Are pushrods and springs really needed?

[Erikclaw]

At least we can speak our minds and not worry about getting smacked for saying something in the heat of the moment.

 

[Jeff@Spartan]

Never called him that

Are you ***ing retarded?... If the ball catches the lip of the rocker arm it compresses the spring/springs opening the valve.

Well....not exactly that.

LOL

 

[CamTom12]

We used to roll them across glass to check for bends.

A buddy of mine managed to bend one into an S-shape on an LT1. Stock pushrod, upgraded valvespring. Pretty wicked.

It wore a groove in the head.

 

[Craig@MFI]

Are you ***ing retarded?... If the ball catches the lip of the rocker arm it compresses the spring/springs opening the valve.

Right here

 

[BFT]

There yah go

 

[Craig@MFI]

Craig!! Dont derail the original purpose of this thread!!! Shame on you...

Lol sorry wouldn't want to do that...never

 

[cfdeng7]

We used to roll them across glass to check for bends.

A buddy of mine managed to bend one into an S-shape on an LT1. Stock pushrod, upgraded valvespring. Pretty wicked.

It wore a groove in the head.

Granite service plate (+/- .0001 across the the plate) is best but not everyone has access to them... one of the perks of working in a machine shop.

 

[bigrpowr]

craig.... relax. while it probaly wasnt the right thing to do, i think jeremy is the only person who should be bitching here.

 

[Black_Lightning91]

I just can't see how a push rod that is supposed to maintain full contact with the lifter and rocker at all times. Could bend enough to allow the top of the push rod to contact the outer lip of the rocker and not have shortened by the same amount or more than the lip of rocker to where the ball seats. Forgive my ignorance but can someone show me to some diagrams a video or something about this because I just can not see it.

 

[lubeowner]

If it is bent it does not follow the path that it is suppose to. It can start wondering around because of its curvature and then pushes on rockers etc at a point it was not designed to. Like the lip, there for pushes the rocker higher since it is not seated with the "little oily ball thing" in the cup.

I agree this statement except for the pushes it higher part, you have to figure that the push rod is now bent and probably a 1/4 of an inch shorter. So pushing this other spot is only compensating for the rod being shorter.

In the end a bent push rod 99% of the time is the result of another problem and does not cause engine damage. Yes it is possible but not very probable..

I agree with upgraded springs in high boost applications. I also agree with upgrading push rods if you want. I don't think many on here need them but whatever floats their boat. What i dont agree with is telling people that bending a push rod will ruin your engine.

On the name calling comments, yes it makes me want to try harder to prove my point. I always try to look at name calling with the elementary playground theory that they have nothing intelligent to add to the discussion so name calling is all that is left.

 

[Dzchey21]

Right here

Sometimes you gotta remember that mods are members too. We don't get paid and moderators still have opinions too. While I agree with speaking your mind Robert probably shouldn't have said what he said. Jeremy also has a way with not getting to the point directly ... not saying that's an excuse or saying Robert is justified... just saying that if Jeremy had a problem with what he said I think he would have said something.



Enough with that derail tho.... the rest can be handled in pm's or another thread if you wish.

 

[lubeowner]

Now on to how does a bent push rod cause engine damage? I don't know as I can't see how a push rod can. If it is straight it opens the valves like normal. It is bends it doesn't open the valves. I fail to see how a bent push rod and thus a none opening valve can cause a valve contact the piston. Valves contacting the pistons are caused by the valves not closing fast enough which has to do with either springs not being heavy enough for the given application, I.E. high back pressure or engine rpms. Or some outside impact causing the valve to stay open, like a debris, a piece of metal off some other mechanical failure.

Anyways, do whatever you like and makes you feel happy. That should really be all that matters.

I guess I thought my first post in this discussion was direct enough.

What I do that pisses some of you off is I make a statement. Someone will disagree with it and want to discuss it. Then to back it up, I discuss with the most simple concept of it, in this discussion, push rod length, bent vs straight. If I could have gotten the discussion participants to agree on this concept then I would have moved on to push rod deflection and how much it would increase on a already bent push rod.

So this discussion is basically dead, since we cant even get through the most basic concept of length. So we might as well move it to smack talk and have some fun, like the good ole days.

I am ok with someone that I am having one of these discussions with, after a while, getting mad and calling me names. What I have an issue with is the guys who jump into a thread, don't offer any discussion one way or anther and call me names. That is childish. The guy in the discussion is just acting off frustration and that is human.

 

[BFT]

I have seen it first hand in my old race car. Being that it's not a diesel truck, it can happen.

