Nick's Failed Lifter - High Power Engines.

[FRP]

Hi All

Glad Nick posted the pics of the failed lifter I sent him.

Here is where we are on this. I have solicited opinions from Hank, Marc, and Javad and asked Javad to get back to me on whether they have seen this type of failure with the INA "Lightweight Lifters". The failure was caused by trampoline like flexing of the top of the lifter until the metal fatigue let it shatter.

Hank has no use for them at all and just feels they are built too light for H.D. use. Marc says he has had problems with them failing to hold internal pressure and sometimes "pumping down" and then failing to recover, but, did not know of this type of total mechanical failure.

I have no personal experience with this type of failure and 034 has been selling these lifters for years.
Surely we would have heard of this stuff before if it had been a problem, but then again Hank has apparently seen some problems with them before.

I can say without hesitation that I am personally no longer comfortable using them, at least in high horsepower engines with high mechanical and dynamic loading of the lifters. This is based on me seeing how thin the lifter body material is on the exploded part.

Turbo engines at high boost run in constant dynamic pressure in the cylinders which adds to the force required to open the valves - especially the exhaust valves. *All of the lifters that were in the process of failing in Nick's motor and the one that blew up were exhaust lifters.

I am wondering if these lifters have been cheapened by the manufacturer but have no way of knowing.

What I can say for certain is that I have never used them in an engine at the power level of Nick's. Unfortunately, big motors have a way of finding their own weakest link and that has happened here.

It is however important to be deliberative and systematic in analyzing any parts failure so I am sending the Cams to a professional S.A.E. cam engineer to have the lobes analyzed in a computerized reader that will tell us everything about the shape of the lobes with the exact shape of the opening and closing ramps being of critical interest and importance. If they check out well then it is all on the lifters. The same person will be checking out the lifters - both broken and about to break - so I can count on a good reading from him there as well.

I will say that a factor that certainly did not help things was that Nick's cams were Cat billet cams which have lobes that are .050 narrower (.525 vs. .575) than the factory cams (or Cat Cams cast version) thereby increasing the stress concentration on the top of the lifter. I have no idea how much of a factor this may have been.

It is important to note that whatever the structural liabilities of the INA light weight lifters turns out to be - they did not fail to provide stable, high rpm operation of Nick's valve train and did not pump down operating against the very elevated BMEP in the cylinders of his engine.

Retrospectively, it is instructive that the factory lifter is substantively heavier even though it operates between much lighter springs and much slower cam lobes at lower rpm. Unless some corrupting problem shows up in the lobe profiles we will be removing these lifters from Matt's engine and replacing them with new OEM units.

I'll keep you posted on the findings.

Now as for the liabilities of big power engines. We should all remember that the factories and factory race teams with zillions of dollars, super computers and gangs of extremely qualified engineers - BLOW STUFF UP! It does not matter the arena, it happens everywhere in every series despite the aforementioned advantages they enjoy. Nick has been very unlucky with his experience and we have had some really weird and unusual things to deal with but it is nothing that can't be overcome and I am sticking with him in the process.

If an engine has a robust basic design and individual component strength is high enough then some pretty incredible hot rod stuff can be done - with an acceptable level of reliability - due to all of the great aftermarket parts we can choose from. And remember, the amount of time a street operated engine is at full stress is relatively small compared to Daytona or LeMans !

I can't think of a production engine that better meets these qualifications than the Audi I5

Enthusiast users like all of us are always to some extent captive to what the industry provides for our use. BUT, what we can control is the quality of machine work and quality of assembly that we put into our projects and these factors are, in the long run, far more determinant to long term success.

We all are, as someone adroitly pointed out, all involved in automotive R & D to varying extents. The important thing is to deal with suppliers and builders that will stand behind their work when things go wrong.

Is there a theoretical "happy medium" for horsepower vs. reliability ? Of course. But just think of how long all of us are going to be dead ! Or as Mark Donohue famously said - "There is no such thing as too much horsepower - only not enough" !

[loxxrider]

But just think of how long all of us are going to be dead !

or as Lil' Wayne so eloquently put it, "YOLO!"


Jeff, thank you so much for keeping us updated on this matter. It interests me deeply from both an engineering standpoint and as an enthusiast with goals of an engine making in excess of this engine's power at higher RPM. I think we will run into some teething problems as well, but hopefully they will be fewer thanks to the learning gleaned from this engine (sorry Nick!).

By the way Jeff, I love the way you describe the top of the lifter as trampolining. That is exactly how I would envision it looking in an FEA simulation. Please continue to keep us informed!

[roortube]

I havent had these lifters explode per se, but build 3 engines in 2012 using them. Within a couple hundred miles i had issues with all 3 engines and lifter failure
It was more like the diaphram failed and the lifters seperated on 17 of the 60 lifters. I swapped them all to stock el cheapo aftermarket replacements and havent had a lifter issue since. Not a tick as long as the oil level was close to correct..

[elaw]

Not to oversimplify too much, but this sounds like a classic case of reduced safety margin + increased stress = boom!

The OEM lifters were designed with a large safety margin and pretty much never break. Someone somewhere along the line recognized the OEM ones had more margin than most people needed, and designed "lightweight" ones that are thinner and have less strength margin but still enough for most situations. But not enough to handle the stress put on them by this particular engine.

[yodasfro]

http://www.motorgeek.com/viewtopic.php?f=1&t=215

http://www.audiworld.com/forums/12v-v6- ... d-2589005/

[audifreakjim]

Fuck Audi world has a lot of adds.

Knock on wood, I have been running the AFC lightweight lifters for 40k miles. Just 7A cams, but ~30 psi of boost and frequent trips past 8k.

[Marc]

Fuck Audi world has a lot of adds.

and now motorgeek, too...

[varia]

I habe AdBlock, I dont see any