Chainsaw Repair
Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Modified Ported Work or Race saws => Topic started by: Uncle Lee on November 06, 2014, 08:11:18 am
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Not sure if this is in the correct forum. Kev you move it if you wish.
This is a project i had been thinking about for awhile. I previously sent a 166
cylinder to US Chrome to have it replated but they couldn't do it do to a groove
that went right to the top. They said they could bore it over size. So i sat on it
for over a year and then i purchased another 166 basket case. Thought now
whould be a good time to think hard about using this damaged cylinder. I did
some basic research with optional pistons and found the Stihl 084-088 piston
would be the easiest to make work and would be giving me a 4mm overbore.
Bought an aftermarket piston from Randy. Now the work. The 184 has a taller
crown hight and 13mm pin. 166 has a 14mm pin. I found a local small machine
shop that offset bored the pin hole the 14mm and .017 offset. That lowered
the piston and put me where i wanted with plenty of squish. Next move was
to add to the exhaust side piston skirt as when the piston was at tdc it uncovered
the port. So i welded aprox 3mm to the piston skirt. Next i assembled the saw
and ran it with a stock unmodded 166 muffler. She ran great and is 8 seconds faster
than a identical 166 with same B+C. Both saws cut in the same log on the same end.
Both saws matched as close as i could get and the big bore is 8 seconds faster.
But i still had a feeling there was more to get out of it. I then realized i didn't do
anything to the intake skirt. It is closing the intake much later than the stock 166 so
i took it appart and welded the intake side to match the 166. I probably didn't have
to go that far and will take some off later. I also had a not so nice muffler so i did the
double barrel muffler mod. Ran it in the same log again and gained almost 4 seconds.
Thats almost 12 seconds over stock. Saw seems to pull like a freight train. The next
step will be to advance timing a couple degrees and take maybe 1mm off the intake
skirt to give me a bit more duration.
Keep in mind guys i'm no porter at all and a complete rookie at modding saws but this
one i'm very pleased with so far.
Uncle Lee
(http://i234.photobucket.com/albums/ee127/leeha1959/166with084piston001_zps1e765991.jpg) (http://s234.photobucket.com/user/leeha1959/media/166with084piston001_zps1e765991.jpg.html)
(http://i234.photobucket.com/albums/ee127/leeha1959/166with084piston002_zps05a4e45d.jpg) (http://s234.photobucket.com/user/leeha1959/media/166with084piston002_zps05a4e45d.jpg.html)
(http://i234.photobucket.com/albums/ee127/leeha1959/166with084piston003_zpsa111e9b6.jpg) (http://s234.photobucket.com/user/leeha1959/media/166with084piston003_zpsa111e9b6.jpg.html)
(http://i234.photobucket.com/albums/ee127/leeha1959/166with084piston004_zps7e8989bb.jpg) (http://s234.photobucket.com/user/leeha1959/media/166with084piston004_zps7e8989bb.jpg.html)
(http://i234.photobucket.com/albums/ee127/leeha1959/166with084piston006_zps1e3a75c5.jpg) (http://s234.photobucket.com/user/leeha1959/media/166with084piston006_zps1e3a75c5.jpg.html)
(http://i234.photobucket.com/albums/ee127/leeha1959/166with084piston007_zps44909ce5.jpg) (http://s234.photobucket.com/user/leeha1959/media/166with084piston007_zps44909ce5.jpg.html)
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First video with stock muffler and untouched intake side skirt.
Uncle Lee
(http://i234.photobucket.com/albums/ee127/leeha1959/th_166with084piston001_zpsaaa1dbc0.mp4) (http://i234.photobucket.com/albums/ee127/leeha1959/166with084piston001_zpsaaa1dbc0.mp4)
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Second video with welded intake skirt and modded muffler.
Uncle Lee
(http://i234.photobucket.com/albums/ee127/leeha1959/166-084%202nd%20video%20001_zpsrvrzylrc.mp4) (http://i234.photobucket.com/albums/ee127/leeha1959/166-084%202nd%20video%20001_zpsrvrzylrc.mp4)
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Very nice work!
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Nice job as always Lee. I believe this fits in this area.
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Good job
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Thanks Guys
Also forgot to mention that this was stock at 118cc's and now
with the 60mm bore it's at 136cc's. Quite a jump. Compression
is at 185 and not even broke in yet.
Lee
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The 166 has been awakened?
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I have liked your thinking on alot of these projects in the past Lee. 8)
That 394 piston idea used for a stocker was cool info too. ;)
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Here or the Dolmar board is perfect.
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Kevin,
I still have that 166 with the 394 piston in it. Been meaning
to put one of the Wiseco piston kits in her but it ran good
with the 394 piston. Boy that was a long time ago.
