Author Topic: Port timing.  (Read 5973 times)

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Offline 3000 FPS

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Re: Port timing.
« Reply #60 on: February 20, 2013, 09:26:48 pm »
I usually like a blow down of 20 and what your talking about is close.
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Offline jmester

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Re: Port timing.
« Reply #61 on: February 21, 2013, 05:57:58 am »
Also do you guys case match your lower transfers. I think I am going to raise those trans to 120* and see what happens. I did raise the exhaust last night. Went a little overboard. It came in at 99*. On older 0 model stihl saw is the cylinder coating Chrome. Because it was very soft. Should give me a blowdown of 22*.
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Offline aclarke

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Re: Port timing.
« Reply #62 on: February 21, 2013, 03:53:21 pm »
Port shap I.e round or flat plays a role on the way the motor runs as well as ring life.  You may try staggering the transfers vs. Having the top flat or if its a quad transfer motor open the intake side first then mains a few degrees later. As mentioned earlier by 300fps the shape and direction plays a big role, not just duration.   Some of the engine simulation software allows you to change transfer port angles, etc where you can see the different power characteristics generated by merely changing angles....

Offline aclarke

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Re: Port timing.
« Reply #63 on: February 21, 2013, 04:07:18 pm »
if its a Mahle cylinder most likely Nikasil

Offline jmester

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Re: Port timing.
« Reply #64 on: February 21, 2013, 04:14:14 pm »
I took the transfers up to 120. They are not staggered. I will think on that one that sound like a neat concept. I am working on putting back together. Will try to post a video when I get it finished up. To see what you guys think of it.
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Offline jmester

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Re: Port timing.
« Reply #65 on: February 21, 2013, 04:22:47 pm »
Would it be advisable to advance the ignition timing, or see where it is at first.
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Offline 660magnum

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Re: Port timing.
« Reply #66 on: February 21, 2013, 04:56:46 pm »
The more advance the timing is, the harder it is on your hand and arm when starting the chainsaw
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Offline jmester

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Re: Port timing.
« Reply #67 on: February 21, 2013, 05:37:38 pm »
Do you guys think that 130lbs of compression is too low for new rings. I had too clean the cylinder up ,the piston and rings were boogered up prettty good. Thanks for all the feedback and help.
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Offline 660magnum

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Re: Port timing.
« Reply #68 on: February 21, 2013, 05:49:00 pm »
You'll have to be the judge yourself. At 130 lbs it does need something done.

Rings don't cost much. Clean things up and throw in a set of rings and see what you got?

I bet it will last a while?
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Offline jmester

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Re: Port timing.
« Reply #69 on: February 21, 2013, 05:56:33 pm »
It is 130 with new rings, they should come up some as they seat in. I wonder if we will get 150 out of them.
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