Read Gum dust and Stihl HD Filters

[isuzurover]

Perhaps someone mentioned it, but when working out flow rates of air through engines and filters, it is not just capacity but also volumetric efficiency (VE) that matters.

Anyway - back on filters... Here is some more detailed reading for anyone interested.
Image A in figure 3 gives you an idea what fibrous filters look like close up.
Filtration Efficiency of Aerosol Particles Below 20 Nanometers - Aerosol Science and Technology

Also notice that is the particles are small enough (generally <0.5 micron) then collection efficiency will go UP as particle size decreases

Have a look at the "sieves" or "meshes" - Image A and B in fig 3. Have a look at how they can collect particles MUCH smaller than the size of the gaps.

 

[tdi-rick]

[snip]


Filtration Efficiency of Aerosol Particles Below 20 Nanometers - Aerosol Science and Technology

[snip]

Hey, I've seen one of those authors names before ! :monkey:

BTW, tried to save it as a PDF but it came up with an error

 

[masculator]

That just sounds like that whoever is mixing the oil isn't mixing it properly ?

Most two stroke oils these days contain solvents to aid mixing and keep the oil in suspension, (particularly the JASO spec ones) but some still don't and the old time race oils didn't and we had to mix and mix and shake just ensure dispersion in the fuel.
I've watched a few people 'mix' their mix and it's been a cursory up and down shake and that was it :msp_rolleyes:

No it is more that the oil is not remaining in suspension or for that matter dissolving thoroughly in the fuel, you can even see that the oil loses the colouration and the solvents when you pull the carby down. When I mix fuel I put the oil in my can then go to the servo, can guarantee that mixes it. Really if the person mixing it was the problem they would still be having the issue and would have before they swapped to that brand. they have swapped back to what they were using and no more issues. They have even taken our advice and gone away from using united as their petrol supplier. Now the only time we see there equipment is for the regular servicing again instead of breakdowns.

 

[masculator]

No probs mate,maybe we should have a thread for the Ozzys to have yack and talk BS.

consider it done!

 

[tdi-rick]

fair enough but it could still be a mixing issue.

While not trying to defend Penrite (I've had issues with their advertising and philosophy of 'thicker is better'in the past) if the user has gone to something like one of Castrols blends where they use a reasonable amount of solvent to ensure good mixing that can overcome any potential problems.

I use Motul 8002T and there aren't any added solvents so I really make sure I mix it well, but it's a pure race oil.
Motul 510 and 710 2T meet injector specs so i suspect they would mix very easily.

The oil that came with the Makita (blended by Spectrum in the US) mixed very easily as it is fairly thin (meets injector oil specs) so obviously has some solvents in it.
Castrol TTS mixes really easily too

 

[MCW]

Castrol TTS mixes really easily too

It mixes really well but the fumes from the saw when running TTS are pretty acrid. It'll take your breath away and burn the nose when milling or stumping. I don't use it anymore because of that fact and it's price.

 

[tdi-rick]

It mixes really well but the fumes from the saw when running TTS are pretty acrid. It'll take your breath away and burn the nose when milling or stumping. I don't use it anymore because of that fact and it's price.

Yep, I can't cope either, it gives me a hell of a headache.

Mentioned in another thread recently too, but Trav just insinuated I was a nancy boy.

 

[husq2100]

So I walked into the loacl Kart shop and these are the oils they had on the shelf:

Castrol R30
BelRay GK-2
Elf HTX976
Elf HTX909
Fuch Silkolene Pro KR2
Fuch Sikolene Pro CCA Ultra
Motul Kart Grand prix 2T
Xeramic Synmax Full Syn 2T
and some Amsoil that I didnt get written down

oh and Maxima 927....

its a bugger having options hey

 

[tdi-rick]

So I walked into the loacl Kart shop and these are the oils they had on the shelf:

Castrol R30
BelRay GK-2
Elf HTX976
Elf HTX909
Fuch Silkolene Pro KR2
Fuch Sikolene Pro CCA Ultra
Motul Kart Grand prix 2T
Xeramic Synmax Full Syn 2T
and some Amsoil that I didnt get written down

oh and Maxima 927....

its a bugger having options hey

and none of them work that well on a filter

 

[MCW]

Yep, I can't cope either, it gives me a hell of a headache.

