Stihl 044 questions, new piston required.

[chilipeppermaniac]

YES, Also, I will post a few pics of cylinder.

And yup, I am aware of the limits of your personal experience, pioneerguy600 but I am also pretty sure general experience may allow some hypothetical reasoning on why the shapes are different, and how these differences may cause the saw to react. For example, my "dummy" brain says on the original cylinder, MORE air is going to flow to the transfer ports with the larger cutout. However, if I hark back to my understanding of plumbing, one can flow more water through bigger pipes, but if one wants more pressure in pipes, one trick is to step down from larger pipes to smaller before reaching the spigot.

I am wondering what the logic vs actual performance differences will be between these 2 pistons.

Also rather than eat up an 044 how to with my 075 stuff, I will post the pics and refer more questions elsewhere. Although when I get differences in 075, there is a shot that 044 OEM pistons have differences too.

 

[lone wolf]

Someone recently had posted about Meteor pistons and said the quality was bad they sent him a second one and the same crap ,it was way off spec. I would strongly recommend OEM if you want to do it do it right the first time.I wonder if they are now made in China after reading about how bad the piston was that poster received. OEM or go home!

 

[ZeroJunk]

Someone recently had posted about Meteor pistons and said the quality was bad they sent him a second one and the same crap ,it was way off spec. I would strongly recommend OEM if you want to do it do it right the first time.I wonder if they are now made in China after reading about how bad the piston was that poster received. OEM or go home!

Well, there are saws and then there are saws. I have no problem with aftermarket for most stuff.
I'm thinking if I had a good not abused 044 I would spring for an OEM piston. Getting them cost plus 10% makes it a little simpler for me. Provided they even offer them anymore. May not. I'll check in the morning if my dementia doesn't kick in.

 

[huskihl]

The Hong Kong Zama is original. I’d clean and rebuild it

 

[chilipeppermaniac]

Ok markings on insides. New piston first, Old one next

 

[chilipeppermaniac]

Ok Old piston markings inside

 

[pioneerguy600]

YES, Also, I will post a few pics of cylinder.

And yup, I am aware of the limits of your personal experience, pioneerguy600 but I am also pretty sure general experience may allow some hypothetical reasoning on why the shapes are different, and how these differences may cause the saw to react. For example, my "dummy" brain says on the original cylinder, MORE air is going to flow to the transfer ports with the larger cutout. However, if I hark back to my understanding of plumbing, one can flow more water through bigger pipes, but if one wants more pressure in pipes, one trick is to step down from larger pipes to smaller before reaching the spigot.

I am wondering what the logic vs actual performance differences will be between these 2 pistons.

Also rather than eat up an 044 how to with my 075 stuff, I will post the other marks pics and refer more questions elsewhere. Although when I get differences in 075, there is a shot that 044 OEM pistons have differences too.

Ya, it would only be hypothetical guesswork on my part as to why the windows are different and without further study of the crankcase and knowing the crankcase volume then a larger window may cause sluggish flow or it may add volume to the amount of air fuel mix reaching the top end. It would likely reduce velocity, sometimes bigger is better but not always as there are many factors that affect actual power gains in these machines.

 

[chilipeppermaniac]

Ya, it would only be hypothetical guersswork on my part as to why the windows are different and without further study of the crankcase and knowing the crankcase volume then a larger window may cause sluggish flow or it may add volume to the amount of air fuel mix reaching the top end. It would likely reduce velocity, sometimes bigger is better but not always as there are many factors that affect actual power gains in these machines.

Thanks bro pioneer.

Ya know, the more I spend looking over things instead of just buying factory parts and saying, OK these should be a 1 for 1 swap. "Two OEM Top ends no problem, swap out old for new" But as I am learning and will also transfer to my 051 when it comes time to reassemble, I will need to scour over the old vs replacement top end parts on that saw too.

So, after reading your statement above, I grabbed both the old cylinder and new one. Surprise, The new Cylinder is also noticeably different in that the original has thinner fins and wider gaps, while the new one is thick fins and narrower gaps. It is also possible that the exhaust and intake ports are slightly different size too. Measuring is the only way to confirm this. I will try to get pics to show these exterior differences. Yes, the new cylinder came with the new piston as a matching set.

 

[chilipeppermaniac]

Now you guys are also getting me curious to pull my 044 apart to see what is happening inside that jug.

