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Stihl 440 hop up.

SamT1

SamT1

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So I returned from vacation to find my Chinese plastics and handle. While I have this saw apart I figured I’d do some upgrades to it.
First thing I’m gonna do is clean it good and check the compression. What’s the compression range I want? If I remember 150 is good. What’s the best process for getting a good reading?

For sure I’m gonna mod the muffler. I’m thinking drill a second exhaust hole beside the first (same size if there’s room to use the spark arrestor) and put a small piece of tube around them like a exhaust pipe to keep debris and rain out. Point it foreword Remove any baffles inside.

If the compression is still good is there anything else minor to do to the engine? If it fails compression the sky is the limit I guess?

I need some new felling dogs. I have a tooth broken off. I’d like a dual set that’s a little more aggressive than stock. Any suggestions?

Anyone ever do any painting on a saw?

Sam
 
Rick Stephens

Rick Stephens

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I'll be interested to hear what is recommended. My 440 is getting long in the tooth and needs a disassembly and cleaning. It has a MM that made a big difference. I should re-ring it, since compression is down to 130. Otherwise still a great saw. Should be a fun thread.

Rick
 
pioneerguy600

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On OEM sets you would need to check the squish clearance to see if the cylinder gasket can be omitted and the cylinder sealed to the crankcase with a good sealant, many things will work well, Dirko, Hondabond, Yamabond ,Permatex anaerobic and Seal All to name a few. A clearance of .019 - .022 is considered safe, I run much closer but watch my fuel mix very closely to prevent carbon buildup on the piston crown. A muffler mod is easily doable for most anyone, these two changes are a start and get fair gains on the 044, real port work and more extensive machine work will really bring out greater gains.
 
SamT1

SamT1

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On OEM sets you would need to check the squish clearance to see if the cylinder gasket can be omitted and the cylinder sealed to the crankcase with a good sealant, many things will work well, Dirko, Hondabond, Yamabond ,Permatex anaerobic and Seal All to name a few. A clearance of .019 - .022 is considered safe, I run much closer but watch my fuel mix very closely to prevent carbon buildup on the piston crown. A muffler mod is easily doable for most anyone, these two changes are a start and get fair gains on the 044, real port work and more extensive machine work will really bring out greater gains.
Thanks. I have tools to check deck height and stuff, I used to build the performance VW bug engines. Will that change my fuel octane requirement if I went into that .019-.022 range?
 
SamT1

SamT1

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Well we failed the compression test this evening. I couldn’t even hit 120. No wonder this saw feels a lot weaker than my twin. (It does have somewhere between 400 and 500 cords on it) I tore it down to the jug, but I need a lot of brake cleaner to get it clean enough to go further. Looking in at the piston everything looks really nice besides the rings. They look very loose to me. Like they barely touch the wall.

So next I clean the sucker up and pull the jug off and see what’s up? Do I just stick new rings in it and go again or since it’s high hours go farther? I see all the big bore kits, what’s the skinny on going 52mm vs just re ring and muffler mod?
 
Jasonrkba

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Just depends on your budget. Rings, bearings, seals and gasket deletion might set you straight. Although 400/500 cords of wood is a lot of cutting.
 
pioneerguy600

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For my builds I just give them a good polish with red/ reddish brown Scotchbrite pads, they will remove the glaze but not damage the cylinder lining. Chainsaw cylinders do not need a sharp crosshatch for the rings to seat in, they may take up to 10 tanks of fuel run through before they reach their max compression.
 
motorman1

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Oven cleaner works good too. Do not leave it on very long though. I've had a few high hour saws and fortunately, I've only had to replace rings and rubber parts to freshen them up. Usually just fuel lines, rings and carb diaphragms. YMMV.
 
pioneerguy600

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You must check the bearings on the big end of the rod at the crank pin, any up and down slop would be bad, side to side movement is ok as the needle bearings will allow that. The blue color is from heat treatment at the manufacturing level.
 
ncfarmboy

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If it was mine I would put a new Meteor ($38.00 or so) in it comes w/Caber rings. That's what I did when I picked up an 046. Same for my 395.
Also did a little grinding on the 046 as the skirts are wider on the Meteor than OEM. It's an animal and I'm a Dolmar man.
Shep
 
SamT1

SamT1

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You must check the bearings on the big end of the rod at the crank pin, any up and down slop would be bad, side to side movement is ok as the needle bearings will allow that. The blue color is from heat treatment at the manufacturing level.
No play it feels excellent to me.

I have a meteor piston coming now. Hopefully I can run it without the gasket. I guess I’ll start tinkering with the muffler when the kids are asleep.
 
SamT1

SamT1

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I did the muffler this evening too. Only took 30 minutes. Turned out pretty good I think for a guy that knows nothing.
I drilled another hole about 1/4 inch from the original and then cut out the bridge between them. It’s around 80% of exhaust port siZe. Still under the factory spark arrestor (not pictured). What do y’all think for a first time job.
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