Stihl ms 460/660 Hybrid. 469e

[NateSaw]

Raising transfers.... Too much blow down for now. And staggered timing. An unnecessary variable added on another novice theory. May be hurting the thing. But, I left room to raise. I'll be back in for sure.
Note the chip in the plating. Chamfered with a diamond. Can't complain as the price was right.

 

[NateSaw]

Intake landed at 73* after machining. Al noticed the skirt never makes it past the roof. So we decided I should nip it to make intake 76*. He pointed out I should epoxy roof to prevent damming @ skirt. I wouldn't have thought to do that.
Another trick Doc taught me. Modeling clay to mask jb! I use it ALL THE TIME NOW!

 

[NateSaw]

Cured and ground. I want to widen when I go back in to raise transfers.

 

[NateSaw]

OK so here's the final numbers, 1st attempt. As you can see my less than scientific approach to machining , got me a thou and a half lower than I wanted... But alas... I think the 460 rod grows less than the 660...so I'll roll the dice on a greedily tight squish.

 

[NateSaw]

Next I had to figure out the muffler. 1128 all the way. But they don't align with the port....

 

[NateSaw]

This is where my lack of craftsmanship kicked in. Means to an end. I used the heatshield to make a new back. I cut out the original port, bolted the shield to the jug, bolted the muffler to the case, and tacked with a mig.

 

[NateSaw]

Followed by my usual blunderbust pipe deflector ...

 

[NateSaw]

If you zoom in on this picture, you can see more areas of the cylinder that needed relieving to make the top cover fit...
The intake side fins, and provision for the spark plug wire, the little nipple on the top cover. My disc sander and @Mastermind recommended se-51nf buckeye burr made all the external grinding a quick endeavor.

 

[NateSaw]

Eventually it fit. I had a 461 cleaner cover laying around... In assembly I messed around with different clocking on the intake boot. I knew it was going to be a problem. But... I wanted to run it. So I jammed it in. It wrinkled and buckled and did things that only a gymnast can do. And I cussed and cut my finger. For some reason I did not take a picture of the boot installed.

 

[NateSaw]

Anyhow, I took it to work, and we ran it. Snappy. Very snappy. But it didn't piss Rev past 10k. Airbound for certain. Fun to run cause it made noises. But bogged in the cut. So... Back to the intake. The trouble was not only alignment, but the gap between the port and the tank housing being so tight... 7mm at the top of the port, and 15mm bottom. Not a lot of room to make an compound S turn with a half inch of offset.

 

[NateSaw]

My first attempt was with a 460 boot, which with its half moon not matching the nice round 660 port, was a lay down for a dePORTation. I ordered some 660 boots from @Duke Thieroff . I cut one up thinking I could make it using the bulge as the carb mating surface. Doc pointed out I NEED the french ticklers to keep fuel atomized. So that one was round filed. I had to use one full length. But the only way it would relax was to pull it through the tank housing intact...

 

[NateSaw]

When pulled through the tank housing, it looked good between the cylinder and tank. But the pass through needed to be hogged out as to not bear down on the boot. Best I could hog, there's still contact. I smoothed and chamfered as much as possible. This WILL be an Achilles for longevity. These will eventually chaff through.
I'm trusting Stihls' over engineering. So far the studs seem to take proper torque still. The fiber reinforcement these guys do is second to none. This plastic is tough sh*t.

 

[NateSaw]

Soo... As you guessed, this build needed an intake riser...
Not a proper print. But a good enough. The riser needs to accommodate the buldge in the boot that now resides just inside the tank assy firewall. And give enough room for some shifting.

 

[NateSaw]

Face and true...

 

[NateSaw]

I need a mill. Everyday, I need a mill. Made a center line the hard way, measured off the edge of the center drill hole, subtract half that diameter, add half diameter of stud holes, center punch, chuck up stock in vise on drill press, eyeball, pray, double check, drill, then use tailstock to recenter ish in lathe chuck, and proceed. I was spoiled at the machine shop. Edge finders are my friend.

 

[Mastermind]

Nate, just because you can do something does not mean that you should. LOL

 

[NateSaw]

Continuing, while grumbling how I need a mill.

 

[NateSaw]

Nate, just because you can do something does not mean that you should. LOL

Oh, I agree whole heartedly brother. Stay tuned as I fall flat in my face This thing still ait there yet. I'm here for entertainment purposes only.

 

[NateSaw]

Parted off, leave it heavy, flip it and face it true.

 

[NateSaw]

Installed without boot to illustrate orientation. With to illustrate the fruits of labor.