MS180 air filter mod

[mad_mat222]

Went to service the saw and the filter has leaked again. Round peg into an oval hole never works and over time the filter stops sealing around the intake tube. The more revs = more suction on the filter which pulls it off the intake tube = more dirt bypass ‍‍


The design is really poor. You can see the dirt bypassing near the flat part of the tube(for the carb impulse). Dirt can be seen on the clean side of the top cover as well

So this is my fix.

The intake tube OD in the air box is 26mm. Got a bit of pvc tube close enough and a socket that had an OD of 26mm. Heated up the pvc with a butane torch and used the socket as a mandrel and stretch to size. Allow to cool on the socket but keep moving on the socket to keep uniform sizing. I sprayed a little silicon in the socket to help removal.

Placed on intake and mark angle of filter. Start cut on pvc above intake tube. I just used the bench grinder to shape. Deburr. Refit and re check. Find a fairly long split pin. I chose a 3.2mm x 40mm stainless pin. Make sure pvc is pressing filter down firmly but not crushing it (There are several plastic locating tubs underneath filter). I happened to have a 3.3mm drill and drilled a hole through. I located the hole touching the filter so the pin would also help hold it down. insert pin on the short side. This prevents the pin being able to fall out and enter the engine. Using a pin this way, makes it a quick change.

Green pen shows contact area with pvc. A seal is created between pvc and intake tube and filter. Also draws the air away from the leak prone area of the intake tube.

The only concern I have is that the pin may wear it’s way through the plastic.



Forgot to take a pic but just need to adjust the front of the mod to give clearance for the sealing lip on the top cover. I heated mine up a bit and made the front of the mod more vertical.

 

[Jasonrkba]

I never understood what Stihl seen in this design. There is a lot they could have done differently with these saws that would have made them much better and wouldn't have costed more.

 

[J D]

I never understood what Stihl seen in this design. There is a lot they could have done differently with these saws that would have made them much better and wouldn't have costed more.

For homeowner grade equipment the goal for most manufacturers these days is to produce a product that lasts the warranty period & that's about it... Case in point

 

[HarleyT]

The dirt seems to be entering here. Is that an aftermarket filter, they fit poorly. And yes, I know dealers that sell the aftermarket ones as oem.

 

[mad_mat222]

100% genuine. They fit ok when brand spankers when All the edges are square, but over time the edges compress around that intake tube and pass dirt because there is no sealing edge. The filter is literally just resting against that tube. Whoever came up with the idea of sticking a dirty great hole in the middle of an air filter needs to be keel hauled.

 

[MagraAdam]

I have to say that I don't have a problem on my 170, and it gets a lot of use. I use after market filters and they are fine.

 

[SawTrash]

The air filtration on the MS180 appears to be the same as on the MS170 and yes, it does work very well but only UNTIL the cover is taken off or the filter is removed.

Once the filter is disturbed it cannot be reused satisfactorily and a new one is required.

Whether the design is good or not depends on which side you are on. From the owner's point of view it's bad, from Stihl's or the dealer's it's good.

My fix is easy, cheap and works well.

Using the original filter as a template cut a slightly larger piece from a vacuum filter bag. Punch a 7/8 inch hole as shown in the pic. Vacuum all the dust and grit off the old filter and replace. Put the newly cut piece
over and work it tightly around the intake spigot. Replace cover carefully. Saw wood.

I have not noticed any diminution in performance - and there's no way to adjust the 170 carb anyway.

 

[J D]

I have not noticed any diminution in performance - and there's no way to adjust the 170 carb anyway.

Sounds like a good fix. I have a couple of older saws I use the trimmed vacuum filters on & it has worked well so far.
For the 170/180's I usually either replace the fixed jet in the carb with one of the earlier, slightly bigger ones... Or drill it out by 0.05mm to get them running right

 

[MagraAdam]

do your filters start out round or oval in the hole. Mine are round.. https://www.chainsawspares.com.au/2x-air-filter-cleaner-for-stihl-chainsaw-017-018-m

 

[mad_mat222]

do your filters start out round or oval in the hole. Mine are round.. https://www.chainsawspares.com.au/2x-air-filter-cleaner-for-stihl-chainsaw-017-018-m

Early 170 and 180’s had a round hole. Later models went to the oval shape. Not sure what year.

