hacker-pschorr

As he talks about the pistons pushing harder on the crank, imagine what that's doing to our super soft rod bearings.

SwayBar

If you're an old 2-stroke motocross racer like me, then you'd know all about being 'on the pipe'.

It's when you're riding along in the pits, you get out on the track and give it the gas, it hits a certain RPM and the bike literally takes off - you better be pointed in the right direction. During a race, you always want to be on the pipe if you expect to have any chance of winning the moto because that's where all the horsepower is.

Likewise I suspect for our cars it would be 'on the cam' where the powerband reaches its maximum volumetric efficiency, or maximum torque, and the car feels like it's taking off.

Petza914

Perfect comparison!

hacker-pschorr

The great Smokey Yunick once said (paraphrasing) that if you take all the engines damaged by detonation and put them on one pile.
Then take every other failed engine for any other reason and make another pile.
The detonation pile will be significantly larger.

The point in the powerband where detonation potential is at its absolute highest it peak torque, second is below the power band (lugging).

So yes, as the guy in the bike video points out, spinning the engine faster than you really need to does technically wear out rotation and moving parts more so than not spinning them as fast, but that's greatly outweighed by the damage done to an engine by lugging it around and tip-in detonation. There is no free lunch and we own cars with engines designed to spin, not classic big blocks.

This really seems to be an American thing. Deeply engrained into our history are muscle cars with 2-speed transmissions with big block engines that fell on their face after 4,500 RPM that needed all the torque in the world to get out of the hole.

You know Joel. He used to host dyno days with the Vette club and he'd try and talk all the big block owners out of attending. They would always leave upset when a stock C4 (96 LT4) put down better numbers.

SwayBar

WAY back in the day I had a 1970 Dodge Challenger R/T with a 440 Magnum, 4-speed, headers, Hush Thrush mufflers which exited in front of the rear tires, solid aluminum Centerline wheels, and Kelly Supercharger 50's on the back.

That car looked good, sounded good, and was quick - but - valve float at 5200 RPM! At the time it didn't bother me because I didn't know any better, but laugh about it now. That car was a lot of fun...

Funny story about Joel!

hacker-pschorr

You'd be shocked how common this still is today with engine builds. We had a resto-mod Chevelle in here recently with a custom built big block. All the right parts - except for one - valve springs. They were good springs, but not for a big block spinning to 7,000 rpm like this one was designed to do. I called down to another shop that is known for building cars like this (but not this one) and he laughed, said he gets into arguments with all the "old school" engine builders who refuse to install proper valve springs in engines. Various reasons, but mostly chalked up to "that's how I've always done it!!" sure, back when engines couldn't withstand the rotational force of 6,000 much less 7,000 RPM.

We're going to spin Jim Page's big block past 7,000rpm. Multiple guru's said he's running too stiff of a valve spring. Then we ask them the last time they built a big block to spin past 7,000 and the phone goes very quiet, one yelled back: "Why the hell would you want to do that??"

Twin Turbo Todd and Luke say this is the way to do it. I'm going to trust them.