084 milling saw .... er, I mean, PROJECT saw

[mtngun]

Thanks for the part #, Erick.

The only aftermarket piston I have been able to find is Golf. Nothing listed on the Meteor website, and the guy in Greece says he doesn't have an Espian piston for the 084.

So...... looks like I will be re-using the OEM piston. It does have some wear, but it the clearance is still acceptable.

But...... I've got to figure out how to remove the old rings. They are stuck. I've drenched them with Kroil, and at the moment the piston is in the oven at 275 degrees. Hoping that'll eventually work them loose.

Yeah, so far I'm not hurting on this project, cuz I didn't pay that much, and I figured it would need a teardown and some new parts regardless of what the seller claimed. New crank bearings, seals, and gaskets will add about $100 to the cost, but as long as the crank and cases are good, I should end up with a rebuilt saw for a fair price. Not a steal, but about the going rate.

 

[Jacob J.]

When it comes to the big saws, I just go ahead and spend the coin on OEM pistons and rings. Bryce has NOS OEM Stihl 084 piston and ring sets in his e-bay store for $95, which is $60 less than list price right now...

 

[mtngun]

I don't know that splitting the cases is warranted yet (unless you do this kind of work and have the tools???) I'd probably just pull the seals and flush everything out really well .

All the paint inside the crankcase will have to be removed, because it has softened and is peeling. Seems like splitting the cases is unavoidable.

There is some rust on the outside of the crank bearings, but I couldn't see the bearings themselves. I'll probably change them just to be sure.

I'll have to make a case splitter. I've got a press, if the need arises. Any other tools ?

BTW Seal and gasket set.... 1124 007 1050 much cheaper than buying them individual.

Thanks again.

 

[Jacob J.]

All the paint inside the crankcase will have to be removed, because it has softened and is peeling. Seems like splitting the cases is unavoidable.

There is some rust on the outside of the crank bearings, but I couldn't see the bearings themselves. I'll probably change them just to be sure.

I'll have to make a case splitter. I've got a press, if the need arises. Any other tools ?

Thanks again.

If there's rust on the crank itself or any part of the bearings on either side, it's quite likely that the bearing cages are already cracked or will crack soon when the saw is returned to service. So your decision to split the case halves is a wise one.

 

[mtngun]

When it comes to the big saws, I just go ahead and spend the coin on OEM pistons and rings. Bryce has NOS OEM Stihl 084 piston and ring sets in his e-bay store for $95, which is $60 less than list price right now...

Thanks for the tip, Jacob.

Even a tightwad like me might shell out $95 for new OEM. Are you allowed to say the name of Bryce's ebay store, cuz an OEM piston is not showing up in an ebay search ?

Jacob, do you have any thoughts on the 084 intake timing, and the partial bridge ? Would you remove the bridge ? Does the bridge help with thrust loading ? How would you set the intake duration on a milling saw ?

 

[Erick]

When it comes to the big saws, I just go ahead and spend the coin on OEM pistons and rings. Bryce has NOS OEM Stihl 084 piston and ring sets in his e-bay store for $95, which is $60 less than list price right now...

:agree2:

 

[Jacob J.]

Thanks for the tip, Jacob.

Even a tightwad like me might shell out $95 for new OEM. Are you allowed to say the name of Bryce's ebay store, cuz an OEM piston is not showing up in an ebay search ?

Jacob, do you have any thoughts on the 084 intake timing, and the partial bridge ? Would you remove the bridge ? Does the bridge help with thrust loading ? How would you set the intake duration on a milling saw ?

He must have sold out...I bought one back in January and he had four left at that time. They were early NOS pistons with the 1.2mm rings, but some of the earliest ones because they had the heavy wrist pin.

Intake duration on a milling saw for me would be a flat, wide port. I would give it another 2-3 degrees or so duration. I usually leave some of the bridge in place since it does help some at higher RPM. I do take it down somewhat, roughly half of it.

 

[jnl502]

seems like a great project even with the issues of rust and peeling paint. a oem piston is the way to go. seems to me the piston out of the saw is a little ruff to put back since u are going to all the trouble to split the cases and all new bottom end. i believe it will be a good saw in the end and can't wait for more pict. on the build i have a 084 but never a reason to do anything to it but may have to someday so good details please i like to learn all the best
jnl

 

[mtngun]

He must have sold out...

