ESE's works engine tuner

[jato]

heys guys i need to make some thrust washers for the small end of the rod and bearing. easily accesible materials i can use are aluminum, copper, brass, zinc, nickel silver ( mix of copper, nickel, zinc ?). is copper my best choice ?

also has anyone made theyre own oiling slot or holes in the rod small end ?

I expect someone will be along with an exact recommendation in due course but keep in mind a hi spec 125 will typically subject those small end washers to 5000 odd G's about 200 times a second so will destroy anything but a "tough" metal so that rules out copper , ally , and brass and possibly nickel silver (do you know the % of the mix? ). I know the last 1000rpm used to shorten the life of the hardened steel ones used in some of the 80's race bikes. what stroke and rpm are you looking at?

[F5 Dave]

We used hardened steel washers out of some Honda . They lasted ok but needed to be checked and changed as they brinneled eventually.

[Frits Overmars]

...the roller mass should simply be roughly equal to the bike + rider mass.

You can forget all about the mass of bike and rider. You said it yourself, and Wobbly dotted the i's: you need to replicate the acceleration rate as seen on the track.
That is a value you can measure, and though the mass of bike and rider will have a direct influence on the acceleration rate, those masses themselves are irrelevant.

if I want portability, I need to overdrive the roller to be able to reduce its mass sufficiently (so a chassis dyno will not work due to the required roller mass).

There are several dynos with a wheel-driven drum geared to a flywheel that spins at double the drum rpm, with 1/4 of the inertia and the mass that the drum would otherwise need to have. Below are some portable examples, with and without upgeared flywheel.

[mantonakakis]

Thanks Frits, very helpful, as always.
With good controls, I suppose a brake dyno could also be made to replicate on-track acceleration, and potentially weigh less, at least if there's enough heat capacity built in for a test cycle like Wobbly described.
Convert output torque or power as measured to the acceleration that would result with specified mass and "road load" constants (can be found with a coast-down test), and set up a closed-loop control of output speed... Of course you would still want to be sure to include rotational inertia into the torque calculation.
A few years ago I worked on automatic transmission calibration for Toyota, and our multi-million dollar chassis brake dyno seemed to read about half of the actual torque when accelerating in first gear... I suspected that despite its high price tag, the manufacturer forgot to include the substantial roller inertia in their torque calculation. Maybe they assumed their dyno (which had a "road load" mode to simulate driving on the road) would only be used for steady-state testing?

Another interesting memory - the US EPA allows OEMs to conduct their own fuel economy and emissions testing in-house. The chassis dyno we used for that testing had a screen that the driver could view, with the most boring video game in the world. There was a continuously scrolling target speed plot (the official test cycle), with a dot showing the current wheel speed. The operator "drives" the car, using both pedals to change speed as needed, doing their best to keep the dot on the line. There are obvious ways to cheat the test (since it is done in house on good faith), but the EPA allows it to happen this way regardless. I guess they don't have the budget to do it all themselves?
Anyway, this reminded me of a previous discussion I saw here about using a dyno to simulate actual tracks, and I imagine the same methodology would work - derive your road load from a coast-down test and use previous track data to generate the test cycle (target speed trace? Or perhaps use a distance-based cycle instead, or ideally some combo, since you still want to measure maximum engine performance in the areas of the track where you can go full throttle). From my experience, the biggest challenge will be to stay awake! Or maybe a race simulation is more engaging than a fuel economy cycle...

[lohring]

My inertial dyno experience is with engine driven flywheels and smaller engines. If you would be interested I wrote an article on these dynos at namba.com/content/library/propwash/2019/april/16/ I have a spreadsheet that calculates some of the factors like stress and acceleration for this style flywheel. Below is a picture of our dyno.

Lohring Miller

[mantonakakis]

My inertial dyno experience is with engine driven flywheels and smaller engines. If you would be interested I wrote an article on these dynos at namba.com/content/library/propwash/2019/april/16/ I have a spreadsheet that calculates some of the factors like stress and acceleration for this style flywheel. Below is a picture of our dyno.

