Nik's Poulan Thread

[Acornhill]

An ebay seller has 6 of them:Poulan 4200 Chainsaw Piston New STBX242 | eBay

yes, that is Bryce, you can't beat that knowing he has it in stock and you can have it in 5 days.

 

[redunshee]

Poulan 3700

Have I moved to Quebec? Seems part of this page is in French. Oh well. Picked up a 3700 advertised at 150 psi. Well, turns out my reading shows 120. Other than that saw is in good shape. Handle needs a little welding and that fix is in process. Decided to get some new rings but I had some old rings better than what was on the piston. Came up with a ring gap of .070. The ring pin measures approx. .053 resulting in an effective gap of .017". Seem reasonable for old rings? What is acceptable/desired? Wonder if new rings will lower that number. Far as I can tell squish is at least .032( largest solder I have). Plan to lower the squish but wonder if I get it to .018 -.020, if it will affect the port timing. Don't know much about porting but from what I've read there are issues associated with grinding the upper or lower sections of the ports. Seems that reducing the squish is effectively doing the same thing.

Bob

 

[Acornhill]

helicoil a spark plug chainsaw cylinder?

Can you helicoil a spark plug chainsaw cylinder? and be confident that it is not going to blow out?

 

[redunshee]

Can you helicoil a spark plug chainsaw cylinder? and be confident that it is not going to blow out?

I did on my 3800. I didn't use a helicoil but a Sav-a -thread by Helicoil. Has been holding fine. Only issue I had was removing the insertion tool w/o have the threaded insert coming out. There are severa lYouTube videos re the process.
Bob

 

[Wagnerwerks]

Bob, which half of your handle needs welding?

 

[a. palmer jr.]

I did on my 3800. I didn't use a helicoil but a Sav-a -thread by Helicoil. Has been holding fine. Only issue I had was removing the insertion tool w/o have the threaded insert coming out. There are severa lYouTube videos re the process.
Bob

When I put an insert in my VW aluminum head they recommended using red Loc Tite to hold it in. Probably have to let it sit for a while before removing the tool.

 

[Acornhill]

I did on my 3800. I didn't use a helicoil but a Sav-a -thread by Helicoil. Has been holding fine. Only issue I had was removing the insertion tool w/o have the threaded insert coming out. There are severa lYouTube videos re the process.
Bob

Bob, do you have a part# for the save a thread?

 

[a. palmer jr.]

Have I moved to Quebec? Seems part of this page is in French. Oh well. Picked up a 3700 advertised at 150 psi. Well, turns out my reading shows 120. Other than that saw is in good shape. Handle needs a little welding and that fix is in process. Decided to get some new rings but I had some old rings better than what was on the piston. Came up with a ring gap of .070. The ring pin measures approx. .053 resulting in an effective gap of .017". Seem reasonable for old rings? What is acceptable/desired? Wonder if new rings will lower that number. Far as I can tell squish is at least .032( largest solder I have). Plan to lower the squish but wonder if I get it to .018 -.020, if it will affect the port timing. Don't know much about porting but from what I've read there are issues associated with grinding the upper or lower sections of the ports. Seems that reducing the squish is effectively doing the same thing.

Bob

I just read an article on how to determine MINIMUM ring gap. The formula they give is: cylinder bore (measured in inches)X.005. I suppose you could just guess on how much over that is not acceptable. Using that formula for a 3" bore you should have a minimum ring end gap of 15 thousandths. It is slightly more for nitrous or blown engines: boreX.0055
I read another article that says to have .004-.005" for each inch of piston bore which would be 12-15 thousandths and a little excess gap doesn't affect performance much if at all. There is also the matter of ring tension, a worn out ring doesn't compress against cylinder walls as much as new ones, you can use ring end gap sometimes to check for worn rings and assume they were installed with proper end gaps to begin with..

 

[cowroy]

Have I moved to Quebec?
Bob

Log out of arboristsite and then log back in, and your language should be all back to English.

