Cracked transfer, What can i do?

[cgraham1]

I kinda wanted to see what would happen if the transfers were hogged out...

 

[Chainsaw Jim]

I kinda wanted to see what would happen if the transfers were hogged out...

This one would be considered to have hogged transfers...

 

[Brewz]

I ended up selling this saw to a young fella who is starting up his own contract fencing business.
He used it for one day and the limited coil failed.
I told him to bring it back and I put the unlimited coil and flywheel I had for my project on it and gave it back to him.

I have been trying to get hold of him to find out if its running well but he wouldn't answer his mobile or respond to text messages.

Finally tonight I get a text back to say he has been busy and it is running awesome.

That made my day!

 

[Redfin]

This one would be considered to have hogged transfers...

Is the bridge still intact?

 

[Brewz]

If anyone has an 064 cylinder with a busted transfer or other recoverable damage they want to send me, (I will pay post) I will remove the transfers completely and port it to see what happens, but I wont be doing it on the good one I have.

Would be interested to see it ported the same as the one I am building now, same numbers and port design.

 

[jake wells]

it should make good power open or closed a lot of older saws were open port and ran fine and produced good power.

 

[Tim]

I have a Stihl 056 super that had a cracked transfer port. I asked some people in a chainsaw repair group what I should do and one said to grind the crack down and run it while another said some remove them both when that happens. I decided to remove them both and showed pictures and then people said I would have to blend it rather than leaving the ends of the bridges intact. Another said I would definitely have to fix the port timing.

I kind of want to try it as is with the bridge ends intact, but I'm concerned about the rings catching. Thinking about it I would think the rings would have a better chance of catching with the bridge ends removed because that would make a wider open space.

I don't know much about porting so I prefer to do as little as necessary to get it going.

Does anyone have any advice on what I should do? The cylinder was in great condition other than the crack so I would like to salvage it if possible. Would it be safe to try it with the bridge ends intact? I did bevel the edges.

 

[drf256]

Probably will be just fine.

Gotta do a nice bevel. I finish all of my work with a brake hone now. Will smooth even the most minute elevated area in the jug.

My worry would be one side of the bridge sticking out into the bore a bit.

Put a ring in it with the gap over an area of porting where it will make it all the way to the chamber. Make sure you leave the grooved part of the gap down so you can retrieve the ring with a pick if necessary.

Push it though the bore slowly with an inverted piston. Close your eyes doing it. If you don't feel any change in resistance/catching anywhere, you're likely good.

Any pics?

 

[jb-chainsaws]

Just an opinion thrown in there, but I'd grind them both out to run as an open port, then fill the back side of the port some to reduce the volume and cross sectional area of the port, should help with charge velocity.

Then put a nice tight roof on the uppers, and play with some numbers. He who does not try something for fear of failure will never succeed. I say have some fun with it and see how it runs

 

[Chainsaw Jim]

The rings don't travel below the bridge so you only need to angle the top corner a little bit to give them a smooth ride.

 

[Tim]

Here are some pictures. Definitely nothing fancy, I just want to make it work. I don't know anything about porting so I'd like to make it simple. If it runs really poorly then I might mess with it more.

So do you guys think it should start as is and not be at risk of causing more damage?

 

[Tim]

Today I installed the cylinder as is and it started fine and seems to have plenty of power. I didn't have a large log handy but there were chunks of 6 x 6 pine laying around where I was. I cut one by putting the bar along the length with a 24" bar and it cut through easily. I then put three chunks side by side to make 18" and it easily cut through. It also has an 8 pin sprocket on it.

When I first had it going it would not idle without the chain spinning. Even at 1,800 to 2,000 rpm. I reset the ignition timing by the marks on the case and stator plate (I originally had it advanced) and switched the clutch with another that appeared to have way less hours on it and tightened the chain so there wasn't any slack but could still easily be advanced by hand. It will now idle at around 2,200 rpm without the chain spinning. I think if the chain had a little slack it would spin. I don't think the chain advance problem is clutch related, although it might be.

I can't tell yet if it has gained any power but it doesn't seem to have lost any. I did put a thin .2mm cylinder gasket instead of .5 and the compression after warmed up is just under 150 psi. Next time I mill some lumber I'll run it side by side with my 056 magnum to see how it compares. I should have put better rings in it but I didn't know what would happen. I put in one lightly used Caber and one well used OEM. I may put in two good rings if I run it a while and nothing bad happens. It also has a Golf piston that has fairly low hours but got scored when I was running it in this cylinder before.