Lee
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Kevin,
I still have that 166 with the 394 piston in it. Been meaning
to put one of the Wiseco piston kits in her but it ran good
with the 394 piston. Boy that was a long time ago.
Lee
My memory works like that. Some things are stuck in there and some things just wash away anymore. :'(
I just always thought that was a cool idea you had when the 166 pistons were scarce. Boring the pin bosses etc. :o 8)
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That was a good solution to a piston that wasn't available.
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How was your experience with US Chrome? Heard through the grapevine they've modernized and are producing a fine finished product. Have had mixed results with other platers...
Adam
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The only issue i have had with US Chrome was they did two 166 cylinders
at the same time and both the piston wouldn't go to the top. Must have
had a bad taper or i'm proper bore. They made it good and fixed them.
They have have done about two dozen for me and i'm in good with them.
Lee
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Lee, thanks.
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I have a model airplane friend in Idaho that makes pistons for small gas two strokes when a suitable example is not available commercially. His work so far has included 30 - 60cc singles and multiple cylinder engines of the same bores.
He has also made up several engines utilizing some commercial parts and some parts he fabricates on his own. His work looks like it is CNC work but it's not.
He has also straightened twisted cranks for me.
Here is a reed valve twin he made up with a custom crankcase and commercially available cylinders/pistons and crank assemblies.
(http://img.photobucket.com/albums/v11/jamesirl/Ro41583.jpg) (http://smg.photobucket.com/user/jamesirl/media/Ro41583.jpg.html)
The crankshaft utilized two single cylinder crankshafts adapted together. The finished product looks no different than similar sized commercially available examples.
(http://img.photobucket.com/albums/v11/jamesirl/Ge95698.jpg) (http://smg.photobucket.com/user/jamesirl/media/Ge95698.jpg.html)
He's recently made several custom fitted pistons for a line of problem engines. He used 4032 aluminum from McMaster-Carr. I have several in process pictures but they are fuzzy cell phone pictures.
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I'd be curious to know what alloy he uses. I made a number of pistons out of 7075 T6 but had too many seizure issues. The pistons "moved" a lot from stresses induced during machining and the cyl wall clearances had to sloppy to not seize. May try it again with a more appropriate alloy like 4032 or 2618 although the latter is nearly impossible to find.
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I added the 4032 in my previous post
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4032 is the way to go . I have build about 10 of them and still waiting for one to fail . No problem with seizure without any fancy coating on the skirt . Same clearance as stock except i make the portion above the ring .001 smaller than stock . Machines VERY well too .
For those who are not familiar with 4032 , its high silicon aluminum (12%). Silicon reduces expansion , wear and the tendency to stick of low silicon aluminum .
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Adam, my first pistons I made were out of 4032 , I found i had no problems of any kind until I tried to really high rpm the big bores , the 60 mm piston worked perfect and I still have that piston here . I put it in a real used 3120 and put it to work cutting big firewood and ran it for a solid week then took it out to see how it looked , I figured if the thing blew up I was not out alot of money . If you phone Wiseco and need just 1 or 2 pistons of a bore they donot do they use 4032 or a different number alum. but I cannot remember it now maybe 4031 something like that. I seen the alum. sitting on the floor last time I went threw the piston plant . There are other guys making pistons and I have tried them but they may work great in a snowmobile engine but broke all to hell in a nitro motor , When you got chainoil all over your boots and the piston pin goes out the pipe its not a good day ;D
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Thanks for the info. That opposed twin looks like sweet motor. Looks like the crank is forged with an added machined center section. Great idea.
Adam
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Ed, I think I remember seeing a picture of one of your pistons many years ago. I may try another with the 4032 for fun. Spent a ton of time machining them and got frustrated after seizing a few motors. I'll see if I have any pictures
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That is correct about the crank. There were two cranks turned end for end with new longer crank pins pressed into a circular connector plate. There was a big decision about the plate to make it a "Dog Bone" or circular shape. Finally for crankcase volume considerations it was made circular. The back crankshaft was cut off and the bearing sets in a blind pocket. The original single cylinder engine (doner Parts)was a cantilever design with a read valve and carb at the rear.
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Great info guys. What's the minimum # of units (of a custom piston) that Wiseco will do? About what do they charge per unit?
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Thats a neat idea of putting the bearing in a blind hole in the crank as the shaft isnt needed with your application.
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These are 62mm that i never used after seizing the 60mm version...
