Worth widening the exhaust port?

[fields_mj]

I'll start off by saying that I looked into this topic many years ago, but I've never actually done it. I'm in the process of replacing the piston and rings in my 036. Over the weekend I slipped the new (OEM) piston in, put a couple of the bolts back into the cylinder, and used a sharpie to mark the edges of the exhaust port onto the new piston to see how much the skirt extended past the exhaust port. On the clutch side, the skirt only extended 1/8" past the mark left by my sharpie. My understanding is that 1/8" is about as low as I should go. On the flywheel side, there was a little more room. On that side, the skirt extended right at 3/32" past the sharpie mark. I'm not sure how much is normal, but if I'm only talking about having 1/32" on one side of the exhaust port, is it really even worth messing with?

I haven't measured the squish yet, but I will. I'm considering doing something different for the base gasket to get my squish down to around .025". I have NO desire to raise or lower my ports, and I'm NOT messing with a timing wheel. I understand the general concepts, and how those are used (but I'd need to watch a few vids again to refresh my memory). Before I'd be willing to do any of that to an OEM cylinder, I'd need to ruin a few Chinese imports first for practice, and I don't have time for that at this point.

 

[huskihl]

That’s about how much there is on most saws. Some allow you to go wider, and some don’t allow even as much as yours

 

[Mad Professor]

I'll start off by saying that I looked into this topic many years ago, but I've never actually done it. I'm in the process of replacing the piston and rings in my 036. Over the weekend I slipped the new (OEM) piston in, put a couple of the bolts back into the cylinder, and used a sharpie to mark the edges of the exhaust port onto the new piston to see how much the skirt extended past the exhaust port. On the clutch side, the skirt only extended 1/8" past the mark left by my sharpie. My understanding is that 1/8" is about as low as I should go. On the flywheel side, there was a little more room. On that side, the skirt extended right at 3/32" past the sharpie mark. I'm not sure how much is normal, but if I'm only talking about having 1/32" on one side of the exhaust port, is it really even worth messing with?

I haven't measured the squish yet, but I will. I'm considering doing something different for the base gasket to get my squish down to around .025". I have NO desire to raise or lower my ports, and I'm NOT messing with a timing wheel. I understand the general concepts, and how those are used (but I'd need to watch a few vids again to refresh my memory). Before I'd be willing to do any of that to an OEM cylinder, I'd need to ruin a few Chinese imports first for practice, and I don't have time for that at this point.

That’s about how much there is on most saws. Some allow you to go wider, and some don’t allow even as much as yours

I'll cc @huskihl as he's done more port work than me

I think you'll gain more from the compression increase setting squish, than you might lose by the small change in port timing.

I'm not sure how much for instance 0.010" (a gasket) translates into degrees in rotation. Maybe some of the experienced porters here could comment on that. You can also surface the base of the cylinder and keep the gasket.

I would take the time to polish the ex port and carefully match it to the muffler opening/gasket. Then work on the muffler for better exhaust. Cleaning up the windows on the piston, is easy, and will help too.

This is a used 036 cyl I rescued from a lean seize/straight gas and shows the polished ex port.

 

[fields_mj]

That's a nice looking exhaust port! Are there any tips to getting a finish that nice? I ordered some miscellaneous parts (bar nuts, carbs, air filters) a couple years ago and added a couple of CHEAP AM cylinders to the order just to have something to practice on. I have the 1/8" carbide burrs, 600 grit sanding drums, as well as some kind of imbedded rubber abrasive bits that I used. I don't remember any of them leaving a finish that good.

I'll take another look at the piston to make sure, but from memory, I don't remember having any flash or mismatch on the casting.

I totally forgot about matching everything up to the gasket and heat shield. I will absolutely do that.

As far as timing goes, my thoughts go something like this. I'm absolutely certain that there are gains to be had by optimizing the timing. I'm also absolutely certain that it will take someone with more skill and experience than me to correctly optimize the timing. I my hands, the odds are about even as to whether such efforts from me would pay off, break even due to crappy workmanship/inexperience, or mess up the cylinder to the point of needing replaced. My normal setup for this saw is to run it with an 18" bar and .325 chain with a standard spline clutch drum and a 9 pin rim. Its a nice setup for bucking firewood but I wouldn't complain if I could give it a little more torque.

