|
|
Post by ruffcut on Jun 15, 2022 12:05:11 GMT -5
Started to teardown a 20 MCS I picked up last weekend. Stopped short of splitting the crankcase and popping off the cylinder since I was getting a hair over 90PSI on the compression. I noticed something through the exhaust port that I didn't like so I split the case to investigate and this is what I found.  20220615_122634  20220615_122309
The piston is pretty gouged but the piston rings from what I can tell is ok. As for the cylinder, I can barely feel the rub mark with my finger nail so it's not too bad. So what do you think? Also, how much slop/play should the connecting rod to the crank be? I know they are needle bearings but I can wiggle it side to side pretty good. Not use to that with other saws I've done in the past. Thanks! |
|
|
|
Post by w30bob on Jun 15, 2022 14:17:46 GMT -5
I think OUCH! Ok, not really. Those cylinders are expensive to find, about 4 or 5 times what you paid for your saw......if you can find one.....so as long as it's not a deep gouge in the cylinder you should be ok.....I'd leave it alone. The piston is probably also a bit pricey, but I've never looked for one. Since the gouge is below the bottom ring only......the rings should still seal just fine. I'd dress the piston down to knock of any high spots, but nothing more. You don't want to change the piston to wall clearance any significant amount or you're asking for trouble. As for the con rod slop.......depends what you mean. I assume this is a bottom guided rod, but don't have one in front of me to check.......but if it is then the top of the rod needs to float to find its center. If it were mine I'd pop the pin out and have a looksee at the rollers and the contact surfaces. Use a magnifying glass and anything abnormal will become immediately apparent. Also sort of depends on what you want to do with the saw. If you're planning on clear cutting a few acres with it......start looking for new parts. If you just want to get it running so you can tell your pals at your 4th of July party that 'yeah, and it still runs' and show them...and then put it back on the shelf for another year.......you should be fine as is. Gotta love those rings though.....THOSE are piston rings!!!
;O)
bob
|
|
|
|
Post by ruffcut on Jun 15, 2022 15:11:25 GMT -5
Just by looking at the cylinder pic, it looks bad but I can barely feel it with my nail so I think I'm fine there. The piston on the other hand, yeah it's rough but below the bottom ring. There are two pistons, no rings on ebay that are listed right now. One of them is new OEM but for $150, I might ponder on that for a while. I defiantly want to get it up and running but I'm not lugging it around to cut stove wood. Just like to show it off and run it from time to time. Maybe do a cut once in a while.
|
|
|
|
Post by edju1958 on Jun 15, 2022 17:38:04 GMT -5
I'm in the process of buying a pick up truck load of Homie parts.If you can give me the part#s for the piston & rings I'll look on the manifest to see if I have them. As for the "slop" from side to side that's perfectly acceptable.It's when you have play when you can move the piston up & down on the con rod where you have to worry (called radial play).I found this out the hard way as some members like to talk down to me & make me look like an idiot in front of other members.
|
|
|
|
Post by ruffcut on Jun 15, 2022 18:19:55 GMT -5
Only part # I have is for the piston A-71168 and I got that info from Ebay. As for the rings I have yet to find the #. I cannot find a parts list or service manual for the 20 MCS.
|
|
|
|
Post by bobby167 on Jun 15, 2022 19:05:31 GMT -5
Is there a tag with numbers / letters on this? I think it should be on recoil toward front of saw. If you can find anything, post pictures. 20MCS shows 3 rings used. Built from 1950 to around 1952.
|
|
|
|
Post by edju1958 on Jun 15, 2022 19:41:42 GMT -5
I just went through the parts manifest & didn't find anything with the part # you gave me.If Bob Johnson pulls through & gets out of the hospital he might have something,but he's got a long road ahead of him.
|
|
|
|
Post by ruffcut on Jun 15, 2022 19:54:48 GMT -5
The only tag is on the starter housing. It has SN# 310630 stamped and the rest is dealing with fuel mix, spark plug and point gap specs. I may check tomorrow to see if the piston is stamped, maybe the rings as well. I'm noticing a few of the parts having numbers on them.
Update! That part # I gave you is wrong for the piston. It's A-71380, sorry!
|
|
|
|
Post by ronaldt on Jun 15, 2022 20:50:25 GMT -5
That serial number tells me it is a 1950 model (first year for gas powered Homelite saws). Congrats on your purchase! Doesn't help with your piston questions but it is exciting to me!
|
|
|
|
Post by ruffcut on Jun 16, 2022 4:28:26 GMT -5
That's pretty cool that it's a first-year build! Had a little more time to look at the parts last night. I noticed when I split the crankcase there was no gasket material of any kind. Is that typical? One thing I forgot to mention the drive belt is shot. Did read there are alternatives for the belt. The fuel tank at one point was brazed at the mounting bracket as well as the clutch drum. The chain sprocket looks pretty worn. The manual oiler seems to pump oil. Took the carb apart and it's not looking too bad. The air filter is still intact but dirty. For the most part, it doesn't look too bad considering the age.
|
|
|
|
Post by bobby167 on Jun 16, 2022 7:17:06 GMT -5
Found IPL for your 20MCS in my files. You will have to go to chainsawcollectors.se You have to register, to see it. Once your in, go to board index, search for 20MCS IPL. Have any problems, let me know. I can copy mine & send to you if you can't locate it.
|
|
|
|
Post by ruffcut on Jun 16, 2022 9:44:08 GMT -5
Saw Builder, Thank you very much for the info. I'll register there when I get a chance.
|
|
|
|
Post by w30bob on Jun 16, 2022 15:10:17 GMT -5
Hi ruff,
I've got the 20MCS IPL as a PDF that I can email you if you send me your address (either via PM or here). It's about a 10MB file. You're correct, the piston is PN AA-71380.......and they are stupid expensive on eBay!
;O)
bob
|
|
|
|
Post by ruffcut on Jun 16, 2022 17:52:19 GMT -5
w30bob.... Thanks for offering the IPL but I found a copy. Yeah, the piston is pricy and the jury is still out on that one!
|
|
|
|
Post by bobby167 on Jun 16, 2022 19:05:03 GMT -5
ruffcut: Don't want to get your hopes up, but, do a search on this model & see what sellers are asking for this saw. Condition is everything, but for what you paid for it, you might be shocked. Not saying yours is worth that much. Research it some. As ronaldt said, serial number show's it was one of first one man saws from Homelite,1950 Some say 1949 to 1952 others 1950 to 1952. Good luck
|
|
|
|
Post by sparky on Jun 25, 2022 15:25:34 GMT -5
Tractor restorers have used JB weld to fill cylinder gouges as a last resort. You might use it to fill the piston gouge and work it down with sandpaper. Just a thought.
|
|
|
|
Post by ruffcut on Jul 8, 2022 15:16:42 GMT -5
Tractor restorers have used JB weld to fill cylinder gouges as a last resort. You might use it to fill the piston gouge and work it down with sandpaper. Just a thought. Interesting, never thought of that! I might have to give it a try. |
|
