Stihl ms 460/660 Hybrid. 469e

[NateSaw]

Also, not a ton of meat in the band to cut out of the 46 BB. I got just enough out to run a 660 piston with a base gasket.

Whats the band look like stock?

 

[NateSaw]

Also, not a ton of meat in the band to cut out of the 46 BB. I got just enough out to run a 660 piston with a base gasket.

My 460 BB band is ready for use. It's fat and flat...
And when you pin the 660 to the 460bb slug, it looks like you've got everything you need to make up for that early-ish intake and then some....

The compression height on the 660 slug appears to be 0.072" higher. You would have to make a spacer gasket, and/or shave the crown.
660 compression height =22mm
Crown to skirt=43.1mm
Pin to skirt=21.1mm

460bb compression height =21.6
Crown to skirt =39.6mm
Pin to skirt =18mm
You have 0.030" squish, you need to lift jug 0.042" to have zero, 0.062" to have 0.020". Figure that out and you have way earlier port timing.

 

[NateSaw]

My 460 BB band is ready for use. It's fat and flat... View attachment 412099
And when you pin the 660 to the 460bb slug, it looks like you've got everything you need to make up for that early-ish intake and then some.... View attachment 412100
View attachment 412101
The compression height on the 660 slug appears to be 0.072" higher. You would have to make a spacer gasket, and/or shave the crown.
660 compression height =22mm
Crown to skirt=43.1mm
Pin to skirt=21.1mm

460bb compression height =21.6
Crown to skirt =39.6mm
Pin to skirt =18mm
You have 0.030" squish, you need to lift jug 0.042" to have zero, 0.062" to have 0.020". Figure that out and you have way earlier port timing.

You'd have way too early exh though... Maybe.

 

[Mastermind]

I wonder how it would have done with an OEM 395 jug?

The saw is a 064. I tired a big bore 066 jug on it....and the piston was crap. Even free ported on the exhaust floor at TDC. That's why I tried the 395 piston. It ran pretty well, but not as good as it did with a OEM 660 top end.

Here it is, 11 years ago. It was running out of fuel in the last cut....fuel filter was too restrictive.

 

[Powerstroke Cowboy]

The saw is a 064. I tired a big bore 066 jug on it....and the piston was crap. Even free ported on the exhaust floor at TDC. That's why I tried the 395 piston. It ran pretty well, but not as good as it did with a OEM 660 top end.

Here it is, 11 years ago. It was running out of fuel in the last cut....fuel filter was too restrictive.

Thanks for the explanation and video! That looks and sounds like a runner.

With AM BB cylinders having less than desirable transfer ports. Small and not shaped right, hurts power. That plays a part in low power output.

What I wonder is how many of the cylinders are out of round, or have a very uneven plating/final hone job? I've seen some where they have shiny spots in the bore where the rings hit, and places where the rings skip. I wonder how much power is lost from that alone?

The best BB are probably the hybrid ones where all parts involved are OEM.

 

[NateSaw]

The saw is a 064. I tired a big bore 066 jug on it....and the piston was crap. Even free ported on the exhaust floor at TDC. That's why I tried the 395 piston. It ran pretty well, but not as good as it did with a OEM 660 top end.

Here it is, 11 years ago. It was running out of fuel in the last cut....fuel filter was too restrictive.

Damn!

 

[Mastermind]

Damn!

That was when it was slow, and I was a terrible operator.

 

[NateSaw]

Thanks for the explanation and video! That looks and sounds like a runner.

With AM BB cylinders having less than desirable transfer ports. Small and not shaped right, hurts power. That plays a part in low power output.

What I wonder is how many of the cylinders are out of round, or have a very uneven plating/final hone job? I've seen some where they have shiny spots in the bore where the rings hit, and places where the rings skip. I wonder how much power is lost from that alone?

The best BB are probably the hybrid ones where all parts involved are OEM.

Meteors are decent. Idk if they big bores... But as a hybrid.

 

[Mastermind]

Meteors are decent. Idk if they big bores... But as a hybrid.

I built a 044/046 hybrid using a Meteor top end once. I was far less impressive than ones I've done using OEM parts.

 

[huskihl]

I built a 044/046 hybrid using a Meteor top end once. I was far less impressive than ones I've done using OEM parts.

