Model Engine Maker
General Category => Chatterbox => Topic started by: steamer on February 05, 2022, 06:40:58 PM
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Has anyone created an excel spreadsheet for the trimble method of sizing piston rings?...and can I get a copy?
Dave
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Dave does anyone have the formulas for creating them? I can make it…
I see that Strictly IC has the magazines for $24 on Trimble Method. There are issues 7,8 and 9.
Don
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Dave does anyone have the formulas for creating them? I can make it…
I see that Strictly IC has the magazines for $24 on Trimble Method. There are issues 7,8 and 9.
Don
Hi Don
I think I have the SIC issues involved .....I believe....I just was trying to not make a project out of it. I'll see if I can dig them up, but was wondering if anyone had one already and was willing to share.
Dave
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Dave send them to me and I would be happy to make the spreadsheet for you.
Don
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I seem to remember there are a couple of multipliers he uses and it's hard to see how they are arrived at.
Brian had a long thread going on HMEM about rings with a lot of discussion about trimbles formula at one point and how he got these figures
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Dave send them to me and I would be happy to make the spreadsheet for you.
Don
Let me paw through the stack...and dig them out. thanks Don.
Dave
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Try this one. I dont understand it but it looks cool.
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Try this one. I dont understand it but it looks cool.
Thanks Steve! I found a Trimble reference, and it matched Ron Colonna's Offy build exactly, so I check that engine against this and it also matches. Is that one of your spreadsheets?
Dave
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Dave:
It's been a long time since I used Timble's method for rings. But if I remember there were a couple of graphs that fed values into the equations, or at least used for checking the results. I find it hard to incorporate graphs into spreadsheet calculations. so for me it was easier to work out the formulas by hand.
In his articles Trimble eluded to the underlying development but didn't go into any of the math. It would be quite an endevour to reproduce the underlying equations.
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Not mine Steamer. I've had that for years.. not even sure when or where i got it.
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Thanks Hugh,
I have them, and I hand calculated what I need, and then Steve handed me this spreadsheet. Which I find interesting. It implies.....I think.....that I need to be within that triangular zone between installation pressure, working stress, and installation stress. I checked against one of Ron Colonna's builds where he states he following the method exactly and it all agrees, so I'm fairly confident in the outcome What the graph is saying is it's "deadly corner" and I need to be careful. I might want to make them thinner perhaps, but at .020" they're pretty thin!!!
Dave
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Not mine Steamer. I've had that for years.. not even sure when or where i got it.
Thanks Bubba! It agrees with a hand calc....
Dave
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You are welcome to use mine. I removed some code related to Trimble oil control rings (which had some assumptions I was never clear on) and also some piston sizing calculations (relating to some other engine builds).
But I believe for the basic Trible compression ring it's doing the job. If you spot any errors, please let me know.
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You are welcome to use mine. I removed some code related to Trimble oil control rings (which had some assumptions I was never clear on) and also some piston sizing calculations (relating to some other engine builds).
But I believe for the basic Trible compression ring it's doing the job. If you spot any errors, please let me know.
Thanks Petertha!!!
Dave
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Hey Petertha, States the file is corrupted, and I can't open it ....
Dave
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PM-d you. I wonder if .XLS spreadsheets are not an allowed upload format?
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I was able to download and open it. You might try again Dave.
What version of Excel are you using? I opened it with office 365 (the new *stupid* subscription version of the office tools).
Kim
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It opens ok in Libre Office.
Ian.
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Petertha sent me a hard copy via email and it opened just fine.....and when I try opening it the file on the forum this morning
IT OPENED........must have been a burr..... :facepalm:
Thanks Petertha!!!
Dave
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I'm always a bit apprehensive about sharing home brew tools for personal consumption, but here are a few things I should mention just as FYI if you are not as familiar with Excel or possibly importing differently into other apps.
In the calc tab, if you hover over a (red) input cell that shows a little red triangle in the corner signifying a comment, it reveals some information related to that parameter to help you along.
In the fig-13 tab (which is named to coincide with plot recreation of SIC Figure 13) I directly import the Trimble parameters from calc tab (blue font). I also allow input any arbitrary parameters I call Engine X in order to show how it compares against the 4 constraint curves. You can turn this on & off using the plot filter button
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Thanks Petertha! I'll dig into that for sure. my rings appear to be .0192 thick and .032-.037 wide.....little buggers!!
Dave
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Those are huge! I just made the largest rings I ever made yesterday. They were .022 x .043. Made 42 of them needing 36. I look at builds like Rupnow and others with one inch or larger bores and think holy cow look how big the rings are. Cracks me up that you think they are little buggers. Eye of the beholder.
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Those are huge! I just made the largest rings I ever made yesterday. They were .022 x .043. Made 42 of them needing 36. I look at builds like Rupnow and others with one inch or larger bores and think holy cow look how big the rings are. Cracks me up that you think they are little buggers. Eye of the beholder.
That it is bud!!! I'm contemplating the oil control rings :o