NASTY ZO6

Anyone have experince with these? Just saw them @ the shop my tuner uses for the dyno. Says they are direct replacement bolt ons. May need to use the shim provided...that's it.

They look really nice!

KLLRVET

Hey, that's my motor! LOL

NASTY ZO6

^^^LOL!!!! It's looking good bro. You should be stoked to get it back in!

fperra

I have them on my car. You need tall valve covers or the YT valve cover spacer.

BgBoost1

....MAN that end rocker is awfully close to the cylinder head!!!

From the engines that I have seen, they don't add any HP and just add weight where you do not want it. Besides the bearing failures in some 07 rockers, has anyone seen a Stock LS7 Rocker Fail?

MTIRC6Z

"just add weight where you don't want it"...so how much weight do they add? Have you actually weighed them? Do you know how much the stock rockers weigh? What about where the weight is located? Please let us know the exact facts which have caused you to draw your conclusion, it would be most enlightening and appreciated.

Cheers, Paul

BgBoost1

Paul,

I would be glad to enlighten you, and give you exact rocker weights but I am not here to argue a point and compare rocker weights with anyone. If you took my post as me saying that “I am the LS7 rocker weight expert”, I apologize to you because I am not. I just use information that I see and hear to my advantage and was asking the question if anyone has seen a stock LS7 Rocker Fail?

I will tell you that (from what I have seen and heard) they are heavier at the valve tip which (from what I have seen and heard) is not where you want additional weight on a roller rocker.

If you want to really be truly appreciated and enlightened a simple search will show you this:

http://forums.corvetteforum.com/c6-z...7-rockers.html

Is this thread you will see a member "Weapons Grade Torque" who said he lost HP using them on a DYNO at Lingenfelter (a trusted shop) , and another member "tjwong" who admits that the stock rockers are lighter. Also Hinson Motorsports (who is selling them) admits that they are for "reduced valve train wear" not for HP or Weight.

You can also search on LS1 Tech and ZO6Vette.com and find a few people who are claiming that the YT's have more weight at the tip of the rocker due to the roller. It seems that the same thing is being said about them. But I don't know...again I never claimed to be a rocker weight expert.

You have to ask yourself this question…………….Why doesn’t Katech use them?

http://forums.corvetteforum.com/c6-z...r-the-ls7.html

Also why have I heard Charlie at RPM, and Eric at HKE both say that they don't result in any HP gain on an LS7, but they can reduce friction and wear, but add a little weight to the tip of the rocker?

Cheers!

Michael_D

You don't upgrade to full rollers for HP gains, you do it for longevity / reliability and sometimes, lighter valve train weight when it is needed for high rev apps. The stock rockers are quite good, but a full roller is typically better (largely brand specific). Not sure why folks want to argue over rockers so much. It's just physics....

mirage2991

complete waste of time, the important part of the rocker, the trunion bearing, is already rollerized from the factory...roller tips add virtually nothing...and far as weight...about as worth as having 20acres of FL swamp land....
Unless you go higher ratio, I would spend the money elswhere...

fperra

Wrong. Roller tips reduce side loads on the valve guides, hence, reducing wear.

spra4u

How about valve guide wear from the apparent swipe motion of the factory rocker. Now this is something I have NOT experienced personally, but heard it from a local shop who has worked on a few LS7s.

Michael_D

Roller tips, (if set up correctly with the right geometry) will reduce valve guide side loading due to a smaller contact patch on the valve stem tip as it should (again, if set up correctly) ride in the middle 30% of the stem tip. It has nothing to do with quantifiable power gains. There is also the potential for less friction due to reduced side loading as well, but I personally do not think that argument has much merit considering modern lubricants and metallurgy.

You must be kidding about the weight. Weight is always a factor to consider with valve train components. A lighter rocker means less resistive weight and inertia above the fulcrum point which will require less spring pressure, which is less stress / strain on the valve train. Rocker weight is less important that the spring retainer, but still valid.

Is it a waste of money?? That's up to the individual and what the application is. Sometimes yes, sometimes not. The same argument could be had regarding forged or steel crankshafts. Forged are rarely "needed" at street / strip power levels and will not increase power unless they are lighter in weight and have windage reducing characteristics. But, forged cranks are always a better choice.

Again, this is just simple physics and pointless to argue (unlike the meaning of life or politics). I'm not sure why I bothered to respond at all.

MTIRC6Z

I haven't put the YTs on a gram scale, but I have done so with another brand full roller which a forum sponsor (aka. reputable tuner) had told me was TOO heavy. What I found was this reputable tuner clearly hadn't actually weighed anything and if I shared what my gram scale told me it would be most embarassing to them...probably also to those who go on about how heavy things are without actually weighing them

Anyone know how heavy a stock length (aka. 7.750") pushrod is, and what happens to that weight when you need to shorten the pushrod by .300" for the new full roller??? Now granted the YTs don't require a shorter pushrod, but other full rollers do have that advantage. Further more, when you take the rocker apart you may also find out that the full rollers tend to have a much heavier trunion (ie. weight which has no bearing on valve dynamics).

Point is, there's potentially a lot more going on with a product then simply declaring that it's "too heavy"...maybe someone who actually has the YT full rollers has done that sort of analysis? I'm not here to argue either, I'd just like to get some real data from someone who clearly knows more about this stuff than I do. Besides, when someone says something is "too heavy" wouldn't the best way to defend that position be to "compare weights"?

Cheers, Paul

PS. Bgboost1, you mentioned you'd be glad to enlighten me but then seem to have failed to follow through with actual quantitative data, why is that? Personally I'd appreciate it since I mentioned, I don't actaully have any real data on the YTs and I am curious about them.

mirage2991

hold your horses guys, I was talking about adding hp...
weight? well I paly with BBC, were we have real weight issues...but its cute that most sbc/ls guy think they have "heavy valvetrain parts" and want to replace they oh so heavy parts with lighter one (pun intended 100%)
Side load, yup, again, canted valve set up is were they are of huge help, which we don't have either...but I would supect the offset on the exh rocker (if my memory serves me right) could maybe benefit...

BgBoost1

Paul,

I would be glad to enlighten you, and give you exact rocker weights but I am not here to argue a point and compare rocker weights with anyone. If you took my post as me saying that “I am the LS7 rocker weight expert”, I apologize to you because I am not. I just use information that I see and hear to my advantage and was asking the question if anyone has seen a stock LS7 Rocker Fail?

Again....I am not here to argue and compare rocker weights with anyone. If you want "actual quantitative data" then I suggest that you purchase a set and weigh them, then you have access to all the actual quantitative data you want and will become the expert.

Cheers!

KLLRVET

Many stock rockers have failed

BgBoost1

Besides the bearing failure that seems to have gone away, how many other instances do you know of where the rocker has failed?

Jason at Katech says they have never seen one fail.....

Everett Ogilvie

I believe there was a limited timeframe/duration in which the stock rockers had some issues (some '06 rockers I think), but supposedly none since.

I specifically asked Jason at Katech about the rockers when they built my engine and if we should go with Yella Terras and he basically said they would only build the engine with the stockers, and I think that is all they use.

KLLRVET

The bearing failure is specifically what I was talking about.

sublime1996525

I had them on my 02 H/C Z06 and didn't have any issues with them.