# Stihl 084 and 088



## GeorgeWLogger (Feb 6, 2003)

I am wondering what is the differance in the two models? The specs. are the same on both.
Model Displacement (cm³) Power(kW/HP) Weight (kg) 


STIHL 084 121.6 6.3/8.6 9.4 
STIHL 088 121.6 6.4/8.6 9.9 

Was it changed to meet emissions/EPA Regulations? Or is there major internal differences in the two powerheads?


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## kdhotsaw2 (Feb 6, 2003)

*stihl084/088*

Hello George,
The 088 and the 084 are the same sized motors but there are considerable differences inside. the 088 develops more power than the 084 does when they do stock. the factory changed a number of the things we were doing on our woods modifications, all for the better. they changed the combustion chamber volume from 13.5 cc to 11.5 cc. they lowered the squish clearance from .043 to .034. both these mods increased compression. they changed the transfer duct so it is now a straight shot into the barrel. the tonsil that hung dowm into the 084's inlet duct is now gone. they increased the exhaust duration slightly and changed to a slightly larger cast aluminum muffler. Also went to the newer fiberglass flywheel. probably has 1-1.5 more foot pounds of torque. also the lower transfer area in the case is larger so you can process more air-fuel mixture. all in all the 088 is a better saw
i have 2 new 088's left to modify if anyone is interested. put in a photo of one of my 084's making a .9 second cut in a 8 by 8 cant
ken
[email protected]
530-589-2744


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## Ryan Willock (Feb 6, 2003)

Ken, what is the biggest bar that a stock 088 can effectively pull in the softwoods out your way??? i've seen pics of people running 72'' bars but was wondering:angel:


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## kdhotsaw2 (Feb 6, 2003)

*088 bar length*

hello ryan,
up on the north coast in california in the redwoods they are currently using up to 8 ft bars with skip chain . lots of 4-5 foot bars used on that sized saws. we should check with uncle Art(Art Martin) , I think he used to use longer bars than that when he was falling up there
That is a 28 inch bar i'm using in the photo to test that size racing chain but normally use my 17 inch bar. can get the cutting time downto .6 seconds with that sized bar and chain with a pipe fitted to the 084 stihl. that particular saw now belongs to none other than the legendary gypo logger john lambert
ken


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## GeorgeWLogger (Feb 6, 2003)

Ken,

Are you saying that the 084 is not a "good saw"? Or that in its original form was lacking power? Stock to Stock, how much more power does the 088 have over the 084?

GeorgeW


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## Ryan Willock (Feb 6, 2003)

thanks Ken!! on that size bar are people running 3/8ths or .404??


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## kdhotsaw2 (Feb 6, 2003)

*stihl 084*

Hello George,
The original stock 084's just didnt run all that great stock. when we modified them they ran very well. they were designed 10-15 years before the 088's came out. Stihl realized that they could make power by changing some of thier port timing figures and some of the bottlenecks in their 084 designed saw without losing any of their dependability so they incorporated many of the features we put in our modified saws. viola! more torque, more cutting power. the hp and torque figures are almost the same but the two saws don't run the same, the 088 has 10-15 more power stock and 35-40 % more power modified.
ken
[email protected]
530-589-2744


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## GeorgeWLogger (Feb 6, 2003)

Ken,

Can the performance gains be aquired by only cylinder modifications? Or are crank case mods also required?

GeorgeW


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## kingcole1111 (Sep 29, 2008)

*need 084 cylinder*

hey i was wandering where a guy could find a parts 084 or where to get cylinder for one for 150.00 or less


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## GASoline71 (Sep 29, 2008)

Start a new thread... you'll get more hits that way...

try ebay.

Gary


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## markvanzee (Sep 11, 2011)

kdhotsaw2 said:


> the tonsil that hung dowm into the 084's inlet duct is now gone.
> 
> does removing the little tonsil increase power?


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## blsnelling (Sep 11, 2011)

markvanzee said:


> the tonsil that hung dowm into the 084's inlet duct is now gone.
> 
> does removing the little tonsil increase power?


 
I would not remove it.


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## 2dogs (Sep 11, 2011)

Sometimes an 8 1/2 year old post is a gem, like this one.


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## mtngun (Sep 11, 2011)

2dogs said:


> Sometimes an 8 1/2 year old post is a gem, like this one.


