WoodDean
ArboristSite Guru
There's a lot of good info in those posts. Thanks cantdog.
I am sooooooo doing that piston check thingy.
I am sooooooo doing that piston check thingy.
Jonsered Chainsaws
- Thread starter briantutt
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WoodDean
ArboristSite Guru
Time for ez off
I broke the sad ebay 80 down this afternoon. I think I can save the jug...maybe....the piston had a small dent at the bottom of the skirt??? Ignition leads were broken, so they weren't gonna start that puppy. Clutch cover and many other parts to go on the 90 project...that's a plus! Good flywheel, good recoil spring...lots of usable parts already bagged & tagged. Wrist pin has a pretty good valley where the bearing has been riding...I don't know what is acceptable there, but I'm suspicious. I think I'll pass on the next sad looking ebay 80.
WoodDean....After the EZ-OFF, don't use anything stronger than a ScotchBrite pad to clean up your piston...can't hurt it that way. I looked for a jug gasket and all I have is a Husky 2100 set....won't do you any good. I was hoping to get a master to template off from the sad 80, but it fell apart in pieces. So apparently we both need sources for jug gaskets. That piston is really gunked up....wonder what kinda gas/saw mix he was usin'?? Let me know how the redneck, piston drop works. I don't have anything apart at present that's worth testing!
I'm coming into the real world with a new, $400 android phone and a better cell plan. So....will take decent pics now I suspect.
Kevin
WoodDean....After the EZ-OFF, don't use anything stronger than a ScotchBrite pad to clean up your piston...can't hurt it that way. I looked for a jug gasket and all I have is a Husky 2100 set....won't do you any good. I was hoping to get a master to template off from the sad 80, but it fell apart in pieces. So apparently we both need sources for jug gaskets.
That piston is really gunked up....wonder what kinda gas/saw mix he was usin'?? Let me know how the redneck, piston drop works. I don't have anything apart at present that's worth testing!I'm coming into the real world with a new, $400 android phone and a better cell plan. So....will take decent pics now I suspect.
Kevin
WoodDean
ArboristSite Guru
After cooking a fine Valentines day dinner of hamburgers and boxed mac and cheese, I cleaned off the EZ off.
WoodDean
ArboristSite Guru
The top took a couple of soakings. Didn't see your scotchbrite post till later.
I may have ruined it. That stuff was tacky like tar not flakey like carbon.
I may have ruined it. That stuff was tacky like tar not flakey like carbon.
Nice...now polish with a ScotchBrite pad and move on to more fun.
What's the valley like on your wrist pin where the bearing has been runnin"?
Kevin
What's the valley like on your wrist pin where the bearing has been runnin"?Kevin
WoodDean
ArboristSite Guru
The grooves turned out really well.
WoodDean
ArboristSite Guru
Wrist pin looks good. The ring piece came out with cantdogs tip.
Thanks so much guys
Thanks so much guys
You can have some scratches on the top, but the sides should not. Always try to follow the actual machining lands/marks.....if you can still see them.
Kevin
WoodDean
ArboristSite Guru
The sides are nice and smooth.
Too bad I don't have a gasket. Now that the ring and piston issues are resolved I think that's all I need.
Do we have any other gasket options?
Too bad I don't have a gasket. Now that the ring and piston issues are resolved I think that's all I need.
Do we have any other gasket options?
Maybe Robin has an idea. You could always make one by pressing the gasket material against the jug and then cutting out the impression. Tricky but doable....maybe Robin has one on file and he can send it 100% as a pdf or whatever....cut one from that.
Kevin
Kevin
WoodDean
ArboristSite Guru
I just googled gasket material and they sell the stuff at auto zone. Fel-pro, cork and rubber but the latter two probably won't take the heat.
It's a dense fiber material...available at like NAPA or any good auto store. No cork or rubber in that application. You have to get the right thickness though....
