion are marginal....

i've already honed it...and it smoothed out..the grooves are still there..but there isn't anything sticking up that will catch on anything...I might not use this cylinder..i was just thinking that if it grenaded i wouldn't mind a bit...heck who knows...it may last a year and run like a scalded *ss dog

 

[joesawer]

Doing what you are and posting it is a great thing.
I wish that I knew how to draw arrows and circles on your pics in order to point out stress risers.
An extreme example would be too take a piece of wire and cut into it part way with a pair of side cutters, now bend the wire a few times and see where it breaks. All of the metal is still there but it has an extreme stress riser.
Notice how the pics of Dean's piston, all of the curves are very smooth. No sudden changes in angles, no scratches and grooves. Now think of the arches on a very heavily loaded bridge, if the arches have an iconsistant radius, or a deep score in the steel, that is where it will break first.
The "land" on the inside of the piston could be blended to the rest of the piston imo, in order to get rid of some more metal.
Imo the post between the crown and wrist pin is smaller and the raduis is smaller than I would have left.
This makes me want to get started on an old flat top 066 that I picked up a while ago. Thinking of trying to build a pipe saw out of it. It will be my first effort at an expansion chamber saw.

 

[Lakeside53]

If you're really sure you knocked off the high spots, that cylinder will likely run o.k.. Amazing how little damage it received considering the piston!

 

[PES+]

It was not a clip that did that damage

It ate something substantially larger than a pin clip.....looks like a carb screw of some kind

Once you oversize the bore at the bottom of the cylinder the piston will rock and the intake skirt will take the flex stress only so long before breaking

I can't wait till you run it so you can blame the cheap piston for the breakage

The fact is with the work your have done and the oversized bore it would come apart no matter who made the piston.

BTW just making the piston lighter will not raise your RPM appreciably but I guess you already knew that

 

[sILlogger]

If you're really sure you knocked off the high spots, that cylinder will likely run o.k.. Amazing how little damage it received considering the piston!

yea..it was one of those deals that I had it wound up cutting off a big limb knot and it just shut off...(i knew that wasnt' good) did the 1/2 mile trek to the truck and i pulled the muffler and seen the damage(metal in the muffler..i knew it was fubared then!) got on the phone and ordered me up my new 660 and picked it up the next day.

It ate something substantially larger than a pin clip.....looks like a carb screw of some kind

well....seeing as i pulled the saw apart and a piece of the broken wrist pin clip was still in the groove that it was riding in kinda told me that it has broken. and the saw was thoroughly inspected and i've rebuilt the carb since then...and rebuilt the saw and ran it a couple hundred hours.

so i would say that between the obvious broken wrist pin clip and no other missing parts that the wrist pin clip caused the damage

Once you oversize the bore at the bottom of the cylinder the piston will rock and the intake skirt will take the flex stress only so long before breaking

I can't wait till you run it so you can blame the cheap piston for the breakage

The fact is with the work your have done and the oversized bore it would come apart no matter who made the piston.

BTW just making the piston lighter will not raise your RPM appreciably but I guess you already knew that

you are missing the intire point behind this whole post...This isn't about trying to blame somebody if the piston fails...this is about me trying to learn something and getting info from knowledgeable people about it on a public forum so that others can learn from it(i'm playing guinea pig here)

and as for the piston..It is from Baileys..they are a great company and i've got an 046BB kit from them that prolly has close to 1000 hours on it and i couldn't be happier with them..i stand behind there products and did several thousand $$ worth of business with them last year. so that being said i think quite highly of their products

as for oversizing the bore..i honed the entire cylinder. yes..it prolly increased the bore several thousands of an inch. and will now allow for an increase in piston movement within the cylinder. but i doubt it is gonna be hammering around in there

i lightned this piston for several reasons...to lower the weight of the reciprocating mass=less stress on bearing, and a faster spool up for the saw (not going for a net increase in rpms, just want it to get the quicker)...and to increase the flow through the piston to help performance...

The entire point of this thread is for me and anybody else that wants to learn from those that know what they are doing and build saws everyday...