 

[Mad Professor]

I did the ex port with wet/dry detergent and my fingers. Start coarse and work to fine. It will help on carbon buildup too. The other ports I just smoothed any flash/flaws, didn't port the saw. I don't have proper tools to do porting well. That cylinder was ugly to start with, piston was trash.



I run 3/8 RM/RS chains and 20" bar on my 036s as they swap out with my 038 saws. If you have the clutch upgrade the rims do too. The 0.325 might cut faster? I use that on my 026/028S and 16" bars.

The 036 is my favorite firewood saw.

 

[fields_mj]

That piston looks pretty rough!!! LOL Mine wasn't nearly that bad, and the cylinder was still in great shape. Still waiting on the tool to leak test it. I wasn't paying enough attention and ordered the wrong thing the first time around. I can certainly see where having a polished port would help. I'll certainly give the wet/dry a try. Heck, knowing me, I'll probably end up trying to buff it to a mirror finish LOL

The 036 is definitely my go-to saw for almost everything. I don't normally consider myself to be afflicted with CAD, but the 036 was definitely worth acquiring a backup for. I've thought about adding a 70cc saw to the mix to see if I like running it more because most of what I cut is in the 12" to 18" range, but I just can't see myself reaching for anything heavier than my 036 unless I really have to. At that point I just jump straight to 90cc and get the work done.

I've never had anything against 3/8 chain. It just happened that none of the used saws I bought ever had 3/8 on them. Everything happened to either be .325 or .404.

 

[Mad Professor]

That piston looks pretty rough!!! LOL Mine wasn't nearly that bad, and the cylinder was still in great shape. Still waiting on the tool to leak test it. I wasn't paying enough attention and ordered the wrong thing the first time around. I can certainly see where having a polished port would help. I'll certainly give the wet/dry a try. Heck, knowing me, I'll probably end up trying to buff it to a mirror finish LOL

The 036 is definitely my go-to saw for almost everything. I don't normally consider myself to be afflicted with CAD, but the 036 was definitely worth acquiring a backup for. I've thought about adding a 70cc saw to the mix to see if I like running it more because most of what I cut is in the 12" to 18" range, but I just can't see myself reaching for anything heavier than my 036 unless I really have to. At that point I just jump straight to 90cc and get the work done.

I've never had anything against 3/8 chain. It just happened that none of the used saws I bought ever had 3/8 on them. Everything happened to either be .325 or .404.

That P/C got a bad straight gas but cyl cleaned up fine. Saw was free. I put all OEM parts in it, nice enough for a new B/C. For some reason it came with a 28" ES bar I refurbished that bar for use on my 066.



If I have smaller stuff I'll grab a 026/028S and the 036, Bigger a 038M instead of the 50ccs. Usually the 066 is overkill.

 

[fields_mj]

My dad has an 028AV that he traded in his '78 041 for (plus a few $$ of course). Its a nice firewood saw also. An older friend of mine (mid 70's) has cut almost exclusively with an 026 since they first came out. I'm normally felling, limbing, and bucking dead shagbark hickories that are in the 20" range. 90cc is definitely overkill for that. The 026 and dad's 028 do the job just fine, but the 036 definitely gets the job done faster. I looked at a few 038 saws over the years. An 038M would be stronger than my 036, but it weighs almost as much as my 064 so I opted against it. If I find myself wanting more than an 036 can give, I'm either noodling a big knotty piece that I can't lift onto a splitter, or (less likely) I'm into a log that could be anywhere from 26" to 36". I don't mind going to 90cc for those occasions, especially since all of my splitting is done in the back yard.

 

[Mad Professor]

My dad has an 028AV that he traded in his '78 041 for (plus a few $$ of course). Its a nice firewood saw also. An older friend of mine (mid 70's) has cut almost exclusively with an 026 since they first came out. I'm normally felling, limbing, and bucking dead shagbark hickories that are in the 20" range. 90cc is definitely overkill for that. The 026 and dad's 028 do the job just fine, but the 036 definitely gets the job done faster. I looked at a few 038 saws over the years. An 038M would be stronger than my 036, but it weighs almost as much as my 064 so I opted against it. If I find myself wanting more than an 036 can give, I'm either noodling a big knotty piece that I can't lift onto a splitter, or (less likely) I'm into a log that could be anywhere from 26" to 36". I don't mind going to 90cc for those occasions, especially since all of my splitting is done in the back yard.