BUT, I will use my smarts and let sleeping dogs lie. As that saw is working as it should and not giving me any troubles. Although it couldn't hurt to pull the muffler and look inside.

 

[stihltech]

First things first. Why is the piston scored? A vacuum and pressure test before disassembly is part of the diagnosis procedure. Crank and bearing check. NO freeplay. ZERO. Look at bearing cages for cracked and/or missing ball separators and roughness. I am always suspect of a carburetor when no leaks are found. Truthfully, I will rebuild 1 out of 20 carbs. High speed nozzle debris causes a lot of issues.
That small pin 044 was a real performer in stock form. Spend the time and it will keep going for years. Oh, and grease the recess in the oil pump bushing before pressure and vacuum testing.

 

[freeasaburt]

All very good advice here, thanks a lot. I realise I should get a vac/pressure tester. What I'm used to is spraying e.g. brake cleaner on a running saw, and checking if the sound changes . Well, 'used to', my experience is limited but I have good friends that know way more than me, and obviously there's this forum too . As well as youtube.
Hardware stores i went to yesterday didn't have a T27, gonna order it online together with some other stuff; I found a Dutch webshop that sells Hyway, so it's possible i'm gonna go for that brand rather than a Meteor. Elsewhere on this forum I read that they're manufactured in the same factory anyway (Meteor is coated in Italy though). I guess this also means that their properties are the same (being heavier than OEM, and then there's the thing with the narrower con rod in the 10mm saws).

The exhaust was very greasy on the inside. I guess the saw was tuned rich. Idle way too high too, I think I'm gonna set is to factory recommended settings after cleaning it, and work from there. (probably gonna start with an ultrasonic bath, with 'Tickopur R33', great stuff; doesn't mean you don't have to disassemble it, but it's easy, fast and effective, and a good start).

Run a 5 MM .8 tap in your muffler screw holes before you go too far. That right one looks a little funny.

Threads are actually pretty ok, what you see is dirt, I'm quite sure (don't have the saw here atm).

 

[chilipeppermaniac]

First things first. Why is the piston scored? A vacuum and pressure test before disassembly is part of the diagnosis procedure. Crank and bearing check. NO freeplay. ZERO. Look at bearing cages for cracked and/or missing ball separators and roughness. I am always suspect of a carburetor when no leaks are found. Truthfully, I will rebuild 1 out of 20 carbs. High speed nozzle debris causes a lot of issues.
That small pin 044 was a real performer in stock form. Spend the time and it will keep going for years. Oh, and grease the recess in the oil pump bushing before pressure and vacuum testing.

stihltech, as I have been mentioning, my development in saw running, saw maintenance and saw repairs has been educated by seeing examples of testing for the WHY's as addressed in your statement above.

When I experienced my first saw's running issues, I sought to learn diagnostics by searching, HOW DOES A CHAINSAW WORK?
One key and most vital test was the various places to test any poor running saw for pressure AND vacuum leaks. As I have posted youtube clips in the forum, this vac and pressure tests are vital to assessing the saw itself plus is even important to confirm, healthy fuel lines and impulse lines, a dirty or good fuel filter, a properly functioning carb and even vented tank cab.

One other lesson that was invaluable for me to learn, was that the simple act of removing the muffler to see inside the chamber. It was explained that whenever looking to buy a used saw, prospective buyers can easily avoid regret if they simply are permitted to remove the muffler to verify a good top end, or a damaged and scored one. Obviously how a jug gets scored can have a number of causes. Straight gas, lean running/air leaks, and dirt, are the main culprits. Bearing issues, heat, dirty filters, and free play of the crank big and small ends, are all contributing factors that bring failures to a saw.

Vac and Pressure tests will reveal a leak or no leak condition. Presence or absence of scoring, will show if a saw has had leaks, dirt inside, or not. According to all my studying of saws, trimmers, blowers, etc, verifying if a saw has AIR LEAKS or not, plus how a saw gets them are the key to correcting any failures found.

