044/046 Hybrid Build

[earlthegoat2]

Over the next few days I will be posting some pictures and commentary about my hybrid build. There seems to be precious little on the net about this. I did not find it to be an overly complicated project but a few instructions could really go a long way. This was my first build of this type and I may have missed a few steps or did not clearance something where I should have.

Truthfully I'm not too sure of the longevity of the build. I got a little bit too far into it before I realized there may be a problem with the cylinder and small end on the rod. That is what prompts me to use a few aftermarket parts including a Meteor piston and some Hyway and Cross branded products.

For a bit of a teaser, here is when I enlarged the cylinder holes from M5x0.8 to M6x1.00.

One case half vised up, drilled, tapped, and dressed down by hand with 220 grit paper.





The cylinder holes are through holes too. They are not blind. The last picture below shows what I am talking about. You can see the tap protruding in the upper left area of where the flywheel would be.

 

[GCJenks204]

@Canadian farm boy would be a good source of answers if you have questions. I think he has 4 of these in the shop right now.

 

[Deets066]

Over the next few days I will be posting some pictures and commentary about my hybrid build. There seems to be precious little on the net about this. I did not find it to be an overly complicated project but a few instructions could really go a long way. This was my first build of this type and I may have missed a few steps or did not clearance something where I should have.

Truthfully I'm not too sure of the longevity of the build. I got a little bit too far into it before I realized there may be a problem with the cylinder and small end on the rod. That is what prompts me to use a few aftermarket parts including a Meteor piston and some Hyway and Cross branded products.

For a bit of a teaser, here is when I enlarged the cylinder holes from M5x0.8 to M6x1.00.

One case half vised up, drilled, tapped, and dressed down by hand with 220 grit paper.

If you have the 10 mm wrist pin then you aren't going to build a hybrid

 

[earlthegoat2]

Well pics are being a pain. Ill try and upload the old fashioned way.

More pics and commentary to come. I do have this saw finished and running and so far it is a ripper. I leaned pretty hard on it in 30" live oak with a 20" bar on the saw and it was running way too rich at the time and it still did not bog down.

 

[Adirondackstihl]

 

[drf256]

Thanks for posting. Please keep the info and pics coming.

 

[Aciera]

I know Leadfarmer loves running them.

 

[earlthegoat2]

I have some milling to do today but I should be able to get another round of photos and info later this evening.

 

[blsnelling]

There seems to be precious little on the net about this.

You should be able to find a lot of info on this build. These hybrids have been very popular over the last few years.

 

[earlthegoat2]

I have since found a bit. There is a pretty good one on here from last year but its not detailed enough for someone who has never done one before. Canadian Farm Boy was the main contributor to the build. Dalls 044 Hybrid was the title.

Basically, when I became interested in this build I was attempting to search for "putting an 046 cylinder on an 044" and got very little. This was in January of 2016. If I would have typed "044 hybrid" or "046 hybrid" I would have found more info. Didn't really know they were called that until more recently. Not new to chainsaw repair but definitely new to chainsaw hot rodding.

 

[Deets066]

I would check wrist pin diameter before you get too far.

 

[earlthegoat2]

Like I said. For better or worse, this thing is together and running. I used it to free cut the sides of a log I was milling today. Pretty tough cutting and conditions and probably not the type of work you would want to be doing with a saw that had less than a few minutes on a fresh rebuild.....it was either that or unracking the 660 off of the mill to do it. Nah.

I did check wrist pin diameter though. I checked to make sure the 3 old Stihl ones I had were the same diameter as the Meteor one I ended up using. The Meteor one was .001 larger and still slid into the pin hole on the Meteor piston. I figured it was best to go with the Meteor pin in this instance. I have no idea what the factory spec is.

 

[leadfarmer]

I know Leadfarmer loves running them.

It's me go to saw [emoji38]

Sent from my SM-G900V using Tapatalk

 

[Aciera]

It's me go to saw [emoji38]

Sent from my SM-G900V using Tapatalk

You are a kind soul......tried to adopt mine as I remember. Lol

 

[leadfarmer]

You are a kind soul......tried to adopt mine as I remember. Lol

My memory is as short as.........[emoji38]

Sent from my SM-G900V using Tapatalk

 

[earlthegoat2]

Little more fun. I'm not going to show it but there was a stripped case bolt so I ended drilling out and tapping all of them to M6 too then I reassembled the case. Here is what I ended up with elongating the holes on the 460 cylinder to fit the 044 bottom.

Then there is a comparison of the old Stihl 52mm piston with the new Meteor I used. The Stihl is smoother with few casting marks. The Meteor has a little more meat on it for those of you worried about increased reciprocating weight. I ended up cleaning up the sharp casting marks on the piston but did not remove any more material.

 

[earlthegoat2]

Now onto some firmer issues. The base of this 460 cylinder is apparently slightly wider than the 044 so some light grinding is required on one side or the other. This only required grinding on one side and it was probably less than 20 thousandths.

Once the cylinder is lying flat on the crankcase, the fitment of the cylinder screws comes into play. Note that earlier I enlarged the holes of the crankcase. This theory was that the cylinder of the 460 had M6 sized holes and as such, M6 screws should be holding it down. Since you end up having to elongate the holes anyway, re threading the crankcase holes to M6 is not strictly necessary. However, I thought it prudent to do so.

Since I did this, I ordered some M6 socket head T-27 torx screws to use to secure the cylinder down. Since the holes had been clearanced inward towards the cylinder there was some fitment issues with the head of the screw bumping into the side of the cylinder. I chucked the screws into a drill and ground them down until they fit. This was more of an issue than elongating the holes and more important to getting a proper cylinder to crankcase fit. In the pics you can see the grind marks on the screw heads as well as the areas on the cylinder where the screws scrubbed the side as they were being fit and ultimately driven in.

 

[earlthegoat2]

Put the piston on the rod and you really see how close it comes to hitting the crankcase opening. I thought I was going to have to do some clearancing there but I figured since big bore kits exist for 044s and they use the same diameter piston as an 046, that this would be OK. It turned out it was. Still does not mean you could do a little clearance there.

I chose to run a base gasket. I was in a hurry and did not have any means of checking squish so I just used the gasket. You have to enlarge the holes on the gasket to M6 as well but no additional clearance has is needed.

 

[Wonkydonkey]

ummm. you got me all worked up. I wanna see this beast at work chewin and spitting some wood fibres

 

[earlthegoat2]

Here is the cylinder installed. It is a snug fit but to get to this point no clearance has is needed externally except the side of the base of the cylinder which was discussed earlier.

However, to complete assembly the flywheel is going to need some clearance get from the outside of the transfer port on the cylinder. In this instance, I was not quite sure how much clearance was needed and I had no clue how thick the transfer wall was so I was hesitant to grind there. ( I have since learned that you can take material from there for the purpose of clearancing the flywheel and would go that route in any future builds). Instead, I simply put a small bevel on the flywheel. Yes, this will throw it out of balance but since running the saw I have seen no ill effects.