 

[PES+]

I understand what you are doing...but comments from the peanut gallery persuaded me to point out the problems you will encounter....

Make sure that there are no spots around the gouges that stick further in than the adjacent wall and all you will have then is a loss of case charge through leaking back out the intake....not that big a deal really but the filter will get soaked pretty quickly and it will be a little ticklish to hold a tune

 

[Bowtie]

That 3000 I acquired has a score that reminds me of pics of your cylinder, but piston is fine, wierd. Anyway it runs great and idles just fine. You may not have any problems. Those who never try never fail, and never learn.

 

[timberwolf]

I doubt you have increased the bore several thou, the plating is only a couple thou thick, buy the looks of the pic, honestly it does not look like the honeing was anything more than rubbing it with some sand paper wrapped on a soda biscuit.

However if you have honed out the cylinder any amount, it sets up a real problem, in that the looser the piston to bore fit, the more the piston slaps around and the higher the forces will be on those shaved down webs of your modified piston skirt.

The learning is all good though, but just if you work with junk, don't expect anything but junk results. I'm sure someone will chime in here to knock me saying that and tell of saws that were put together from junk parts and ran amazing, but what races have been won with junk heap saws?

 

[PES+]

Stop making sense......

I doubt you have increased the bore several thou, the plating is only a couple thou thick, buy the looks of the pic, honestly it does not look like the honeing was anything more than rubbing it with some sand paper wrapped on a soda biscuit.

However if you have honed out the cylinder any amount, it sets up a real problem, in that the looser the piston to bore fit, the more the piston slaps around and the higher the forces will be on those shaved down webs of your modified piston skirt.

The learning is all good though, but just if you work with junk, don't expect anything but junk results. I'm sure someone will chime in here to knock me saying that and tell of saws that were put together from junk parts and ran amazing, but what races have been won with junk heap saws?

This is AS chainsaw forum...........

I already said precisely that

 

[ciscoguy01]

Question

Yeaaaaaa, ummmmmmmm... What exactly is the purpose of that??? Is it just the weight of it that makes the difference??? I really know nothing of modding except about mufflers... I'm pretty interested actually. Looks super nice, but that doesn't mean anything I guess...

opcorn:

 

[sILlogger]

I doubt you have increased the bore several thou, the plating is only a couple thou thick, buy the looks of the pic, honestly it does not look like the honeing was anything more than rubbing it with some sand paper wrapped on a soda biscuit.

However if you have honed out the cylinder any amount, it sets up a real problem, in that the looser the piston to bore fit, the more the piston slaps around and the higher the forces will be on those shaved down webs of your modified piston skirt.

The learning is all good though, but just if you work with junk, don't expect anything but junk results. I'm sure someone will chime in here to knock me saying that and tell of saws that were put together from junk parts and ran amazing, but what races have been won with junk heap saws?

too be honest i'm not sure if that pic was before or after i had honed it...(it was almost a year ago) but i know ive honed it since.

i completely understand what you are saying with the honing the cylinder and the the piston being loose..it will wobble more and increase the pressure put on the skirt supports..understandable...

as for working with junk...its not that im trying to patch this saw together with junk to get it back going..i have every intention of putting a good p&C on it....but with THIS piston that i have lightened..i wanted to see how long it would last before it grenaded..and if i could do it in a cylinder that already had problems than it wouldn't bother me as bad when it grenaded than when i trashed one of my good used cylinders...know what i mean? just want to see if i went to far and how long it lasts...so both myself and everybody else will know

I really do thank you for your replies

 

[klickitatsacket]

Yeaaaaaa, ummmmmmmm... What exactly is the purpose of that??? Is it just the weight of it that makes the difference??? I really know nothing of modding except about mufflers... I'm pretty interested actually. Looks super nice, but that doesn't mean anything I guess...

opcorn:

Lightening the piston will give you a little more performance, most of which is in acceleration and a little more RPM. However the biggest bennifit gained by lightening a piston is in the reduction in the abuse of your bearings. ANY weight that can be pulled out of the reciprocating mass will pay back in big ways for your bearings and crank. This is especially true for an engine that has been modified and is running even higher RPM.