Darned ! ! !

Then I'll try to salvage my used OEM piston and use Caber rings. It's got a heavy, non-tapered wrist pin. I haven't measured the rings yet -- because they are still stuck -- but they appear to be 1.2mm thick. The piston measures better than it looks. The trick will be freeing the rusted-in rings.

Intake duration on a milling saw for me would be a flat, wide port. I would give it another 2-3 degrees or so duration. I usually leave some of the bridge in place since it does help some at higher RPM. I do take it down somewhat, roughly half of it.

Thanks for the advice.

Dropping the jug to set squish and do a pop-up will increase the intake duration 4 or 5 degrees. I was just wondering if it needed to increase even more, cuz it seems awful conservative. I guess I can take it one step at a time -- you can always remove more metal later, but it's hard to put it back.

 

[volks-man]

mtngun and jacobj,
will an 088 p/c fit the 084?

 

[mtngun]

I believe the pistons are interchangeable but the cylinders are different.

 

[Jacob J.]

mtngun and jacobj,
will an 088 p/c fit the 084?

No, and it's not even feasible to try and convert an 084 chassis to use an 088 top end, they're completely different animals.

I believe the pistons are interchangeable but the cylinders are different.

Yes, pistons are the same but the cylinders are way different.

 

[fatjoe]

Thumbscrew on filter???

Nice. The center nut is for holding on the air filter cover, should be the thumb screw that also holds on the filter.

Isn`t the filter held on the same as an 044?Mine doesn`t have any kind of thumbscrew, unless I lost it.The one screw that holds the cover on, is the same one that hold the filter on.Isn`t your 044 like that.Maybe I`m wrong and lost it, but seems to be designed that way.Maybe the 084 is different.

 

[mtngun]

Isn`t the filter held on the same as an 044?

Yes and no.

I believe the 084 does use the same air filter as the other big Stihls. The filter cover is held on with a single thumbscrew, just like your 044.

Look at the left arrow in the pic. There's supposed to be some kind of special nut there, and another one on the right side. The special nuts are missing. Erick offered a part # in a previous post. Then the filter cover screws onto the stud that is in between the arrows.

 

[fatjoe]

Yes and no.

I believe the 084 does use the same air filter as the other big Stihls. The filter cover is held on with a single thumbscrew, just like your 044.

Look at the left arrow in the pic. There's supposed to be some kind of special nut there, and another one on the right side. The special nuts are missing. Erick offered a part # in a previous post. Then the filter cover screws onto the stud that is in between the arrows.

Yes I see that, but the cover holds the air filter on, right?There isn`t a seperate thumbscrew for the filter, is there?Someone said in a previous post that you were mising a thumbscrew, and I thought the filter was held on by the cover, like an 044.The only thing your missing is the two nuts that hold on the filter shroud.

 

[mtngun]

Fatjoe, yes, the cover holds the air filter onto the orange piece shown in the picture -- is that called the filter shroud ? It seems to be missing the nuts for the shroud. Sorry for the confusion.

Kroil finally worked its magic on the rings, at least enough to get one ring end started. Yes, they are 1.2mm thick. The piston cleaned up decently.

 

[Brmorgan]

That piston still has plenty of life in it; I wouldn't bother looking for a new one right now. Especially if it's going to be used for milling - why use a new one and keep the old one for the spare? Use it now and keep an eye out for a good deal on a new one; you should be able to find something fairly cheap by the time you need it.

In my recent 084 searches, I've seen mention that the screws that fasten the newer HD filter mount plate (like you have) to the case are different than the ones on the old cartridge filters like mine has. That may or may not be what you're talking about there, I dunno. I don't see any nuts in my IPL for that area though.

 

[mtngun]

The muffler cover and muffler got a soak in phosphoric acid to clean up the rust. The muffler is still soaking 'cuz it's rusted extra bad. I want to remove all the loose rust from inside the muffler, otherwise, if rust flakes off while the saw is running and starts bouncing around inside the muffler, it might bounce through the exhaust port and do some damage.

Cover after acid bath.

After paint.

 

[Jacob J.]

Here's part of the IPL showing the nuts for the filter base in picture 1, and the nut for the filter cover in picture 2 (not pictured is the nut running the saw):

 

[mtngun]

Thanks Jacob, I had looked at that IPL but failed to notice the "slotted nut."