BraumrAg SX92/Giantz "92cc"

[BaronVonChickenPants]

Can anyone identify what this might be a clone of?

https://www.ebay.com.au/itm/283968247319

I have 1 each of the Giantz and BraumAg SX92 mkii, not the gen2 which is actually the mkiii. They are the same saw with the exception of the pull cord mechanisms, the Giantz has a clock spring you pull against that unleashes into the motor half way through the pull.

I have had the Braumr for a while and it has worked pretty hard slab milling iron bark and spotted gum with a 42" bar. It would be full depth cut at full noise for ~30 mins at a time before stopping to fill fuel and oil and go again. With 1 fuel stop it took 1 hour per cut on 6m long 1m wide spotted gum that had been dead a few years.

The math says they are closer to 87cc:
51mm dome top piston
43mm travel from bottom of muffler port to squish band.

I put the original 24" in a safe place, which is yet to be discovered. While shopping for a new 24" bar I found the identical looking Giantz saw for basically the same price as a bar and 2 chains. Take from that what you will.

When the Giantz arrived I pulled both saws down to compare and perform a bgd.

Compared to my Husky 281XP the carb, transfer ports and muffler port are enormous.

The carb mounts directly to the crankcase.

Muffler port is 41 x 16mm. Which seems pretty wide for a 51mm piston, even with a support in the middle.

There is a lot more scoring than I expected on the piston and cylinder for a saw with maybe 200 hours on it.

Open to suggestions on how to minimise the scoring and possible replacement cylinder and piston made with less chinesium.

 

[Deets066]

Milling for that long with that big of a bar is asking a lot of any saw. Almost need another source of cooling.

 

[Deets066]

I wanna see pics of that slab.

 

[Maintenance Chief]

I'm not sure what it's supposed to be a clone of ,but that cylnder almost looks like a Homelite.

 

[Nutball]

Probably a clone of chinese saw. they seem to clone their neighbors stuff a lot with like 5 versions of the 365xp clone and such.

Australian wood is tough on any was I'd imagine.

Anyway, I'd run a good oil at 32:1, an oil with a very high boiling point/flash point or whatever they measure. An oil that removes carbon might help, so the black doesn't absorb heat into the piston and cylinder as much. Maybe tune the engine half way through a cut so it is tuned at those high temps, put the base gasket back in since compression builds heat. Maybe even set up a water tank to drip or mist water to where the flywheel can suck it through, but that may or may not cool the flywheel side of the cylinder too much.

I wonder if turning down the diameter of the piston a hair would help?

 

[sixonetonoffun]

Be fun to try a SHINDAIWA 757 piston.

 

[BaronVonChickenPants]

I wanna see pics of that slab.

With the 42" bar and Alaskan mill end clamps I'm limited to only 950mm, this log was wider than that so we took a vertical slice off to make it fit.

Cut rate was 100mm per minute.

5 inch slabs were cut then vertically cut into 5 inch posts.

Other slabs were cut to 3 inch thick then 2 or 5 inch pieces

 

[rogue60]

That's impressive milling the hardwood you have with a BraumAg!
What mix ratio are you running?
Even more impressive if you have been running 40:1 or 50:1 milling.
Scoring on the exhaust side like that means the engine needs more oil whether that's tune or not enough oil in the mix is unknown as yet.

 

[Deets066]

That's impressive milling the hardwood you have with a BraumAg!
What mix ratio are you running?
Even more impressive if you have been running 40:1 or 50:1 milling.
Scoring on the exhaust side like that means the engine needs more oil whether that's tune or not enough oil in the mix is unknown as yet.

Exhaust side scoring is usually tune.
Even if it’s tuned we’ll for normally cutting, it may not be fat enough when building that much heat over long cut times.

 

[smokey7]

A bridged exhaust is a tricky thing to make work. It's very easy to make a score point. Seen it in the old ocean pro bridged port 440 and 550 Kawasaki jugs.

 

[rogue60]

A bridged exhaust is a tricky thing to make work. It's very easy to make a score point. Seen it in the old ocean pro bridged port 440 and 550 Kawasaki jugs.

I know in the bike world they drill holes in the piston to help get more oil on the bridge.
Like this

 

[Lightning Performance]

Sand that piston for bridge clearance imo.
That bridge could be expanding and causing carbon scoring well into your run.

