Matt's first 064

[Spladle160]

Hmmm.... what to do, what to do

 

[mdavlee]

Hmmm.... what to do, what to do
View attachment 191560

If you’re sure it’s .017” run it. I’ve run them as tight as .014” on 50 and 52mm bore.

 

[Spladle160]

Thanks Mike, That's exactly the reassurance I'm looking for. I can manage to get that measurement down as low as 15 thou if I really work at it using my cheap calipers with just the tips on half the solder and a little pressure. I'm probably just digging into the solder.

 

[Spladle160]

I put my degree wheel on it and here's what I came up with the exhaust starts to open 101 degrees after TDC / the transfers open 124 degrees after TDC / and the intake opens 74 degrees before TDC. What do you guys think of the numbers? Should I lower the intake? I'm very hesitant to try anything on the upper transfers since I'm just working with a dremel but feel good enough doing the intake, exhaust, and blending in lowers if that's the right thing to do.

 

[Spladle160]

 

[huskihl]

I'm not an 1122 pro by any means, but if it were me, I wouldn't raise your exhaust. I'd widen it to within 1.5mm of the skirt. Maybe flatten it slightly, but still have an arc shape to the roof. And I'd lower and flatten the intake floor to 80ish. I dont know on that model if the intake should be widened or not

 

[Redfin]

If you cant raise the transfers I would not give it any more ex duration.

 

[Spladle160]

Can't/Won't/Skeered and probably should be without the right tools and experience. I'm thinking I'll drop the intake closer to 80 and widen it, widen and shape the exhaust and call it a day. How much timing do these things like?

 

[Redfin]

Enough till it kicks. Then back it off.

 

[Canadian farm boy]

I gotta agree with everything that Redfin and Mr sausage said.
Lower the intake to 78-80.
Maybe knock the lip off the lower transfer inlets
Don’t change the exhaust timing, just wider like what has been said.

Everyone has a different style to how they port a saw. Different shapes and sizes to the ports as well as different timing numbers for different models. Personally I like to keep the intake floor curved and I don’t generally widen the intake port. Imo keeping the intake floor curved and not widening it helps to reduce wear on the piston skirt and keeps the intake velocity up which I believe helps with throttle response and torque due to reduced spit back and higher case compression.

 

[Spladle160]

I went ahead and did the exhaust, intake, and blended the transfers in. I was very pleased with myself until I mounted the jug and the intake had snuck all the way down to 82. I figure I'll go ahead and run it first before deciding whether or not to raise it back up. I took .025 off the flywheel which ended up being about 7 degrees.

 

[Spladle160]

Still waiting on a few parts but it's getting there.

 

[srcarr52]

I'm not an 1122 pro by any means, but if it were me, I wouldn't raise your exhaust. I'd widen it to within 1.5mm of the skirt. Maybe flatten it slightly, but still have an arc shape to the roof. And I'd lower and flatten the intake floor to 80ish. I dont know on that model if the intake should be widened or not

Darn, I got here too late. I really like to keep these below 80 (160 duration) intake timing. If you can fall at 78, 156dur after machine work to the jug you have a really nice cylinder.

101 to 100 is good on the exhaust, spins plenty fast but still has plenty of torque.

I know the OP can't change the uppers but I would shorten the blowdown to 20 or less.

 

[Spladle160]

Since I'm waiting on some more parts may as well continue my learning experience and play with raising the intake. @srcarr52 @Canadian farm boy how far should I go back up? 80? 78?

 

[Canadian farm boy]

Since I'm waiting on some more parts may as well continue my learning experience and play with raising the intake. @srcarr52 @Canadian farm boy how far should I go back up? 80? 78?

Imo I’d bring it up to 78. That will get your intake duration closer to your exhaust duration. If you don’t like it you can always go back down to 80

 

[Spladle160]

Good call, with the way my measuring and grinding went the first time maybe I ought to bring it up a little extra high.

 

[Mattyo]

Glad the tools worked out!!! Great job so far!

 

[Spladle160]

Got the exhaust raised up. Made sure I'd have plenty of meat to cut on. What's the general consensus on widening it?

 

[Canadian farm boy]

Got the exhaust raised up. Made sure I'd have plenty of meat to cut on. What's the general consensus on widening it?
View attachment 192116

You mean the intake. Lol.
I wouldn’t widen it personally. I’d just lower it to 78-80 and keep the floor slightly curved.

 

[srcarr52]

Lower back to 78. Widen it to the max of the piston. The bottom can be almost flat, just open the middle .020” or little more first to make sure the skirt can’t rock in and catch it. Corners can be very sharp.