Mentioned in another thread recently too, but Trav just insinuated I was a nancy boy.

Trav has a point Rick but remember he's 6'7" so gets fresh air from the stratosphere unlike us. He's too far away to get "fumed"

The worst I've had was stumping about a 50" fresh Pine tree with the 42" bar and 3120. The TTS AND the pine sap was something else straight off the big Husky's exhaust...

 

[tdi-rick]

So I walked into the loacl Kart shop and these are the oils they had on the shelf:

Castrol R30
BelRay GK-2
Elf HTX976
Elf HTX909
Fuch Silkolene Pro KR2
Fuch Sikolene Pro CCA Ultra
Motul Kart Grand prix 2T
Xeramic Synmax Full Syn 2T
and some Amsoil that I didnt get written down

oh and Maxima 927....

its a bugger having options hey

I can tell you which ones I wouldn't use in a saw

 

[tdi-rick]

Trav has a point Rick but remember he's 6'7" so gets fresh air from the stratosphere unlike us. He's too far away to get "fumed"

The worst I've had was stumping about a 50" fresh Pine tree with the 42" bar and 3120. The TTS AND the pine sap was something else straight off the big Husky's exhaust...

hahahah, I'm told 5" can make the world of difference

 

[husq2100]

I can tell you which ones I wouldn't use in a saw

go on.....................................

 

[tdi-rick]

go on.....................................

R30 and HTX909, unless you were pulling 15,000RPM or more in the cut

Too dirty unless you are pulling the head frequently for a decarb, but 909 is possibly the best two stroke oil ever blended for outright protection for high HP/high revs.

You still using 927 ?

 

[husq2100]

im blending 927 about 50/50 with husky xp.....at 40-1 in all work stuff. When i get this 272 built it will run 927 straight....

 

[masculator]

hahahah, I'm told 5" can make the world of difference

Not when you are on your knees pushing a 660 with a 42 inch bar in a gb mill it doesnt!!! its loud and oily and makes the throat burn! be you 3'6" or 10'8"

 

[MCW]

Not when you are on your knees pushing a 660 with a 42 inch bar in a gb mill it doesnt!!! its loud and oily and makes the throat burn! be you 3'6" or 10'8"

Bloody hell Trav, are you saying you know somebody 10'8"???
How long are the rails you got for your GB? I've got a 60" and 42" setup for mine. I wish I had time to use it more

 

[masculator]

Bloody hell Trav, are you saying you know somebody 10'8"???
How long are the rails you got for your GB? I've got a 60" and 42" setup for mine. I wish I had time to use it more

Not sure but it would take lots more than the 42 inch bar I run! and no I don't know anyone that tall!would have to check just what it would take but I would reckon 50 wouldn't be out of the question!

 

[MCW]

Not sure but it would take lots more than the 42 inch bar I run! and no I don't know anyone that tall!would have to check just what it would take but I would reckon 50 wouldn't be out of the question!

I had to get my own rails. I got my GB mill when GB were going through the ringer for the 2nd time and it was an absolute nightmare - in the end I just got a few bits in a box and was told you find the rails and you'll have to build it yourself!
I used Unistrut and alloy tube. Made it to the length I needed - Unistrut is tough as all hell but heavy.

 

[Stihlman441]

Ok guys i have an up date on the new Stihl HD2 filters for 440 to 880.
As you allready know how we Ozzys have truble with the very fine Red gum dust getting through the old HD filter the one with the felt pre filter on it.
The other day i was cutting dry Swomp gum with the newish Snellerized 660 (with the old HD filter) and a 460 with the new HD2 filter,used two or three tanks of fuel in each.
These are pics of the 660 with the old HD filter.you can clearly see the dust stuck on the spit back cover.