There is no such animal as a 044BB. That would be a stock 046.
My 044 -> 046BB rebuild worklog
- Thread starter Martinm210
- Start date
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are you sure you know what your talking about ???
LOL, Hi Brad..
LOL, Hi Brad..
Hi.....uh...whoever you are
yo2001
ArboristSite Operative
044BB kit is 52mm, line right up. 044 with 046BB kit is 54mm and need to have the holes slotted and case shaved.
Martin, if you need a tank or other things for 044, let me know. I'm gonna part one out.
yer too busy ??
yer been drinkin ??
yer tired ??
yer memory is fadin ??
i'm still lookin for a lathe for ya ..........>???????????
yer been drinkin ??
yer tired ??
yer memory is fadin ??
i'm still lookin for a lathe for ya ..........>???????????
Martinm210
ArboristSite Operative
The 044 and 046 are the same stroke, but the bore in the case is a bit too small, and the holes for the jug are a little too wide, so you have to do some shaving. It's really no more difficult than porting though, so if you've got some cheap digital calipers and a dremel, you can make it work.
This is what I'm working on right now, taking some pictures as I go so when I'm done, I should be able to show you what the mod takes.
I think I'm good on this one, but I'm not sure I'm done with my collection just yet. After doing this one I might do one more, it's been fun so far..:greenchainsaw:
stihl only
ArboristSite Operative
yes i do
i am sorry if i confused you on what i was asking.i know what i put on my saw but am very jelous of the 046bb on his 044, wish i would of known...you could do it. my name is cody, hope you guys dont mind me asking questions..if every thing works good for him i have a parts saw i could restore and do the same thing...cody
i am sorry if i confused you on what i was asking.i know what i put on my saw but am very jelous of the 046bb on his 044, wish i would of known...you could do it. my name is cody, hope you guys dont mind me asking questions..if every thing works good for him i have a parts saw i could restore and do the same thing...cody
thanks
the reason i ask, is i love the way my 044 runs with its bb which makes it a stock 046 but i also have a parts saw that i could do this to if it works for you,if i do this it would be my first complete rebuild.need all the help i can get.thanks for your time...cody looks great
the reason i ask, is i love the way my 044 runs with its bb which makes it a stock 046 but i also have a parts saw that i could do this to if it works for you,if i do this it would be my first complete rebuild.need all the help i can get.thanks for your time...cody looks great
Martinm210
ArboristSite Operative
This is the differences I found measuring up the base of the 044 vs the 046.
I ended up using my mill to speed up the process, then just used a 3/8" saw file to touch things up. You could easily do this with just a file though.
Then a quick test fit and I found that I needed to trim the side of the base. The casting on these aftermarket jugs is pretty poor, so this will probably vary depending on the quality during that day. You can see this if you compare the distances from the hole to the edge. Mine needed about .5 to 1mm removed from the flywheel side to get it to sit down. Still working on that, I'll post more as I get it done. The base will bolt down fine now though, and you could probably make the holes bigger than 5mm, I just wanted a nice centering tight fit, so I barely made them big enough for the screws.
Interestingly, the 044 actually had two different sized holes.. One side measured 5.15mm average, the other was 5.50mm, not sure why they did that. The 046BB jug used on average 6.71mm all the way around.
I ended up using my mill to speed up the process, then just used a 3/8" saw file to touch things up. You could easily do this with just a file though.
Then a quick test fit and I found that I needed to trim the side of the base. The casting on these aftermarket jugs is pretty poor, so this will probably vary depending on the quality during that day. You can see this if you compare the distances from the hole to the edge. Mine needed about .5 to 1mm removed from the flywheel side to get it to sit down. Still working on that, I'll post more as I get it done. The base will bolt down fine now though, and you could probably make the holes bigger than 5mm, I just wanted a nice centering tight fit, so I barely made them big enough for the screws.
Interestingly, the 044 actually had two different sized holes..
One side measured 5.15mm average, the other was 5.50mm, not sure why they did that. The 046BB jug used on average 6.71mm all the way around.
