Dr. Destructo blows a rocker apart
 

So just one more thing we'll have to address when building these FA20 motors.

http://elementtuning.com/store/wp-co...RockerFail.jpg

Somehow it appears the rocker roller pin walked out and punched it's way out the valve cover today on the way to the dyno. How convenient :bonk: No question about it I've been running our Pro Comp engine, Hydra EMS, and 60 Trim turbocharger very hard to 9k rpm and at 22-23 psi on E85. I've also been running a mix spark and fuel cut traction control strategy which when using the spark but tends to have a ton of "popping" but is not an uncommon strategy for racing traction control.

I'm not going to say this is a normal failure but we'll clearly be addressing this in our motor builds as we need this roller pins to stay in place under extreme conditions!!

Trying to get this racing program off the ground!

https://fbcdn-sphotos-b-a.akamaihd.n...a84933543bc692

Has anyone seen this specifically yet? I've heard some chat of dropped valves and then the rocker spitting but this is different, just the roller failed.

Thanks,
Phil Grabow

9k rpm?! never seen this one.

Now you have.

http://instagram.com/p/r5sBnItvc5/?modal=true

Still making power ?

So how do you keep oil pressure happy?

What you can't tell? :lol: The heads are not stock, we have +1mm Ferrea intake and exhaust valves, multi-angle valve job, bowls ported, and valve springs. It's an amazing improvement compared to the stock stuff which I agree chokes pretty hard after 7500 RPM.

https://fbcdn-sphotos-f-a.akamaihd.n...67d101ae40ac9b

Oh that's a saga that I don't want to cover all over again. We've documented it here but some of it we do keep a secret as part of our engine build. It's was a long process of testing and trying different things but we eventually were able to hold adequate oil pressure to 9k RPM.

http://www.ft86club.com/forums/showthread.php?t=63723

Was there any damage to the valves or surrounding pieces beyond the valve cover?

Also, since you're already experimenting with spark cut for traction control, what about working in anti-lag during shifts? Any benefit there? The popping is probably late fuel detonation in the exhaust pipe, so why not harness that to keep the turbo spinning?

Phil, was there any sign of the other pins walking? Could this have been an isolated incident?

Thanks for sharing this with the community!

This happened today and all we had time to do was pull the valve cover and peak inside. Honestly besides the hole in the valve cover all we see so far is a very small impression in one cam lobe. There were no signs of overheating due to a lack of oil so the pin just wasn't pressed in tight enough for this application.

I did also cut apart my oil filter and there is no debris in it as I was worried since the hole dumped oil very fast. We still need to pull out the motor and perform a leak down to see if we got away with murder.

The turbocharger doesn't lose spool with the Hydra traction control because it doesn't close the throttle plate. Now you do have an option to lower boost as one of the strategies but fuel cut has always been the smoothest. I was playing with using a combo of fuel and ignition cut cycles as I was loosing traction in 4th gear. There's two schools of thought in regards to traction control strategies on race cars and one is cut spark so you don't get a lean condition and the other is cutting fuel (random cylinders) doesn't cause a lean condition because of the sudden injector stop. I'm pretty convinced over the years random fuel cut cycles not only works better but is safer.

The Hydra does have anti-lag strategies for launch and flat-foot shifting. For drag cars we do use the anti-lag to target specific boost levels for launch and then it cycles off. For flat-foot shifting its not needed as the throttle stays open so we don't loose boost.

Thank you for the detailed response; I appreciate it.

I wish I could find evidence from more than just my memory but I vaguely remember hearing about this happening on a couple cars, even a stock one. Or maybe that was the rocker itself breaking, can't remember.

Element tuning, exposing fa20 weaknesses one failure at a time!

Trying new things and going beyond the limit, I respect that!

Shit must be getting serious now...........Formula 1 Tyres...............:D

One of the main reasons I went with the Element Tuning Hydra Standalone and Hydramist meth injection was that Phil took the time to answer my questions thoroughly and was very knowledgeable on everything FA20.

I'm a very happy customer. I think more people should consider running the Hydra Standalone.

I know my dealer has seen broken valve springs and then broken valves which can spit the rocker out. I can see a case if using a factory valvetrain that you could float a vakve at 9k rpm and spit the rocker.