 

[huskihl]

All very good advice here, thanks a lot. I realise I should get a vac/pressure tester. What I'm used to is spraying e.g. brake cleaner on a running saw, and checking if the sound changes . Well, 'used to', my experience is limited but I have good friends that know way more than me, and obviously there's this forum too . As well as youtube.
Hardware stores i went to yesterday didn't have a T27, gonna order it online together with some other stuff; I found a Dutch webshop that sells Hyway, so it's possible i'm gonna go for that brand rather than a Meteor. Elsewhere on this forum I read that they're manufactured in the same factory anyway (Meteor is coated in Italy though). I guess this also means that their properties are the same (being heavier than OEM, and then there's the thing with the narrower con rod in the 10mm saws).

The exhaust was very greasy on the inside. I guess the saw was tuned rich. Idle way too high too, I think I'm gonna set is to factory recommended settings after cleaning it, and work from there. (probably gonna start with an ultrasonic bath, with 'Tickopur R33', great stuff; doesn't mean you don't have to disassemble it, but it's easy, fast and effective, and a good start).



Threads are actually pretty ok, what you see is dirt, I'm quite sure (don't have the saw here atm).

One thing to remember regarding aftermarket cylinders. There are very few that run as well as an OEM cylinder. Port size, height, and transfer direction are usually terrible and they only run about 75% as strong as an OEM cylinder. If you need to get it fixed up on the cheap just to make a running saw to cut firewood, that’s one thing. But keep in mind that you’re carrying around a 70 cc saw that runs like a 55-60 cc saw. I’m sure there are exceptions to the rule, but I haven’t seen it. Most of the guys that brag up the aftermarket cylinder kits don’t post any before and after videos in the same wood with the same chain. And those same guys who talk about how great they run afterwards probably also did a timing advance and muffler mod, which helped get them up to par. Or their timing advance and muffler mod made the saw louder and snappier, so in their mind, it must run better. Also known as placebo effect

 

[freeasaburt]

I wasn't able to remove the (oem) cylinder yet, but I'm hoping it's salvageable. I have been looking into AM pistons, mainly, the one that's in there now doesn't look terribly scored from the exhaust port, so that's a good thing at least... Fingers crossed for when I get my new T27 wrench
I realised I shouldn't order a piston yet as oem (expensive...!) as well as AM cylinders seem to be sold exclusively as a kit wit the piston included. On the other hand, having an extra one at hand could be useful.

 

[lone wolf]

Well, there are saws and then there are saws. I have no problem with aftermarket for most stuff.
I'm thinking if I had a good not abused 044 I would spring for an OEM piston. Getting them cost plus 10% makes it a little simpler for me. Provided they even offer them anymore. May not. I'll check in the morning if my dementia doesn't kick in.

I wasn't able to remove the (oem) cylinder yet, but I'm hoping it's salvageable. I have been looking into AM pistons, mainly, the one that's in there now doesn't look terribly scored from the exhaust port, so that's a good thing at least... Fingers crossed for when I get my new T27 wrench
I realised I shouldn't order a piston yet as oem (expensive...!) as well as AM cylinders seem to be sold exclusively as a kit wit the piston included. On the other hand, having an extra one at hand could be useful.

Thats what I suspected it didn't look terrible clean it if you can and buy only OEM. Just dont remove too much material a few lines it will run.

 

[stihltech]

stihltech, as I have been mentioning, my development in saw running, saw maintenance and saw repairs has been educated by seeing examples of testing for the WHY's as addressed in your statement above.

When I experienced my first saw's running issues, I sought to learn diagnostics by searching, HOW DOES A CHAINSAW WORK?
One key and most vital test was the various places to test any poor running saw for pressure AND vacuum leaks. As I have posted youtube clips in the forum, this vac and pressure tests are vital to assessing the saw itself plus is even important to confirm, healthy fuel lines and impulse lines, a dirty or good fuel filter, a properly functioning carb and even vented tank cab.

One other lesson that was invaluable for me to learn, was that the simple act of removing the muffler to see inside the chamber. It was explained that whenever looking to buy a used saw, prospective buyers can easily avoid regret if they simply are permitted to remove the muffler to verify a good top end, or a damaged and scored one. Obviously how a jug gets scored can have a number of causes. Straight gas, lean running/air leaks, and dirt, are the main culprits. Bearing issues, heat, dirty filters, and free play of the crank big and small ends, are all contributing factors that bring failures to a saw.

Vac and Pressure tests will reveal a leak or no leak condition. Presence or absence of scoring, will show if a saw has had leaks, dirt inside, or not. According to all my studying of saws, trimmers, blowers, etc, verifying if a saw has AIR LEAKS or not, plus how a saw gets them are the key to correcting any failures found.