I've got a small bunch of 038 saws. A Magnum and Supers converted to magnums, saws were free. A bit heavy but I'm fond of them, reliable and easy to work on.

The Magnum I got from a logger friend free and it's well used and ugly but is still all OEM and P/C looks almost new inside. But it was one of the dirtiest filthiest saws I' ever saw when I got it. Wasn't running because the pump side of the carb cover was full of sawdust. It got a bath down to the bare cases and new filters.

The 038S were lean seizes I got for free, saws looked OK but P/C trashed. 1st conversion I did with NOS OEM parts the next one a Tecomec Italian kit. Refurbed what was needed, all new rubber parts. They chug through bigger rounds a lot more easy than the 036. I'll be worn out before they will.

 

[fields_mj]

At that price, I'd love them too

 

[Mad Professor]

At that price, I'd love them too

I had a few hundred into the conversions but all new P/C rubber, wear parts, new chains.....so they run like new.

 

[fields_mj]

I had a few hundred into the conversions but all new P/C rubber, wear parts, new chains.....so they run like new.

That's still a really good price. My biggest problem with OEM saws, especially the pro models or larger saws, is that people want top dollar prices for a saw that's either trashed or at least is ready for a rebuild. If you can get the carcass for a reasonable price (ie $50 or less), it makes it a lot easier to put OEM parts back in it. When they want hundreds of $$ for a saw that has been straight gassed, forget it.

 

[Mad Professor]

That's still a really good price. My biggest problem with OEM saws, especially the pro models or larger saws, is that people want top dollar prices for a saw that's either trashed or at least is ready for a rebuild. If you can get the carcass for a reasonable price (ie $50 or less), it makes it a lot easier to put OEM parts back in it. When they want hundreds of $$ for a saw that has been straight gassed, forget it.

Understood. My first 038 conversion a nice looking 038S was free, I found a OEM/NOS 038M P/C set for $150. With the rest of the parts that were all NOS/OEM I was under $300.

If got a few more projects if I find the time. I have a running (good P/C) 064 that needs a new ignition I paid $200 for that. Need to fabricate mounts to be able to use the newer coils. This was a CL find.

But it came with a box of other (3) saws/parts. One is a very nice looking 026 that seems to be straight gassed, I have spare NOS OEM P/C kit and piston kit I got cheap for spares for my running saws.

Another is a partially cannibalized 028S but has OEM P/C in good shape, that is a spare for my running 028S.

The third saw was also partial, but turned our to be a 024S. Lots of parts that fit my 026 saws.

There is also a herd of 056, two run but need work, and parts saws. Of the runners both are 056M one needs ignition and well worn, the other just needs an oiler and is nice shape. I have $50 into those and the latter came with another lean seize 026.

I never did Huskys but was given a 61 that was running but sat for years, and a 257 that looks OK but know no history of.

Don't have time for all of the above.....

 

[fields_mj]

Understood. My first 038 conversion a nice looking 038S was free, I found a OEM/NOS 038M P/C set for $150. With the rest of the parts that were all NOS/OEM I was under $300.

If got a few more projects if I find the time. I have a running (good P/C) 064 that needs a new ignition I paid $200 for that. Need to fabricate mounts to be able to use the newer coils. This was a CL find.

But it came with a box of other (3) saws/parts. One is a very nice looking 026 that seems to be straight gassed, I have spare NOS OEM P/C kit and piston kit I got cheap for spares for my running saws.

Another is a partially cannibalized 028S but has OEM P/C in good shape, that is a spare for my running 028S.

The third saw was also partial, but turned our to be a 024S. Lots of parts that fit my 026 saws.

There is also a herd of 056, two run but need work, and parts saws. Of the runners both are 056M one needs ignition and well worn, the other just needs an oiler and is nice shape. I have $50 into those and the latter came with another lean seize 026.

I never did Huskys but was given a 61 that was running but sat for years, and a 257 that looks OK but know no history of.

Don't have time for all of the above.....

Now that I'm in saw repair mode, I'm hoping to also have time to fix my 064. It locked up on me a couple of years ago. Pretty sure it has an air leak, so now I'll have a chance to test for that. I haven't even pulled the cylinder off yet. If I can get it back up and going, I'll probably look for a 25" bar to run on it to keep the weight down and give me something lighter than my 066 clone and its 28" bar.

