I do like the technology, combusiton chamber design as one example, that a contest like the pump gas drags and moreso the engine masters contest brings about. It's critical to the progression of cylinder head design. Still for the handfull of guys smart engough to run hard on pump gas there are probably 100 or a 1000 guys damaging their engines, thinking they can casually duplicate the performance.

.7 or 1.5 SF seems unlikely. Durability tests interest me. Does anyone know where I can find a site dedicated to durability tests and their results, maybe for GM, LT1, or how about the HT 383. It's undergone some extensive testing.

We've established peak average cylinder pressure at 900-1400 psi, what about cylinder pressure during detonation? What's it take to displace carbon/aluminum and leave it attached to the plug.

 

EAP tells me that an engine I already have running good that the cyl pressure is over 1700 psi.This is on C-12 VP fuel and it runs 10.30's with no damage so far.The plugs look good.It is running 37* timing across the board and 13-1 A/F ratio.With further tuning I hope it will be quicker.

 

I do, but I work on "other" cars that are similar. I really dont want to say what team, because then I cant say stuff like "our $20 bolts did this" or whatever. I wouldn't be able to talk about work at all in any way shape or form.

 

I think we run mo-tec

 

OEM dyno durability tests are interesting, to say the least. For marine engines in particular like the Vortec 8100, they will run the engine at hp peak rpm under full load for 55 minutes, then idle the engine for 5 minutes to finish out an hour, then repeat for 300 hours. They do change oil on a certain schedule, and perhaps spark plugs. If your boat will go 45 mph with a couple of 8100s running wide open at 5600 rpm, that's about 13,500 miles, and one heck of a lot of gas...maybe 6000 gallons per engine with a .40 BSFC.

During development of the Vortec 4200 I6 for the Trailblazer, etc. 24 engines were run on dyno durability for 150,000 miles. It probably wasn't constant hp peak rpm like the marine test, but it was under lots of full throttle loads. Additionally, five of those engines continued on for 300,000 miles. They were still running, but the dynos were needed for other work. That's 100 continuous days 24/7. A WAG woud be somewhere around 350-500 million total revs under load.

 

Whether it seems unlikely or not, it's a fact.

You won't find durability results anywhere but within an OE's records, or shouldn't anyway. They're not considered public knowledge.

I can tell you one of our durability tests that must pass multiple times before an engine can be launched is 625 hours of the following cycle:

1) 1200 rpm "idle" for 2 minutes
2) peak HP rpm for 5 minutes
3) 1200 rpm "idle" for 2 minutes
4) peak TQ rpm for 5 minutes

We run at least one "double bogey" (1250 hours) version of this test before an engine is launched too.

 

Unless the OE wants to brag.

http://www.sae.org/automag/techbriefs_05-00/11.htm

http://www.canadiandriver.com/articles/jk/at_010424.htm

FWIW, in the 60s 100 hrs at WOT 5000 rpm was a bogey, at least where I worked.

 

Hehe, good point.

However, do you notice how generally those writeups are worded? For instance, did all components pass an inspection at the end of the test or was the engine just running acceptably? That's where a lot of the fallout occurs.

 

pontiac ehh?


...wait, was it pontiac?

 

Yep.

 

94 bird, I did notice you just said FEA FS that's a little different than real world FS depending on how the analysis is set up, and as you pointed out, the criticality of the component in question.

My boss mentored me during the FEA set up of pistons at Zollner Pistons in ProE, so I can dig it. We also pressure pot tested the pistons with strain gages attached in a hydraulic cylinder to verify and correlate the FEA results.

As fas as new piston designs go we also did a battery of tests, hot scuff, pressure pot, NVH, durability, and temp plug (just to name a few). I always read the internal reports and regularly visited the lab (dyno cells). And, therein lies the problem, internal reports. Likely not accessable to the outside world. Unless the OE wants to brag.

Chevy High Performance made some statements about the HT383 a while back stating that one test it went through was a 50 hour test wherein the last minute (or something like that) of every hour was at WOT, making 550 hp, at 7,500 RPM. That's pretty impressive to me, and translates to over 300 10 second runs (even cooler).

Makes me wonder what the LT1 testing may have been like. Any one know?

 

I have to admit this response puzzles me. FEAs are the closest thing we have to a "real world FS" until we run durability tests. The only thing you can tell when running a durability test is the component's FS is greater than or equal to 1 if the component survives the test. When sampling limited numbers of engines in durability tests that's really not good enough. Computer simulation is MUCH more accurate now than in the days of Zollner and is a very useful tool.

Many of those tests are still done today, with the exception of "pressure pot" testing. I've been a piston engineer for years and have never heard of that. Then again I believe Zollner ceased being a piston company before I graduated college. Are you talking about some kind of crown pulsation test in a rig where strain gauges are put on the piston to verify loads on various parts of the piston when applying a certain load? Tempplugs are not used as commonly anymore. Hardness relaxation is used on most engines at end of test to give a good idea what temperatures the piston saw during it's life. That's the same method used with tempplugs but it's just using the base aluminum alloy as your tempplug.

GM durability tests are basically a standard and are accessible, especially if you work for any GM supplier or the like. It's the results of those tests that are hard to come by.

 

I agree, I worked at Zollner over a decade ago. I'm sure the technology and tools are better now. I still believe as did my boss that computer testing results need to be verified. And, Zollner verified the results with many different tests.

I think that's what it was called "pressure pot", bascially a hydraulic cylinder housing the piston in question with strain gages attached. Hydraulic fluid pressure applied and the results studied. And in the case is saw, actual compbustion bowl edge stress was verified with the FEA results (correlated). This stress was the result of a DI diesel piston being bent around the piston pin from combustion forces.

As far as I know there are only three major piston manufacturers in the World: Zollner, AE (federal mogul), and Mahle. To the best of my knowledge Zollner still ships 25,000 or 35,000 pistons a day.

I'm still interested in any GM durability tests you or anyone else can direct me to. Thanks. Pm me with any information you don't want in the general public and I'll give my fax or phone.

 

You're correct about the 3 major piston manufacturers in the US. Federal-Mogul (took over AE), Mahle, and KS (took over Zollner). There are big players in the Japanese and Korean market though that are becoming big players here in the US. Art Metal (make Honda pistons) and Aisin (Toyota) are 2 of them. KS also merged with Unisia Jax who was a kaisen of Nissan.

How times are a changin.

 

Hopefully they brought all that there computerized high technology with 'em.
Sheeeoot, I better call over there and see who's still working.

Any internal engine strenght calculations or testing information will still be appreciated. Anybody.