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

[mtngun]

I think I have the proper rotor that would of worked out for you.

Darn it, I forgot that you had a bunch of Stihl parts.

How are you going to organize the sale of those parts ? Web site ? Ebay ?

 

[luvsaws]

Dang,what can't you do with that lathe!

 

[parrisw]

Darn it, I forgot that you had a bunch of Stihl parts.

How are you going to organize the sale of those parts ? Web site ? Ebay ?

ha ha, no idea yet. I've been slowly selling a few parts on here, that's it so far. I'm planning on Ebaying them though, once I finally get organized.

 

[Hddnis]

Nothing like the satisfaction of making something work.



Mr. HE

 

[mtngun]

One of the threads that attaches the muffler to the case was stripped. A previous owner had "repaired" it with one of those plastic expanding inserts that are used for drywall and concrete.

Santa has yet to leave a timesert kit in my stocking, so I bought a 6mm perma-coil kit off the 'bay for $11 delivered. This would be the first time I've ever installed a thread insert, so I was a little nervous.

The damaged threads were drilled out with a 1/4" drill.

Then the hole was threaded with the supplied tap.

A supplied tool was used to screw in the insert. Then I used a punch to break off the coil's tang.

It actually seems to work. :rockn:

 

[leeha]

I have used 100's of those heli coils and they work great.
Never had a problem.



Lee

 

[wooddog]

I wish I had a heat gun, but that's pretty far down the wish list at the moment,

Steal the wife or girl friends hair dryer Sir.

 

[Tohya]

A cup of boiling hot water is enough to soften most hoses. Hot tap water may have worked ok as well.

 

[Scandy14]

Looks like you are making good progress.

 

[Mastermind]

Did the kit recommend that you use loctite on the insert?

 

[parrisw]

Those inserts work well, but not as good for repeated use. You got a lathe, just make a threaded insert! You can use some ready rod, chuck that in the lathe drill it out and tap to the size you want, then drill and tap the case to fit the ready rod, then use some permanent loctight on it.

 

[Mastermind]

What's happening on the project?

 

[mtngun]

Did the kit recommend that you use loctite on the insert?

Sorry for the delayed response, I overlooked your question about the loctite.

The kit didn't say anything about loctite, but I put some hi-temp thread locker on the insert. Muffler bolts have a tendency to rattle out, so I think this particular insert needed the thread locker.

The 084 project has been inactive for lack of a PTO side crank bearing. It's proprietary, and Stihl no longer carries it. However, rumor has it that the 088 crank bearing is a substitute. An AS member, Super3, has ordered one of the 088 bearings, and we'll see what it looks like when it shows up.

Also, the bar never showed up, and the seller kept changing his story and about if and when he mailed the bar, and then stopped talking to me altogether. I filed a mail fraud complaint with the USPS, since I paid with a postal money order. It can take up to 6 months to process a mail fraud complaint, plus, this case is not black and white, since I did receive the powerhead, just not the bar. But, the bar is a big deal, because milling bars are expensive, and the bar was advertised as being nearly new.

So....... hopefully the 088 bearing will fit. Then I'll have to scrounge up a bar and some milling chains. It may be mid-summer before the 084 begins to earn its keep.

 

[Mastermind]

Sorry for the delayed response, I overlooked your question about the loctite.

The kit didn't say anything about loctite, but I put some hi-temp thread locker on the insert. Muffler bolts have a tendency to rattle out, so I think this particular insert needed the thread locker.

The 084 project has been inactive for lack of a PTO side crank bearing. It's proprietary, and Stihl no longer carries it. However, rumor has it that the 088 crank bearing is a substitute. An AS member, Super3, has ordered one of the 088 bearings, and we'll see what it looks like when it shows up.

Also, the bar never showed up, and the seller kept changing his story and about if and when he mailed the bar, and then stopped talking to me altogether. I filed a mail fraud complaint with the USPS, since I paid with a postal money order. It can take up to 6 months to process a mail fraud complaint, plus, this case is not black and white, since I did receive the powerhead, just not the bar. But, the bar is a big deal, because milling bars are expensive, and the bar was advertised as being nearly new.

So....... hopefully the 088 bearing will fit. Then I'll have to scrounge up a bar and some milling chains. It may be mid-summer before the 084 begins to earn its keep.

I'm looking forward to seeing this project move forward. I've been watching it closely as I'm trying to learn all I can about repairing the bottom end of these saws.

I realized just how little I knew about the inner workings of these when I posted at the beginning of this thread that I would probably just fire it up and see. I felt dumb when I saw the rust on the bearings in your saw. I couldn't believe how much damage had been done to this saw by damp storage conditions.

I have an 046 apart right that has the paint peeling from the inside of the cases. I wondered what you had done to yours in this area.

 

[mtngun]

Planning the 084 build. Case is in pieces at the moment, so I had to guess the case volume for the time being.

Blue is stock. 131 intake duration, 170 exhaust, 24 blowdown.

Red is stock + muffler mod

Violet is pop-up piston, mild woods port, 155 intake, 170 exhaust, 24 blowdown.

Factory spec is 8.2 - 8.6 HP, but MOTA says "BS."

Realistic milling speed is 6000 - 10,500 rpm, so I'm focusing on those speeds and ignoring what is happening at 12,000 rpm.

It's looking tough to get high power out of this engine without making it peaky. Raising the intake duration increases peak power, but sacrifices low end. There's no free lunch. 155 intake duration seemed like the best compromise.

 

[Steve NW WI]

Maybe someone will blow holes in my theory, but I'm looking much more at the torque curves than I am HP. With your mods, it's gonna pull down to about the 6500 you mentioned as the bottom end of milling speeds, before it runs out of torque and stalls. If ya can work something to move the peak torque just a tad lower without sacrificing too much on top, it might work better for ya, but as it is, it's gonna be a huge improvement over stock or MM'd.

I expect with a little trigger time, you could keep it happily singing along at or above 7k and be perfectly content with the mods you're looking at.

 

[mtngun]

If ya can work something to move the peak torque just a tad lower without sacrificing too much on top, it might work better ....I expect with a little trigger time, you could keep it happily singing along at or above 7k

That's pretty much what I was thinking.

Unfortunately, there doesn't seem to be any way to boost the low end without sacrificing power in the cut, so this was my best compromise.

 

[mtngun]

I've learned a few things since I started this project, including how and why to check squish velocity. The pop-up I'd cut had constant squish, following the contour of the head, and max squish velocity was around 58 m/s. Yikes ! :msp_ohmy:

So the piston went back in the lathe and got more taper leading up to the pop-up, so that squish increases as you travel up the taper.

The new squish taper is actually non-linear, but I'm hoping this linear 2 degree computer model will err on the safe side. It puts the max squish velocity back in the safe zone.

 

[mtngun]

Case volume was bigger than I had guessed. Case compression will actually be 1.58. That'll flatten the power curve a bit, so I'm fine with it. :msp_thumbup:

As JJ pointed out, these older model Stihl jugs don't have much meat on the base. I didn't want to shave any more than necessary off the already skinny base, so I'm going to run without a base gasket, but even so, I still had to shave off about 0.040". Ouch. :msp_unsure:

A while back, I ran across a NOS crank for a good price, so this build got a new crank as well as new crank bearings and seals. The old crank felt OK, but I was worried that the big end might have some rust damage.

That's as far as I got today.

 

[Mastermind]

Glad you see you back on this build. I've been waiting.

The software you are using, is it really expensive? Or can a cheap bastard like me afford it???