Author Topic: Two stroke Timing Calculator  (Read 1681 times)

Offline Ramon

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Two stroke Timing Calculator
« on: March 20, 2014, 08:56:31 AM »
Hi Guys - I have posted this here as I feel it's more relevant to 'Own Design' rather than 'Plans and Drawings'. If it's felt it should be moved however that's fine by me.

When the first installment of the Eta article appeared in ME I was contacted by a potential builder - Roger Woolett - with a query on the timing as drawn. I explained that it had been derived by careful measurement from the original parts then checked using the timing calculator on Ron Chernich's MEN site. In course of this email discussion I mentioned what I felt was a slight shortcoming onRon's calc in that you need to know the position of the ports first to arrive at a given amount of timing period. Once found it was then necessary to tweak said positions to give more or less timing periods. I had felt that if this could be reversed it would add considerably to Ron's excellent facility - incidentally the only one I'm aware of.

Roger said he was able to create a spread sheet that would allow this and the attached is the result of his stalwart effort. My only part has been to check each version, pass comment and leave the rest to Roger - though I knew what a spread sheet is I certainly have no idea how to make one work let alone the mathematical brain to do so  ::)

Roger has now finalised the sheet and has asked me to offer it on here for use by all. This allows the desired timing in degrees of intake, transfer and exhaust to be entered which then gives the positioning of the relevant port edge relative to the crankshaft centreline. It is not intended as an alternative to Ron's MEN calculator but as an addition. It does however have the bonus of being 'all on one page' and Roger has built in a scaling factor for those wanting to go up or down a size.

I'm not aware of many if any on here who 'design their own' so this may not have a great deal of interest but this is offered to all should you have a need. For that you have to thank Roger - his knowledge and desire to create it surpassed all expectation - my input very much that as a bystander with the odd comment. For me though it's an extremely useful aid and for and for that I am extremely grateful.

One thing is that if it is of use - I think you'd agree, it would be nice to let Roger (who is not a MEM member) know his effort was worthwhile.

Regards - Ramon

« Last Edit: March 20, 2014, 09:00:50 AM by Ramon »
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Jo

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Re: Two stroke Timing Calculator
« Reply #1 on: March 20, 2014, 09:03:44 AM »
That is really useful Tug  :ThumbsUp:,

Please say thankyou to Roger from us for the spreadsheet  8)

Usus est optimum magister