Dolmar 64xx/73xx/79xx series, smurfs and solo 665/675/681 thread

[mettee]

Like this, I stick them to the top of the piston with grease. In this pic they had just gotten stuck to the squish band. Not a big deal if that happens just measure them and lay them out so you can keep track.

 

[mettee]

I did that. Even cut some small chunks of solder and held them in place with grease along the perimeter of the piston and reinstalled the cylinder. Those are where my measurements came from.

Then what you got is what you get unless you cut the base and squish.

Make sure you are getting the solder all the way to the edge. If you have it down in the lower area that's why the measurement could also be larger.

 

[huskihl]

I did that. Even cut some small chunks of solder and held them in place with grease along the perimeter of the piston and reinstalled the cylinder. Those are where my measurements came from.

Tight to the outer edge is tighter. Like .013” usually. Difficult to measure with the 4 corner method and grease. Bend it in an L shape and check the fw side through the plug hole while you roll the fw back and forth 10 times over it

 

[sledneck22]

Tight to the outer edge is tighter. Like .013” usually. Difficult to measure with the 4 corner method and grease. Bend it in an L shape and check the fw side through the plug hole while you roll the fw back and forth 10 times over it

I did that again tonight with some different solder. I’d say about 8 different measurements. Making sure the solder was pushed up against the sidewall of the cylinder. Lowest I can read is .023. So I’m just gonna run it. I think that’s pretty good.

 

[huskihl]

I did that again tonight with some different solder. I’d say about 8 different measurements. Making sure the solder was pushed up against the sidewall of the cylinder. Lowest I can read is .023. So I’m just gonna run it. I think that’s pretty good.

Are you sure the rod and wrist pin bearings are good? And how thick is your solder?

 

[sledneck22]

Are you sure the rod and wrist pin bearings are good? And how thick is your solder?

I check for vertical play in both. No noticeable play by touch. I’ve had a couple saws I’ve rebuilt where I knew. Nothing off that sorts but .010 might be hard to feel. Idk. Maybe I need a wrist pin bearing or just blow the bish up and try again lol.

 

[huskihl]

I check for vertical play in both. No noticeable play by touch. I’ve had a couple saws I’ve rebuilt where I knew. Nothing off that sorts but .010 might be hard to feel. Idk. Maybe I need a wrist pin bearing or just blow the bish up and try again lol.

Yeah I’m not doubting, just curious and trying to save you a cylinder if that’s the case. I am mostly asking because every one of them I’ve seen has been .013” on it’s very outer edge. But it’s entirely possible that the guy before you sanded or lathed that ring out of there

 

[mettee]

I check for vertical play in both. No noticeable play by touch. I’ve had a couple saws I’ve rebuilt where I knew. Nothing off that sorts but .010 might be hard to feel. Idk. Maybe I need a wrist pin bearing or just blow the bish up and try again lol.

Don't blow it up!

 

[davidwyby]

Start it. If it makes bad noise it’s bad.

 

[mettee]

Don't listen to him

 

[Wilhelm]

I wouldn't mind having a peak if it's easy to un-stash. if it's a pain, then I wouldn't bother. Thank you for offering regardless of what direction you so choose.

It is not a pain, cardboard box with spare parts is in the house - should be easy and comfortable access.
I'll look into it!

 

[sledneck22]

Yeah I’m not doubting, just curious and trying to save you a cylinder if that’s the case. I am mostly asking because every one of them I’ve seen has been .013” on it’s very outer edge. But it’s entirely possible that the guy before you sanded or lathed that ring out of there

I guess I did take a picture of this cylinder at some point. So obviously this was mid process of cleaning up the lowers and there’s obviously no gasket at this point. The shape of the flairs on the bottom of the cylinder are how it was received. Not sure if that’s normal for these.
But you can definitely see the tight band in the top of the cylinder which is where I was taking measurements. It was noticeablely more clean/lacked carbon as compared to the rest of the head. I think someone once played with this cylinder as well?

 

[huskihl]

Not sure what you mean by the “flairs”. Can see you did a little bit of work to the lowers, but the uppers are stock. Can also see the shiny ring where someone may have ground it out

 

[sledneck22]

So I circled in red what I'm refering to as the "flaired" cutouts. swooping cutouts for the bottom end to feed into the lower transfers. I was unsure if those were typical for a 7910 cylinder or not. But they were very sharp with some dings so I beveled them a bit. Probably not much concern as the windowed cylinder shouldn't even travel over them. I just didn't want to remove much meat as they seem quite thin.
I also circled in green the base band. I think it was cleaned up by someone at some point because it doesn't have any build up like the rest of the cylinder head had. But it also don't have room to either in regards to combustion area.
I used a couple different solder diameters. I ended up getting the most consistent results with the .040 or .050 wire. I can't remember off the top of my head which it was. Pretty narrow stuff though.
I appreciate everyone's time and responses. I'll check once more before I button the rest of the saw up tonight but in the end, "it is what it is" and "it isn't what it isn't".

 

[huskihl]

So I circled in red what I'm refering to as the "flaired" cutouts. swooping cutouts for the bottom end to feed into the lower transfers. I was unsure if those were typical for a 7910 cylinder or not. But they were very sharp with some dings so I beveled them a bit. Probably not much concern as the windowed cylinder shouldn't even travel over them. I just didn't want to remove much meat as they seem quite thin.
I also circled in green the base band. I think it was cleaned up by someone at some point because it doesn't have any build up like the rest of the cylinder head had. But it also don't have room to either in regards to combustion area.
I used a couple different solder diameters. I ended up getting the most consistent results with the .040 or .050 wire. I can't remember off the top of my head which it was. Pretty narrow stuff though.
I appreciate everyone's time and responses. I'll check once more before I button the rest of the saw up tonight but in the end, "it is what it is" and "it isn't what it isn't".
View attachment 349211

The cylinder extension cut out for the lower transfers is like that from the factory. Not concentric from front to back, but usually the same left and right

 

[sledneck22]

It is not a pain, cardboard box with spare parts is in the house - should be easy and comfortable access.
I'll look into it!

You don't have to dig it out. Kevin answered my questions in regards to the stock cylinder.

 

[Wilhelm]

You don't have to dig it out. Kevin answered my questions in regards to the stock cylinder.

OK, if You say so.
Sorry, I got stuck in town after work and then bucked my neighbors firewood logs till 8PM local time.

Let me know if You want any pictures after all.

 

[whitesnake]

Would be kinda odd for someone to cut the band and not do any other work to the cylinder?? Just my thoughts but I guess anything is possible.

 

[mettee]

The squish band looks stock. I don't think it's been modified. The couple I have are fairly clean in that ring.

If the ring is still there, it hasn't been modified.

I'll post pics in a sec

 

[mettee]

Two cut bands, the ring is gone