Dang Harley, are you the saw police? Chill
Stihl 026 Pro - Not Enough Bar Oil?
- Thread starter SteveSr
- Start date
Help Support Arborist Forum:
- Joined
- Dec 6, 2014
- Messages
- 21,181
- Reaction score
- 25,045
Yes.... I was kidnapped by them......... sniff.....
You are worse than the ,Energizer Bunny!!....LOL
Bilge Rat LT 20
ArboristSite Operative
Is this a new, unused bar?
I have found with a brand new bar you need to make sure the oil holes in it are clear. I usually enlarge the holes a little myself.
The oil holes line up with the saw oil slot?
With the new bar the chain slot is tight and the rail tops need to be broken in to run smooth. Any paint needs to be worn off too.
I found that running the chain a little looser than normal prevents the chain from binding due to the bar heating up/expanding. After a tank or 2 of gas the lack of oiling and chain tightening go away. Then everything is normal.
I have seen this on 2 saws with new Stihl bars in the last few months.
Try sloshing a little gas mix in the oil tank to clean it and the filter of any old crud from sitting.
Tank pressure will move more oil out. If the tank goes into a vacuum oil flow is restricted.
I have found with a brand new bar you need to make sure the oil holes in it are clear. I usually enlarge the holes a little myself.
The oil holes line up with the saw oil slot?
With the new bar the chain slot is tight and the rail tops need to be broken in to run smooth. Any paint needs to be worn off too.
I found that running the chain a little looser than normal prevents the chain from binding due to the bar heating up/expanding. After a tank or 2 of gas the lack of oiling and chain tightening go away. Then everything is normal.
I have seen this on 2 saws with new Stihl bars in the last few months.
Try sloshing a little gas mix in the oil tank to clean it and the filter of any old crud from sitting.
Tank pressure will move more oil out. If the tank goes into a vacuum oil flow is restricted.
SteveSr
Addicted to ArboristSite
This bar and chain is almost new so I will take your advice and try loosening the chain a bit. It is a Stihl bar and I would hope that they know how to drill the oil holes but I will double check. I have seen similar issues minus the leaking cutting big sappy pine but nothing this bad that it wouldn't cut 8" maple.
Just asking, but is the chain correct size for the bar? I saw this issue with a husky last week, the old guy was using a .050" bar with what he thought he bought was a .050" chain. While we were trying to figure out why the saw would not oil correctly and bog down in a cut we removed bar and the chain noticing the bar was worn out you might as well say, then we checked the numbers on both come to find out the chain was a .063" chain after I looked it up on oregon's website, it wore the crap out of the bar and was not oiling properly. I ordered him the a new husky bar with the correct size chain, after the install we tested it on a piece of ash at his place and now the saw oils and cuts like it should.
SteveSr
Addicted to ArboristSite
I have heard of this before in a thread about bar reconditioning. This particular b&c combination has been used on similar saws without this issue.
abikerboy
ArboristSite Operative
I don't think that any parts have been mixed up. Op says it's a stock 026 pro, with new piston & cylinder, which the pro version comes with the adjustable oiler from the factory. To the op, I'm wondering if the oil pump bore or oiler piston isn't just worn out. That would explain both the low volume of oil and the leaking, as the oil may be just flowing around the worn oiler piston and leaking from the bar oil hole even when the saw is at rest. I was just looking at a parts breakdown on the pump for that saw, and it doesn't appear to have any O-rings or seals on the piston, so I can see where any extra clearance between the piston and pump body would easily throw things out of whack.
SteveSr
Addicted to ArboristSite
To continue the saga... I removed oil pump and flushed as much as possible with kerosene. BTW, to get the outlet hose off of the pump without damaging it just heat up the pump a little with a heat gun or hair dryer and this will soften the hose enough to allow it to be pulled off without damage. Same thing for reassembly. Came back the next day and it was still leaking.
Came back today and did some research via several different IPLs to see if the pump had changed over time. My IPLs only go back to 1999 and not the origin of the "Pro" models, I believe in 1996. It looks like the pump has remained unchanged until the somewhere in the mid MS260 era where it looks like they added a rear bearing to the pump piston.
Next I decided to tear the pump all the way apart to see if there was still crud in it that wasn't flushed out. I used a small drill bit as a drift to punch out the roll pin that holds it all together. Once it was in pieces I could figure out how it was supposed to work.
The oil pump is a piston pump. For this to work requires a check valve on each side of the pump. Upon disassembly no check valves could be found in the pump. A closer look at the pump piston revealed the secret. The piston itself rotates and the tip of the piston is machined to cover/uncover both the intake and output ports during rotation. this is what provides the check valve action. I wish I held the patent on this clever design!
For a leak to occur requires several conditions:
1. The tank vent valve has to be working to allow oil tank pressure build up as temperature changes. No pressure - no leak!
2. There is a direct potential leak path right through the pump around clearances between the piston and pump body. In this case dirt/crud in the pump may be your friend!
3. There appears to be a "bad" rotation position of the pump piston which may uncover both input and output ports of the pump facilitating a leak. I thought that I noticed this characteristic when applying air to the pump inlet while rotating the piston.
