346 porting (first time)

[drf256]

Dan,

Excellent build thread. You're porting came out great, and David's degree program is fascinating. Intake height measurement used to be a big trial and error thing for me, now it should be much simpler. I will certainly use this method for cutting my card stock and will verify with a wheel, at least for the first few times.

I don't recall what you said about why the saw originally wouldn't run right. You're stuck vac testing everything now. It's a good habit to get into anyways. The first leaker you've got, and you have to tear back down, will teach you that right quickly.

You've got porter's addiction now.

 

[Ironworker]

I don't think that there's a big difference between a 191 and 199. I've used the 191 on a 357 and 359, both ported and they work fine. When's this 346 gonna hit some wood.

 

[paragonbuilder]

When's this 346 gonna hit some wood.

Unfortunately I have very little time for "playing" right now, so I do it when I can. I hoping to pressure and vac check it tonight. And I need to get to my dealer and grab some new fuel lines and I should probably grab a new ring too.
I'm hoping to be making a video before the weekend is over.

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[paragonbuilder]

Dan,
You've got porter's addiction now.

Is there a cure for this?


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[beaglebriar]

I've been following along. The porting looks great and I'll be watching for the video.

 

[paragonbuilder]

Ok. Time for the vac test. I use my compression tester hose with the shrader valve removed.

She's holding good at 8in.hg.
I just used the base gasket in case the seals were shot, even though I'm deleting it.
I'm going to check squish again with and without it.


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[paragonbuilder]

With the gasket.

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[paragonbuilder]

So I've always just stuck my solder in the plug hole. This time I did this. Interesting. I had .014, .0145, .0125, .014
So I'm guessing the squish band is inconsistent.
On a 50cc saw is this ok? Or really pushing it.



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[paragonbuilder]

So this is really cool!
I just ran my numbers in David's program and here they are if I set squish at.020

Exhaust 105.81
Intake 74.55
Transfers 124.66/123.16
And at .014

Exhaust 106.39
Transfers 125.56/123.03
Intake 75.07




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[Ironworker]

I always get inconsistent numbers when I check squish.

 

[mdavlee]

So I've always just stuck my solder in the plug hole. This time I did this. Interesting. I had .014, .0145, .0125, .014
So I'm guessing the squish band is inconsistent.
On a 50cc saw is this ok? Or really pushing it.



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How thick was the solder to begin with?

 

[paragonbuilder]

How thick was the solder to begin with?

.030


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[mdavlee]

.030


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I bet you're measurements are even tighter than that. That .032" at .014" will be .010" or so with plastigauge.

 

[paragonbuilder]

I bet you're measurements are even tighter than that. That .032" at .014" will be .010" or so with plastigauge.

Yeah I was thinking as I spun the flywheel back and forth and could feel the solder that if I could feel it it wasn't crushed enough. I guess I need to get different solder.
I'll make it .020. I think I have a beer can somewhere. [emoji23]


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[mdavlee]

Yeah I was thinking as I spun the flywheel back and forth and could feel the solder that if I could feel it it wasn't crushed enough. I guess I need to get different solder.
I'll make it .020. I think I have a beer can somewhere. [emoji23]


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If you have an old piston and stick on sandpaper you can open it up to .018-020".

 

[paragonbuilder]

If you have an old piston and stick on sandpaper you can open it up to .018-020".

Ahh! And bump my compression a bit too! That's a great idea!
If I do that my timing numbers will be
106.39
125.56
123.03
75.07

Still ok?


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[paragonbuilder]

Probably don't need all those decimals. Just what the program gave me.


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[Tor R]

I bet you're measurements are even tighter than that. That .032" at .014" will be .010" or so with plastigauge.

I've used plastigauge in one year now, very happy with the system.
Have you ever tryed tin thread?

 

[mdavlee]

I've used plastigauge in one year now, very happy with the system.
Have you ever tryed tin thread?

No I haven't.

 

[paragonbuilder]

Link to the plastiguage?


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