Martinm210
ArboristSite Operative
And this is the issue at hand with the case. Need to shave off enough to clear the new piston skirt bore. The blue pen marks are a little conservative, again this could be easily shaved off with just a dremel tool. It would obviously be best to split the case again, but with some careful masking, I may be able to do this without splitting.
I'll attempt some of this shaving later tonight and report back..
I'll attempt some of this shaving later tonight and report back..
lovetheoutdoors
Addicted to ArboristSite
nice pics and even better work..thanks for sharing
Martinm210
ArboristSite Operative
Thanks! Photo nut here as well, I've been accused of being overly visual more than once...can't help myself. My camera is another toy as well..
And the case shaving was a success, although I wouldn't recommend trying to do it with the cases together, that was the hard part.
I would simply mark what you need up front, then do the shaving when the cases are apart. I didn't have the BB kit when the cases were apart, so I couldn't mark it very well.
Anyhow, this should do the trick to the case:
It's got some room to spare both around and down, so I think it'll be ok.
Now how about that cylinder....time for some mapping stock and seeing what sort of cleanup I need to do on the ports. For starters I'm sure I'll want to round out the inlet port bottom. It almost has a reversed curve to it and not very piston skirt friendly. Other than that, I may just add some width to the intake and exhaust and clean up the shapes nice and symmetrical.
And the case shaving was a success, although I wouldn't recommend trying to do it with the cases together, that was the hard part.
I would simply mark what you need up front, then do the shaving when the cases are apart. I didn't have the BB kit when the cases were apart, so I couldn't mark it very well.
Anyhow, this should do the trick to the case:
It's got some room to spare both around and down, so I think it'll be ok.
Now how about that cylinder....time for some mapping stock and seeing what sort of cleanup I need to do on the ports. For starters I'm sure I'll want to round out the inlet port bottom. It almost has a reversed curve to it and not very piston skirt friendly. Other than that, I may just add some width to the intake and exhaust and clean up the shapes nice and symmetrical.
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polexie
ArboristSite Operative
Very good rebuild with excellent pics!!
Amazing job.
Thanks for sharing,
Lex
Amazing job.Thanks for sharing,
Lex
stihl only
ArboristSite Operative
Interestingly, the 044 actually had two different sized holes..
My educated guess would be that the two smaller holes are to accurately locate the cylinder on the crankcase, and the other two are left a little larger so they don't have any impact on location.
I would guess the extra .71mm on the BB cylinder is so they don't have to hold a tight spec to locate the holes where they should be??
Lakeside53
Stihl Wrenching
One thing.. you should locate the hole spacing from the crankcase.. those will be much closer tolerance than the cylinder. Tram the crankcase level and square, then screw in some 5mm threaded dowel pins - or make some on your lathe by turning the heads of some 5mm bolts. You could also turn 4 rods to the minor diameter of the 5mm female threads and insert them (hand push fit). Then use an edge finder and read the measurements off your dials. If your bolt heads are all the same (the torx used on stihl are remarkably accurate and concentric), you can just locate off the side of the heads.
Me.. I go to my boxes of test pins (they are in 1 thou increments) and find the correct fit, and just put one into the case holes, one at a time, and with an edge finder or optical sight, measure the spacing on my mill with the dro (I could use the dials, but..).
You'll find the holes will line up on "easy numbers", like 44.5 or 44 etc.. almost never 44.23 etc... If the x and y are not the the same it just means your case is off square, but you can use simple trig to calculate those back to the layout.
Me.. I go to my boxes of test pins (they are in 1 thou increments) and find the correct fit, and just put one into the case holes, one at a time, and with an edge finder or optical sight, measure the spacing on my mill with the dro (I could use the dials, but..).
You'll find the holes will line up on "easy numbers", like 44.5 or 44 etc.. almost never 44.23 etc... If the x and y are not the the same it just means your case is off square, but you can use simple trig to calculate those back to the layout.
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Lakeside53
Stihl Wrenching
or they didn't care when made!:greenchainsaw:
Martinm210
ArboristSite Operative
Thanks!