The pump is now back on the saw and it will be a few days before I can check it again. I suspect that it will probably still leak. Mounting the bar may actually slow it down or at least give the oil a place to go.
In response to others questions about pump wear being the issue this appears to have been a homeowner's saw with very little use. The pump parts that I was able to examine showed absolutely no signs of wear.
Came back today and did some research via several different IPLs to see if the pump had changed over time. My IPLs only go back to 1999 and not the origin of the "Pro" models, I believe in 1996. It looks like the pump has remained unchanged until the somewhere in the mid MS260 era where it looks like they added a rear bearing to the pump piston.
Next I decided to tear the pump all the way apart to see if there was still crud in it that wasn't flushed out. I used a small drill bit as a drift to punch out the roll pin that holds it all together. Once it was in pieces I could figure out how it was supposed to work.
The oil pump is a piston pump. For this to work requires a check valve on each side of the pump. Upon disassembly no check valves could be found in the pump. A closer look at the pump piston revealed the secret. The piston itself rotates and the tip of the piston is machined to cover/uncover both the intake and output ports during rotation. this is what provides the check valve action. I wish I held the patent on this clever design!
For a leak to occur requires several conditions:
1. The tank vent valve has to be working to allow oil tank pressure build up as temperature changes. No pressure - no leak!
2. There is a direct potential leak path right through the pump around clearances between the piston and pump body. In this case dirt/crud in the pump may be your friend!
3. There appears to be a "bad" rotation position of the pump piston which may uncover both input and output ports of the pump facilitating a leak. I thought that I noticed this characteristic when applying air to the pump inlet while rotating the piston.
The pump is now back on the saw and it will be a few days before I can check it again. I suspect that it will probably still leak. Mounting the bar may actually slow it down or at least give the oil a place to go.
In response to others questions about pump wear being the issue this appears to have been a homeowner's saw with very little use. The pump parts that I was able to examine showed absolutely no signs of wear.
SteveSr
Addicted to ArboristSite
Thanks to the nasty weather and other priorities it has taken a while to get back to this. I also wanted to do enough testing to verify that my conclusions were valid. Since I disassembled, cleaned out, and reinstalled the oil pump the saw has been used 3 different times.
The results are that the saw has not leaked bar oil onto the garage floor since the pump cleaning. It also appears to be putting out more oil than it did before the pump cleaning. Unfortunately, I don't have a good way of measuring bar oil output.
So it would appear that the crud from the oil tank can make its way into the pump where it can impede oil flow as well as allowing oil to leak past the oil pump piston.
The results are that the saw has not leaked bar oil onto the garage floor since the pump cleaning. It also appears to be putting out more oil than it did before the pump cleaning. Unfortunately, I don't have a good way of measuring bar oil output.
So it would appear that the crud from the oil tank can make its way into the pump where it can impede oil flow as well as allowing oil to leak past the oil pump piston.
Well, I thought I would revive this thread because there is so much useful information and it occurred almost exactly a year ago in winter. I ran into the same problem with my Stihl 036. The saw was being stored for about a year in the garage and we have had some very cold January weather. I decided to service the saw, which was showing some oil leakage on the storage shelf. It had only about 1/4 tank left. I started the saw, still a bit cold, ran it awhile, tuned it a little, and then cleaned it up for a Pic to post here.
After letting it sit for two hours, I noticed a leak, raised it up above a drip pan with a block of wood and let it sit overnight in the shop at room temp. Next morning the pan was full of bar oil and the engine had leaked almost all of it out. I removed the bar and chain, removed the thin steel inner plate, cleaned things up, and noticed the oil tank vent hole was threaded for M4 but no screw was there. I installed a short M4 screw in that hole and waited. Drips stopped.
Next I filled the tank with fresh oil and watched some more. No drips. I reassembled everything, including the bar and chain, started the saw and ran it. Oiler was working fine. Then I took the saw and put it back above the drip pan and let it sit overnight. Next morning not a drop had dropped. I started the saw again to make sure I was still getting oil to the bar, and it was working flawlessly. Now is it possible that the short M4 screw I installed was the cure? Frankly, I'm not even sure that this threaded hole was a tank vent.
After letting it sit for two hours, I noticed a leak, raised it up above a drip pan with a block of wood and let it sit overnight in the shop at room temp. Next morning the pan was full of bar oil and the engine had leaked almost all of it out. I removed the bar and chain, removed the thin steel inner plate, cleaned things up, and noticed the oil tank vent hole was threaded for M4 but no screw was there. I installed a short M4 screw in that hole and waited. Drips stopped.
Next I filled the tank with fresh oil and watched some more. No drips. I reassembled everything, including the bar and chain, started the saw and ran it. Oiler was working fine. Then I took the saw and put it back above the drip pan and let it sit overnight. Next morning not a drop had dropped. I started the saw again to make sure I was still getting oil to the bar, and it was working flawlessly. Now is it possible that the short M4 screw I installed was the cure? Frankly, I'm not even sure that this threaded hole was a tank vent.
