Run in stand/dyno build.

[dave roach]

Safety glasses not going to stop a 40 ton wheel LOL

 

[Mike Bontoft]

This is what I run most days. The direct drive makes for a straight forward build and at the RPM we are running with the model engines I don't see an easy solution to changing engine/ Inertia ratio but it does mean the wheel needs to be matched to engine output. Unfortunately this means the dyno has a fairly narrow window of application. When Lohring and I were starting to dyno different sized engines we talked about having additional wheels that would live on the shaft and could be attached/ detached a little bit like barbells to increase or decrease inertia.

 

[Terry Keeley]

This is what I run most days. The direct drive makes for a straight forward build and at the RPM we are running with the model engines I don't see an easy solution to changing engine/ Inertia ratio but it does mean the wheel needs to be matched to engine output. Unfortunately this means the dyno has a fairly narrow window of application. When Lohring and I were starting to dyno different sized engines we talked about having additional wheels that would live on the shaft and could be attached/ detached a little bit like barbells to increase or decrease inertia.

Very cool, got a photo of the entire unit? Is it a Stan Hewitt dyno Hewitt Inertia Dyno or homebrew? What motor is that?

 

[Mike Bontoft]

Dyna Pro Dynamometers Ltd. Had it about 7 years now. Great dyno! I'll record a dyno run when I get chance. Honda GX160 for Cadet karting

 

[Terry Keeley]

Dyna Pro Dynamometers Ltd. Had it about 7 years now. Great dyno!

Nice! Kart motor?

 

[Terry Keeley]

Nice.

https://engine.honda.ca/gx/horizontal_crankshaft/gx160/specifications
Your's puts out way more than the stated 5.5 hp tho.

Would love to see a run on it!!!

 

[Wasted wages]

GX160 ??

Same motor on my pressure washer!! lol

 

[Mike Bontoft]

. 8 to 12 years old and looking to Formula one.

 

[Terry Keeley]

. 8 to 12 years old and looking to Formula one.

I worked with a guy whos' kid was in a Briggs class, the motors were strictly regulated. He used to buy a dozen motors and take the best parts to make one good one.

Is that what you're into?

 

[ids987]

I’m loving what you’re doing here Terry. Awesome stuff.

 

[LohringMiller]

"Your's puts out way more than the stated 5.5 hp tho."
There's a reason the winner thanks Bontoft Engines. Mike is one of the great engine tuners from offshore power boats to model boats.

Lohring Miller

 

[Terry Keeley]

Looking at it again I think what happened in that first run was the one-way clutch bearing let go. I hope it's gonna be up to the task.

Clutch locked the wheel up at about 10.5, steady climb to 13, one way let go (rpm sensor is on the housing, not the wheel). Brought the power back, bearing hooked back up at about 13K, motor dragged the wheel down to about 10.5 where the collet unscrewed and clutch let go, wheel coasted down.

CHT seems OK, EGT is wonky but I'm just using an Eagle Tree thermocouple for now.

I looked up the rating for the CSK15 clutch bearing, 13.5 nm which is about 10 ft.lb...

 

[Mike Bontoft]

Everything looks good up to about 13500. and you are nowhere near the torque limit on the clutch bearing. Does the clutch bearing have any kind of rpm mechanical limitation? The kart dyno has a one way bearing but the most it ever see's is about 3000rpm. One of the reasons we did not include a one way bearing in the small engine dyno was a concern about how high centrifugal force on the rollers might effect its operation, this coupled with the fairly low torque throughput at certain RPM's and the rotational spikes of the engine, We discussed it and thought it could be troublesome. Having no data on any of this we decide to forgo it and rely on the drive key shearing in the event of a engine malfunction. Just a thought!
I must admit our build was a very close copy of what Midwest engines had built. So we went the safe route. I like the fact you are trying to improve upon this design. I always enjoy the lessons I learn through my failures. Keep up the fight!
Off subject but I think you will appreciate this. Christmas present from my wife, just finished. Hemingway Kits The Dynamic Tool Post Grinder

 

[Terry Keeley]

Everything looks good up to about 13500. and you are nowhere near the torque limit on the clutch bearing. Does the clutch bearing have any kind of rpm mechanical limitation? The kart dyno has a one way bearing but the most it ever see's is about 3000rpm. One of the reasons we did not include a one way bearing in the small engine dyno was a concern about how high centrifugal force on the rollers might effect its operation, this coupled with the fairly low torque throughput at certain RPM's and the rotational spikes of the engine, We discussed it and thought it could be troublesome. Having no data on any of this we decide to forgo it and rely on the drive key shearing in the event of a engine malfunction. Just a thought!
I must admit our build was a very close copy of what Midwest engines had built. So we went the safe route. I like the fact you are trying to improve upon this design. I always enjoy the lessons I learn through my failures. Keep up the fight!
Off subject but I think you will appreciate this. Christmas present from my wife, just finished. Hemingway Kits The Dynamic Tool Post Grinder

Yup, torque for about 5 hp at 25K is only one ft.-lb (192 oz-in) so nowhere near that limit. Can't find any rpm data for it. Seemed to work OK with the fan to 28K but that's not the load of the wheel of course.

