Good video on the differances between a short rod and long rod engine

[Wild one]

The 5.7 is generally considered to be long rod production engine with a decent rod/stroke ratio.

MIND BOGGLING ENGINE GEOMETRY - Rod Ratio Explained

Here we have two engines. Both have the same bore and the same stroke. As you can see the only difference is the length of their connecting rods. At the same...

www.youtube.com

 

[HEMIMANN]

The 5.7 is generally considered to be long rod production engine with a decent rod/stroke ratio.

MIND BOGGLING ENGINE GEOMETRY - Rod Ratio Explained

Here we have two engines. Both have the same bore and the same stroke. As you can see the only difference is the length of their connecting rods. At the same...

www.youtube.com

= oversquare?

 

[Wild one]

= oversquare?

Basically yup,lol. But it's the relationship between bore diameter and crankshaft stroke that determine over or under square,the rod length usually doesn't figure into that equation.

 

[HEMIMANN]

My old understanding was undersquares were rev'rs, oversquare were torque'rs.

 

[Wild one]

My old understanding was undersquares were rev'rs, oversquare were torque'rs.

That's a bit backwards from what i know.Over square is usually a big bore/short stroke combo,and under square are usually small bore/long stroke combo's

5.7 is 3.917 bore and 3.578 stroke = over square.

6.4 is 4.09 bore and 3.72 stroke = over square

 

[HEMIMANN]

Mebbe I'm having a dyslexic day. But we are on the same wavelength.
Little 2 stroke chainsaw motors barely go up and down at a million rpm.

 

[pacofortacos]

Engine masters had a good episode on short vs. long rod engine - amazing how little difference it actually made on how the motor ran - all else being the same.

 

[Wild one]

Mebbe I'm having a dyslexic day. But we are on the same wavelength.
Little 2 stroke chainsaw motors barely go up and down at a million rpm.

Honda built a 4 stroke 6 cylinder 250cc bike engine back in the 60's,that really didn't make any power until it was above 15,000 rpm,lol

https://www.hemmings.com/stories/article/1966-honda-rc166

The Honda RC166 Might Be the Best-Sounding Motorcycle on Earth

It has an inline-six that can rev to nearly 20,000 rpm.

www.roadandtrack.com

 

[HEMIMANN]

Honda built a 4 stroke 6 cylinder 250cc bike engine back in the 60's,that really didn't make any power until it was above 15,000 rpm,lol

https://www.hemmings.com/stories/article/1966-honda-rc166

The Honda RC166 Might Be the Best-Sounding Motorcycle on Earth

It has an inline-six that can rev to nearly 20,000 rpm.

www.roadandtrack.com

I was gonna get a Magna when they came out in 84 (1st V4, water cooled). Glad I couldn't afford it. I wouldn't be here.

 

[Wild one]

I was gonna get a Magna when they came out in 84 (1st V4, water cooled). Glad I couldn't afford it. I wouldn't be here.

I raced pro motocross for a local Honda dealer back in the mid to late 70's,but i never would buy a street bike,lol. I knew it'd either kill me or put me in jail,as when i was on bike as a kid,it had 2 positions to the throttle idle and wide open. Things haven't changed much,lol

 

[Wild one]

This is a decent article on rod length and the differances in an over square and under square engine.

How Rod Lengths and Ratios Affect Performance

Changing the length of the rods with respect to the stroke of the crankshaft offers some advantages in certain situations.

www.enginebuildermag.com

 

[crackerjack1957]

I raced pro motocross for a local Honda dealer back in the mid to late 70's,but i never would buy a street bike,lol. I knew it'd either kill me or put me in jail,as when i was on bike as a kid,it had 2 positions to the throttle idle and wide open. Things haven't changed much,lol

Wiser & less athletic......LoL

 

[Scottly]

Piston speed is critical...Too heavy a piston moving too fast and **** flies out the side. If you have a really longggg stroke, that piston has a longer distance to travel every time around and eventually, those speeds are too fast. Shorten that distance and you can spin it faster without making the piston go too fast...

 

[Wild one]

Wiser & less athletic......LoL

I'm not so sure about the wiser,but definitely less athletic,and sure don't heal up near as fast, lol.

 

[crash68]

Honda built a 4 stroke 6 cylinder 250cc bike engine back in the 60's,that really didn't make any power until it was above 15,000 rpm,

How about a one cylinder that probably beats that four bagger..

This is a single cylinder F1 engine – 20,000rpm, 300cc, 90bhp!

Thank you to NordVPN for sponsoring this video! Holiday Season Deal! Go to https://nordvpn.com/drivetribe to get a 2-year plan plus 1 additional month with a...

youtu.be

 

[HEMIMANN]

Piston speed is critical...Too heavy a piston moving too fast and **** flies out the side. If you have a really longggg stroke, that piston has a longer distance to travel every time around and eventually, those speeds are too fast. Shorten that distance and you can spin it faster without making the piston go too fast...

That would be inertial bearing loads for the technofiles. Exactly the reason diesels are built so stout. High stroke to bore ratio, compression ratio or boost, and peak cylinder pressure = beaucoup torque and bearing loads.

 

[Wild one]

How about a one cylinder that probably beats that four bagger..

This is a single cylinder F1 engine – 20,000rpm, 300cc, 90bhp!

Thank you to NordVPN for sponsoring this video! Holiday Season Deal! Go to https://nordvpn.com/drivetribe to get a 2-year plan plus 1 additional month with a...

youtu.be

What the F1 guys are doing with pneumatic valve trains is amazing these days

 

[crash68]

What the F1 guys are doing with pneumatic valve trains is amazing these days

Koenigsegg has really pushed the cam-less engine, they make the fastest revving production engine out there. https://youtu.be/MVVBJG6Nt_I

 

[Wild one]

Koenigsegg has really pushed the cam-less engine, they make the fastest revving production engine out there. https://youtu.be/MVVBJG6Nt_I

Only problem is i don't know anybody who'll buy me one as a X-mas gift,lol. There's even a specific 2.5 million dollar motor home built to haul your 4 million dollar car in an under belly storage system. Nothing like 6.5/7 million rolling down the road as a package,lol.

 

[Scottly]

That would be inertial bearing loads for the technofiles.

That there's a big word Goes back to what i always say...People buy horsepower, but they drive torque. 200ft/lbs can make a lot of HP if you can spin it fast enough...But engaging a clutch at 30K RPM doesn't work very well.