(http://i1184.photobucket.com/albums/z329/Aclarke123/20141108_142913_zpsf3fe4c58.jpg)
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heavy compared to Eds 62mm wiseco pistons
(http://i1184.photobucket.com/albums/z329/Aclarke123/20141108_142936_zpsba374939.jpg)
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your pretty thick on the piston skirts , that causes seizing cause the thicker grows more in size than a thinner skirt . I keep mine as thin as the stock piston from the factory and have never seized a piston but I never put a piston in without coating the hell out of it either and pay very close attection on piston clearance , A couple 1/10's of a thou makes a huge difference , If its a race motor run it abit loose and if on gas run it looser again. As far as Wiseco goes you need to design your piston and it is not to be the same as anyone elses but Wiseco is pretty much just like a Hooker on the street corner , if you got the money they will build you anything
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Ed thanks for the input, probably why I had issues.
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Very cool. Thanks for posting pics Adam
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Great info guys. What's the minimum # of units (of a custom piston) that Wiseco will do? About what do they charge per unit?
I was thinking the min order to start was 24 then min from there 12 for reorders. Ed or Lee you should know for sure.
1 offs Vince Loy used to make but it was way up there.
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Wiseco will build you a single piston but its going to cost you about the same amount as 12 pistons , On a first time order you may have to order as many as 24 pistons in 1 size , my last order is 48 pistons with the 52mm pistons costing the most
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making a piston the outside by far is the easy part, its the inside thats the hard part as everything is tapered but not on a even taper and cutting under the piston bosses is alot of fun on a taper , the outside of the piston is also tapered and not round its oval so when the piston grows in size from the heat it becomes round , First piston took me 24 hours to make and I never got that time under 20 hours as I donot have CNC, Wiseco does the outside of the piston in about 30 to 35 seconds and does 2 at a time but I think there machines might cost abit more than my lathe ;D
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Thanks for that info as well. My thinking was towards the NLA Husqvarna 1100/2100/298/2101 and Homelite 2000/2100/3100 pistons. Don't think it'd be too hard to sell 20 of those if the price wasn't sky high. Nothing's available yet for the Homelites, and the current AM pistons for the Huskys are $30 ebay specials that aren't worth $30........
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Hi Aaron,
Ive already inquired with Ed to add the Husky 2100 piston to his list because I know I could sell 20 of them.
But as Ed reminds me...these will not run in stock Husky jugs, the rings will peel the plating off.
I don't know about the Homies but unless customer wants to send jug to get replated for 300 bucks, 200 dollar piston is of no use.
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Aaron find out what Lee had Wiseco do for the 1mm rings in the 166 pistons. They could be run in stock bores.
(http://www.chainsawcollectors.se/phpbb3/download/file.php?id=13173&t=1)
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they have rings to run on chrome bore but they are not making any more of them so its old stock, same with the 60mm you can buy the ring to run on chrome bore , Wiseco doesnot make a ring to run on chrome bore in the 52mm piston
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Hi Aaron,
Ive already inquired with Ed to add the Husky 2100 piston to his list because I know I could sell 20 of them.
But as Ed reminds me...these will not run in stock Husky jugs, the rings will peel the plating off.
I don't know about the Homies but unless customer wants to send jug to get replated for 300 bucks, 200 dollar piston is of no use.
I've found that a 395 piston runs really well in the 2100.
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Hi Aaron,
Ive already inquired with Ed to add the Husky 2100 piston to his list because I know I could sell 20 of them.
But as Ed reminds me...these will not run in stock Husky jugs, the rings will peel the plating off.
I don't know about the Homies but unless customer wants to send jug to get replated for 300 bucks, 200 dollar piston is of no use.
As long as they're replicas of the stock 1100-2101 Husky 'thick ring' pistons, 2100CD rings are easy to get. Just regular 56mm 1.5mm thick rings. Cabers and stock 394XP rings are fine. Would there be any other reason why the pistons you're talking about can't be ran in an OEM 2100CD bore?
NOS rings for the Homelites are still around. Equivalents can also be gotten from Otto and Hastings if needed.
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I've found that a 395 piston runs really well in the 2100.
Isn't the crown height way off? IIRC, the jug has to be lowered quite a bit to get things in line. I'd rather not cut that much from a good cylinder if possible...
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they have rings to run on chrome bore but they are not making any more of them so its old stock, same with the 60mm you can buy the ring to run on chrome bore , Wiseco doesnot make a ring to run on chrome bore in the 52mm piston
What thickness are the rings? Stock 1100-2101 Husky 'thick ring' pistons take 1.5mm 56mm rings. Can't recall what the thickness of the later Husky 2101XP 'thin ring' piston rings are offhand. For my purposes, I'd rather have a thick ring piston in my saw anyways. I'm not racing the saw, and replacement rings are easier to get. Cabers, or stock 394XP rings....
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Thin husky rings are below 1mm. (.8-.9) If I remember correctly
In regards to ring compatibility, are you guys referring to old school hard chrome bores with the porous **** looking appearance?
