Hey guys my buddy goes to this machine/speed shop to get all his parts and what not, I consider them idiots cause they keep selling him parts and promising him 11's and hes not close lol, not to mention i watched them take apart heads with a hammer before.. but anyways they told him that 1.6 roller rockers will wear out your valve guidesl.. now is there any truth behind that?? I wouldn;t think so cause it s a roller tip so its not liek its gonna rick the valve back and forth right?? they also told him that castrol oil is why his bearings lookedbad after 2000 miles, not the machine work they did. lol thanks guys

 

First of all they probably didn't take apart his heads with a hammer, some guys hit the edge of the spring with a mallet to break free the valve keepers.
Castrol has had a reputation for years (as has Quaker State) for gumming up engines, that being said, both of those oils are great, maybe even better than the other oils on the market for lubrication unless the oil is extremely overheated or is not changed at regular intervals. So some guys are of the opinion that those oils are no good, that's not necessarily true.
The reason (I think) that they say 1.6 rockers will damage the guides is because of how rockers work. Basically, they slide over the top of the valve, while doing this there is a considerable amount of force against the guide, and they do wear out eventually. So would a 1.6 wear them out sooner?, maybe a little, but the fix for that is to use a roller tip rocker, whether it's a 1.5 or a 1.6. by the way, if you do use a 1.6 you really really need to check the pushrod guide slot for clearance, some guys get lucky, but every head that I've put 1,6 rockers on, needed work on the giude slot.

 

Taking heads apart with a hammer is no big deal. Socket, extention, BFH - since most retainers need to be "persuaded" to let loose, anyway, a good whack will loosen the retainer and pop the keepers out - viola, you've got one valve disassembled.

As Sheep was relating, high lift with stock-type sliding rockers will put more side-force on the guides than lower lift. Since 1.6's increase lift, slight increase of force. But, as stated, roller tips take care of that.

Otherwise, sounds like they're making excuses for poor quality work.

 

If proper geometry is maintained 1.6 rockers won't wear out anything any faster. Now if you just throw something on there and never check for the proper setup, that could be a problem.

 

What would checking involve??

 

You want the rocker's contact point to be in the center of the valve tip through its motion. If it isn't centered, you can move it in or out with longer or shorter pushrods depending on which side of the valve tip it's rubbing. Simply mark the tips with a marker and cycle through a few revolutions and you can see the wear pattern. This is what adjustable pushrods are used for. You can determine the proper length with them. There is less side loading on the guide with the valve geometry set up properly. Roller tip or not, you want the contact in the center.

 

This can be debated. Some manufacturers will tell you that it is much more important to have the smallest sweep path possible across the tip of the valve, be it centered or not.

Ideally you would want the smallest path AND it be centered.

 

i take heads apart with a hammer and a special tool i made from a piece of 3/4" pipe. took apart a set of ford heads yesterday took about 2 minutes at most.

 

It doesn't make the slightest difference whether the contact pattern of the rocker tip on the valve stem, is in the center of the valve stem or not. No difference whatsoever.

Manufacturers don't tell you that, that's what you hear in the McDonald's parking lot.

Think about rocker ratio for about 2 seconds, and a blinding flash of the obvious may occur to you. The rocker ratio is the ratio between 2 distances: the distance from the rocker pivot point (usually the stud) and the valve tip, divided by the distance from the push rod seat to the rocker pivot point. In order to change the rocker ratio, one or both of those things has to change.

You can't move the valve itself over. You can only shorten the push rod side length just so much before you end up with problems. So most higher-than-stock ratio rockers use a combination of the 2 things. If your rockers lengthened the pivot-to-valve-stem length, then you're not going to be able to center the contact, no matter what you do.

Valve guide wear is caused by side loading on the valve stem. That is caused by rockers that force the tip to slide across the valve stem as it moves in its arc. And that in turn is caused by improper push rod length selection.

