Will Strato charged motors be less reliable long term?

[fordf150]

Let's be fair, they did develop elastostart. That's what - a bit of rubber in the starter handle? Gotta get up early to get ahead of those German engineers.

Flippy caps

 

[Chris-PA]

Flippy caps

"Wait a minute Fritz, I think we can add some more parts to this fuel cap!"

 

[Trx250r180]

I think in simple English what Ben is trying to get across is if both engines spin over the same amount of times use 10,000 for a number the strato saw using less fuel has has less oil on the bearings a regular saw that uses say 20% more for example will have had 20 % more oil ran through the bearings

 

[fordf150]

So who had the 4 mix trimmers first? Shinny or Stihl?

Good question

My quick Google search came up with 2001 for both of them. Summer for Stihl and fall for shindiawa

 

[redtractor]

I think in simple English what Ben is trying to get across is if both engines spin over the same amount of times use 10,000 for a number the strato saw using less fuel has has less oil on the bearings a regular saw that uses say 20% more for example will have had 20 % more oil ran through the bearings

The simple answer that seems to missed here is that the fuel savings are not from less mix (lube) to the bottom, but raw fuel not being used to push the exhaust gases out. All the mix going into the tank is for combustion, not waste.

 

[heyduke]

there's been a lot of irrelevant and incoherent noise on this thread but the central question, do strato saws hold up well or fail due to poor lubrication, has mostly been ignored. my only strato is a husky 575 with a lot of hard hours on it and plenty of abuse. it's pretty much replaced all my other 70cc class saws, my 272 and even my 84cc makitas. so let's cut to the point. husky strato saws have been around for a few years. has anyone experienced a crank bearing failure? don't all try to talk at the same time!

 

[fordf150]

Quite a few big end rod bearing failures on Stihl 362....can't say if it was because of less mix passing through the case or just poor quality though

 

[bwalker]

The simple answer that seems to missed here is that the fuel savings are not from less mix (lube) to the bottom, but raw fuel not being used to push the exhaust gases out. All the mix going into the tank is for combustion, not waste.

Except that the oil is deposited in the crank case prior to the fresh fuel charge being expelled out the exhaust in a traditional two stroke. So all that unburnt hc loss also leaves behind oil in the crankcase.
What's lost on quit a few is that upon entry into the motor the fuel portion of premix is vaporised and the oil portion is deposited in the crankcase.
The bottom line is a strato engine has much less oil flowing through it.

 

[heyduke]

Quite a few big end rod bearing failures on Stihl 362....can't say if it was because of less mix passing through the case or just poor quality though

this is a discussion of stratified charge chainsaws. i'm not familiar with 362's. the stihl website mentiontions that they feature "m-tronic" carbs but doesn't say anything about stratified charge or even low emissions. i'm confused, but it sounds like you've worked on them. are they stratos? if so, how do they acheive stratified charge? is there a separate circuit for injecting fresh air? thanks in advance for clearing this up.

 

[windthrown]

Cause I am sure you have worked on a few more 461's then Brad has?

No, because I have talked to the engineers that have designed them. Oh, but that makes me a ******* moron here, right? Because a garage hack thinks he knows more than the Stihl engineers that designed the saws. Yah, I have heard that argument.

 

[windthrown]

Well, that's an old discussion here - perhaps they are, but there is little evidence in the port configuration or timing. It's hard to see how it is unconventional in any way other than that cooling dohicky under the piston. Take a look at a Tanaka Pure Fire engine for a real exhaust delayed scavenging design.

Does Stihl actually claim the 461 is an exhaust delayed scavenging engine?

And talk about cooling and lubrication concerns!

I have posted it here several times before, to the blind it seems. Stihl calls the MS461 and the MS661 design "delayed scavenging" in their technical bulletins and emails to me, yes. From Stihl engineering: "...compared to the previous fresh air stratified two-cycle engine, the newer stratified scavenging on these saws uses exhaust rather than clean air." They say that the design of the carburetor and intake manifold are the same as those of previous conventional two stroke engine without fresh air stratified scavenging, but after the intake manifold the designs are different.

As for cooling concerns, that is exactly why they also added the 'Intake side ramp' in the crankcase. That is what the Stihl engineers call what you refer to as the 'cooling dohickey'. Its job is to shift the direction and velocity of the fuel charge for maximum cooling and lubrication. The design is not the same as the Tanaka engines. Call it what you want, but when the transfers open on the downstroke of the 461 and the 661, exhaust gases are stuffed into the transfers to create a stratified layer of exhaust gas between fuel charges. Its that simple.

Frankly I do not comprehend the bone-headed insistence about this, but WTF. Everyone is an expert here, and the Stihl engineers apparently do not know shiit about the saws that they design. Typical non-technical understanding of the world. They told us that the Tomahawk cruise missiles that we designed and built at GD would not work I the first Gulf War, but they did. Then the advanced cruise missile program that I was working on was cancelled. The Navy said, "we don't need it."

