transfer work

dk27 · Dec 3, 2009

Hi folks,
successfully woods ported 5 saws to date.From a poulin pro 255 up to and including a husky 372. The results have been truly amazing .Would never have believe these saws could produce the amount of torque that they do now.Feel quite comfortable and confident porting.

But what to do with the transfers?Lots of advice and instructions on porting.But not much to be had on transfers ,other than if you dont know what to do don't touch them ,which may be the best advice.

Would any one be willing to start a transfers for dummie or transfers 101?

Some questions that come to mind.

1.Can the passage from the bottom of the jug to the transfer ports be smoothed out or polished? Kind of rough on the 372 or does this aid in mixing?

2.when widening,is this just the sides like when you do the intake and exaust ?or the roof and floor?

3.The "divider" that seperates the passage way into two halfs is quite blunt can this be sharpened up?

Thanks for any help or input.Would like to thank all the modders that are so willing to share their hard learned knowledge with the rest of us!!

Evan · Dec 3, 2009

Brad told me to widen upper transfers to the intake side. dont go wider then the skirt same as you would with the intake and exhaust port.

yeah ive seen brad the better porting guys blending and smooth the passage from the bottom end to trasnfers on the 372. they also are sharpening the divider.

i never raise or lower anything.

this is my 440 cylinder. you can see the uppers mostly blended to the intake side fiarly mild, could have gone wider

heres a pic of stock 044 cylinder next to my ported 440 cylinder. lowere transfers hogged out to the cylinder base

this saw runs very good and is cutn a good deal faster then my stock 044

woodgrenade · Dec 3, 2009

I like how the side by side comparo Evan. Rep to you!

dk27 · Dec 3, 2009

Yep,pics are great Evan,Thanks

My lowwer transfers are rough like that also.that 's what i'd may want to smooth out.

Evan · Dec 3, 2009

i leave the transfers rough and dont poilish them this is suposed to aid in keeping the fuel automized as the intake charge makes its way through the trasfers

by rough i mean not polished.

isaaccarlson · Dec 3, 2009

A rough surface has a thicker boundary layer and

many little eddies that would allow air/fuel to separate. A smooth surface has a much thinner boundary layer and no eddies. I would make them shiny. A rough surface does not like to flow well.

dragrcr · Dec 3, 2009

its not all about flow, a little turbulance is good for keeping the fuel atomized.

isaaccarlson · Dec 3, 2009

seems to me the fuel would want to stick to the wall where there is less flow.

its like water blowing off your car as you drive. The areas that have good flow and thin boundary layer shed water REAL QUICK. But the areas with thick boundary layer pretty much stay wet. same principle IMHO

blsnelling · Dec 3, 2009

You're spot on Evan. Looks good.

madhatte · Dec 3, 2009

Evan: good work, and the side-by-side is priceless.

Isaacarlson: you make a good point bringing up boundary layer. My feeling is that in this case, the particle-to-surface ratio is small enough that surface tension overrules boundary layer effect, and that a slightly rough surface will bind a few particles, causing a film layer which actually promotes laminar flow rather than restricting it. The in-between spaces will remain turbulent, and the air/fuel mix in suspension. I've got a pretty solid background in fluid flow and thermodynamics, and I'm pretty sure I'm not too wrong.

Fellow engineering nerds, help me out here?

ironman_gq · Dec 4, 2009

general consensus and dyno work on all engines with wet intake (fuel in air not direct injection) say that the intake should not be polished as it promotes fuel drop out and puddling. a slightly rough surface keeps the fuel atomized and evenly distributed in the air charge.

nmurph · Dec 4, 2009

thanks Evan and OP. OP, i am in the same boat as you regarding transfers. there is a lot a terminology about where to grind.
Evan, thanks for the comparo pics.

AUSSIE1 · Dec 4, 2009

If you do a search you will find a ton of info on porting and transfers on the 372 with plenty of photo's as well.
There is a lot you can do to your lower transfers.

Evan · Dec 4, 2009

AUSSIE1

i know there was some 372 porting stuff going on. i was interested aswell about the 372 transfer so i searched last night and didnt come up with much of anything.

if it was your thread that gives me a place to start. i still maintain that the search engine isnt very user freindly

alright im off an searchn

Evan

scotclayshooter · Dec 4, 2009

isaaccarlson said:
many little eddies that would allow air/fuel to separate. A smooth surface has a much thinner boundary layer and no eddies. I would make them shiny. A rough surface does not like to flow well.

Timberwolf did some flow bench testing and rough or smooth made no difference, The flow at the walls is very small.
The exhaust port is polished to slow down carbon build up but will flow just as well left rough.

AUSSIE1 · Dec 4, 2009

Evan said:
AUSSIE1

i know there was some 372 porting stuff going on. i was interested aswell about the 372 transfer so i searched last night and didnt come up with much of anything.

if it was your thread that gives me a place to start. i still maintain that the search engine isnt very user freindly

alright im off an searchn

Evan

Yeah there's heaps Evan.
I'll try and do this BB372 cyl I got here over the next couple of days.

Evan · Dec 4, 2009

been searching. even went to searchn 371 stuff because i think aussies saw is 371

i am done searching.

AUSSIE1 · Dec 4, 2009

Evan said:
been searching. even went to searchn 371 stuff because i think aussies saw is 371

i am done searching.

Here's just one.

http://www.arboristsite.com/showthread.php?t=115378&highlight=transfers&page=3

When I get a chance I''ll find some more.

Evan · Dec 4, 2009

bumpn this back to the top.

im searchn for the 372 porting threads

dragrcr · Dec 4, 2009

scotclayshooter said:
Timberwolf did some flow bench testing and rough or smooth made no difference, The flow at the walls is very small.
The exhaust port is polished to slow down carbon build up but will flow just as well left rough.

Did you even read his post, it is not about flow.... jeez, if the walls are too smooth, on an intake that is wet, the fuel tends to puddle in the low pressure areas...:censored:

transfer work

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