 

[leecopland]

language choice

I just read an article on how to determine MINIMUM ring gap. The formula they give is: cylinder bore (measured in inches)X.005. I suppose you could just guess on how much over that is not acceptable. Using that formula for a 3" bore you should have a minimum ring end gap of 15 thousandths. It is slightly more for nitrous or blown engines: boreX.0055
I read another article that says to have .004-.005" for each inch of piston bore which would be 12-15 thousandths and a little excess gap doesn't affect performance much if at all. There is also the matter of ring tension, a worn out ring doesn't compress against cylinder walls as much as new ones, you can use ring end gap sometimes to check for worn rings and assume they were installed with proper end gaps to begin with..

If you go to settings at the top of your page, you will find a language box bottom right hand side of the settings page. Choose the one you prefer.

Regards,

Leeuttahere2:

 

[OhioGregg]

Don't matter to me what language its in...I just look at the pictures anyway.


Gregg,

 

[67 Mustang]

Don't matter to me what language its in...I just look at the pictures anyway.


Gregg,

Lose your glasses again, geezer? :msp_tongue:

 

[OhioGregg]

Lose your glasses again, geezer? :msp_tongue:

LOL, No Steve, But when they say the mind is the first thing to go..they ain't kidding. Especially when ya start off with a short supply to begin with.


Gregg,

 

[3000 FPS]

Have I moved to Quebec? Seems part of this page is in French. Oh well. Picked up a 3700 advertised at 150 psi. Well, turns out my reading shows 120. Other than that saw is in good shape. Handle needs a little welding and that fix is in process. Decided to get some new rings but I had some old rings better than what was on the piston. Came up with a ring gap of .070. The ring pin measures approx. .053 resulting in an effective gap of .017". Seem reasonable for old rings? What is acceptable/desired? Wonder if new rings will lower that number. Far as I can tell squish is at least .032( largest solder I have). Plan to lower the squish but wonder if I get it to .018 -.020, if it will affect the port timing. Don't know much about porting but from what I've read there are issues associated with grinding the upper or lower sections of the ports. Seems that reducing the squish is effectively doing the same thing.

Bob

Bob I have dropped the cylinders on these before down to around .025 to .028 squish. It does not seem to have adverse affects on the port timing and will still give you a compression of 170 psi to 180 psi. I don't know about you but when these saws start getting that high in compression they get hard for me to pull over. Just widen the exhaust port and intake alittle and do a muffler mod. That saw will put a smile on your face.

 

[TLG]

Can you helicoil a spark plug chainsaw cylinder? and be confident that it is not going to blow out?

Acorn, You might check with McMaster-Carr. They did supply Keenserts which are a solid threaded insert. It has loctite on it and stakes to drive in as a keeper. Don't know if they make them for plugs though. Also unless your tool to insert is plastic I wouldn't recommend 271 loctite and then leaving tool in for a couple hours. You won't get the tool backed out of the hole. I wouldn't be afraid of an insert as long as proper drilling and insert tapping w/lubricant is performed. TG

 

[redunshee]

Bob, which half of your handle needs welding?

Left half. Seems that's the side that is most prone to break.

 

[redunshee]

I did on my 3800. I didn't use a helicoil but a Sav-a -thread by Helicoil. Has been holding fine. Only issue I had was removing the insertion tool w/o have the threaded insert coming out. There are severa lYouTube videos re the process.
Bob

Bob, do you have a part# for the save a thread?

Sure do. It's 5334-14. Size is M14x1.25 mm. It comes with 3inserts. A short,normal and long.
I believe I used the normal or middle sized insert. It's a kit.
Bob

 

[Acornhill]

Sure do. It's 5334-14. Size is M14x1.25 mm. It comes with 3inserts. A short,normal and long.
I believe I used the normal or middle sized insert. It's a kit.
Bob

thank you, i wil be doing this as soon as i can locate the kit locally or purchase on the bay.

 

[cmarti]

LOL, No Steve, But when they say the mind is the first thing to go..they ain't kidding. Especially when ya start off with a short supply to begin with.


Gregg,

I thought it was the eyes..... got bi-focals yesterday......it's a long slide down now

 

[jerrycmorrow]

I just read an article on how to determine MINIMUM ring gap...

good info. how do you determine, other than compression, what and acceptable maximum ring gap would be?