How to calculate port height without degree wheel?

[Nutball]

Anyone good at maths here? I don't have a degree wheel yet . Is there a good way to use % stroke length to find the degrees of a distance from TDC? I'm about to go grind on a cylinder and I want to know how far to grind.

 

[Deets066]

Anyone good at maths here? I don't have a degree wheel yet . Is there a good way to use % stroke length to find the degrees of a distance from TDC? I'm about to go grind on a cylinder and I want to know how far to grind.

There is software just for this, can’t remember who brought it to light.
Maybe @David Young ?

 

[srcarr52]

There are a few online calculators, or you can make an excel spreadsheet to do it like I did.

 

[huskihl]

I think one program was called Torquesoft

 

[Deets066]

I think one program was called Torquesoft

That’s it

 

[p61 western]

@paragonbuilder had a pretty good way of doing it.

 

[Nutball]

Thanks, Torquesoft is helping

 

[srcarr52]

Here are a few online calculators.

http://www.csgnetwork.com/timingportdurationcalc.html

http://www.torqsoft.net/piston-position.html

 

[David Young]

The best one now is from a lambretta site. Unfortunately it’s not working now. Or I would have a link for you.

The benefit is you can have all the ports calculated on one page. It also subtracts squish clearance and piston overall length. Here is what it looks like. This is for an echo 590

 

[David Young]

Oh and last I checked Shaun didn't openly share his excel calculator.

This is a comprehensive calculator, it is a little more challenging to use. You can save this excel to your computer.

http://www.330.dk/inlet.htm

 

[srcarr52]

Oh and last I checked Shaun didn't openly share his excel calculator.

This is a comprehensive calculator, it is a little more challenging to use. You can save this excel to your computer.

http://www.330.dk/inlet.htm

No, I spent too much time trying to explain it to people. Since then it's only became more complicated.

 

[David Young]

Ah gotcha understandable

 

[Al Smith]

Why not just a degree wheel to start with ,easy enough to make .This one is an adhesive transfer I got from McMaster -Carr,6" .I tried to find it in the catalog but could not find the stock number .It's mounted on a circle made of aluminum .To mount it I made the adapters but you could use a rod coupling with whatever size you need,most likely M-8 for most saws ,cost a couple bucks

 

[MAF143]

A large clock dial. each minute is 6*

 

[Newdave]

McMaster-Carr Has them for less than 20.00 "adhesive-back protractor wheels"