The next time I do this, I'll do the case shaving and measuring on the mill. I can't measure very accurately with my calipers. I'll try that and turn some 5mm threaded rod down. I don't have an edge finder yet, but need to pick one up. I do have a small rotary table though, so it might be fun doing the shaving with the rotary to get it perfect as well.
Definitely seeing more quality issues with this 046BB jug similar to my 066BB. This was an NOS branded version from Ebay, but as mentioned they do appears to all be the same manufacturer. There is quite a bit of cleanup that's needed, that's what I'll be working on next after doing some port maps and timing measurements.
But as far as difficulty in getting an 046 on an 044, it's not too bad. I would suggest this:
Moving on the port cleanup work later this weekend then muffler porting and starting the assembly work. Hope to have most of this saw done in another week or two.
The next time I do this, I'll do the case shaving and measuring on the mill. I can't measure very accurately with my calipers. I'll try that and turn some 5mm threaded rod down. I don't have an edge finder yet, but need to pick one up. I do have a small rotary table though, so it might be fun doing the shaving with the rotary to get it perfect as well.
Definitely seeing more quality issues with this 046BB jug similar to my 066BB. This was an NOS branded version from Ebay, but as mentioned they do appears to all be the same manufacturer. There is quite a bit of cleanup that's needed, that's what I'll be working on next after doing some port maps and timing measurements.
But as far as difficulty in getting an 046 on an 044, it's not too bad. I would suggest this:
- Cylinder Head Bolt Hole Slotting - Use a dremel with a small drum or a chain file. It doesn't take much, just a little over 1mm in slotting.
- Case Shaving - I would mark this out with the piston and split the case. Then use a dremel with a small drum sander again and shave about 2mm or so off the edge. Use the piston as a guide and leave some extra room.
- Top cover shaving - Again this can be done with a dremel tool, just needs some shaving in the corner.
- Overall difficulty - Not too bad, hardest part is splitting the case and that's not too bad after getting the tools/methods together. I would definately do it again.
Moving on the port cleanup work later this weekend then muffler porting and starting the assembly work. Hope to have most of this saw done in another week or two.
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Martinm210
ArboristSite Operative
Started back in and worked on a base for the port map, this is what it turned out like.
The intake and exhaust time*areas seem to match pretty well. The one thing that bothered me the most is the almost inverted curvature of the inlet port bottom. I'll at least do some good flash cleanup/smoothing/polishing of the intake and exhaust and also do the port matching at both ends. I figured I'd also try to round off the bottom of that intake port to help protect the piston skirt.
Here is the timing calcs and results. At least there is no freeporting like my 066BB jug.
Overall the 044 -> 046BB is worth an net increase in displacement from 70.7cc to 82.4cc or a 17% increase.
Unless someone has some red flags that this port map/timing they would like to suggest, I'll probably leave the ports pretty much as they are. I could probably go a little wider on the intake and exhaust, but the timing seems to be ok and I don't want to sacrifice any bottom end torque for top end. My hope is that I may be able to run an 8T rim with the right bar and chain in softwoods.
Any thoughts or suggestions on the port map/timing?
The intake and exhaust time*areas seem to match pretty well. The one thing that bothered me the most is the almost inverted curvature of the inlet port bottom. I'll at least do some good flash cleanup/smoothing/polishing of the intake and exhaust and also do the port matching at both ends. I figured I'd also try to round off the bottom of that intake port to help protect the piston skirt.
Here is the timing calcs and results. At least there is no freeporting like my 066BB jug.
Overall the 044 -> 046BB is worth an net increase in displacement from 70.7cc to 82.4cc or a 17% increase.
Unless someone has some red flags that this port map/timing they would like to suggest, I'll probably leave the ports pretty much as they are. I could probably go a little wider on the intake and exhaust, but the timing seems to be ok and I don't want to sacrifice any bottom end torque for top end. My hope is that I may be able to run an 8T rim with the right bar and chain in softwoods.
Any thoughts or suggestions on the port map/timing?
