Mastermind Meets The Husqvarna 3120

[Metals406]

Still sorting out the carb tune....it's tough to get lean enough.

Unless Bertrand set it, I bet the pop-off is nutty high! Probably 20-30 instead of around 12-16(ish).

 

[Mastermind]

The machining part is actually quite simple, and I understood why you did what you did. You wanted to lower the intake port, but couldnt take it all off the base or the piston would hit the top of the cylinder (which is was already doing). Therefore you compromised on the base, machined the desired clearance into the squish, and adjusted the port to achieve the final result.

Is that correct?

What was the driving reasons behind lowering the intake port? Does this increase the charge air by opening the port sooner for a longer duration? I am guessing it is years of experience that gave you the .080" adjustment in the port.

I think one day I'll grab a cheapie chainsaw and hook into it. I have my 4620 Mac at home, it may become the test bed.

Thanks for the help Randy

Graham

You have it all figured out Graham. Yes the .080 comes from using a degree wheel to determing how much the port needed to be lowered to get the timing at the point I wanted, and what I wanted comes from building many, many engines.

Unless Bertrand set it, I bet the pop-off is nutty high! Probably 20-30 instead of around 12-16(ish).

Yep.......it was really high. I used a weaker spring for a guesstimation. I need a pop-off tester.



Video is uploading now.....

 

[Metals406]

You have it all figured out Graham. Yes the .080 comes from using a degree wheel to determing how much the port needed to be lowered to get the timing at the point I wanted, and what I wanted comes from building many, many engines.



Yep.......it was really high. I used a weaker spring for a guesstimation. I need a pop-off tester.



Video is uploading now.....

Don't you have a MityVac?

 

[Mastermind]

Don't you have a MityVac?

Just a vac tester. I'm working on a tester the uses a blood pressure tester bulb....just need the gauge yet.

 

[Mastermind]

With a 9 pin rim 32" bar....

[video=youtube;M7wSs7GX0MU]http://www.youtube.com/watch?v=M7wSs7GX0MU&feature=youtu.be[/video]

 

[WKEND LUMBERJAK]

Looks like it may cut up some tooth picks.:msp_biggrin::msp_biggrin:

 

[wendell]

In that first video I saw those legs and figured you had your wife testing the saw for you.

This get you to #1? :msp_wink:

 

[o8f150]

Randy, you could sue those legs for non-support :hmm3grin2orange:

looks like a pair of chicken legs to me:msp_biggrin::msp_biggrin::msp_biggrin:

 

[o8f150]

Just a vac tester. I'm working on a tester the uses a blood pressure tester bulb....just need the gauge yet.

you mean like this

 

[o8f150]

With a 9 pin rim 32" bar....

[video=youtube;M7wSs7GX0MU]http://www.youtube.com/watch?v=M7wSs7GX0MU&feature=youtu.be[/video]

sounds good, sure holds the rpms
now for the legs you must use a venus shaver:msp_biggrin: sorry,, i couldn't resist

 

[Mastermind]

Some more pics.....of the saw....not my boney legs. :msp_biggrin:

I lowered the jug so much that the flywheel was rubbing the jug here.

So I chucked up the flywheel....

....and cut a bit off.

In this shot you can tell how much larger the exhaust flange outlet is over stock.

Some shots of the muffler mods.

Check out this 066 piston sitting on the 3120 piston.

 

[o8f150]

good job randy,,, very educational seriously,,, wish i could do porting like that,,, guess some day i will

 

[promac850]

You sure know your balls :hmm3grin2orange:

Yeah, I've got six of them. Quantity with decent quality...

 

[o8f150]

Yeah, I've got six of them. Quantity with decent quality...

:waaaht::sick::sick: are you serious??? wake up,,, its only a dream :msp_biggrin::msp_biggrin:

 

[Dan_IN_MN]

I've used a drill bit or a bolt to plug the fuel line too! Nice work! Nice to work on something you don't have to clean up!

 

[Mastermind]

I've used a drill bit or a bolt to plug the fuel line too! Nice work! Nice to work on something you don't have to clean up!

I've had that same bit in a lot of pics.......I've been asked what it's for more than once.

 

[Graham99]

Saw you tested with a Stihl bar in a husqvarna chainsaw. They didnt want to fight did they? :biggrin: All the stihl fans will be saying it's only that good with a stihl bar

Thanks for the explanation earlier Randy.

Regards
Graham

 

[Nardoo]

Finally, I have something to add on a build thread.
I use golf tees to block off fuel/impulse lines. There, I feel much better.

Al.

 

[Roll Tide]

Saw you tested with a Stihl bar in a husqvarna chainsaw. They didnt want to fight did they? :biggrin: All the stihl fans will be saying it's only that good with a stihl bar

Thanks for the explanation earlier Randy.

Regards
Graham

Hey Randy you know that saw wouldn't have pulled half that good without that stihl bar oke:

 

[SawTroll]

Randy, you could sue those legs for non-support :hmm3grin2orange:

Looks like something is wrong with the hight/width relationship in that video......:msp_wink: