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Post by woodplayer on Nov 22, 2008 22:16:53 GMT -5
While taking apart an XL1 today I noticed something strange about the piston and ring. I assume this is a dykes type piston ring arrangement and it is the first I've seen on an XLI (similar to SEZ). What is the advantage and disadvantage of this type of setup. I assume the ring would wear slower due to the large surface area, but likely wouldn't seal as well as thinner rings. Are they more or less desirable than a pair of normal rings and are they very common on the XL1 or SEZ type saws?   |
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Post by MCS on Nov 22, 2008 22:45:03 GMT -5
I think it is for improved ring seal. When the cylinder fires, the pressure will press the ring to the bottom of the groove in the piston and also expand it against the walls with the pressure on the inside edge of the ring. Maybe cheaper to produce too. If one ring gives the same sealing as two, just think how much they will save in production costs  |
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Post by woodplayer on Nov 23, 2008 21:49:18 GMT -5
My thumbnail links didn't seem to work properly, wouldn't open the photo when I clicked it, so I just inserted the full photo, it's a little easier to see now.
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Post by lesorubcheek on Nov 23, 2008 22:39:14 GMT -5
Great post WB! I didn't know the XL-1 used Dykes rings. I knew Homeltie had tried them on other saws like the XL-11x, the 2100, and I think even some of 900 series had 'em (could be wrong though). Gotta wonder if it offered any real advantages over conventional rings. Somebody musta thought so or they wouldn't have tried it. It didn't last though, so there must have been a reason for that too. Wish I was as interested in chainsaws as much back when I was 10 so maybe I could have figured some of these things out.
Dan
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Post by MCS on Nov 23, 2008 22:58:45 GMT -5
The Super EZ has 1.3" stoke, that isn't much. By moving the ring to the top edge of the piston, the intake and exhaust ports are affected somewhat. I wonder if they gained a little power by doing this. Since the EZ is a two ring piston and the Super EZ a Head Land piston - Homelite's term for this design - the design has to provide a beneficial boost in power otherwise they wouldn't have built is that way.
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Post by quiverpup on Nov 26, 2008 16:23:41 GMT -5
i just tore down 3 huskys and a stihl to ebay parts.1 ring with no chrome bore?and everyone says they are the best?i'll take an old homey anyday. those saws where not even 30 years old yet and the cylinders where toast.i hope we can rescue all the old homelites before anyone else realizes how awesome they are!!!!! just my 2 cents
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Post by RandyMac on Nov 26, 2008 23:27:51 GMT -5
Grab a couple of the upright cylinder models, they give nothing away to the horizonal cylinder models of the same time period. The 600D and 700D models really kick ass, if you disenguage the vane governor, plus they are fun to tinker with and last a long time.   I traded a funky plastic foreign job for this 600D, it's probably still junk, this Homelite starts on the second pull. The old 1950s style Homelites are my favorites. The pics show how it looked when I got it, since then it got a cylinder shroud, muffler screen, a 20" bar, new clutch drum with rim sprocket in .404 and because I could, full wrap bars. |
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Post by OBR on Nov 27, 2008 21:23:40 GMT -5
I dont know for sure, but I would guess it to be the 9-23/ 9-26 saws and there 900 series (900, 909, 990, and 995) predicessors. 6.83 cubes or 112 cc. Of course thats if you dont cound the 26lcs which was 123cc?? i think
p.s. i hope to own a 909 someday ;D
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Post by RandyMac on Nov 27, 2008 22:27:41 GMT -5
The biggest? That would be this, at 129cc or 7.88 CI (this one is not mine)  That short bar had a 10" cut, may have been used in construction. |
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Post by OBR on Nov 28, 2008 23:08:43 GMT -5
oh booger, forgot about the 8-29. and id say that 600D looks to be about the right size for a limber dont yall think....  |
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Post by billg on Nov 29, 2008 2:00:03 GMT -5
Great post WB! I didn't know the XL-1 used Dykes rings. I knew Homeltie had tried them on other saws like the XL-11x, the 2100, ........................................ Dan I guess I need to take a closer look in the pile of 2100's here. Bill |
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Post by billg on Nov 29, 2008 2:01:58 GMT -5
The biggest? That would be this, at 129cc or 7.88 CI (this one is not mine) That short bar had a 10" cut, may have been used in construction. That saw looks familar ;D |
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Post by RandyMac on Nov 29, 2008 2:28:32 GMT -5
I'll bet it does. How you doing Bill?
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Post by lesorubcheek on Nov 29, 2008 15:11:59 GMT -5
I guess I need to take a closer look in the pile of 2100's here. Bill Here's a little reference that may help ya Bill.  Dan |
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Post by billg on Nov 30, 2008 2:42:39 GMT -5
I'll bet it does. How you doing Bill? Randy, Just finished picking corn Saturday getting cold now. It's time to start working on saws. Bill |
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Post by billg on Nov 30, 2008 3:10:50 GMT -5
Dan, That is a early 2100 IPL. It shows the 2000 crankshaft. Do you have some of those saws? I will try to attach a copy of the 2100S and S2100 IPL's. They show the 2 ring system and splined crank. I guess I need to go back through the piles and see if there is very early 2100 in there. Bill   |
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Post by MCS on Nov 30, 2008 14:12:08 GMT -5
Well according to the information on Clevite's web page, you can use Nitrous-Oxide in engines that have Dykes Rings. Wow that 2100 could pull a 96" chain  Maybe I'm reading too much into this...... Fire-Power™ Dykes, which are engineered to withstand the punishment of today's high powered, Nitrous-Oxide injected, Turbocharged, and Supercharged race applications. |
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Post by MCS on Nov 30, 2008 14:41:18 GMT -5
Maybe I should stop snooping around for info on these rings  Dykes ring A Compression piston ring which is L-shaped when viewed from the end. When installed in the Piston the horizontal part fits more deeply in the Piston groove while the vertical side rubs against the Cylinder wall. This style of ring gives good sealing and prevents piston-ring Flutter during Acceleration and Deceleration of the piston.  Now we certainly don't want our rings fluttering. In the automobile application it doesn't look like they bring the L all the way to the top of the piston. As I has mentioned earlier, Homelite calls this a Head Land ring. |
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Post by woodplayer on Nov 30, 2008 16:53:07 GMT -5
Before cleaning up the piston and ring it did contain alot of carbon deposits, more than I have ever seen with traditional style rings.
Oldzip was right on being more prone to carbon fouling, however I have no idea when the saw was last run or what oil and mixture was used during it's life.
The diagram by a7ecorsair shows exactly where the deposits were accumulated, between the piston and the vertical "L" portion of the ring.
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Post by lesorubcheek on Dec 9, 2008 19:30:02 GMT -5
Here's a little article that sheds a bit more light on Dykes rings.  I wonder what year the last Homelite saw was made that used them? I'll bet somewhere there's an article that sums up why they quit using them. Dan |
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