Skil 1629 rebuild, June 2014

[67L36Driver]

IDK as we don't have a Staples in River City.

Done by local sign company.

 

[user 122986]

Looks great! Nice.

 

[user 122986]

Restarted my muffler design - want to incude 2 baffles inside, one with 1/4 inch holes, one with 3/16 inch holes. Both have the same total area as the four 3/8 inch holes in the exhaust port. This saw is LOUD without a muffler - but I couldn't wait.
I have not done an optimum carb adjustment (low speed, high speed), and the idle is a little fast.
Short video on YouTube at

Gratifying to see it running. There is a bit of hesitation when throttling up. Setting up the carb will come after the muffler is built and installed (I know, I know, you've read that about the muffler often in this thread).

 

[67L36Driver]

You need to hang out in the Pioneer thread as many of our Canuck members are there and Power Machinery was abundant in the north.

I bet one of them has a 340 or three in their junk. Also try posting in the 'Old Magnesium Swap Meet' thread.

 

[user 122986]

You need to hang out in the Pioneer thread as many of our Canuck members are there and Power Machinery was abundant in the north.

I bet one of them has a 340 or three in their junk. Also try posting in the 'Old Magnesium Swap Meet' thread.

Thanks, 67L36Driver.

 

[user 122986]

The saga continues. Now, clutch worries.
My clutch problem arose after about 3 or 4 minutes of running the saw, doing a few carb adjustments. At idle, occasionally, there is a metallic sound (like dropping a tin can with a few loose nuts in it) and the chain becomes fully engaged. After a half second or so, the chain stops, and the engine continues to idle.
I think it may be a broken pad or a broken spring. I will open it up today. Throttling up engages the chain ok, and throttling down to idle stops the chain - until one of those intermittent engagements occurs.
Any advice before I open the clutch would be appreciated, especially advice about possible replacement parts or substitutes.
Thanks in advance.

 

[user 122986]

I have opened the clutch and found no broken pieces. All 3 springs seem to have the same tension, or at least I can not sense if one is weaker than another.To my untrained eye, all components appear in good condition.
I think the metallic noise is because one of the springs is a little weaker, and the pad extends to make contact with the drum, ringing it like a bell.

Attaching close-up shots of the components.

 

[67L36Driver]

Hey, a little 'lurching' is OK in my book. Not like Underwriter's Labratroies has to be pleased. Or freakin' OSHA.

The Pioneer Farmsaw I drug home today does the same thing. What me worry? Naw.

 

[user 122986]

LOL, 67L36, I guess if I try to reduce the idle a few more hundred rpm, this lurching wouldn't happen. I tried to buy replacement springs today, but nothing comes close - everything is too soft. A local Husky repair shop guy said he uses out-of-the bin springs from the retail floor. None will work for this clutch, all too soft. I could also reduce the mass of the weights but not good in the long run.

 

[Chris-PA]

LOL, 67L36, I guess if I try to reduce the idle a few more hundred rpm, this lurching wouldn't happen. I tried to buy replacement springs today, but nothing comes close - everything is too soft. A local Husky repair shop guy said he uses out-of-the bin springs from the retail floor. None will work for this clutch, all too soft. I could also reduce the mass of the weights but not good in the long run.

How is the clutch drum bearing? Drag there - or dirt/rust, flat spots on the rollers, etc. - could cause the chain to grab momentarily.

 

[user 122986]

Hi Chris, the drum bearing seems ok. After I took the photos above, I cleaned the bearing and the surfaces it contacts, and gave it a very thin coat of lithium grease. When reassembled, the drum rolled smoothly, without any strange noises, for several turns and without any rubbing sounds. The internal surface of the drum looks ok to me.
The sprocket has deep wear marks, so I will replace the drum/sprocket and bearing, when one is available. Hard to nail down what fits what.

 

[Jeff Lary]

I have been reading your thread I just wanted to say that as far as I am concerned it is well written and enjoyable to read. You have done a great job on the old girl, she could still be under a tree out in a field someplace. Keep up the good work and I also wanted to be a part of this so I can see that muffler ! Jeff

 

[user 122986]

<grin>, yes, Jeff, the fabled muffler. Thanks for the encouragement. The muffler will be coming soon (not this weekend).