Kevin
Kevin
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Piston looks pretty good.....as Kevin said, green scotchbrite is very good for cleaning pistons....sandpaper or wet/dri not so much....you want to clean but remove no alum. LOL!! The redneck piston test is just that...but it'll tell you a lot...the only way to know for sure is to measure the piston skirts and compare against new piston measurements. Another redneck way is to put the piston in the cyl all the way and slip different thicknesses of paper between the thurst faces and cyl wall, using paper like feeler gauges until a sliding fit is obtained and then measure the thickness of the paper......should be somewhere around 0.004"-0.008" or so.....again just another less than perfect way to gauge piston wear.
Gaskets....I generally make my own if none are available.....I get a roll of 1/32" from my local NAPA....it being he thinnest they sell.....but the fact is the OEM Jonsereds cyl gaskets are made of very thin paper (like 0.007-0.009... thinner that your average brown paper bag) so you will increase your squish using thicker gasket material. Many saw builders eliminate the gasket completely to increase compression and just use a good quality sealer to obtain a tight joint between the cyl and case. I'm kind of a gasket guy but have done this on several more modern ported saws with no problems, however I have never tried it on one of these old saws nor have I even checked squish on one to find out where it actually was. Let me look around later today when I get over to the shop.......I have quite a few NOS Jonsereds cyl base gaskets...I may have an extra or at least can make a scan of one.
Gaskets....I generally make my own if none are available.....I get a roll of 1/32" from my local NAPA....it being he thinnest they sell.....but the fact is the OEM Jonsereds cyl gaskets are made of very thin paper (like 0.007-0.009... thinner that your average brown paper bag) so you will increase your squish using thicker gasket material. Many saw builders eliminate the gasket completely to increase compression and just use a good quality sealer to obtain a tight joint between the cyl and case. I'm kind of a gasket guy but have done this on several more modern ported saws with no problems, however I have never tried it on one of these old saws nor have I even checked squish on one to find out where it actually was. Let me look around later today when I get over to the shop.......I have quite a few NOS Jonsereds cyl base gaskets...I may have an extra or at least can make a scan of one.
WoodDean
ArboristSite Guru
Good news boys . . . . . . . I'm fairly certain I passed the redneck test this morning. Actually, the piston wouldn't slide all the way down to TDC without me pushing on it and it made a little sucking noise when I pulled it out.
Rings? I don't need no stinking rings.
Rings? I don't need no stinking rings.
WoodDean
ArboristSite Guru
Kev, you get that $400 phone working yet? Let's see some pics!
Always good to see.... Love those 90's! I grew up with that sound! Looking forward to seeing you resurrect this 90! Also looking forward to Robins build thread on the 910E. That might be just the inspiration I need to make mine run again 
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Robins right on the gasket material..it's really THIN....buy the thinnest stuff you can find. The further you move your jug from the base, the less compression you have. They tried to deliver the phone yesterday when I was working...required a sig. The FedEx center is 120 miles away, round trip...so that blows my weekend playing with it.
Kevin
Always good to see.... Love those 90's! I grew up with that sound! Looking forward to seeing you resurrect this 90! Also looking forward to Robins build thread on the 910E. That might be just the inspiration I need to make mine run again
Love me a good 80/90 workin' hard in the woods. My 80 is a hot-rod, my 90 is a little beast.
Kevin
Checking squish:
I don't why he doesn't use Plastigage of the appropriate gauge....? Seems to me these dome top pistons on the 80/90 are pretty damn close to hemispherical combustion, i.e., 'hemi'. A little more camber and a tighter fit and you're there-except for spark plug placement etc. And you're going to need a gauge in the center of those dome piston tops...in addition to where he says in the vid.
Kevin
I don't why he doesn't use Plastigage of the appropriate gauge....? Seems to me these dome top pistons on the 80/90 are pretty damn close to hemispherical combustion, i.e., 'hemi'. A little more camber and a tighter fit and you're there-except for spark plug placement etc. And you're going to need a gauge in the center of those dome piston tops...in addition to where he says in the vid.
Kevin
