PORTING A REED VALVE SAW (Stihl 009)

[Echoboy86]

Hello fellow saw Addicts!

First time poster here long time lurker/ reader.
I was wondering if anyone of the learned porters that frequent this site could point me in the right direction with porting my little house brick (Stihl 009)???

So far I have gutted the muffler and opened up the exhaust port to 68% of the bore diameter. These modifications saw the saws free RPMs and throttle response pick up considerably, it runs much, much cooler than it use to. However, even though the free RPMs are up there it is now gutless as all get out in the :msp_angry:!

The good thing is that these little saws have a riser block sandwiched in between the cylinder and crankcase + a gasket top and bottom. This combined with a squish clearance of 0.034 means I have lots of room to cut the squish band and turn down the base of the cylinder, and adjust the upper and lower transfers.

This is my thinking on the subject so far, what do you fellas think???

also, I put the degree wheel on the saw today and these are the numbers I came up with;

Exhaust: 103*
Duration: 154

Transfers: 132*
duration: 96

Intake: Reed valve case induction, not sure how to measure for this one???? or how much it affects things???)View attachment 302378

cheers guys

 

[Mastermind]

Raise the transfers a few degrees.....

You've added to the time/area of the exhaust and now you'll need to get the balance back....

 

[Echoboy86]

Cheers randy, should I aim for around 20* to 22* blow down? I believe I'm at 28* at the moment.:msp_biggrin:

 

[Mastermind]

Cheers randy, should I aim for around 20* to 22* blow down? I believe I'm at 28* at the moment.:msp_biggrin:

Don't take that big of a bite........start with 24*....

 

[Echoboy86]

Hey fellas! I finally got the saw ported and back together!!!:cool2:

thought I might give you another rundown on what we started with; a rather shabby looking Stihl 009, rather long in the tooth but still kicking. when I received the saw, I broke it down, split the case and rebuilt it; replacing the standard stuff like crank bearings, seals, gaskets, piston rings, fuel filter, carb kit and air filter.

while rebuilding I measured the squish and wasn't surprised to see it was only at .035":msp_thumbdn:!
finding this I replaced the bottom gasket with one at .012" to bring the squish down to .025", I also opened up the exhaust port to 69% of the bore diameter.

once it was back together I fuelled it up and used it for a while, around 5 to 10 tanks and was less than impressed with the performance:msp_mad::msp_thumbdn:.

Well I finally pulled the plug and did a comp test..... 155psi! at this point I was thinking, well crap! that was a colossal waste of time! then I rallied and said screw this I want this old house brick that everyone on this site bags the crap out of, to be the meanest one out there! why you ask??? BECAUSE I CAN! and I would be cool to have one and fry the pants other guy with his 200t or 338xp (ambitious I know but, I can dream can't I!?)

So with this in mind I ordered an new piston and ring set and pulled the saw down ready for porting.

story isn't finished yet but, its late and i'm going to bed.

oh, but before I do, here is the saws now as it looks now. Its wearing a 16" bar and 55 drivers of 3/8 LP PS3 chain and custom velocity stack with oiled UNI filter foam pod!

 

[Echoboy86]

Here's a link to the first attempt at hopping up this house brick. I tried to insert the video but can't seem to work out how to do it!?!?

It was tunned to fat but even if I had leaned it out it wouldn't have helped the POS at that point!

STIHL 009 - YouTube


Oh and she's blowing right on 180psi after the second build with all the port work.

 

[ptjeep]

Nice work on the saw! I like the little 009 saws, they make funny noises when started. Did you raise the transfers like Randy mentioned? From my little experience, just widening the exhaust and intake wont yield much gains without messing with the transfers. I'm anxious to see it wheni ts done.

 

[moody]

Personally I think you went too wide on the exhaust. Some say 60% is the limit I prefer to stay under 55% of the bore size. You'll just have to try it and see how it works out.

 

[pops21]

Personally I think you went too wide on the exhaust. Some say 60% is the limit I prefer to stay under 55% of the bore size. You'll just have to try it and see how it works out.

Its been a while since I have been into a saw but I swear the limit was 70% of the width with some people accidentally going over 70% with no ill effect (although not recommended). If your only going 55% you are not opening it up much. Every saw I have done, STOCK width was around 55%.

 

[moody]

Its been a while since I have been into a saw but I swear the limit was 70% of the width with some people accidentally going over 70% with no ill effect (although not recommended). If your only going 55% you are not opening it up much. Every saw I have done, STOCK width was around 55%.

On a reed valve 55% was when I stopped getting gains.

Please note you're not putting any more fuel and air in so there's no reason to go that wide.

 

[Echoboy86]

Hey fellas, I have done a lot more than just set the squish and widen the exhaust but I've been working 6 days a week and there's lots of other things that have just been more important than posting results/videos on here, not to mention it just started raining finally! which is really good because we need it but, not to conducive to saw testing:msp_sad:. (I know, I know, put up a tarp and get cutting you useless bugger! Is what your all thinking)

I have some nice 15" stringy bark eucalyptus there to test it out in so if it clears for an hour or so this afternoon I'll be on it, trust me!

I was worried that I might have gone to far with the exhaust moody but I did 2 cuts with it after work yesterday and it cuts pretty well, but I'll let you guys decide.

Here's a quick photo of the transfer work and cut squish band I did (sorry about the **** quality but, my good camera is out of action and i had to use my cruddy i phone camera!:msp_unsure

 

[splitpost]

Hey fellas, I have done a lot more than just set the squish and widen the exhaust but I've been working 6 days a week and there's lots of other things that have just been more important than posting results/videos on here, not to mention it just started raining finally! which is really good because we need it but, not to conducive to saw testing:msp_sad:. (I know, I know, put up a tarp and get cutting you useless bugger! Is what your all thinking)

I have some nice 15" stringy bark eucalyptus there to test it out in so if it clears for an hour or so this afternoon I'll be on it, trust me!

I was worried that I might have gone to far with the exhaust moody but I did 2 cuts with it after work yesterday and it cuts pretty well, but I'll let you guys decide.

Here's a quick photo of the transfer work and cut squish band I did (sorry about the **** quality but, my good camera is out of action and i had to use my cruddy i phone camera!:msp_unsure

looks like your squish aint cut evenly and may have some high spots

 

[Echoboy86]

Your partially right split post, the squish is most definitely cut evenly, the flash from the camera on the left hand side of the photo makes it look uneven but, it did have some machining lines that look like high spots but I smoothed them out with some 600 and 900 grit wet and dry paper on the end of the Delrin mandrel I made for turning down the base. It really didn't take much at all to clean up.

The bearing blue you see was to check for these spots and machining marks so I could see whether I had cleaned them up, I had just stared applying it and realised I should take a photo because I would probably put the saw back together with out any evidence of what I did. Cheers for the input mate, its nice to chat to another Aussie on AS.

P.S. the run out on the lathe was around 0.001" and I test the whole way along the mandrel from where it enters the cylinder base right the way along to where the live centre.

 

[DanS]

how did you enjoy putting in the individual connecting rod bearings? real pain in the backside! even using grease, i nearly pulled by hair out.

 

[Echoboy86]

Haha! yep major pain in the arse bro. I've been back into that saw again several times and into an 015, so its not such a chore now. Patience is the key the though (just a poor design.)