 

[J D]

Just came across this

 

[K-techcowboy]

Went to service the saw and the filter has leaked again. Round peg into an oval hole never works and over time the filter stops sealing around the intake tube. The more revs = more suction on the filter which pulls it off the intake tube = more dirt bypass ‍‍
View attachment 912379View attachment 912380

The design is really poor. You can see the dirt bypassing near the flat part of the tube(for the carb impulse). Dirt can be seen on the clean side of the top cover as well
View attachment 912381View attachment 912382
So this is my fix.

The intake tube OD in the air box is 26mm. Got a bit of pvc tube close enough and a socket that had an OD of 26mm. Heated up the pvc with a butane torch and used the socket as a mandrel and stretch to size. Allow to cool on the socket but keep moving on the socket to keep uniform sizing. I sprayed a little silicon in the socket to help removal.

Placed on intake and mark angle of filter. Start cut on pvc above intake tube. I just used the bench grinder to shape. Deburr. Refit and re check. Find a fairly long split pin. I chose a 3.2mm x 40mm stainless pin. Make sure pvc is pressing filter down firmly but not crushing it (There are several plastic locating tubs underneath filter). I happened to have a 3.3mm drill and drilled a hole through. I located the hole touching the filter so the pin would also help hold it down. insert pin on the short side. This prevents the pin being able to fall out and enter the engine. Using a pin this way, makes it a quick change.

Green pen shows contact area with pvc. A seal is created between pvc and intake tube and filter. Also draws the air away from the leak prone area of the intake tube.
View attachment 912392
The only concern I have is that the pin may wear it’s way through the plastic.

View attachment 912397

Forgot to take a pic but just need to adjust the front of the mod to give clearance for the sealing lip on the top cover. I heated mine up a bit and made the front of the mod more vertical.

Wish I could get away with that but I already don't get enough air in my alcohol burning 180c

 

[MS420]

Short time lurker, first time poster.

I found this forum after looking for info on the MS170 and discovering the marginal air filtration arrangement that this thread discusses. After reading through the above and a little thought I’ve had an idea:

Executive Summary.

Perhaps we can make a better air filter for these using woven stainless steel mesh and 3D printing.

Background.

The first chainsaw I ever used, growing up on an orchard, was a Stihl 031AV. As many of you would know better than me, it has a filter “box” that consists of stainless mesh on a plastic framework. Easily “dust off-able” in the field and washes out easily back in the workshop. Infinitely reusable provided you’re careful with it. I gather that many other Stihl saws have used similar over the years.

As several have commented in this thread, air filtration on the MS170/180 could have been done better (by Stihl) but we now have the means at our disposal to do it better ourselves.

Woven stainless steel mesh of various grades and in small quantities is readily available on eBay at relatively low cost and with 3D printing available to the home user/hobbyist, the idea of printing a plastic framework and embedding some suitable stainless mesh in it looks quite doable. With the right grade of plastic used, the centre “oval” to go around the intake tube could be a snug but slightly flexible fit and with a few strengthening ribs in the right place the finished article should be robust enough to be reused many times over and provide superior filtration and in-field serviceability without the “bypass” that anyone with a 017/018/170/180 will have seen.

Now I don’t have a 3D printer or any direct experience in using one but if there’s someone on this forum who does I’d be happy to work with them on a prototype or two and see what we can come up with. We’d need to do two different versions (for early and late airboxes, but the differences are small and what works for one ought to readily adapt to the other.

If the idea has legs, maybe a small production run could be arranged. Or the files and “how to” we develop could be put in the public domain for anyone to use.

Any experienced 3D printing fabricators out there?

 

[BrianC]

Someone comes up with the concept, I can get it modeled and printed for next to nothing.

 

[C George]

Stihl makes a HD 3 stage air filter for the 170 / 180 saws ,,, so much better than the oem filter. I still use a little grease around the center hole for sealing

 

[C George]

https://www.google.com/search?q=sti...#fpstate=ive&vld=cid:f9bde55b,vid:-UrUNLp4bWk

 

[C George]

Put a small amount of grease around the lower outer part of intake hole

 

[C George]

If you want to make your 180 run the way it should after installing the Stihl 3 stage air filter , remove the intake insert , silicone over compensating part of the intake snorkle and drill a 1/16" hole in carb snorkel top to allow the fuel diaphram to move . Now you have a great running 180