Solenoids can still act against valve springs. Failure of the solenoid would be similar to a flat cam... reduced lift. No extra risk for interference.
Solenoids can also stick in the energized position, and they can also get a failed signal and stay energized, which is where the risk is. Albeit it is more likely that they would fail in the de-energized position due to the spring. the work I do involves solenoids on industrial equipment, and i.m.e. about 40% of solenoid mechanical failures are stuck in the energized position, with about half of those being broken springs, the other half some form of seizing (galling, debris causing lock-up, bent post preventing retraction). Most electrical failures are a loss of signal, with only a small portion being an improper energize signal, but these are not directly solenoid related, these are control system failures. failure of the coil typically results in a fail to de-energize, or it 'functions' but does not fully stroke upon an energizing signal (typically result of low magnetic field caused by a short between windings)
Broken springs are already a concern with cams, and lifters can get stuck due to a burr in the oil gallery, (or in my case a broken plunger retaining clip).
for solenoids, primarily ASCO types. I engineer control valves, we use ASCOs on safety and trip systems, so they do see significantly less cycles, and less controlled enviroments, than the use being discussed here, but there are some constants in electrical solenoids.
That's only the mechanical side.
Horizontal Drills.
This is old thinking. This 7.3 does not have small restrictive heads with small valves. It has high flowing heads with giant valves, beehive springs, lightweight retainers, aluminum roller rockers etc. This engine does not run out of breath at 4000 rpm, it's max HP occurs at 5500 (with a truck cam).Not to get back on topic, but isn't the 7.3 a truck engine? I recall back in the stone ages trying to use a truck engine in a car. They were built for endurance and torque, with very heavy internals, small valve heads, low compression and very restrictive intakes and exhaust. It took a ton of work to get them to perform how you like for use in a car... unless you use your car for pulling stumps. I'm no expert, but from what I've read about this 7.3, it seems like there may be better choices... like a Chevy LS7
All I'm saying is it is never as simple as it looks. I'll wait and see when somebody actually uses the 7.3 in a Mustang and how much it costs. There is always something... excess weight, inadequate cooling capacity, clearance issues, so forth.
It's still basically a 6000 rpm motor in a 7500 rpm world.
Fixed. Mr. Wolfe has obviously been bringing his drag racing avocation into his professional world. Not saying it was wrong for him to do so, but it has brought along a few biases.
Until it at least gets an aluminum block, it's going to remain heavier than necessary for use in a car. Durability for extended towing or for carrying heavy payloads where higher power levels are required on a continuous basis just isn't necessary in a car like it is in a truck that works for a living.
And as just a 3-valve design it'd already be close to 500 hp/500 ft*lbs with about the same amount of cam as what the weakish 4.6 3-valve uses.
The potential that it has and the potential it could have had are two different things.
Make no mistake. I don't think it's going to be simple.
It's a 6000 rpm motor because the cam dictates where the power falls off. Looking at the dyno graph, the power just starts to taper off as it approaches 6000 RPM. 6500 RPM should be no problem with this engine, which is right in line with what the competition is putting out.
Right or wrong, one can infer that they designed these engines with more than just stump pulling in mind.
Heavier then necessary, but not excessively. Nothing I have seen in this design points to this engine being a pig. I think some in here get too caught up with previous notions that big block truck engines have to be boat anchors.
Are you aware what the valve size is on this engine? Shrouding? Lift? A bit more to the equation than just area. A bigger bore allows for larger valves. And this is already stated to have beehive springs to allow for large lift values.
Indeed. What side of the fence you are on seems to follow what your preferred engine is (except of course for me). I prefer the coyote, hands down. I love the potential this engine has...based on all of the current information and components we know...for the right applications. I would love to see this thing in a shelby cobra kit car...or a foxbody.
I am in injector development now. Diesel injectors, especially piezo actuated, will last hundreds of thousands of miles if they aren't seeing deposits, contamination, or excessive heat. The main issue is the poor quality diesel in the USA, not the reliability of the technology. I have analyze a number of injectors that had 300k miles or more, yet they still passed performance testing. Pretty amazing when you consider these injectors are injecting 3-7 times a cycle at 2000+ bar.
7 years working with solenoid and piezo injectors, and I have only seen one or two cases of the solenoid failing in the energized position. When we have a "stuck open" condition, it usually isn't because of a failed solenoid. It's due to the mechanical systems attached to them (nozzle needle stuck open, actuator stuck due to deposits, valve group failures, etc). Not saying it won't happen in a solenoid cam system, but I don't see the failure rate being any higher than what you get with mechanical cams/valves.
It's a 6000 rpm motor for a more basic reason than that. 4000 fps mean piston speed is still a pretty good guideline for a large displacement engine. Unless you like doing periodic refreshes.
Mr. Wolfe was also behind the Cobra Jet. Do you really think that when he started with this engine program he forgot all about that and what he does in his spare time? That some of the reports mention that 'performance' was at least kept in mind tells me that his drag racer side showed up in the office.
In this era of 450 lb V8 engines, even with aluminum heads an iron-block 4" stroke OHV engine is going to tip the scales at roughly a hundred lbs more. For a car these days, that is getting into boat anchor territory.
Volume, not area. If you scale the displacement up from 4.6 to 7.3, it should follow that other dimensions would scale up as well. Valve sizes would necessarily have to scale up. But all I was looking at was what it could have been with a 3-valve design based on how that turned out in the 4.6.
This 7.3 could have been so much more. And it still could be, in destroked aluminum-block 3-valve SOHC trim, where the head size argument mostly goes away (the 7.3's heads are pretty tall themselves).