+1



kdhotsaw2 said:


> the combustion chamber volume from 13.5 cc to 11.5 cc. they lowered the squish clearance from .043 to .034. both these mods increased compression. they changed the transfer duct so it is now a straight shot into the barrel. the tonsil that hung dowm into the 084's inlet duct is now gone. they increased the exhaust duration slightly


If true, that's good data.

The compression ratio on my 084 was indeed lame, in stock form.

084 transfer duct looks just like other Stihls to my eye.

084 exhaust duration about 170 degrees, dunno why it would need to be increased.


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## Man of $tihl (Sep 11, 2011)

mtngun said:


> +1
> 
> 
> If true, that's good data.
> ...


 
The comp on my stock 084 is about 140 psi. What is the norm?


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## 7hpjim (Sep 11, 2011)

Mine is @ 150, I didn't think that was too bad!


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## blsnelling (Sep 11, 2011)

mtngun said:


> 084 exhaust duration about 170 degrees, dunno why it would need to be increased.


Same on mine. Very high for a work saw.



7hpjim said:


> Mine is @ 150, I didn't think that was too bad!


 Mine is 170-175 cold


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## 7hpjim (Sep 11, 2011)

blsnelling said:


> Same on mine. Very high for a work saw.
> 
> 
> Mine is 170-175 cold


 
I saw the vid of your 084 build, yours is a totally different animal now!!


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## what-a-stihl (Sep 19, 2011)

*084*

I'm building a 084 now and I just purchased a gas tank/handle assembly but after reading this post it sounds like a 088 should be the saw to build. Is the handle/tank the same between the two? Or if I do build the 084 are there any mods i should do as I'm building it? thanks


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## w8ye (Sep 19, 2011)

I have a stock 084 with a .404 full compliment chain X 30" bar.

I use it to buck big trunks. It pulls the chain just fine. I run the mixture at the 2/4 point.


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## heyduke (Sep 27, 2011)

*084 -088*

to modify an 084, can you just bolt on an 088 top end, or do you have to go to work with a grinder?


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## Oldsawnut (Sep 28, 2011)

I have had problems with the rubber mounts not holding up with the longer bars with the 088's especially the upper rear one.


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## heyduke (Sep 29, 2011)

so, not to beat a dead horse, but can you bolt an 088 top end on an 084 case? some saws can benefit from this. for instance you can use a husqvqrna 272 cylinder/piston on a husky 66 and gain some power and torque. does the 084 case have the same displacement as the 088? do the carburetors match up? has anyone tried it?

thanks

heyduke


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## mtngun (Sep 29, 2011)

heyduke said:


> so, not to beat a dead horse, but can you bolt an 088 top end on an 084 case?


I'm told that it is not feasible to put an 088 jug on an 084, though I haven't tried it myself.



> does the 084 case have the same displacement as the 088? do the carburetors match up? has anyone tried it?


They tell me that the carbs can swap. Not sure about 088 case displacement, but it is not important. Chainsaw case volume tends to be tight, prolly more due to space limitations than power enhancement. Bigger case volume makes the power curve broader.


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## heyduke (Sep 30, 2011)

thanks mntgun-

i won't think about the 084 to 088 field modification again. i suspect that the 084 may actually be superior for the kind of work i do anyway, less peaky, tamer, with a bit more huevos at lower rpms. i agree that larger cases and ergo, longer strokes make for a broad power band. compare the husky 272 with the stihl 046 or 044. they both have about the same power but the stihl has it all over the place and the operator doesn't have to think too much.

thanks again for the help.

heyduke


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## Naked Arborist (May 24, 2013)

088 Mag came in tonight with a plug in the compression release :msp_scared:. I put in a new release before starting it. It needs some spring cleaning, the once over and something to eat.


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## peter92 (Nov 21, 2017)

mtngun said:


> I'm told that it is not feasible to put an 088 jug on an 084, though I haven't tried it myself.
> 
> They tell me that the carbs can swap. Not sure about 088 case displacement, but it is not important. Chainsaw case volume tends to be tight, prolly more due to space limitations than power enhancement. Bigger case volume makes the power curve broader.


so can a 088 top be put on a 084 as i have to replace my 088 case and was thinking of using a 084 case


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## Neckerson (Nov 21, 2017)

Not without either a whole bunch of machine work, or a magic wand...


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## weimedog (Dec 27, 2020)

What are the threads on those crank shafts? Clutch & Flywheel side?


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