 

[blsnelling]

When I first had it going it would not idle without the chain spinning. Even at 1,800 to 2,000 rpm. I reset the ignition timing by the marks on the case and stator plate (I originally had it advanced) and switched the clutch with another that appeared to have way less hours on it and tightened the chain so there wasn't any slack but could still easily be advanced by hand. It will now idle at around 2,200 rpm without the chain spinning. I think if the chain had a little slack it would spin. I don't think the chain advance problem is clutch related, although it might be.

Shouldn't the idle be set more like 2,800?

 

[Tim]

Shouldn't the idle be set more like 2,800?

2,500 for idle. I actually had the same problem with another 056 super after doing an ignition repair using a Nova II module. It runs fine but I have to tune it down to 2,000 rpm so the chain won't spin. I thought it was because of the ignition repair but this has a normal Bosch electronic with no repairs. Maybe I just need new clutch springs. These saws are probably around 30 years old. There were also a couple different styles of clutches and drums, perhaps I have a mismatch if that is possible.

 

[Tim]

I ended up pulling it apart and grinding the corners off the bridge ends. There were enough responses about the bridge ends in another group to make me paranoid enough about a ring snagging. I also had to repair the ignition, put all the proper clutch parts on and a good working clutch and since I was in there I put better rings in.

It now starts, runs and idles good with no chain spin and seems to have plenty of power. I cut several cookies off a 20" diameter Tulip Poplar log and it cut through fine. The compression is just under 150 psi.

 

[Tim]

Just thought that I'd give an update on the cylinder. I thought the saw was running fine and actually posted it for sale in a Facebook group and got a nasty comment about trying to sell a saw with that type of repair. That being a valid concern (piston ring snagging) I decided to run the saw and it would run for a little while then die. Long story short, with lots of tinkering I found the problem was partially the carburetor. The idle seems to go all over the place but with a freshly cleaned carburetor with a new rebuild it seems to stay running and the throttle response is really good even when it idles down. With the last carb it would idle down then flood and also foul plugs. I've pulled the cylinder several times and every time it has transfer that I have to clean up. I cleaned up the transfer and put in new aftermarket piston rings. The compression is nearly 155 psi right after putting it back together. I have a lot of milling to do this year so I'm going to see how long this will go for and I'll keep updating. I've already milled five 6 x 6's and several boards with it. it seems to be running pretty strong but when I get to the bigger logs I'll see how much torque it really has. If it's weak I might do some more modifying. If so I may need advice.

 

[blsnelling]

Without going back through this thread, have you vac tested this saw? If there's scoring every time you pull it apart, something is wrong, and I don't think it's your modified cylinder.

 

[Tim]

Without going back through this thread, have you vac tested this saw? If there's scoring every time you pull it apart, something is wrong, and I don't think it's your modified cylinder.

Yes, every time I take it apart I pressure and vac test it before I put it back together. The first time I took it apart it did not hold pressure well because it had a spring clamp on the intake but it held vac. I put a screw clamp on.

The second time I took it apart I realized that I tightened the clamp too much because it tore in the middle right under the clamp. It did hold pressure and vac originally but maybe tore when using it. I actually don't think it leaked but it might have.

The first couple times I tuned the L pretty lean because that was the only way it would idle without flooding really fast.

The last time I had it apart it held pressure and vac fine and I only ran it to see if it still had idling problems but it had too much piston slap so I took it apart again and put the other piston back and new rings. It was tuned normal that time.

I pressure/vac test it for 5 minutes each and if it moves any then I find the leak and fix it until it will hold for five minutes without moving.

So the first two times maybe it was an intake boot leak and/or a bad carburetor or my tuning it too lean on the L screw. The third time maybe it was from a sloppy piston. The carburetor on now seems okay but it still idles up and down a little. The throttle response is really good though, even when it idles down.

It doesn't have a sloppy piston now and it started fine and idled good but I only had it going for a minute. It holds pressure and vac and I don't think I tightened the clamp too much. It has new aftermarket rings with about .010" ring end gap. The carburetor has a new rebuild kit also which was in the other carburetor but didn't help it.

I mixed up a batch of 32:1 and I'll do some light milling tomorrow with a rich mix and see how it goes.

 

[Tim]

Also, I originally thought it was the cylinder causing the idle problems and put on a 52mm piston and cylinder. It idled poorly still so I put on a freshly cleaned carburetor and made nine milling cuts and the saw ran fine but with a little idling fluctuation, mostly when turned sideways. After pulling that cylinder it looked perfect, no transfer.

 

[blsnelling]

A lean tune on the L needle will not cause your piston to score.