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Degree wheel?


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I built the motor I'm just habing the domes cut. Don't really have a builder. Not even sure on who I'm having cut the domes. If I haven't mentioned it yet I'm new to the whole drag world and building a motor for that reason. Lol. So what all do I need to measure and remember I'm a newbie.

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Timings come into play with designing a dome so why would the builder not want the specs?

 

Im not even sure what j madd and trickedcarbine are talking about or why.

I'm saying he should be checking the deck height with the base gasket in place.

As for the reference to the degree wheel, I was just clarifying the reason some guys use a wheel when coming up with the numbers for domes. Obviously I only gave the most general reason which would be finding absolute TDC. However, if the motor is ported it would help an experienced builder to know when the ports are opening and closing to know the actual trapped volume that will be compressed/ignited. That way they can spec the proper sized dome. Guess I should of added that in my first post.

 

But if you already have the motor assembled, just throw a L sheped piece of solder in there and figure out what it is and make your changes from that measurement.

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I'm saying he should be checking the deck height with the base gasket in place.

As for the reference to the degree wheel, I was just clarifying the reason some guys use a wheel when coming up with the numbers for domes. Obviously I only gave the most general reason which would be finding absolute TDC. However, if the motor is ported it would help an experienced builder to know when the ports are opening and closing to know the actual trapped volume that will be compressed/ignited. That way they can spec the proper sized dome. Guess I should of added that in my first post.

 

But if you already have the motor assembled, just throw a L sheped piece of solder in there and figure out what it is and make your changes from that measurement.

Yes as far as the degree wheel... He wanted to to degree/ measure between the bottom and the top of the exhaust port.

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For example if the piston is 0.020" out of the hole and you want a squish of 0.040", just order new domes with a 0.020" step.

I think you miscalculated. That would be .000 squish. If the piston is .020 out the hole, you would need a .060 step to yield a .040 squish. Am I thinking right?

That's right. My example was backwards.

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Timings come into play with designing a dome so why would the builder not want the specs?

 

 

Im not even sure what j madd and trickedcarbine are talking about or why.

If your using trapped compression ratio then you would need to know the exhaust port duration. I stand corrected in my assumption that you wouldn't need a degree wheel. I thought this was more of a cookie cutter build.

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Did you port this engine? If so, how did you port it without a degree wheel?

I bought there motor in pieces. The cylinders are the way I received them. Was told there was some clean up port but I honestly don't know.

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Dude throw a .020 gasket in it and torque it to spec. Then check deck height. I use a digital mic dropped in the hole then rotate the piston through TDC. Bam your done.

 

Then degree your durations with a wheel. pretty straight foward.

Do you measure to the center of the piston and if so do you just use a parallel and subtract that thickness?

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If your using trapped compression ratio then you would need to know the exhaust port duration. I stand corrected in my assumption that you wouldn't need a degree wheel. I thought this was more of a cookie cutter build.

in reality it probably is but checking the exhaist numbers doesnt hurt and providing the cylinders havent been decked (doubtful) or the cases decked there is no guess work. Assemble with domes check squish and adjust base gasket to suit.
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BTW..... Did you used to have a serval? Orange and black bike?

Yup that's me. Pretty sure I met you a few times out at Phil's. Still have it just want an actual drag bike now. Lol.

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