Rebuilding And Porting An 084

[tree monkey]

300.00 plus a new clutch from jms.

better get more then a lap dance for that.

hows about a jms cylinder?

 

[jake wells]

better get more then a lap dance for that.

hows about a jms cylinder?

hell no use that crap for a paper weight.

 

[blsnelling]

The YUGE intake port. I really wanna add a few degrees of duration.......so I might trim the piston skirt a wee bit. At 71°it seems pretty short.

76?

 

[Brewz]

Well ok.........back to the damn 084. lol

Timing numbers after machine work. Hey @Brewz .....

Ex: 99
Tr: 124
In: 71

Took .030" outta the squish, and .038" off the base.

Clearance is .023"

I have found 99/121/74 to work great with massive power and a wide power band.
I have tried them with the intake down further at 79 or 80 and they are more violent and peaky.

I usually slightly widen the exhaust and flatten the roof a bit to take advantage of the raised uppers, widen the transfer tunnel towards the exhaust port some and open the uppers flat.

A red97 port on the flywheel side with a 3/4" hole under it and the factory outlet elongated all the way along

They tow like a freight chain at 12500 RPM running an unlimited coil

 

[Mastermind]

76?

I have found 99/121/74 to work great with massive power and a wide power band.
I have tried them with the intake down further at 79 or 80 and they are more violent and peaky.

I usually slightly widen the exhaust and flatten the roof a bit to take advantage of the raised uppers, widen the transfer tunnel towards the exhaust port some and open the uppers flat.

A red97 port on the flywheel side with a 3/4" hole under it and the factory outlet elongated all the way along

They tow like a freight chain at 12500 RPM running an unlimited coil

So......for a dedicated milling saw. 99/121/74 ?

There is a slight lip in the intake. I'll knock it off and see where it lands.

 

[Brewz]

I have one at 99.5/124/73 with stock uppers.
Its strong but feels half ported.
I built one for someone who wanted usable torque for big hard timber and milling. He didn't want a difficult screaming monster.
I took it to 99/121/74 and it was a torque monster and he loves it.
I have another 084 I messed with opening everything up more and took it to 99/122/80 from memory and its a screaming monster that opens your eyes with a 25" bar in softer timber but is all or nothing with a longer bar.

 

[Brewz]

Pictures are of the saw I built to be usable.

Here it us in use cutting 11000 Jenka hardness dry Eucalyptus with full chisel, full comp 404 and an 8 tooth sprocket.
I was getting tired by this stage, had tested about 8 saws and cut up the entire tree in 35*C heat and tropical humidity.

I stopped after this run

 

[Brewz]

This is the "more" ported saw with the lower intake.

It goes harder but I wouldn't use it for milling

 

[Mastermind]

I have one at 99.5/124/73 with stock uppers.
Its strong but feels half ported.
I built one for someone who wanted usable torque for big hard timber and milling. He didn't want a difficult screaming monster.
I took it to 99/121/74 and it was a torque monster and he loves it.
I have another 084 I messed with opening everything up more and took it to 99/122/80 from memory and its a screaming monster that opens your eyes with a 25" bar in softer timber but is all or nothing with a longer bar.
View attachment 82257

View attachment 82258

Yeah, I can see 124 being too low on the uppers. I've gone as high as 118 on em, brutal, but peaky.

 

[RI Chevy]

Nice job Brewz. [emoji106]

Your 2nd video looked like some shag bark may have been jamming the sprocket a bit.

But nice strong saw there.

 

[Brewz]

This is my half ported 084 with a 36" bar, 404 full chisel full comp and 8 tooth in dry dead rock hard eucalyptus

Its at 99.5/124/73 from memory and I lowered the intake down from about 69*

All 3 saws have about .020 to .030 from the band and blow around 170 psi cold

 

[Brewz]

I ported that saw above before I had a 90* tool and I plan to go back in and touch it up to 100/122/74

My call is 22ish blowdown with a flatter exhaust roof, and dont go too low on the intake as they seem to like plenty of case compression for running a long bar.

I have spoken to some racing guys here in Aus and they have said they will run great with a lower exhaust and they do, but its more of a shot bar race setup from what I have found

 

[Mastermind]

Great job on all of those big beasts Brews.
Thanks for sharing your experiences.

@blsnelling has a bad ass 084. It was the first one I ever ran actually.

 

[Mastermind]

I ported that saw above before I had a 90* tool and I plan to go back in and touch it up to 100/122/74

My call is 22ish blowdown with a flatter exhaust roof, and dont go too low on the intake as they seem to like plenty of case compression for running a long bar.

I have spoken to some racing guys here in Aus and they have said they will run great with a lower exhaust and they do, but its more of a shot bar race setup from what I have found

I'm gonna leave the exhaust port stock. It has a lovely shape, and beautiful bevels. Normally I would widen, and reshape it, but this saw will live on a mill, and I want the rings to live a long happy life.

 

[Time's Standing Stihl]

@srcarr52 what are the numbers on mine? It's a handful

 

[mdavlee]

One of mine has exhaust at 85 and 40 degrees of blowdown

 

[Dub11]

Now theres some lube for y'all

 

[Sleeper]

Beaver lube and solvents company is about 1 hour from where I live. Their "Bolt Buster" for breaking rusted stuff loose is better than PB Blaster. No bull.

 

[huskihl]

View attachment 82299

Now theres some lube for y'all

Tested and approved by @tree monkey himself, too, I see

 

[Mastermind]

I couldn't stand it......ended up widening the exhaust a little.




Hey.........that's not a 084 jug. lol