The first prototype of the Mini Metro A series turbo ran 100 hours at full power on its first attempt.

That's the 'quick' test on a proto which means you've got everything working and the real development can start.

Cheers

Greg Locock


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I could believe it, "redline" like most other limits tends to be a statistical guesstimate rather than a hard/fast failure point. Much like knock limits there's going to be some leeway built-in for production variation, hence the various stories of "free" hp and fuel economy. Running at constant high rpm, even with highly cyclical loads also tends to be a bit easier on everything vs pulling the traditional lug curve (rpm sweep), which is why stationary engines tend to live longer. Extended, months-long automated testing is standard practice tho in engine development to validate durability with speed and load cycling dependent on specific application. When you delve into the details of application specific testing things get really interesting as theory and simulation meet historical data and "abuse." On the boring end of the spectrum you have testing for stationary engines which might be going from no load to thousands of hp or vice-versa in a fraction of a second, simulating a breaker being thrown on a big generator. On the fun end, its not uncommon for race teams today to rerun entire races in the dyno cell to prove hardware changes will hold up to their drivers' (even bad) habits on a given track. Personally I always enjoy working in the cell so long as the engine is alive and not puking parts at me.

You tube has lots of videos of dyno disasters. Some funny, most are scary.

je suis charlie

If automotive journalism can be believed, 100 hour full-power engine tests date back awhile. Supposedly- Bunkie Knudsen insisted on changing to forged crankshafts in the 1958 Pontiac V8 engines after cracks occurred in cast cranks during such tests.

I've worked at 3 different companies, they all used it.

Cheers

Greg Locock


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It's a promo video, but I'm quite sure they've done it ... many times.

https://www.youtube.com/watch?v=z87iFASgDwk

When I worked at a heavy duty truck engine manufacturer, we had a number of accelerated life tests with colorful names like ROCK CRUSHER and SUPER ROCK CRUSHER. They involved advancing the injection timing, jacking up the fueling and consequently boost pressure to specific targets of peak combustion pressure and exhaust gas temperature. Typically they would cycle between peak torque, peak power and an over speed speed condition. 1000 hours was common. Oil consumption tests for the piston ring pack were 2000 hours. I also ran a 1000 IN^3 V8 1000 hour NATO tank engine qualification cycle as my last project. The engine passed but if you knew where to look there were tell tale cracks starting to appear on certain components. We had a visiting executive from a foreign engine company open the dyno cell door and go stand next to the engine running full power in the plane of rotation without even hearing protection. No way I was going in after him to drag him out! If you have ever seen the damage done from a broken rod or crank shaft, you don't want to be standing next to it. We once had a flywheel break off and it made a couple of full loops around the test cell, climbing the wall, running across the ceiling and on around.

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FWIW, the 1939 Studebaker Champion was claimed to be the first US production engine to survive 5,000 RPM at full power load on the dyno for hours on end. (JMHO, but this is an example of engines which are long-lived at full load because they are specifically design limited so as not to make enough horsepower to hurt themselves.)

Another dyno legend is in the late 1960s Ford wrote a mechanical tape program to replicate every transmission shift, load and throttle position expected for the twenty-four hours at Le Mans. By the end of testing, the engine team promised The Deuce the 427" would survive and win, "Providing the drivers will shift when they're supposed to."

jack vines

I dont recall which cell it was (one of the ends in EEE, the original Ford Engineering Lab next to the HF Museum), but the same cell was used with modern digital controls to test drive the engines for both '06 and '16 LeMans efforts.

I cant say I've ever heard of anyone being hit with ejected engine parts in the dyno cell but have known of plenty of burns from fluid leaks and close calls. I believe it was my third week in engine development I had a large ~7 lb diesel injector take a chunk out of the concrete wall ~2' from me when an overspeed condition allowed piston contact and its subsequent ejection through the valve cover and past me. I stopped entering the cell when running unless absolutely necessary after that. There is however the usual racing stories of humans catching parts, Don Garlits' severed foot being a great example.

The "Spintron" machine was used for similar endurance testing of new camshaft designs.

Talking about engine injuries, I know of a guy that lost his leg from a clutch flying apart during an over rev condition on an engine on an oil rig, he had just started the engine and it took off, I don't know what the engine was .
So I'm guessing they use something other than fire proof sheet rock on those dyno cells, for the engines dgallop worked on.

Every dyno cell I've ever been in has been either CMU walls with reinforcement and concrete fill, or several inches of reinforced concrete with a 'soft' ceiling. Windows are ballistic glass. The 'soft' ceiling serves as a safety measure to direct explosive energy away from where people are likely to be.

Our dyno cell walls were cement block with rebar & cement filling the holes in the blocks. That runaway flywheel did some serious damage to the blocks. I don't remember the ceilings exactly. Most of the cells had 2 engines with the dyno in between them so you could run the development engine on the day shift and the endurance engine on night shift. We had rolling block & tackle to lift the back engine up and over the dyno & front engine. The windows had wire mesh embedded in them. I think there were 7 panes set at 2 or 3 different angles. The mercury barometers that occasionally "blew" during an over boost condition were probably the biggest hazard. There were always little beads of mercury floating around.