D Dave sent Dallas one of the first meteor 661 prototype cylinders and he ran it for a bit. And then sent it up to me to see what I thought. The arrow was backwards, so if you follow that you had a ring gap in the center of the exhaust. And it was 30% slower than a stock OEM cylinder. Even ported with a Wiseco, because of the angles up inside the transfers that were inaccessible, I couldn’t get that cylinder to run as good as a stock OEM 661 cylinder.

 

[NateSaw]

D Dave sent Dallas one of the first meteor 661 prototype cylinders and he ran it for a bit. And then sent it up to me to see what I thought. The arrow was backwards, so if you follow that you had a ring gap in the center of the exhaust. And it was 30% slower than a stock OEM cylinder. Even ported with a Wiseco, because of the angles up inside the transfers that were inaccessible, I couldn’t get that cylinder to run as good as a stock OEM 661 cylinder.

That's wild!

 

[drf256]

Nate,

A dab of Al filler here. 2 spots on each side. Can hand grind at the end. I have 4047-supposed to be same alloy as slugs. 4043 would work. Quick dab and done. Shouldn’t anneal the piston.



I don’t think you need to worry about the lowers too much unless they are truly shrouded. You have some leeway because you have case/jug volume mismatch there. I’d even them out, use slug 2 with the welding, and shorten blowdown-especially because you’ll be lowering case pressure with any lower mods.

Edit. You can just do 2 dabs on the exhaust sides of the ring groove. You’re short circuiting case pressure out of it now.

 

[Moparmyway]

with the piston in perfect position at bdc. What's you fellers favorite way to mark the piston, in order to get it back in the cylinder off the saw... Mark out exh and intake ports? Who's got a great trick?

Stick 2 rings in the cylinder, with the piston on the rod, slide the cylinder over the piston. The piston will move to BDC as you push the cylinder down. Get at least 2 bolts tight (diagonally opposite from each other) then you can remove the cylinder. Now remove the piston from the rod and SLOWLY lower the piston down into the cylinder untill it rests on the 2 stacked rings.

You are now witnessing BDC

 

[Mastermind]

That's wild!

Completely unsurprising to me.

 

[Mastermind]

Stick 2 rings in the cylinder, with the piston on the rod, slide the cylinder over the piston. The piston will move to BDC as you push the cylinder down. Get at least 2 bolts tight (diagonally opposite from each other) then you can remove the cylinder. Now remove the piston from the rod and SLOWLY lower the piston down into the cylinder untill it rests on the 2 stacked rings.

You are now witnessing BDC

Great idea.

I use this to check timing numbers, and their relationship to the ports a lot. I made some studs for this so I don't have to take the bolts in and out.

 

[Moparmyway]

Yuppers, one ring will work, but it’s too easy to shift the one ring while manipulating the piston, so 2 rings gives you some wiggle room without worrying about anything moving in the bore

One ring for checking timing numbers !!

 

[Mastermind]

Yuppers, one ring will work, but it’s too easy to shift the one ring while manipulating the piston, so 2 rings gives you some wiggle room without worrying about anything moving in the bore

One ring for checking timing numbers !!

Agreed !!!

 

[NateSaw]

Completely unsurprising to me.

Yeah, cause you aren't a noob.

 

[NateSaw]

Stick 2 rings in the cylinder, with the piston on the rod, slide the cylinder over the piston. The piston will move to BDC as you push the cylinder down. Get at least 2 bolts tight (diagonally opposite from each other) then you can remove the cylinder. Now remove the piston from the rod and SLOWLY lower the piston down into the cylinder untill it rests on the 2 stacked rings.

You are now witnessing BDC

Thanks Kevin!

 

[Mastermind]

Yeah, cause you aren't a noob.

Bruce and I did some things with me porting oem jugs, and him sending them to China to be copied. I got to see firsthand that the Chinese are 100% capable of doing very nice work. The prototype cylinders they sent us back for the 661 were absolutely beautiful. They ran almost as well as oem jugs that I ported.

Then, after giving them the green light....they sent Bruce 100 units of the most fughed up looking crap I'd ever seen.

Yep....they are capable. No....they are not honest, and will fugh over anyone for a buck.

The moral of the story? You have no idea what you are going to get when you buy this garbage.