Do you have a girdle?

[bret]

Check out sky dynamics new cylinder girdle. http://www.skydynamics.com/frame.htm They claim to have fixed the cracked baffle problem, and engine flexing by tying the cylinders together. interesting product!

[airguy]

Originally Posted by bret

Check out sky dynamics new cylinder girdle. http://www.skydynamics.com/frame.htm They claim to have fixed the cracked baffle problem, and engine flexing by tying the cylinders together. interesting product!

They also claim increased horsepower, which causes my BS meter to twitch more than just a little bit. It's gonna take a lot of engineering drawings and equations to convince me you are going to get any more power out of that arrangement.

"These girdles substantially limit the cylinder's natural X-Y movement to increase durability and horsepower in high power applications."

[EFG]

I think their argument is like stud girdles on high HP automotive applications, the girdle doesn't MAKE horsepower, it ALLOWS more horsepower to be made without shortening the life of the engine.

They might want to work on their wording there.

Valvetrain stud girdles are well proven in V-8s, not so sure that directly applies to "cylinder" girdles on a Lycosaurus however. But, ever forward with innovation.

Here are the ones I run on my small block TPI chevy 383, 10.5 to 1 compression.

http://www.jegs.com/p/AFR-Airflow-Re...20890/10002/-1

[ColoRv]

I tried pretty hard to buy one of their maxi sumps at one point. Never had any luck and when I spoke to the owner his answer for when they would be available was something like 'when we find a foundry that will make them for us'. A couple months later, still no joy so I went with Superior for far less money. I can find a foundry to make me a lifelike rendition of a pile of dog poo made in magnesium in about a week. Something is off when a client is standing with a fist full of money and you cant sell them your flagship product in two months. I hope they got it together, but in short...if its not in stock..don't hold your breath.

[LifeofReiley]

Originally Posted by airguy

They also claim increased horsepower, which causes my BS meter to twitch more than just a little bit. It's gonna take a lot of engineering drawings and equations to convince me you are going to get any more power out of that arrangement.

"These girdles substantially limit the cylinder's natural X-Y movement to increase durability and horsepower in high power applications."

My BS meter just went up in smoke after I read that...

[aerhed]

For some reason I'm picturing case cracks all over the place.

[Ironflight]

Originally Posted by aerhed

For some reason I'm picturing case cracks all over the place.

Just what I was thinking. Anytime you constrain motion that has worked for a couple of million hours, you are going to transfer that stress somewhere....

[RVDan]

I am also nnot a fan of Magensium in what might be high stress vibratory loads. It loves to work harden and crack.

[BillL]

Absolutely, all the above. Linear motion on one head results in torsion on the adjoining barrel assembly? Hmmm . . . . Cool idea, but, I will pass.

[DanH]

Originally Posted by airguy

They also claim increased horsepower, which causes my BS meter to twitch more than just a little bit.

I'm just spitballin', but try this theory.

The port cylinders bend a wee bit downward and the starboard cylinders bend upward, both in reaction to piston side load during the optimum crank angle portion of the power stroke . Side loading gets worse as combustion gas pressure is increased, or (generally) as stroke is increased. The bending cylinder can be modeled as a spring. Most of the available energy goes into pushing the connecting rod and some goes into compressing the spring. Of course the spring stores the energy and returns nearly all of it when the opposing pressure is released, but by then it's too late to result in crankshaft torque.

Originally Posted by BillL

Linear motion on one head results in torsion on the adjoining barrel assembly?

And yet, a large diameter cylinder would be quite stiff in torsion, and if the cylinder were monolithic, rather than a two-piece screwed head and barrel assembly, it might withstand the forces pretty well.

You know, cylinders like the ACE AX50 cylinders on Kevin's test mule:



On the other hand, if one borrowed the idea without considering the screw joint, life may be compromised. Unacceptable to most, but if your customers are performance types who clearly don't mind some loss of engine life in return for HP....