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Jag engines (This includes the old AJ16 straight six and the V8s) where subjected to thermal shock tests- where at full operating temperature and high load the engine was flushed in the dyno with coolant suddenly at -20 deg C to test the integrity of the cylinder head gasket.

Other established OEMS have similar procedures.

www.auto-scape.com

Sideways To Victory!

I don't see the reason after the noise started that the operator didn't shut this down, there was plenty of time to do so.
https://www.youtube.com/watch?v=ZfttA0mds-c

When something starts to let go, you really don't have to run it till destruction to know what will happen, unless it was a test of the crankcase/block structure.

the 8V396 is a mechanically injected engine, and most of the marine versions of it I have been around did NOT have an electric shutoff, most used a Morse type cable on the shutdown lever on the side of the fuel injection pump.

Looking at the video, appears the control valve for the dyno goes full open, hitting the engine pretty hard based on the apparent torque reaction, likely the dyno operator was dealing with the load control and since it doesn't look like an external shutdown cable is visible, probably wasn't to thrilled about getting up close to the engine at that point to shut it down.

These were nice engines, at the time one of the best horsepower to weight ratios around on the marine propulsion applications. But real pricey to repair.

MikeL.

But real pricey to repair.

je suis charlie

I can't remember which manufacturer it was, probably BMW, but their test regimen was cycling the engines from peak torque past peak HP to redline for 3 days, while the cell the engine was in would go from the lowest possible temp a car should drive in to the highest.

Mobil 1 also did the million mile BMW test, look here:
https://www.youtube.com/watch?v=gHmMlU8Q-V8

that car was on the dyno for 4 years.

They have to go in the dyno cell to shut down the engine? That is too funny. What it is, is not good planning, if I was involved in dyno room design, there would always be a way to shut down the engine in an emergency. With compression ignition engines there would be redundant methods, first being a motor operated induction air shut off valve, and a few other proprietary methods.

We always had a "throttle" control in the control room and could also shut off the fuel supply remotely but that would take awhile to actually stop the engine and was frowned upon because you would have to bleed all the high pressure lines to the injectors to restart. One of the best ways to stop a runaway diesel is a board over the air intake but we never had a remote way to do that. Some diesels when they torch a piston can keep running on their lube oil. Stopping that requires blocking the air. I've seen rags and coats fed into runaway diesels to shut them down.

When I was working on a 1000 cu in V8 diesel development project the head of the injection system group decided it would be a good idea to start an engine that had the governor removed. He was going to hold the fuel racks (the pump was a little V8 the lived in the engine V) with his hands. It started OK but when he lost his grip it started to run away. Fortunately another engineer was able to feed his lab coat into the turbo inlet and get it stopped.

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Ahhh, the "good old days." Today we have multiple safeties on every system with computer controlled limits to shut them down individually, as well as a control on the dynos to expedite stopping engine rotation. The operator doesn't have to respond to engine issues unless he wants it to keep running, which in many cases actually causes more issues as overridden safeties lead to damaged rather than shut-down engines.

I ran and then oversaw operations of our dyno's and test cells mid 80's until 2000, not only did we dyno our own brand engines, but we had a "certified" dyno and test cell for military work, so we saw a lot of other manufacturers engines come thru our cells as well.

A lot of engines we got for the bob tail dyno were what we considered "bare" engines, minimal accessories, and a lot of times no air cleaners, exhaust piping, fuel filters, etc. Especially on marine engines, few engines had any means of shutoff other than a mechanical lever, if we could make it work we had a assortment of cable ran into the dyno operators station. If the engine had an air dam installed on the sir inlet system we also had cables for then as well. We did add a "dump bottle" CO2 fire system aimed at the air inlet that worked most of the time.

Testing older design engines was interesting work, took a lot of time to get them in the cell and hooked up to meet the testing needs, while our internal failure rate on dyno was low (didn't have failures very often but they did occur), we did get a lot of failures on "test only" engines repaired by other facilities. So got to see a lot of scenes like the one from the you tube video above. I can also tell you while it looks like there was plenty of time to respond to the failure shown above, operating a dyno like that had a lot going on,and options for remote "fast" shutdown were limited.

As CWB1 noted above, newer engines have LOTS of built in protections, when we first started dealing with electronically controlled engines in dyno testing we had to jump thru a lot of hoops to actually get them running and up to load, as systems got more complex the engine ECM was looking for other controllers input or permissives to go to rated speed or load up. Many engines now have a "dyno mode" setting in the ECM that allows you to override a lot of the safeties so you can test a bare engine, but access to that feature can be pretty limited.

MikeL

Hard to beat Halon gas if you need to stop an engine. Health and environmental concerns are severely restricting its use these days.

je suis charlie