Ideal geometry occurs about when the push rod length is just shorter than where it produces a contact patch of minimum width. That mimimizes the side forces on the valve, especially when the valve is near fully open (high spring pressure, therefore more force generally on everything). The valve stem is a straight rod of metal, and will respond to a push exactly the same regardless of where on its end surface the push is applied.

Ever notice that the people who think that "centering" the contact point is important, are the ones with valve train problems? It's because they don't know what they're doing, and they deliberately distort the geometry of everything in that particular way, and typically make other mistakes to go along with it due to lack of understanding how it works.

 

No. I've never encountered that in my 22 years of wrenching. I think I understand valve train geometry fairly well, but I do not pretend to know it all by any stretch of the imagination. Cam grinders I know will tell you that they are still learning, and I doubt many people have their level of knowledge concerning valve train geometry. I don't discount your knowledge, quite the opposite, I respect it a great deal. It's your way of responding with snide, condescending remarks that I don't respect. Perhaps you are just having a bad day. If so, go get a beer and let's discuss this further.

 

Well, I'm glad you responded; it's too bad you feel the need to resort to personal attacks. A sure sign of someone who isn't sure of himself (or herself?) I think you completely missed the point.

Let's do a little experiment. Take your marker analogy (a good one by the way), and push on the end of it with the point of a nail or something, and put a scale to the side of it. Push very carefully EXACTLY PARALLEL to the axis of the marker; that is, perfectly in line with the body of it. Measure the side load produced by moving the point of the nail as far toward the edge of the end as you can. Then repeat the experiment, except instead of pushing straight along the marker's axis, push it in some off-axis direction; measure the angle, and measure the force produced at various angles. I think you'll embarrass yourself after that outburst you let loose.

Whatever effect applying the force to the valve stem off-center might have, it is tiny tiny tiny compared to the force produced by the rocker not moving in the same line as the valve. Imagine if you will, just do the obvious mental exercise here, what would happen if the rocker arm had, say, a 1" arm between the pivot point and the push rod seat; and the push rod was ½" too short. As you can no doubt easily imagine, as the push rod began moving the rocker, the tip of the rocker would be moving at about a 45° angle across the valve stem tip, which would produce a HUGE side load; it would make no difference whatsoever that the tip happened to land in the center of the valve at that moment.

At a guess, I'd suspect that the amount of side loading produced in any given valve train from the rocker tip contact point being off-center on the valve stem, compared to the amount produced by the rocker not pushing straight along the line of valve travel, is less than 5%. So yeah, you're right, there's potentially some force there; it's just totally swamped by the REAL ISSUE, which is the force produced by pushing on the valve in some direction other than straight into the guide.

There definitely IS an optimum geometry for the rocker system; that geometry is the one which produces the lowest side load (i.e. the one that pushes as nearly as possible in a straght line, along the line that the valves moves). That's what you adjust the push rod length to do: is to roughly center the rocker's arc on the valve travel. In fact, one of the tools you can buy from one of the otehr manufacturers of such things (Manley) consists of nothing but a little plastic thing you slip over the stud, that is perpendicular to the valve guide; according to that mfr, you just put it over the stud, slide it down until it touches the valve stem, and that's the length push rod you need.

Yes I've read those references you posted; in fact I became rather familiar with the Comp one back when I lived in Memphis and provided Comp with contract engineering services. Made possible in part by having had a math and physics major in college (although admittedly back in the slide rule days, not long after the Civil War). Notice how the Lunati one, with the marker, talks about the pattern being NARROW, which in fact is the only thing the end user can even control about the pattern. You can't change where it's centered, except by buying some other kind of rockers. That's a function of the distance between the stud and the valve guide in the casting, and the length of the rocker. And, like I mentioned, some rockers are deliberately made a little longer than that, because it's easier to increase the ratio by lengthening that arm a little, as well as shortening the push rod end of it. NARROW is the operative concept here, which corresponds to minimum side-to-side motion of the rocker tip across the valve stem, which occurs when the push rod length centers the rocker's arc on the valve's travel. As I said, I personally prefer to approximate push rod length on the short side of that ideal, because that puts the rocker's maximum side travel at the point in the valve's travel when there's the least spring force on everything; which is of course when the valve is near the seat.

