046 cylinder identification

[Canadian farm boy]

There as been some discussion lately with reference to the 046 cylinders.
Last night I took a look at a couple cylinders I have. I found several physical differences with the cylinders that may make it easier for everyone to identify which style cylinder they have on their saw. Hemi cylinder vs a D cylinder.

A D cylinder has a D shaped combustion chamber
A hemi cylinder has a round combustion chamber.
Pics for chamber shape reference

This is a D chamber
This is a hemi chamber

 

[Canadian farm boy]

Externally the there are a few differences that can help with identifying which cylinder is which.
Notice the differences with the cylinder base.

In each of these pictures the D cylinder is on the right.

 

[Canadian farm boy]

Slight difference with the top of the cylinders as well

Again the D cylinder is on the right

 

[Canadian farm boy]

I will mention that I have only ever seen a Mahle branded D cylinders. The D cylinders have an A or B stamped into the center pad on the top of the cylinders. There may be cylinders out there that have a C stamped into them but so far I've never seen one.

 

[Canadian farm boy]

The hemi cylinder in the pictures is a Stihl branded cylinder. I know that there are also Mahle branded hemi cylinders. I currently don't have a Mahle branded hemi cylinder.
Perhaps someone else does and could share a few pictures???

 

[BuckthornBonnie]

Ill check tonight

 

[BuckthornBonnie]

Just a boring hemi stihl -

 

[BuckthornBonnie]

Intake-

 

[BuckthornBonnie]

My first 1128 build was a stock Stihl 460 hemi cylinder. Comp was 165 before break in. Probably 170 now (base gasket).
Strong-running saw for sure.

 

[Onan18]

Great thread Mike @Canadian farm boy thanks for taking the time to do it. Really helps us Stihl illiterate types.

 

[drf256]

Great comparison Mike.

The D jug sure looks like it's been cast better.

Have you checked timing?

 

[Canadian farm boy]

Great comparison Mike.

The D jug sure looks like it's been cast better.

Have you checked timing?

What I've noticed is that the intake and exhaust port timing seems to be fairly consistent. Within a couple degrees from cylinder to cylinder.
Now the transfer port timing tends to be all over the map. I've had stock transfers anywhere from 130* to 120*.
Stock squish clearance also tends to be all over the place. The cylinder I'm playing around with now was .030" with a metal gasket. I've had some cylinders with as much as .055" with a metal gasket.

 

[Canadian farm boy]

I got a couple picture of a Mahle hemi cylinder last night. There's some resemblances to both the Mahle D cylinder and the Stihl hemi cylinder.

046 mahle hemi cylinder

 

[Canadian farm boy]

More pictures of the Mahle hemi cylinder

 

[Brewz]

I just scored this D chamber cylinder to use on a hot hybrid build

 

[Brewz]

I'm pretty impressed with the timing.

 

[Canadian farm boy]

I just scored this D chamber cylinder to use on a hot hybrid build

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I'd love see where you go with the build. How hot are you thinking? Work saw or racer?

 

[Deets066]

I'm pretty impressed with the timing.

That would be a good cylinder to run a pop up in. That way you could get more intake without lowering the ex. and trans.

 

[Brewz]

I'd love see where you go with the build. How hot are you thinking? Work saw or racer?

Yeah thinking very hot work saw to use for a touch of casual racing.
Planning on fitting a tree monkey modded WJ6A carb.

@Deets066
I like the idea of the popup.
Where can I get such a magical thing?

 

[Deets066]

Yeah thinking very hot work saw to use for a touch of casual racing.
Planning on fitting a tree monkey modded WJ6A carb.

@Deets066
I like the idea of the popup.
Where can I get such a magical thing?

From a lathe