In my case the pin the roller rides on physically walked out. Our spring seat pressure really isn't very high in terms of a high performance engine so this isn't a case of too much of a good thing. Oiling was also good and no signs of galling or excessive heat.

Purely a case of a factory part fail in a high performance application. We'll address this on any new builds from here on regardless of this possibly being an isolated insident.

Thanks,
Phil Grabow

I straight up can't help myself running the gears as this motor is downright nasty at 9k! :) We will make it reliable as it's just too good to resist.

I haven't seen the pins walk out yet on the FA20 rockers but I have seen plenty of the FA20 rockers being shot out of their homes.

I have heard of rotor bearings creeping, particularly in the 13,000rpm range on rotaries. this is due to hitting the resonant frequency of the rotor assembly. the fix was to drill and tap the bearing and rotor and run an allan screw in it.
i suspect you might be hitting harmonic resonance of a part in the rocker arm, like maybe the roller pin.
It is amazing to see all the component movement in a high pressure engine like yours. some aircraft engines like the BR710 have a regime where extended time in that regime will cause damage and ultimate failure.

john

With this type of valve train valve tip height is exceptionally important when you increase the redline. That said, as long as the valves are ground to the correct height when installed after cutting the seats and lapping, it shouldn't be an issue.

Its a pretty common issue with these motors.

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I've seen them blow through the valve cover at high revs/power with stock springs, but never with upgraded springs

Did you find out if it damaged any internals yet?

If the others stayed in place ...... maybe this one just wasn't pressed in correctly ... ??


humfrz

Are those rollers swedged on both sides or just one? How much more valve spring pressure is on tbose stock rockers? At the level you are at could be a rocker issue with the higher rpm or just the rollers not pressed properly. ID want to see the other rollers as well.

Good luck regardless.

Dr. Destructo blows a rocker apart
 

Stock spring pressure is very very soft, to the point that opening them is easily done with a finger


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I meant I assumed it was upgraded from stock, was curious on how much additional spring pressure was on rockers and if that combined with higher rpm is going to accelerate deflection, failure or rollers walking. You had rockers walk on stock springs? Were you runing over 7500rpm?

Oh elements car has upgraded springs, but in our case they were stock


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I changed my post, were you running over 7500rpm on high boost when your rockers walked?

Well unfortunately we have 18 other engine builds and are under a timeline to deliver Factor Five their dry sumped race engine so my car has been kicked to the curb. LOL!

I'm rarely lucky so I'm going to say one intake valve is tweaked but until we leak it down we wont know. I may get to it after hours in the next few days but we'll see.

This car is on pump, 12psi and 7800


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So Subaru and Toyota will be doing a recall?

Also lets keep in mind my failure is not a result of spitting the rocker out intact. This failure is either a less than ideal rocker pin installation at the factory or its a result of being used in a higher stressed application than designed for.

In my case I am not a fan of excessively high valve spring seat pressures so we do run only what we need. This does cut down on valvetrain stress and wear. Only in cases where really high ramp rate cams would warrant a high seat pressure spring but you would still have all of the downsides. I would suspect this is part of the reason Element Tuning motors don't have excessive valve bucket wear like so many other engines we see posted with bucket wear. With that said we are still probably double the oem for boosted applications in the 60 psi range.

So we are exerting more force against the rocker roller and we are also spinning it much faster. So I would think more pressure and more rpm exerted against the roller as it follows the cams basically spun the pin (axle) and eventually it walked out. While this may be an isolated incident, I say there is no such thing on an application that is 3-4 times factory HP. We will secure the pins on every engine we build as it's always best to accommodate for a potentially inadequate part. It would be zero consolidation for a client to save $200 only to end up with a paper weight after a $20 rocker fails.

Hey I just realized you guys are in Maryland. I think we need to have an open house for FT86Club at your place. :D

No they wont, these motors weren't made for boost and the majority of the motors i know blowing were fi


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Ha ha that would mean people would know where we are and stop by all the time preventing us from getting all those engines built ;)

Maybe one day when I'm not pissed at my FRS. I think I need a few more trophies and I'll get over it. LOL!

Looks like your rocker spit out but was intact. I would suspect that's due to the light NA valve springs and you just floated a valve.

Yup, funny that the car was barely on any load when it happened. The car is now being shipped overseas though and is getting a 2j or lsx. While the one that is still in the states I'm going to give the fa20 another shot


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