Believe what you like, and interpret what you read how you like, and be as proud as you like of your "22 years of wrenching"; but you evidently have quite a few years less experience at this than some of us, in fact we might even consider you a beginner; and alot less education and real learning as well, and even at that don't fully understand what you read. But I'll take you up on your invitation to have a beer, most any time. Just remember though, I'm not the least bit interested in "comparing" myself or my qualifications with yours though; even though I have no doubt whatsoever, in fact virtually 100% confidence, in how that would turn out. That by itself doesn't make someone right. Reality speaks for itself.

 

All I know is that every head I ever pulled apart had the guide worn in the direction of the rocker travel. Replace the guides and run a roller for cryin' out loud.
I mean the self aligning rollers flop all over the valve tip and they came from the factory.

 

I wasn't attacking you, just responding to what I interpreted as your utter dismissal of what I posted as nonsense. I guess that's where the internet will never replace face to face discussion. I also never questioned your knowledge OR experience, In fact I've read hundreds of great posts by you and learned a good deal from your posts. Being treated like a bench racing idiot by someone I don't know just rubs me the wrong way, as I'm sure it does you by your replies on TGO. Like I said earlier though, you can't "read" someone's voice. Your reply is interesting and does raise excellent points, however I still say that off axis force can't be ignored and accounts for most guide wear. Valve events aren't slow or careful, they are violent at high RPM, so I don't discount the side loading. You lose me on the point of not being able to move the contact area. longer pushrods move the rocker up the stud plane, putting the contact point at the tip closer to the inside of the valve stem. Shorter rods move it out. (I'm talking average through the cycle) What am I missing in this picture that would keep it from changing? Picturing a triangle with a fulcrum moving up one side the point of intersection on the other side, so to speak, to reach the same point moves. BTW, I'll buy the beer, but yougotta bring a pizza.

 

Hey Hey guys, we all play for the same team here lol... Ok but from what I have read a tried to understand you both are saying that regardless of ratio the is a side load that will wear out your guides no matter wut just over a long time?? Also that the switch to 1.6 would require special pushrods to do it right or the wear would be minimal and I shouldn't worry?? If it makes a difference I was going to get the stock replacment LT4 roller rockers from scoggin-dickys... Thanks guys and if you come figure this all out of my car i'll buy the beer and the pizza lol...

 

If the push rod length is correct now, then changing the ratio, by itself, doesn't create a need to change. But it's always a good idea to check your push rod length by way of the contact pattern on the tip of the valve stem whenever making a valve train change.

I don't know what would be meant by "special" push rods; you might need non-stock, or different from what's there, maybe, but not "special" really. Probably not though, IF the ones that are there now, were properly selected when they were installed.

 

Everything is just stock now. stock length pushrods, stock cast heads, stock rockers and all

 

my head hurts after reading this

 

I know that the LS1 engine runs a non-roller tip rocker with a 1.7:1 ratio, so maybe it's not the ratio that is causing the wear problem?

 

The side loading of the valve stem imparted by the rocker is relatively small in even a stock installation. When a roller tip is installed, regardless of the contact point on the tip, the side loading is infinitessimally small. Any guide wear could likely be attributed to previous wear that wasn't repaired during the head reconditioning, or poor stem lubrication.

Since the bearings are apparently indicating lubrication failures, that may bolster their argument. Unless you can disassemble the rotating assembly and check all the clearances, it will be nearly impossible to prove an improper assembly during the rebuild.

However, even as bad as Castrol might be, bearing failures at 2,000 miles should not occur. There is either a lubrication failure, assembly problem, improper break-in, or outright abuse. That lubrication qestion includes the orientation of the bearings, preparation of the crank and case, selection and installation of the oil pump and pickup, installation of the gallery plugs, selection of lubricant and filter, and maintenance of the lubricant and filter.

Good luck.

RB - All your years dealing with Comp must have been wasted. What? Did you just hang out at the water cooler the whole time?