044/46 Hybrid Build

[RI Chevy]

I had an 044 from another guy[emoji849] that used to inhale fuel.
Hybrid also has a bit higher RPMs and displacement.
But buzzes like a bumble bee. [emoji106]

 

[MustangMike]

To measure case volume, just fill with fuel mix and dump & measure, with counter weights in highest position, and with them in lowest position. Not perfect, but will provide a good comparison. No way (IMO) to measure remaining capacity in lower section of the jug.

To rate a saw's fuel efficiency, it should not be based on run time, but on the amount of wood cut. I have posted before (a few times, so I'll spare ya) the rounds of Oak and Hickory my 044 cut on less than a tank of fuel. Very efficient IMO, and it is a good running saw.

 

[MustangMike]

Jeff, no matter if you are a pro or not, less time refilling the saw = more productivity, and being able to finish a project w/o refill is always nice.

Your saw would have to be a real animal to make up for 1 or 2 more refills in a day.

 

[RI Chevy]

Yup. I hear you Mike. [emoji106]

 

[blsnelling]

By all means, take as much of it over as you'd like. I respect your opinion very much.

The way I see it, your around 85 intake and 118 upper roof, 33* of case compression.

I'm at 78/123, 45* case compression.

I'm seeing a case that's too small for the top end, so if increase the intake duration too much, I'm gonna overfill/get alot of spitback-even with flow intertia into case. Maybe youre using that inertia, I dont know.

Thats why I picked 78* for the intake. Its also close to "square" as the ex roof is 101-102*

On the next one I do, I plan on using 3 slugs as testers. One with a notch at the ex, one at the uppers and one at the intake ala @tree monkey did on the 461. That thread is coming.

I'm interested in your theories, I'm a sucker for that stuff. Intrigues me. I'm all ears for anyone wishing to Opine.

Thank you for taking my post constructively! I'll be honest...I'm not much into 2-stroke theory. Gasp! I can hear the air sucking now, lol. I'm all about just doing what works. I've tested what I do and find it to work best...FOR ME.

Gas hogs. I hear this referenced repeatedly as to why not to do this or that to an engine. However, I've never seen any definitive proof either way. The way I look at it, the stronger I make you're saw, the less time the saw is running. I've never had a commercial user of my saws complain about poor fuel economy.

 

[RI Chevy]

I think, depending on what the saw is built for, the art finding a good balance of power and fuel consumption is key.
If your building a cant saw, fuel consumption is not even considered. A work saw is all about balance. Figuratively and literally. Lol

 

[huskyboy]

I’m enjoying reading this thread! Lots of interesting discussion

 

[MustangMike]

Yes, and there may be more than one way to skin a cat. Very likely the right intake # is closely linked to case compression, and all of the port #s must be in sync. A # that results in a gas guzzler on one saw may not have the same result on another. Lots and lots of factors.

 

[tree monkey]

lets look at fuel mileage

lets say X= $25

lets say a stock saw cuts X amount of wood on a tank of gas in 45 minuets. user does 10 tanks a day. 45 min x 10 =450 min or 7.5 hours. Xx10=$250

lets say mod saw 1 cuts X +10%of wood on a tank of gas in 30 minuets. user now does 15 tanks in 7.5 hours. X+10%x15= $412.50

lets say mod saw 2 cuts 90% of X of wood on a tank of gas in 30 minuets, user does 15 tanks in 7.5 hours.Xx90%x15=$337.50

lets say mod saw 2 cuts a faster cookie then mod saw 1

what saw are you going to take to work?