Good to hear somebody gets it. I know I sound like a broken record but this will make or break a motor.When you have a saw in the shop you are expected to diagnose quickly. You are tempted to not do the test, but I have been bit alot by not doing it over the years. Now I do it to almost every saw, depending on the issue, condition, etc. It works!

 

[chilipeppermaniac]

Thanks for confirming my message and for how your experience shows what happens by performing step by step methodical testing. Doing so reveals a yes or no result. Proper and thorough testing eliminates chasing one's tail by guessing or presuming the failure has to be such and such.

I can relate this to a time that our furnace acted up. It took me many cold days of an inoperable furnace that would work but fail when temps dipped into single digits. There are numerous interdependent components in a gas furnace to make the system go through the steps to light up and burn, plus safety components CO wise.

One year there was a bird in the vent pipe. Making sure a good chimney cap was in place eliminates future birds. A dirty filter can cause problems too. But in this case, a bad solder joint was causing intermittent run, no run scenario. The various warning light sequential flashes could point to one cause or another, but it wasn't until I "triggered" the failure in real time that the problem revealed itself.

So, basically all external components could test good for not causing the failure. The problem turned out to be the bus bar where thermostat wires connect, wiggled. I noticed this while using my screwdriver to check that the wires were screwed tight enough. As I did this, the furnace fired up. I had induced a good connection. Then to test for failure, I tweaked the bar and the flames went out. Tried several cycles to duplicate this failure and deemed it to be the cause. I had to jam a folded up piece of a matchbook cover as a shim of the bus bar to push it into "good connection" condition. Ordered and installed a new brain board. No failures in 5 + years.

 

[chilipeppermaniac]

@sithltech, Oh yeah, the curious guy in me, or the sadistic one, sure could have tried to re-flow/solder the connection on the bus bar on the old board, then install it again to confirm if it would be reliable without ordering a new one or as a backup to a new one.

I still may do this, but I also think the same way about my 051 and 075 type 1111 saws. Memory has it that both had low compression. I pulled the saws apart down to the cases. Both pistons and cylinders, scored and carbon buildup exhaust side. I bought 2 top OEM top ends. While analyzing the 075 to determine my step by step choices I see differences in the new vs old piston windows, and the casting of the cylinder. My thoughts are to install the old top end back on, do the pressure and vac tests to confirm if the crank seals and case seals hold. I also will do the same with the new piston and cylinder and compare results. I have new OEM bearings for the 051 and 075 cranks and can split the cases if necessary. The crank seems tight on 075, but I may be less certain of play in the 051. I do want to confirm the health of the cranks and seals of both.

Any thoughts on leaving status quo on the 075 crank/bearings/seals if they all test good? Or should I err on the side of caution to go ahead and put the new bearings/ seals in? My thoughts are if I split cases and install new, the tolerances and seals should yield the longest life vs expecting the possible or eventual failure of the 40 year old seals, bearings, etc?

As I also saw on a you tube video, one can examine the cranks for heat damage ( discoloring of the crank) and thus know if the big end bearings were compromised and potential freeplay is present. Obviously these bearings are non replacable, so a new crank would be in order. What are your thoughts on to split or to not?

Pretty sure my cards are dealt on the 051.

 

[ZeroJunk]

The big end bearing will move left and right, but it should not tilt either way. Maybe 1 degree. I would replace the seals just as a matter of course. You can inspect the crank bearings better that way. The clutch side probably has a sharp step to get the seal over. Make sure you don't drop the spring out of the seal getting it over. One layer of electrical tape to make a little ramp and some grease helps.

Think if I were you I would find an old junker and practice splitting the case. It is not complicated , but you can break the thing.

 

[chilipeppermaniac]

ZeroJunk, thanks,

I hear you there, The other variable I am bringing the table here in 2023 vs 2018 when I first got the saw, is I have a handle on the procedure after reading and a visual of the official service manual for these saws.

I was totally familiar with several methods of doing this on different saws. Some use a tool, some need heat and hammers, or some a different tool for stuffer crank types.

Now all I have to do is get the balls to do it. I am always good at tearing stuff apart, I often get waylayed putting stuff back together because I always want to do it 110% so it is right the first time.