Lohring Miller

Thank you, Lohring!

[Haufen]

Hoping for a sanity check on inertial dyno roller/flywheel design (herein referred to as "roller"). If you feel like reading/thinking through all of this

I did not. Maybe I will give it a go later on. But if you yould like to know ideal dimensions / setup of an engine dyno to duplicate real road conditions, you can do that with the excel sheet from sportdevices. For a simple single roller the weight of the drum shall be twice the vehicle weight (including driver) to get 1:1 conditions (i.e. 4th gear pulls take just as long as on the road)

Sportdevices Excel File Download
Dyno download page

[mantonakakis]

I did not. Maybe I will give it a go later on. But if you yould like to know ideal dimensions / setup of an engine dyno to duplicate real road conditions, you can do that with the excel sheet from sportdevices. For a simple single roller the weight of the drum shall be twice the vehicle weight (including driver) to get 1:1 conditions (i.e. 4th gear pulls take just as long as on the road)

Sportdevices Excel File Download
Dyno download page

I don't blame you!
Their calculations give the same results as mine, so that sanity check is complete.
And the conclusion of 2x vehicle weight matches too (for a 1:1 wheel:roller circumferential speed ratio and solid roller).

[F5 Dave]

Thanks Frits, very helpful, as always.
With good controls, I suppose a brake dyno could also be made to replicate on-track acceleration, and potentially weigh less, at least if there's enough heat capacity built in for a test cycle like Wobbly described.
Convert output torque or power as measured to the acceleration that would result with specified mass and "road load" constants (can be found with a coast-down test), and set up a closed-loop control of output speed... Of course you would still want to be sure to include rotational inertia into the torque calculation.
A few years ago I worked on automatic transmission calibration for Toyota, and our multi-million dollar chassis brake dyno seemed to read about half of the actual torque when accelerating in first gear... I suspected that despite its high price tag, the manufacturer forgot to include the substantial roller inertia in their torque calculation. Maybe they assumed their dyno (which had a "road load" mode to simulate driving on the road) would only be used for steady-state testing?

Another interesting memory - the US EPA allows OEMs to conduct their own fuel economy and emissions testing in-house. The chassis dyno we used for that testing had a screen that the driver could view, with the most boring video game in the world. There was a continuously scrolling target speed plot (the official test cycle), with a dot showing the current wheel speed. The operator "drives" the car, using both pedals to change speed as needed, doing their best to keep the dot on the line. There are obvious ways to cheat the test (since it is done in house on good faith), but the EPA allows it to happen this way regardless. I guess they don't have the budget to do it all themselves?
Anyway, this reminded me of a previous discussion I saw here about using a dyno to simulate actual tracks, and I imagine the same methodology would work - derive your road load from a coast-down test and use previous track data to generate the test cycle (target speed trace? Or perhaps use a distance-based cycle instead, or ideally some combo, since you still want to measure maximum engine performance in the areas of the track where you can go full throttle). From my experience, the biggest challenge will be to stay awake! Or maybe a race simulation is more engaging than a fuel economy cycle...

I presume the EPA has upgraded the sw, so now you can pull over, rob banks, run over people and pick up hookers.

[peewee]

I expect someone will be along with an exact recommendation in due course but keep in mind a hi spec 125 will typically subject those small end washers to 5000 odd G's about 200 times a second so will destroy anything but a "tough" metal so that rules out copper , ally , and brass and possibly nickel silver (do you know the % of the mix? ). I know the last 1000rpm used to shorten the life of the hardened steel ones used in some of the 80's race bikes. what stroke and rpm are you looking at?

We used hardened steel washers out of some Honda . They lasted ok but needed to be checked and changed as they brinneled eventually.

ive no experience with small end washers so i wasnt sure what material to use. not sure what the nickel silver mix would be. 60-20-20 perhaps but i would have to make some phone calls to be sure. would titanium do ok? i could get some of that easy enough. the engine only has to run for a few hours each summer. 58mm stroke at about 10k rpm

did the hardened steel wear a groove and lip in the wristpin and prevent it from being removed out of the piston pin bore ?

