Author Topic: Trimble method for piston rings  (Read 2307 times)

Offline steamer

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Trimble method for piston rings
« on: February 05, 2022, 06:40:58 PM »
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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Offline Don1966

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Re: Trimble method for piston rings
« Reply #1 on: February 05, 2022, 08:03:15 PM »
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
« Last Edit: February 05, 2022, 08:06:47 PM by Don1966 »

Offline steamer

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Re: Trimble method for piston rings
« Reply #2 on: February 05, 2022, 08:11:43 PM »
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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Offline Don1966

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Re: Trimble method for piston rings
« Reply #3 on: February 05, 2022, 08:23:08 PM »
Dave send them to me and I would be happy to make the spreadsheet for you.


Don

Offline Jasonb

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Re: Trimble method for piston rings
« Reply #4 on: February 05, 2022, 08:25:16 PM »
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

Offline steamer

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Re: Trimble method for piston rings
« Reply #5 on: February 05, 2022, 08:30:53 PM »
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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Offline stevehuckss396

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Re: Trimble method for piston rings
« Reply #6 on: February 05, 2022, 11:02:55 PM »
Try this one. I dont understand it but it looks cool.

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Offline steamer

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Re: Trimble method for piston rings
« Reply #7 on: February 06, 2022, 12:03:42 AM »
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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Offline Hugh Currin

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Re: Trimble method for piston rings
« Reply #8 on: February 06, 2022, 12:47:10 AM »
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.

Hugh

Offline stevehuckss396

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Re: Trimble method for piston rings
« Reply #9 on: February 06, 2022, 12:51:06 AM »
Not mine Steamer. I've had that for years.. not even sure when or where i got it.
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Offline steamer

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Re: Trimble method for piston rings
« Reply #10 on: February 06, 2022, 12:52:37 AM »
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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Offline steamer

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Re: Trimble method for piston rings
« Reply #11 on: February 06, 2022, 12:53:45 AM »
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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Offline petertha

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Re: Trimble method for piston rings
« Reply #12 on: February 06, 2022, 01:40:24 AM »
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.

Offline steamer

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Re: Trimble method for piston rings
« Reply #13 on: February 06, 2022, 01:42:19 AM »
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
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

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Re: Trimble method for piston rings
« Reply #14 on: February 06, 2022, 01:48:13 AM »
Hey Petertha,      States the file is corrupted, and I can't open it ....

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

 

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