 

[redtractor]

Except that the oil is deposited in the crank case prior to the fresh fuel charge being expelled out the exhaust in a traditional two stroke. So all that unburnt hc loss also leaves behind oil in the crankcase.
What's lost on quit a few is that upon entry into the motor the fuel portion of premix is vaporised and the oil portion is deposited in the crankcase.
The bottom line is a strato engine has much less oil flowing through it.

After I posted and shut down, that point finally did get through to me. But I will say in place of the other is that when tuned properly on the rich side (not like a box store Wild Thang), plenty of the good modern oil that we have available gets in there.
All the stratos I've seen dead are from lean conditions in the cheap homeowner stuff. The hard evidence is yet to be collected on the better grade saws that have been set up correctly over time, but my money says that we won't see them dead in any greater numbers than any other configuration WHEN PROPERLY SET UP.

 

[blsnelling]

I have posted it here several times before, to the blind it seems. Stihl calls the MS461 and the MS661 design "delayed scavenging" in their technical bulletins and emails to me, yes. From Stihl engineering: "...compared to the previous fresh air stratified two-cycle engine, the newer stratified scavenging on these saws uses exhaust rather than clean air." They say that the design of the carburetor and intake manifold are the same as those of previous conventional two stroke engine without fresh air stratified scavenging, but after the intake manifold the designs are different.

As for cooling concerns, that is exactly why they also added the 'Intake side ramp' in the crankcase. That is what the Stihl engineers call what you refer to as the 'cooling dohickey'. Its job is to shift the direction and velocity of the fuel charge for maximum cooling and lubrication. The design is not the same as the Tanaka engines. Call it what you want, but when the transfers open on the downstroke of the 461 and the 661, exhaust gases are stuffed into the transfers to create a stratified layer of exhaust gas between fuel charges. Its that simple.

Frankly I do not comprehend the bone-headed insistence about this, but WTF. Everyone is an expert here, and the Stihl engineers apparently do not know shiit about the saws that they design. Typical non-technical understanding of the world. They told us that the Tomahawk cruise missiles that we designed and built at GD would not work I the first Gulf War, but they did. Then the advanced cruise missile program that I was working on was cancelled. The Navy said, "we don't need it."

You have "talked to Stihl engineers". I read that as you have read emails from Stihl. Nice try. All you're doing is regurgitating Stihl talk. Doesn't sound like you've every even been inside of one of these saws. For what you're saying to be true, there would have to be some kind of change in the port timing. THERE IS NOT. If the 461 is strato charged, then so is the 460, 046, 026, 066, you name it. Bottom line is, you don't really know what you're talking about. You're just repeating what you've been told.

 

[STIHLTHEDEERE]

"Wait a minute Fritz, I think we can add some more parts to this fuel cap!"

And yet still husky comes out with them as well?

 

[heyduke]

if i recall this thread is about the longevity of stratified chain saws. here we are seven pages in and not one post has mentioned a crankshaft or big end failure due to poor lubrication. so i'm going to conclude that stratified charge has no negative effects on lubrication and unsubscribe. i don't practice any religion and i'm certainly not going to blindly worship a brand of chainsaws. adios.

 

[Chris-PA]

And yet still husky comes out with them as well?

While I don't see the need for either, compare a flip out handle on a screw cap to the Stihl quarter turn flippy cap - what is the relative parts count?

 

[Chris-PA]

if i recall this thread is about the longevity of stratified chain saws. here we are seven pages in and not one post has mentioned a crankshaft or big end failure due to poor lubrication. so i'm going to conclude that stratified charge has no negative effects on lubrication and unsubscribe. i don't practice any religion and i'm certainly not going to blindly worship a brand of chainsaws. adios.

It was inevitable, as there wasn't really any issue to begin with.

 

[Trx250r180]

if i recall this thread is about the longevity of stratified chain saws. here we are seven pages in and not one post has mentioned a crankshaft or big end failure due to poor lubrication. so i'm going to conclude that stratified charge has no negative effects on lubrication and unsubscribe. i don't practice any religion and i'm certainly not going to blindly worship a brand of chainsaws. adios.

You obviously do not know how this site works ,You need to go through at least 10,000 posts and still find nothing benaficial out of the posts ,or anything answered that can be proven right or wrong ,but the bickering back and fourth gives us something to do .

 

[ArcticOverland]

You obviously do not know how this site works ,You need to go through at least 10,000 posts and still find nothing benaficial out of the posts ,or anything answered that can be proven right or wrong ,but the bickering back and fourth gives us something to do .

I know I am but what are you?

 

[fordf150]

this is a discussion of stratified charge chainsaws. i'm not familiar with 362's. the stihl website mentiontions that they feature "m-tronic" carbs but doesn't say anything about stratified charge or even low emissions. i'm confused, but it sounds like you've worked on them. are they stratos? if so, how do they acheive stratified charge? is there a separate circuit for injecting fresh air? thanks in advance for clearing this up.

yes they are strato. separate air valve. just had 6 more dropped off this morning with at least one of them needing a crankshaft