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I used to do a lot of hard chroming back 33-40 yrs ago and I don't remember any of it looking like it had fish eyes or cracks?
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I've found that a 395 piston runs really well in the 2100.
Isn't the crown height way off? IIRC, the jug has to be lowered quite a bit to get things in line. I'd rather not cut that much from a good cylinder if possible...
You do have to cut some off the base to make it work but not enough to get concerned about the flange thickness. I was still able to take 0.010" out of the squish and keep the intake timing below 157 deg duration.
For those of us who are already doing machine work it's a good option.
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All the hard chrome done on Lycoming and Continental, etc aircraft engines looks like it has a web of cracks in the surface. Good for lubrication. That plating was done over the original steel bores. May be a different process over the aluminum bores?
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I was doing draw bench internal mandrels that were 52100 steel.
To the bare eye they looked smooth as a baby's behind but I bet under even a 10 power eye piece, you could see cracks and holes?
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the only good 2100 were the single thin rings ;D
someone, somewhere, stated a fellow in Texas(?) was building thin rings, maybe you folks remember..
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Wiseco uses a thin ring and that is what there setup for when cutting the ring groove , a thick ring breaks when made to turn a real high rpm so that is why the thin ring . Same thing a single ring is way better than a double ring setup at high rpms , the ring lad will break between the 2 rings and that will spoil your day pretty fast . The chrome I'm taking about is what is in most of todays saw bores like the 3120 , 281, 372, 2100. You put a ring meant for say a cast iron bore and it will wipe out the bore in no time , Wiseco could have a ring for 56mm in chrome bore I just donot know but thought I asked and the answer was no
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Found the info on 166 rings
These 1mm rings are a cast ring,
And can be used in a chrome bore and
a nicasil bore. I can get chrome rings that
can be used in the nicasil bore but you can't
put a chrome ring in a chrome bore.
Lee
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It would make sense you can't use a tool steel ring on hard nickle alloy plating like "nicasil".However and for example older engines such as the 125C Mac which had a chrome bore the rings are exactly the same as used on the cast iron bore MC 101 kart engines .Explain that one .
I would have thought that with chrome that's about as hard as you can get .Evidently the alloy plating is harder .Of course with cast iron and its properties it has the ability to absorb oil where hard linings do not .Which in my pea mind does not explain the chrome and not the nicasil .
I would assume then that rings for nicasil are some type of cast iron alloy .I can't ever remember breaking one but I have some old ones in the drawer I could break and see for myself .
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Al, the chrome bore in most of the saws today are pretty soft and not a true chrome but thats what they call it , some chrome bores are so soft you would almost think you can scratch it with your finger nail , dolmar is one of those companies . Nicasil plated bore is by far alot harder , you can see a huge diffence when your porting either , the chrome bore the burrs last a long time , in real nicasil they donot last long at all
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Nicasil is much harder than chrome, but it also has little voids to hold oil this is why you can use a harder chromed or tool steel like rings. Chrome doesn't have the voids to hold oil and chrome on chrome has a tendency to gall, this is why you have to use a cast ring.
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In other forums I've seen many instances of people putting cast rings in Nikasil bores.
My observation is that the cast rings seat and seal OK. They just don't last as long as the hard rings.
The people like them as these engines eventually get crashed and broken up within 100hrs actual run time.
I would venture to say that they would be fine on a cookie cutter or race saw but not for production felling.
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These are model airplane engines. Some planes are as big as a pickup truck.
The people like to see the rings have a good vertical wear pattern within an hour's running time. The cast rings do this well.
The hard rings, you can run them a whole season and they will only show a vertical pattern half way - usually from the top. The pilots feel they are loosing compression.
Typically by the time the hard ring is fully seated, it's time for a new piston/pin bearing, crank/rod, bearings/seals
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I seen a 3120 alcohol saw that someone put a ring that was meant to run on nicasil instead of chrome bore , it had about 45 seconds on it and the chrome was in bad shape in that short of time , it was to bad to run any longer
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These are model airplane engines. Some planes are as big as a pickup truck.
The people like to see the rings have a good vertical wear pattern within an hour's running time. The cast rings do this well.
The hard rings, you can run them a whole season and they will only show a vertical pattern half way - usually from the top. The pilots feel they are loosing compression.
Typically by the time the hard ring is fully seated, it's time for a new piston/pin bearing, crank/rod, bearings/seals
Vertically gas port the piston. It will help those low tension rings seal better, been doing it on alky karts for a long time to control blow by.
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lee would it be hard to put the 3120 piston instead of the stihl piston how close are they
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lee would it be hard to put the 3120 piston instead of the stihl piston how close are they
Try to get him for ya. @Uncle Lee