The majority of the time a push rod won't be the cause of a dropped or floated valve, but dismissingit he probability is stupid. I guess I'm the only unfortunate one.

You also did not mention of the performance loss that can be the outcome of a bent push rod, which I was also speaking of

 

[Dustball8504]

And today on As The Turbo Spins....

Its like a soap opera here LOL

 

[Black_Lightning91]

So I am guess no one has any of the info I asked for in my last post or a way to explain it that makes sense? If so I will continue to think a bent pushrod will only either not open the valve or not open it all the way.

 

[BFT]

most likely bent it because of the valve kissing the piston
http://www.youtube.com/watch?v=GO9W_61x-bc

 

[BFT]

[FONT=Calibri,sans-serif]Just [/FONT][FONT=Calibri,sans-serif]what is valve float?[/FONT]
“Valve float” is a common term for a situation best described as (valve train separation). This occurs due to inertia load imparted into the valve train by the action of the cam lobe against the follower.Weak valve springs are among the most common causes of valve float. Fast lobe profiles, heavy valves, etc force the need for high quality springs with increased pressure. That said, too much pressure can be disastrous to rocker arms and is often unwarranted. Forced induction is another contributor to “valve float”. Because of the increased pressure on the face of the valve, stronger springs are usually warranted.
Flex in the valve train (the majority of which is located in the pushrod) is a prime contributor to valve train separation or “valve float”. The initial loads imparted into the pushrod cause it to bend (somewhat like a pole vaulter’s pole) and then return to a straight configuration. This unloads a sharp energy pulse to the rocker arm, which transfers it into the valve/valve spring assembly. This often results in “valve lofting,” which causes the valve to operate in a different path than that described by the lobe profile. At the same time, the lifter without any load against it, can also be launched off the opening ramp of the lobe and then, as load is re-established, either: strike the nose of the lobe and eventually damage it; land on the closing ramp (like a ski jumper landing on the slope of a hill); or land on the base circle with significant and often damaging impact. If “lofting” can be controlled (by design or good fortune and the lifter lands gently on the closing ramp), it adds to area under the curve and more power. If it is uncontrolled (which happens the vast majority of the time), it can be damaging to valve train components and will compromise performance. Most of the time, power flattens out or is lost when valve train separation occurs. Again, the biggest culprit in causing this situation is the flex of the pushrod.
Many people on website forums tend to think that the “weight” of the rocker arm is the cause of “valve float”. If the rocker is rigid and properly designed, it should contribute very little to “valve float”. Weight in this case is not the prime issue, but rather the “moment of inertia” of the rocker design. “Moment of inertia” is the affect of where the mass of the rocker arm is located relative to its center of rotation. One rocker can be much heavier than another and still have a smaller moment of inertia because of where its mass is located; so weighing rockers to determine their affect of valve float is really not effective at all. (FYI: “mass” is a measure of a body’s inertia; while “weight” is the affect of gravity on “mass.” “Moment of inertia” is unaffected by weight, but is affected by where “mass” is located relative to the center of rotation!). The highest quality aftermarket rocker arms are designed to be rigid (to minimize flex), and have a very low moment of inertia relative to the necessary strength.

Other issues are often misdiagnosed as “valve float”. These issues can mask themselves and give the impression of “valve float”.
11 1. Coil Bind.
Increased lift causes the clearance between the valve spring coils to diminish. The spring can become solid. The minimum recommended clearance is .060”.2.Additional lift can cause the pushrod to travel a different arc. The position of the pushrod in the rocker arm cup and or additional lift can reduce the clearance between the pushrod and the cylinder head. If the pushrod contacts the head during its rotation, it can stall momentarily causing the lifter to expand and pump up, holding the valve open temporarily. The result manifests itself exactly like “valve float”.
3. Proper rocker arm clearance, that is, something interfering with the ability of the rocker to make its full sweep can manifest itself as “valve float”. Clearance should be checked throughout the entire sweep of the rocker arm. The minimum recommended clearance is .60”
Understanding the issues surrounding the phenomenon of valve train separation is paramount in identifying the problem and correcting it. To ensure consistent performance and safety throughout the entire range the engine operates in, valve float must be controlled. Unchecked, valve float can and usually does, contribute to engine destruction.

 

[smokinstroker]

So not to derail but say hypothetically someone has a Bent pushrod/ binded spring. How would one know this has occurred without pulling the top end apart and looking?

Would the truck have noticeable drivability issues?
Or could you still be driving it and not know?

Again just asking not trying to stir or derail.

 

[White_monster]

The engine will sound noticeably different.

 

[BFT]

you can hear it for the most part at idle. its like a thumping noise, youll hear it through the intake for the most part

beat me to it