 

[RI Chevy]

Lol. Good math lesson Scott.
I guess you gotta figure out actual throttle time. Actual wide open throttle time.
Kind of like figuring out fuel mileage going to work. If you drive a 454 that gets 5 miles to the gallon verses a 4 cylinder that gets 35 miles to the gallon, which is better? Say the speed limit is 55, but we want to do 70 and risk it. Is it better to take the 454 gasser, or go with the 4 cylinder gasser to work? Will you get to work any faster driving 454? Which one will drive you further?
Even if one wants to modify that 4 cylinder engine and give it some more ooomph, you may loose a little fuel mileage, but still get there just as fast.
Just playing devils advocate here. Lol

 

[drf256]

Thank you for taking my post constructively! I'll be honest...I'm not much into 2-stroke theory. Gasp! I can hear the air sucking now, lol. I'm all about just doing what works. I've tested what I do and find it to work best...FOR ME.

Gas hogs. I hear this referenced repeatedly as to why not to do this or that to an engine. However, I've never seen any definitive proof either way. The way I look at it, the stronger I make you're saw, the less time the saw is running. I've never had a commercial user of my saws complain about poor fuel economy.

Agree, but trying to figure out why translates it to other saws and more success without failures.

The way I see it, excessive intake without case compression and Physically high transfers will make a saw "peakey". Maybe the rpm will be higher and it will be able to handle more load at a given rpm, but lean on it and its likely to fall out of its powerband sooner.

It's all a balance, and what works for one may not work for another.

I'll take torque and a wide powerband anyday over a race saw, cause I'm not building one in this case.

Really no wrong, just a "different".

 

[blsnelling]

Has anyone ever tested this theory, not just hunch or guestimating?

@drf256, as you already alluded to, you can try numbers similar to mine by notching the crown for the transfers and trimming the intake skirt for the intake.

 

[blsnelling]

Agree, but trying to figure out why translates it to other saws and more success without failures.

The way I see it, excessive intake without case compression and Physically high transfers will make a saw "peakey". Maybe the rpm will be higher and it will be able to handle more load at a given rpm, but lean on it and its likely to fall out of its powerband sooner.

It's all a balance, and what works for one may not work for another.

I'll take torque and a wide powerband anyday over a race saw, cause I'm not building one in this case.

Really no wrong, just a "different".

Honestly, I've never tried to figure out why. I can only tell you what I've seen bring a saw alive.

 

[Chainsaw Jim]

Here's a list for most of the carbs for both the 044/440 and 046/460...

Stock 044 Carburetors:
C3M-S5E
C3M-S5G
C3M-S12B
C3M-S20
C3M-S22
C3M-S23
C3M-S24
HD-10B
HD-11A
HD-15C
HD-17B
MS440 Carburetors:
HD-15C
HD-17B

Stock 046 Carburetors:
HD-8A
HD-9A
HD-14A
HD-16
HD-24A
MS460 Carburetors:
HD-14B
HD-16A
HD-24B

 

[RI Chevy]

Thanks for the list Jim

 

[Fruecrue]

Here's a list of the carbs for both the 044/440 and 046/460...

Stock 044 Carburetors:
C3M-S5E
C3M-S5G
C3M-S12B
C3M-S20
C3M-S22
C3M-S23
C3M-S24
HD-10B
HD-11A
HD-15C
HD-17B
MS440 Carburetors:
HD-15C
HD-17B

Stock 046 Carburetors:
HD-8A
HD-9A
HD-14A
HD-16
HD-24A
MS460 Carburetors:
HD-14B
HD-16A
HD-24B

Used the new bookmark feature on that one.
Thanks Jim.

 

[MustangMike]

Thanks Jim, I printed that info.

Are they all the same size? Any other differences that you know of?

Also, I think I have HD-16 A, B + C carbs. Any idea what the different letters represent? I assume something must be different.

 

[RI Chevy]

Some info I got from Walbro regarding main jet sizes.

 

[Deets066]

Using a set of numbers can net different results depending on how you grind them. I guarantee that if 5 different builders built hybrids with the exact same numbers they would all run different.

Then you have the jug.... The numbers you start with is how I determine how much I want to machine the jug to get closer to the numbers I want and the compression I think I need.

 

[blsnelling]

Using a set of numbers can net different results depending on how you grind them. I guarantee that if 5 different builders built hybrids with the exact same numbers they would all run different.

VERY true!