[peewee]

(do you know the % of the mix? ).

its this https://www.onlinemetals.com/en/prod...ickel%20silver

[41juergen]

Thanks Frits, very helpful, as always.
With good controls, I suppose a brake dyno could also be made to replicate on-track acceleration, and potentially weigh less, at least if there's enough heat capacity built in for a test cycle like Wobbly described.
Convert output torque or power as measured to the acceleration that would result with specified mass and "road load" constants (can be found with a coast-down test), and set up a closed-loop control of output speed... Of course you would still want to be sure to include rotational inertia into the torque calculation.
A few years ago I worked on automatic transmission calibration for Toyota, and our multi-million dollar chassis brake dyno seemed to read about half of the actual torque when accelerating in first gear... I suspected that despite its high price tag, the manufacturer forgot to include the substantial roller inertia in their torque calculation. Maybe they assumed their dyno (which had a "road load" mode to simulate driving on the road) would only be used for steady-state testing?

Another interesting memory - the US EPA allows OEMs to conduct their own fuel economy and emissions testing in-house. The chassis dyno we used for that testing had a screen that the driver could view, with the most boring video game in the world. There was a continuously scrolling target speed plot (the official test cycle), with a dot showing the current wheel speed. The operator "drives" the car, using both pedals to change speed as needed, doing their best to keep the dot on the line. There are obvious ways to cheat the test (since it is done in house on good faith), but the EPA allows it to happen this way regardless. I guess they don't have the budget to do it all themselves?
Anyway, this reminded me of a previous discussion I saw here about using a dyno to simulate actual tracks, and I imagine the same methodology would work - derive your road load from a coast-down test and use previous track data to generate the test cycle (target speed trace? Or perhaps use a distance-based cycle instead, or ideally some combo, since you still want to measure maximum engine performance in the areas of the track where you can go full throttle). From my experience, the biggest challenge will be to stay awake! Or maybe a race simulation is more engaging than a fuel economy cycle...

Come one, a FTP-75 or a WLTC is not too hard to stay awake... but of course you are right, that is very boring to run this tests on chassis dyno.
But if you go into Hybrids, running from "depleting" into "sustainable" mode it can take some hours
We will take robots in the future to do that (like an OEM is now doing in their new certification center in Korea).

[41juergen]

if your talking about boring the hole in the crank wheel, that can be done as most cranks should have plenty of excess metal around the hole. ive got one bored 2mm larger if i recall. was couple years ago when i had it done. still holding together fine

Sorry for the late response peewee. Maybe my wording was not perfect : I'm looking for a conrod that fits to my requirements (want to get a longer rod into the TZ250 4DP engine) and I only can get e.g. Banshee 115 mm rods, but the big end bearing in them is too small to fit the 4DP crank big end pin...
I also checked the other recomendations and tips, unfortunately without success...

[jato]

its this https://www.onlinemetals.com/en/prod...ickel%20silver

I'm not so sure about the nickel silver either now - i see its heavier (12%) than steel and not much stronger than mild steel . 4140/4340 with nitriding could be a likely candidate .
Titanium also but we need someone experienced with that to chime in ...

[F5 Dave]

ive no experience with small end washers so i wasnt sure what material to use. not sure what the nickel silver mix would be. 60-20-20 perhaps but i would have to make some phone calls to be sure. would titanium do ok? i could get some of that easy enough. the engine only has to run for a few hours each summer. 58mm stroke at about 10k rpm

did the hardened steel wear a groove and lip in the wristpin and prevent it from being removed out of the piston pin bore ?

In my case no the wristpin was not damaged by running thrust washers. It was a very long time ago but I think there was reasonable clearance, in fact I was running them only as the piston was wider than stock so I had to contain the bearing.