I have done some work on the clutch. I could not find replacement springs, so I decided to check to see if one of the springs is weaker than the others. I took a 3 inch threaded rod, and added washers to separate the springs. Then I ratcheted a nut on to compress the springs. My thinking is that the weakest spring would be totally compressed while the other 2 still have space between the coils. Wonder of wonders, the average compressed length of each is the same (much more compressed than when in the clutch). So I think all springs are still viable.
I decided to clean all components in the clutch (the bearing and drum hub had already been cleaned and lubricated with lithium grease - not the flyweight contact surface)).
I used my work-wheel in a stand so I could manipulate each flyweight and buff it with a wire wheel. Then I buffed the 3-sided hub with the wire wheel.
Following is my naive description of how I see this clutch working.
This is a 'P-type' centrifugal clutch.
Efficiency is lost because it does not have bonded high-friction lining (sort of like brake pads), just steel on steel. But the hub is very resistant to wear, and the flyweight's contact surface can be considered to be self-adjusting: as they wear, the flyweights fly farther from the center to contact the hub. There are photos below that show the clutch hub with flyweights both without and with springs. All modern clutches I have seen during this rebuild use tension springs. This clutch uses compression springs.
Each flyweight has a pivot, which is just a cylindrical shape appendage that fits into a cylindrical cavity in the hub. The front and back cover plates keep the flyweights in place in the hub. The flyweights are slightly narrower than the hub, so never bind on the front and back cover plates.
I buffed hub and flyweights (no sanding at all), as well as the hub contact surfaces of the cover plates. The hub faces and pivot cavities got the thinnest possible film of lithium grease, and I reassembled the clutch, and sprocket/drum assembly. By thin film of grease, I mean there was no grease visible at all.
I reassembled everything, and took the saw outside for an idle test.

It started and idled for 3 minutes straight, without any of the 'lurching' experienced before.
Apologies for the long-winded entry here.

 

[user 122986]

I ordered a replacement clutch drum w/ sprocket and bearings today. Should be here by week's end (Aug. 12-16). Nothing left to work on but the muffler.

 

[J Beard]

Don't worry about being long winded, your details are great, very easy to understand. Sorry to hear about the paint.
Looks like you got the clutch figured out and working properly.

Now... what was that about a ....muffler?

Keep the updates coming!

 

[67L36Driver]

The clutch shoes or weights may be cast iron instead of steel. Bronze is also used for clutch shoes. You rarely find brake material rivited on chainsaw clutch shoes.

 

[user 122986]

Just stopped for lunch - and to calculate the area for the 2 baffles.
The exhaust port cylinder holes (4 holes that open to a single large exhaust port) are each 3/8 inches - (exactly fits the shaft of a 3/8 inch drill bit).
Area of one hole is pi*r*r. 'r' is (3/8)/2 inches, or 0.1875 inches. 'r'*'r' is 0.0352 (approx.) square inches. Area is then pi*0.0352 sq in. or 0.11 square inches per hole. For 4 holes, that is 0.44 square inches.
I want to add 2 baffles to the muffler, one drilled with 1/4 inch holes, one drilled with 3/16 inch holes.
Total area of the baffle with 1/4 inch holes will be approximately 0.5 square inches.
Total area of the baffle with 3/16 inch holes will be 0.6 square inches. There will also be some leakage around the baffles because I will just tack-weld them in place.
The body is complete, cover plate and baffles still to come, hope to finish this afternoon.

 

[user 122986]

The clutch shoes or weights may be cast iron instead of steel. Bronze is also used for clutch shoes. You rarely find brake material rivited on chainsaw clutch shoes.

You are correct about the flyweights being cast, not sure what material, but they did not buff up like cast iron when I polished them with the wire wheel. The hub is a laminate - 3 layers - riveted together. I was surprised when I cleaned the hub to see very little wear on the inside surface where the clutch flyweights make contact.

 

[67L36Driver]

Cast iron actually makes a good bearing surface for a steel shaft (slow turning, gob of grease lubed).

 

[user 122986]

It has been a day of disappointments, but I made some compromises just to complete the muffler. My original muffler fabrication was with heavier sheet steel, but I discarded that this morning, and started from scratch with a pretty thin sheet of steel. Downside is: welding with arc is risky, but I turned my Mig140 down to lowest current (A) and set the wire-feed speed to minimum. Result: I only blew 2 holes in the metal. Downside: impossible to get a good bead, especially since the metal - although stripped of paint - still has some paint residue, so extra splattering made a good weld impossible. So everything is tack welded only. I'll have to buy some clean welding steel someday to see how that works. I had intended to tack weld corners then braze all the seams (oxy-acet.), but got lazy.
I ended up with a 2 part solution, but with a big muffler chamber. The result is that I just have clearance at the top of the muffler for thick leather gloves (I tested with welding gloves). I will try it as is, but there is room to lower the top by 1/4 to 5/16 inch and maybe put an aluminum plate with air gap above the muffler.
I don't have the correct length bolts to mount the muffler, so hopefully can get those tomorrow and test the saw for sound.
Don't laugh too hard at the workmanship. The thin gauge metal meant frequent re-bending, and problems welding.
Hopefully, it will do until I can find some spare Skil or PM mufflers some day.