MS440/460 Hybrid With Ported Meteor Cylinder Kit

[Mastermind]

I've done this saw once before....not too long ago either. Something happened to it and it ended up slightly scored. Well Brian (trx250r180) was cool enough to let us use his saw as a testbed.

Here's some pics......

The squish has been cut as well as the base already but in these next two shots you can get a look at the stock port shapes.....

The bore side of the port is roughed in but here's a look at the factory exhaust outlet shape. Keep in mind that this muffler is from a saw that has been ported so it's got a non-stock opening.

The shape here isn't a real good fit to the stock one either though.

Now the intake after port work.

Transfers....you may notice a bit of change in the upper transfer shape from what I was doing a while back. It was pointed out to me that the tighter I can keep those upper corners the more time/area I have. I like good advice.

One thing I noticed on the 460 kit is that the exhaust floor is much higher that a stock 460. I've run into free porting on the 460 in the pass so I was happy to see this.

 

[Mastermind]

Here's a few more shots of the ported exhaust flange and at the upper through it....

I'll have it all buttoned up tomorrow for some videos......

 

[young]

vid? :spam:

 

[srcarr52]

Arg! It looks like stumpys been in that exhaust port.

 

[srcarr52]

Arg! It looks like stumpys been in that exhaust port.

PS. I like it!

 

[Trx250r180]

Looking good sir

 

[sgrizz]

opcorn:

 

[Adirondackstihl]

 

[ft. churchill]

I love your posts of the internal work ya do. I can not believe the size of the lower transfer openings on the 460 jug. The way that they smoothly reduce all the way to the upper window must really increase the velocity of the fuel/air charge as it exits into the cylinder. That's got to promote excellent scavenging.

 

[Mastermind]

Arg! It looks like stumpys been in that exhaust port.

It looks really huge but it less than .100 wider and tall than the outlet on a OEM 460 jug. The Meteor cylinder does indeed take some more work to bring it to the level of a ported OEM jug. I took a bunch of material from the jug.....there and in the transfer pockets.

The outlet nozzle casting is actually lower in location than the factory one, that makes the top flange a bit thin once it's mated to the ported muffler from Brian's saw.

Looking good sir

Let's just hope this attempt runs as well as the last one. :msp_sneaky:

I love your posts of the internal work ya do. I can not believe the size of the lower transfer openings on the 460 jug. The way that they smoothly reduce all the way to the upper window must really increase the velocity of the fuel/air charge as it exits into the cylinder. That's got to promote excellent scavenging.

The bridges are thicker in the Meteor jug so a lot of work went into those.

 

[Trx250r180]

Let's just hope this attempt runs as well as the last one. :msp_sneaky:



when it gets home ,should i throw a weld across the top of the outside top of the exhaust port ? i saw someone do that in an xpw thread to give the muffler more sealing area ,or do you think theres enough there ?

 

[srcarr52]

when it gets home ,should i throw a weld across the top of the outside top of the exhaust port ? i saw someone do that in an xpw thread to give the muffler more sealing area ,or do you think theres enough there ?

I do that all the time on huskys since they have a really straight ex port stock, I think you have more than enough sealing surface on this one.

Mastermind, it's hard to tell via the pictures but the casting and plating quality looks really good. What is your opinion?

 

[Tzed250]

Isn't a ported 372 faster?...:msp_flapper:

 

[Dennis Cahoon]

Transfers....you may notice a bit of change in the upper transfer shape from what I was doing a while back. It was pointed out to me that the tighter I can keep those upper corners the more time/area I have. I like good advice.

That goes for all the ports.......the more rectangle, less oval the better.....but, that also gives you a bigger chance of ring snag and faster ring wear. The top edge of the lower transfer can be brought up within thousandths of the bottom piston ring, giving you more bottom tranfer area too. Shape, with good direction is what you should be looking for in the upper and lower transfers. Just my opinion......Hahahahahahaha!

 

[SawTroll]

Here's a few more shots of the ported exhaust flange and at the upper through it....

I'll have it all buttoned up tomorrow for some videos......

I could never really ubderstand what huge flanges on the outside of the exaust ports actually are doing for the saws? Of course it removes a few grams of weight, but apart from that? :msp_confused:

 

[thomas1]

I could never really ubderstand what huge flanges on the outside of the exaust ports actually are doing for the saws? Of course it removes a few grams of weight, but apart from that? :msp_confused:

Gas expansion?

 

[dozerdan]

That's one of the nicest AM cylinders that I have seen. Do the 372 cylinders look that nice, if so I will get one and try it. I see no reason not to use them.

Later
Dan

 

[Mastermind]

when it gets home ,should i throw a weld across the top of the outside top of the exhaust port ? i saw someone do that in an xpw thread to give the muffler more sealing area ,or do you think theres enough there ?

Just run it like it stole your lunch money. It'll be fine.

I do that all the time on huskys since they have a really straight ex port stock, I think you have more than enough sealing surface on this one.

Mastermind, it's hard to tell via the pictures but the casting and plating quality looks really good. What is your opinion?

It is a nice casting overall. And the plating is really nice.....tough too. The exhaust was floor is higher throughout the whole port.....I like that I can now drop the jug a larger amount without free porting but having to cut so much out of the floor was time consuming. Another thing I encountered was that the transfer bridges were thicker that stock.....infringing on the actual transfer passage.

Would these things matter on a stock saw???? No, not at all. The timing numbers are a match for the stock numbers. Plus the squish with a gasket is tighter than a stock jug and compression should show an increase from that.

Transfers....you may notice a bit of change in the upper transfer shape from what I was doing a while back. It was pointed out to me that the tighter I can keep those upper corners the more time/area I have. I like good advice.

That goes for all the ports.......the more rectangle, less oval the better.....but, that also gives you a bigger chance of ring snag and faster ring wear. The top edge of the lower transfer can be brought up within thousandths of the bottom piston ring, giving you more bottom tranfer area too. Shape, with good direction is what you should be looking for in the upper and lower transfers. Just my opinion......Hahahahahahaha!

Thanks for the input Big D. I hang onto all these tidbits.......anything to gain an edge. :msp_sneaky:

I could never really ubderstand what huge flanges on the outside of the exaust ports actually are doing for the saws? Of course it removes a few grams of weight, but apart from that? :msp_confused:

Exhaust gasses are hot and they are expanding............

 

[Mastermind]

That's one of the nicest AM cylinders that I have seen. Do the 372 cylinders look that nice, if so I will get one and try it. I see no reason not to use them.

Later
Dan

The 372 jugs are a bit better in my mind.

 

[blsnelling]

Looks fantastic, Randy, as always.