 

[Mad Professor]

Now that I'm in saw repair mode, I'm hoping to also have time to fix my 064. It locked up on me a couple of years ago. Pretty sure it has an air leak, so now I'll have a chance to test for that. I haven't even pulled the cylinder off yet. If I can get it back up and going, I'll probably look for a 25" bar to run on it to keep the weight down and give me something lighter than my 066 clone and its 28" bar.

Test the 064 before tear down.

Save the OEM 064 cylinder if possible, for pistons OEM is best but Meteor is <1/2 price w/Caber rings. What is the vintage of the 064? Early ones, like mine have the problematic Bosch coil. There are work arounds for that @L34 did some great work on that. I was lucky my 064 already had the HD Air Filter upgrade.

Again not sure of your vent problems on the 036. I'm running 2 036 PROs now, one has been problem free except wear parts/cleaning/upkeep, the other I rebuilt close to new.

If I can help, ask.

 

[fields_mj]

Test the 064 before tear down.

Save the OEM 064 cylinder if possible, for pistons OEM is best but Meteor is <1/2 price w/Caber rings. What is the vintage of the 064? Early ones, like mine have the problematic Bosch coil. There are work arounds for that @L34 did some great work on that. I was lucky my 064 already had the HD Air Filter upgrade.

Again not sure of your vent problems on the 036. I'm running 2 036 PROs now, one has been problem free except wear parts/cleaning/upkeep, the other I rebuilt close to new.

If I can help, ask.

My plan for the 064 was to remove the exhaust and carb and put a rubber seal under them to seal them off, and then do a leak test on it before going any further. I have a coworker who can split the case and replace the seals if needed. If I were a betting man, I'd bet that it has a leak. It's just a question of whether or not there's any additional damage that would make it harder to repair. I had to have the top end rebuilt on it several years ago. I got lucky and had a local forum member reach out to me and offer to take a look at it. He built race saws as a hobby and happened to have a good OEM piston and cylinder sitting on the shelf. He did the work for $50. I gave him a Benjamin and told him to take his wife out for a stake dinner on me. Back then you could do that for around $50.... He warned me then that he thought it might have a slight air leak, but he did have a tester to check it. I normally didn't run that saw wide open for very long at a time. Mostly used it to noodle large rounds which only took 20 sec or so per cut. I started having issues while working on a 36" oak in the yard that the power company took down for me. After the rebuild, it ran fine so I didn't worry much about it. I took down a large (+60") pin oak in the back yard and got a 41" bar for the project. The saw started to seize while cutting up part of the trunk. I suspect the air leak caused it to run lean, and I was running it hard enough that it cost me. After I check for leaks, I'll decide what the repair process is going to look like. My guess is that I'm going to clean it up real good, remove the top end, and then have my co-worker put new bearings and seals in it while I try to clean up the cylinder. I think I also have the original jug for it in my shop. I stumbled across a Mahle cylinder last week while looking for my piston ring tool kit in the shop. I didn't spend a lot of time looking at it, but it didn't look like it was in real bad shape. With a little luck, I might be able to get it running with a set of bearings, seals, and a new piston. As far as the version goes, it has the bigger air filter like an 066. I'm not sure if there were any other differences in them. Also not sure what carburetor is on it. Just never looked.

I'm not sure if I have a vent problem yet on the 036. I know I had been running a rich mix, and I suspect that the tune was rich also leading to a lot of carbon build up that eventually caused a problem. I put a new impulse line on it 2 years ago, along with a new carb and spark plug. The issue was the impulse line, but I tried a new carb and sparkplug first because they are easy to replace. I didn't notice any issues with carbon build up at that time, but it was sure caked up when got into it this time. Had I just put a new plug in it (or cleaned the current one), the saw probably would have ran but I ended pulling the front of the muffler off first just to check on things. Glad I did actually. The vacuum tester arrives tomorrow. Probably won't have time to do anything with it until the weekend, but I should know more after that. In the mean time, I need to order a couple of rebuild kits for the carb. I still have the previous ZAMA sitting on the shelf along with a Tillotson that I picked up that was supposed to be rebuilt but isn't giving the saw any fuel (tried it on 2 different saws). I need to soak them both in some acetone and put new rubber in them and see how they do. I now run ethanol free fuel, but I still like to have a good working carburetor sitting on the shelf...