walker mufflers....

[NWCS]

turn in? you want to lean it out? i like my saws good and rich.. but i expect a saw to last a min of 10 years.. just cant afford to replace them..

 

[bwalker]

A 346 should be spin more than 13,300.
Dedcow, a properly tuned saw will last just as long as a blubering rich one. Not to mention the fact that it will perform better.
Also take into consideration that fact that a overly rich mixture CAN lead to increased carbon deposits which limit longetivity.

 

[njforestfire]

I tach'ed my 346xpg with walker muffler today and it runs 13300 my saw got limiter caps on , but i thought it rev would more then that ,,,, but the high rev screw are turned in as long as it can ,, should i remove the limiters and turn it in more ??

/K

If you remove the limiters, you take the chance of turning the high speed screw in too far...which makes it lean out and you can get a possibly stuck saw. I've done that (stuck 'em) with kart motors (just a bit bigger saw motor).

 

[klickitatsacket]

FishHuntcutwood Yours will be in the mail in the morning. We do our mufflers in batches so that we can just set up and go.

 

[Marky Mark]

My 346 is running close to 15500 easy

 

[ehp]

if you have a demmel tool or something small to grind with just grind some of the limiter off so you can turn your jets to where you need them, a walker's muffler modded saw should be at least 14000 rpm's and I would want it a little higher than that.




Marky you always said your 346pp was a screamer

 

[SWE#Kipp]

does someone know were i can buy a handhold tach for a fair price ??

/k

 

[ErrolC]

mmmm..the scuffing is a result of the engine running hotter..there are some things you can do to help..1st change the piston & ring to freshen it all up (and save the cylinder unit $$)..while you have the top end off..clean it good with tergo strip, paint stripper...tape the exh port off so when you look in th port you see the tape (masking tape) totally blanking it off..make a thin cardboard tube that just slides down the cylinder to cover the walls..so you can see the combustion chamber at the end..and paint the port and chamber with VHT 1800deg paint..silver is the most effective (2 good coats without runs)..VHT paint contains ceramic compounds which significantly help insulate from heat...when you assemble the engine be sure to make a good thick exh gaskit to stop heat from the muffler, soaking back into the engine..from here on there will be less tendency of the piston and chamber from carbon build up and should stay cleaner longer..the scuffing is from piston to cylinder metal contact (from cylinder heat distortion) as well as flakes or speaks of carbon squeezing past the piston as the port is closing

 

[HiOctane]

does someone know were i can buy a handhold tach for a fair price ??

/k

Stihl got one for sure and probably others.If i remember well,its about 140.00 CAN.Check with guys that sells tools like Snap-on.

 

[bwalker]

and paint the port and chamber with VHT 1800deg paint..silver is the most effective (2 good coats without runs)..VHT paint contains ceramic compounds which significantly help insulate from heat..

If doing what you say has any effect at all(which I doubt) all you would accomplish is raising the engines octane requirment. Air cooled engines blead excessive heat through the combustion chamber walls and into the cyclinders cooling fins. The goal is to get heat out, not keep it in.

 

[klickitatsacket]

Ben we have been experimenting with a similar idea. I even went and bought a new laser thermometer to test the what kind of difference it is making. We have brought the cylinder temperature down by almost 60 degrees. The reason is that the heat is being pushed through to the muffler and is not absorbing through the exhaust port. This along with a dual port muffler really helps to get the heat away from the cylinder. This is the same reason that the manufacturers are putting shields between the muffler and the cylinder. this helps reduce heat transfer. There is one small hick up though in this.The cylinder takes longer to expand than the piston does and if you do not let the saw warm up and you jump on it instantly you will take the chance of seizing the top end.

 

[My2cents]

A good Tach can be found at TinyTach.com I purchase one for around $75.00 Inductive and it works great. Nice people to deal with also.

 

[ErrolC]

bwalker: I can see us running into each other a bit..all in our search for knowledge & fun..the idea, and it works in practice, is not to paint the cylinder..just the combustion chamber, exh port and piston crown..to insulate them from combustion & exh gas heat..it works..try it and check your engines head temperature readings..there are companies in USA that specialise in ceramic coating performance engine parts..slightly different materials but same objective..excess heat kills air cooled 2stroke motors..agreed

 

[klickitatsacket]

I just realized that what we are doing is differant than what errolc is doing. we are coating the interior of the exhaust port not the top of the cylinder. A completely differant game. sorry.

 

[bwalker]

I have no doubt that a coating can reduce the cylinder head temps. The heat doesnt just dissapear though. Instead it heats the a/f mixture to higher temperatures thus raising the likelyhood of detonation and neccessitating a higher octane fuel. Again this has been tried in the past by alot ot tuners here in the states and found to be of little value by the knowledgable ones.

 

[Molecule]

interesting idea ... where can I get some high temperature paint? what brands are there? which are best, e.g. what do we look for?

also, re ben's question --- the cooling fins on the top of some cylinder castings seem comparatively useless (as though the design intent is a hotter head), relative to the cooling fins at the sidewalls. Other cylinder castings have very agressive cooling of the head, obviously intending to lower head temps. But, in no case can I see harm done by protecting the piston top and wrist pin, or the exhaust port sidewalls. As to octane, I only run straight white gas (BP-Amoco "ultimate")

Would it be theoretically correct that higher burn temps should increase potential for work output, for a given exhaust temp. In that case, pushing the heat into the gas, instead of taking it out into the cylinder head should increase theoretical output potential, and meanwhile, the paint is keeping the crown temperatures down -- so, ok for the crown -- but watch out, 'cause the sidewall temps will be going up with the gas temp, so lubrication limits may get stretched.

 

[NWCS]

if your thinking of using paint on the piston.. forget it.. no matter what temp its rated for it WILL burn off and be gone within an hour. paints are for external engine use only.. not exposed directly to fire and compression. and you will be adding to potential wear when that paint flakes off inside the engine. you want a professionaly applied coating, a very specialised deal for pistons and internal components. alot of them are ceramic and can take a heck of alot of abuse from that fire, fuel and compression, etc. i would REALLY suggest leaving piston coatings to the shops that have the very expensive setups to do it.

 

[bwalker]

Good call, Decow.

 

[bwalker]

BTW there is a SAE paper authored by Honda where the poliched the piston dome and combustion chamber to a ultra high finisn in a effort to gain efficinacy in a four stroke engine. It actually worked to a minute degree. I dont recall how fine the finish was but it was basicly out of the grasp of your average joe with a buffer and a can of Flitz.

 

[Lawn Masters]

if your thinking of using paint on the piston.. forget it.. no matter what temp its rated for it WILL burn off and be gone within an hour. paints are for external engine use only.. not exposed directly to fire and compression. and you will be adding to potential wear when that paint flakes off inside the engine. you want a professionaly applied coating, a very specialised deal for pistons and internal components. alot of them are ceramic and can take a heck of alot of abuse from that fire, fuel and compression, etc. i would REALLY suggest leaving piston coatings to the shops that have the very expensive setups to do it.

This is exactly what I was thinking. paint will burn off when heated like that, and exposed to fire, or it'll flake, and possibly screw up something inside the engine.