Avengeance

iTrader: (4)

How does the PR look? Maybe a lifter went out? Im trying to figure out the PR would come off alignment and smack the lifter cup on the YT.

TACE02

subscribed. Pretty much same thing happened to me about a month ago. Just got my new setup installed in June and had 800 miles on it, still doing a break in for good measures and in 6th gear around 60-65, tick tick tick. By the time I stopped, it had changed to a thump thump thump...exhaust trying to get out but only having 1 way to travel, through the intake. Here is what I found

#7 exh rocker, which I believe messed up the #7 int manton custom pushrod. Trickflow heads.



Replaced both intake and exhaust pushrods and rockers. Hope no more break!!!

sabastian458

iTrader: (5)

when the tip of the rocker broke away from the rest (not a complete break away) it was still in the path of the pushrod.

3fingas

iTrader: (16)

Moving to a high performance behive is not downgrading in my opinion. Unless you cant because the cam specs exceeds the max lift for the springs. You can set up behives for .650+ lift. You can see the material around the cup is thin. The load on the rocker mostly runs along the top of the rocker and the cup. So eitrher they werent setup right or for some reason the rocker began to fracture. Now you need to find out why if you continue to run them. Guide plates simply stabilize pr and rocker alignment but i wasnt sure you had them or could use them.

Sorry the pics not better, but these have a lot of material around the cup.

sabastian458

iTrader: (5)

how did your bend the pushrod on the rocker that wasnt broken?

sabastian458

iTrader: (5)

Well, I will keep the springs that came with my Trick Flows, as I really have not seen a real reason to spend the extra money to change them out for a single spring rated at the same max lift. If Yella Terra comes back and tells me that I need to, then I will.

sabastian458

iTrader: (5)

Just saw this question. Pushrod is still straight to the eye (not mechanically checked.) The tip that is against the rockers is pitted pretty good, and where the pushrod passes thru the head, there are wear marks from where the pushrod contacted the head when the rocker let go. Other than that it looks fine.

And they pushrods are all marked 7.500 and are TrickFlow brand.

98Z28CobraKiller

iTrader: (17)

I don't think that it caused your problem but to answer your question, the lighter the valvetrain, the more power you make. Ideally you only want just enough spring to keep you from floating the valves. Anything more is stealing power.

sabastian458

iTrader: (5)

Now I know that I dont know everything, but I at least know this. Just be cause it physically looks bigger and beefier, does not mean it is. It all depends are what metal it is made from and the manufacturing process.

Now I am not saying that that rocker is weaker/stronger or anything. Im just saying just because it looks biger, doesnt mean it is.

3fingas

iTrader: (16)

+1. or smackin the seal LOL. I heard their might be a lil 420 party at the track this weds. Weather permitting of curse.

Well these are mikronite'd and cost a few more than the YT's. I dont see these coming apart though I do spin it to 7500 so I'll keep my fingers x'd.

TACE02

excessive build up in the cylinder due to no exit for exhaust??? Something had to give, and my motor is fully built.

TACE02

Well Saturday 29 Aug. 09, I started hearing a nice very loud ticking followed by a subtle boom and lost alot of power while on my way home. Was almost home when it happened. My second rocker... this time #4 intake...a lil over a month ago my #7 exhaust rocker broke and was replaced.

Well got my car home and started to look into what made the noise... not having a clue what it could have been!!! (Sarcasm). took off the valve cover on the passenger side and to my surprise, well not really...

this is what I saw--







So less than 1500 miles in 2 months (since install) I have broken 2 Yella Terra Ultra Lite rockers... Gonna change them all out now, screw it, I want my car to run for more than a month between down times.

sabastian458

iTrader: (5)

that is interesting. such a clean break. I wish mine had broken like that.

What are your cam/spring specs?

Avengeance

iTrader: (4)

Im glad I have the older style with the solid centers. Sorry to see the issues with these on your motors.

TACE02

cam specs are 24X/25X over .600 lift 113+3. Not exactly a baby cam...lol.
Yeah, this issue really sux, cause I had only heard good things about yella terra until now. Not really sure just yet what rockers I am gonna go with yet. Would love some Jesels, but holy **** are they expensive, and unfortunately I spent almost every last penny I had for my current setup... :-(

sabastian458

iTrader: (5)

our issues are with the part that wraps arround the bearings. that seems to be the place of failure.

rsz288

Is Yella Terra coming to the party and getting on top of this? Seems they have a real problem. Maybe the manufacturing has been moved to another country and they are having quality problems.

Quality always great in the past.

LS1ROPER

iTrader: (21)

I really hate to see this happening waited 2 months worth of back order to get YT rockers because I only heard good things about them. With only 375 miles on new 408 I am really nervous now! Have you talked with YT about this?

sabastian458

iTrader: (5)

i actually had an engineer from australia call me last saturday about them. He wanted to make sure i sent the entire set back and not just the broken one. he has been reviewing both threads (here and on ls1gto.com) and said that my install was perfect and that he feels it was something in the metalurgy when the billit blanks were made. He was a really awesome guy to talk to.

sabastian458

iTrader: (5)

the billit blanks are made in the USA and the machining takes place in australia.