I'll keep at it, got the wheel trimmed to 5.5" diameter which changes the inertia from 1 to about 0.7 lb-ft2. I really like the idea of a one way bearing to release the wheel, not only for a failure but at the end of a run too.

That's a very nice toolpost grinder, they've got some cool stuff on that site. Funny, my buddy Rudy just finished grinding a crank for his inline 4 cylinder, he was running one made of 4140 HT but it wasn't holding up so he made one from heat-treated A-2. Ground it with a little Dumore grinder and a 4" chainsaw wheel.

What's that crank going in? Is that a Myford your grinder is sitting on?

ps: Your wife's a keeper, but you already knew that!

 

[Mike Bontoft]

Yup, torque for about 5 hp at 25K is only one ft.-lb (192 oz-in) so nowhere near that limit. Can't find any rpm data for it. Seemed to work OK with the fan to 28K but that's not the load of the wheel of course.

I'll keep at it, got the wheel trimmed to 5.5" diameter which changes the inertia from 1 to about 0.7 lb-ft2. I really like the idea of a one way bearing to release the wheel, not only for a failure but at the end a run too.

That's a very nice toolpost grinder, they've got some cool stuff on that site. Funny, my buddy Rudy just finished grinding a crank for his inline 4 cylinder, he was running one made of 4140 HT but it wasn't holding up so he made one from heat-treated A-2. Ground it with a little Dumore grinder and a 4" chainsaw wheel.

What's that crank going in? Is that a Myford your grinder is sitting on?

ps: Your wife's a keeper, but you already knew that!

Beautiful job Rudy has done! The engine I am building is similar but simpler in design. .
As you probably noticed the crank is only supported at the ends, its a pretty stout piece though and compression is low. I purchased the Myford a few weeks into Covid. The Seal Major castings were purchased a couple of years ago as a retirement project. Well!, little did we know! Not far off a year now!! Very little Karting and recently the clamp down has been tightened even further.
I can say if it wasn't for my hobby shop and many many projects I would have gone loopy long ago. Stay busy!!

 

[Terry Keeley]

I hear you, the dyno is sort of my Covid project. It really sucked that we couldn't run our Can-Am this year and no time trials in Flint.

Myford's are very nice, I know a few guys that have them and are very happy. That's a sweet little engine and quite a shop!

Here's Rudy's inline 4 on the stand and a glow fired V8 he built from Conley plans...

 

[Terry Keeley]

Think I figured out a more likely scenario.

The one-way bearing did let go but not the bearing itself, I think the outer race slipped in it's housing. The clutch took forever to lock up and got hot, that transferred to the aluminum housing and loosened up the bearing fit. The inner race is keyed to the shaft, the outer is a press fit in the housing.

Hmmm...

 

[Mike Bontoft]

Think I figured out a more likely scenario.

The one-way bearing did let go but not the bearing itself, I think the outer race slipped in it's housing. The clutch took forever to lock up and got hot, that transferred to the aluminum housing and loosened up the bearing fit. The inner race is keyed to the shaft, the outer is a press fit in the housing.

Hmmm...

That V8 is awesome! Always been a dream of mine to build one. A massive undertaking though! Maybe the next engine!
Interesting on the race slipping.
Don't shoot me down in flames! lol. Bearing mount Loctite? Lots of surface area!

 

[Wasted wages]

maybe knurl the inner bore, or pin punch it in a few spots, bearing mount locktite, press in the bearing and give it a whirl ????

 

[Terry Keeley]

That V8 is awesome! Always been a dream of mine to build one. A massive undertaking though! Maybe the next engine!
Interesting on the race slipping.
Don't shoot me down in flames! lol. Bearing mount Loctite? Lots of surface area!

Especially he scratch built it from plans. I chromed the iron liners and ground them when I was messing with that 20 years ago, still have all the stuff and plan to try it again some day.

Flames? Never! I take any and all the help I can get. IIRC I put a pretty good press on it, maybe 1/2 thou or so. Rudy texted me saying they make bearings with a keyed outer race and that's what I think I got there, you might even see it in the pic. I'm gonna mount a pully on the end of the wheel and try to spin it up to maybe 8K with the starter before I fire the motor, hopefully it'll be easier on the clutch.

maybe knurl the inner bore, or pin punch it in a few spots, bearing mount locktite, press in the bearing and give it a whirl ????

The inner bore is keyed, outer race pressed in but I might add a key there too.

https://www.vxb.com/CSK15PP-One-way-p/kit10968.htm