My 084 starts out pig rich on big long runs. Half way though the second tank the tune has moved to a leaner condition near a good bucking tune up. So... I fattened it up just a fuzz right there. Now when starting out the next day cold you have to load the saw hard for the first thirty seconds to get it up to temp and to stop four stroking. After the second tank goes in on the same cut it sounds just right. Loads up horribly when cold at anything near half throttle.

 

[Maintenance Chief]

There doesn't seem to be ring location pins in that piston?
And the scoring is wide but no division mark ?

 

[BaronVonChickenPants]

Thanks gents, some great tips to look in to.

I am running 32:1 mix with good oil. But the saw was only tuned normalish.

The ambient temperature was also 35-40 C (95-104 F) so tough conditions for man and machine.

The piston does have locator pins for the ring on the opposite side to the exhaust port.

The Shindawa piston looks similar, but with a flatter top.

The piston from the Husky K970 demo saw looks to have a full lower skirt, would this help stabilise the piston?
https://www.ebay.com/itm/253761196639

Or is the issue more about lubrication?
Drilling holes for the bridge is an interesting idea.

I did a casual afternoon session yesterday on some green silky oak (Grevillea robusta) logs, these were much smaller 300-500mm diameter, longest was 3.6m.

The Giantz saw was tuned richer and the ambient temperature was in the low 20's C.

The cuts were 300mm per minute on the larger logs, much easier going than the gum.

Quarter sawn 75mm slabs, the minister for war and finance has put in an order for a 2ish metre round dining table.

I'll pull the jug off this week and see how it compares.

 

[rogue60]

There doesn't seem to be ring location pins in that piston?
And the scoring is wide but no division mark ?

I agree the bridge is not the problem here.

 

[rogue60]

Thanks gents, some great tips to look in to.

I am running 32:1 mix with good oil. But the saw was only tuned normalish.

The ambient temperature was also 35-40 C (95-104 F) so tough conditions for man and machine.

The piston does have locator pins for the ring on the opposite side to the exhaust port.

The Shindawa piston looks similar, but with a flatter top.

The piston from the Husky K970 demo saw looks to have a full lower skirt, would this help stabilise the piston?
https://www.ebay.com/itm/253761196639

Or is the issue more about lubrication?
Drilling holes for the bridge is an interesting idea.

I did a casual afternoon session yesterday on some green silky oak (Grevillea robusta) logs, these were much smaller 300-500mm diameter, longest was 3.6m.

The Giantz saw was tuned richer and the ambient temperature was in the low 20's C.

The cuts were 300mm per minute on the larger logs, much easier going than the gum.

Quarter sawn 75mm slabs, the minister for war and finance has put in an order for a 2ish metre round dining table.

I'll pull the jug off this week and see how it compares.

Nice I bet it was an easy session milling silky oak compared to the hardwoods you have been milling.
I found Silky oak likes to warp/cup/bow bad when air drying make sure you have the strip sticks about 4in apart (they call them stickers overseas) and put something big and heavy on top the pack.
From your posts I think you already know all that.

As for the scoring I'd personally run more oil 25:1 and tune to that mix you are working the saw at the extreme end of what an industrial 2T can handle.
Just my 2c

 

[Nutball]

As for swapping pistons, you have to watch out for differences in pin to crown height, and how low the bottom of it is since that will affect the intake port timing for better or worse if it even clears the crank case.

 

[Maintenance Chief]

Hold on a dam minute! Your doing work for the minister of war?
No offense intended Sir but maybe you could spring for a higher quality saw? I'm not trying to be "cheeky" but if your making some money with your tools it might be time to invest in them.
I respect your intentions with the off brands but their build quality might not match your work ethic.

 

[rogue60]

Hold on a dam minute! Your doing work for the minister of war?
No offense intended Sir but maybe you could spring for a higher quality saw? I'm not trying to be "cheeky" but if your making some money with your tools it might be time to invest in them.
I respect your intentions with the off brands but their build quality might not match your work ethic.

He means his wife lol
I think so far he's doing a bloody good job using the cheap saw's 1hr long cuts that's tough going on any saw if he sold the timber he could probably buy nice new ms881.

 

[Maintenance Chief]

He means his wife lol
I think so far he's doing a bloody good job using the cheap saw's 1hr long cuts that's tough going on any saw if he sold the timber he could probably buy nice new ms881.

Oh! Haha my mistake.