AllCammedUp

I finished up the installation of my Yella Terra's last night, and I wanted to let everyone know what my experiences/observations with the install were.

Observations

1. As everyone knows, the YT's are much sturdier looking than the stock rockers and they definitely feel like they could take more punishment over the long haul. All in all - a good buy from that standpoint.

2. I know everyone's car will vary on turns to preload, etc. I have TEA 5.3L heads (milled ~0.015) and a TR 224 cam running 7.40" p-rods, and all the preload I could get on them before I hit 22 lb/ft was a hair over 1/4 of a turn from 0-lash. Needless to say, if I used the shim, preload would have been barely (if) anything, so I left the shims off.

3. Oil them down good before you fire it up! I dunked mine in oil before I installed them, and then poured a little bit of oil on top of them before I put the valve covers on. Work the rockers back/forth in your hand to make sure oil gets through the shaft the rockers rotate on, and that eveyrthing feels nice and smooth.

4. Check the front and rear of the head for clearance. I noticed that due to the curvature of the head at the front/rear, the 1/2 and 7/8 rocker pairs had the most chance of 'hitting' as the engine rotated. Make sure you turn the engine over by hand a few times w/ the valve covers off, and use a feeler gauge/eyesight/etc. to make sure you don't have clearance issues. The rockers are a tight fit, but they do seem to make it ok.

Observations/Questions

1. When I fired it up, it was loud as hell for like 1.5 seconds, and it then quieted right down. I noticed that the valvetrain had a very subdued 'singer machine' sound to it, so I noted that and let it idle. After 3 or 4 minutes, the valvetrain was damn near where it was w/ the stock rockers on it, but still just a tad bit 'higher strung' sounding. Don't get me wrong - it had quieted down a good bit, even moreso over what it had done after initially firing it up.

Did anyone else have the same experience? For me, however, the YT's seem to be just a tad bit noisier than the stock setup - at least initially speaking.

Letting the car idle and then revving it slowly to about 3K, the rocker 'sound' will fall off as the revs pick up, but return at idle.

Do I just need a bit more engine running time w/ the setup, or do I need shorter/longer p-rods to help increase preload, or what?

Driving impressions

I let the car warm up, and I took it out for a drive. I can't really say I noticed much, if any, difference. Maybe its just in my head, but I felt that I actually noticed a bit of a drop off in performance. I need to get more miles on the car, I do believe, to allow the PCM to adjust to any differences (if there are any) over the stock setup.

As the motor winds up, I swear it has a 'tighter' sound to it than it did. I suspect it's coming from the little bit of sound I hear from the rockers.

All in all, I can't say that I'm neither overly impressed or disappointed. I guess I'm in the middle on this mod so far. Maybe as I put a few more miles on it, I'll see the PCM adjust a bit and my ***-o-meter will think different.

I just wanted to throw this out and see what others thought. I guess I could always go back to the stock rockers to compare.

Thanks!!

verbs

I noticed a slight high rpm increase in power...I likened it to a bit less than the difference between a steel and aluminum flywheel.

I also noticed my drivetrain really didn't get any quiter at first...in fact it was really noisy for a while after they were installed. The noise did seem to subdue a bit, and now I feel that there definately was a decrease in noise, albeit a slight one.

I did weigh these pieces and noted a 30% reduction in weight over the stock rockers. Some of the advantages like spring/valve longevity, valve float reduction, and durability you won't hear or feel. Something to consider.

jmX

The loud noise when you first start it up is 100% normal. If you ever do a head or cam change you'll hear the same thing, its not a big deal. And you dont really need to soak the rockers in oil...they'll get all nicely oiled very soon after the motor starts and they come packed with some lubricant inside them already from what I could tell. The noise you have now is normal.

I also don't think I've ever heard of YT's NOT clearing the head, so I dont even think thats really a concern unless somebody has one freak head casting or something. They are close, but YT made sure they fit and they've sold tons of them so its a non-issue.

The rest of your impressions I agree with. *Slight* decrease in noise, every cars preload is differen, etc

AllCammedUp

Ok verbs, thanks for the confirmation. That makes me feel better. I think I'm ok based on what you say. Mine quieted down a good bit after the drive - almost to the point where they seemed quieter than the stockers. I think I'm good.

Yeah, I did my own heads/cam, and this wasn't outside the norm on the sounds... I was just expecting it to quieten down quicker than it did.

Yeah, I agree. My heads, though, were close. I was almost afraid to start it up, because I could just imagine the rockers 'peeling' themselves off their pedestals once the lip hung on the head or the back slammed into the inner bank of the head. All's well, though.... they are just a tight fit!

Thanks a lot for the replies, guys. Hopefully this discussion will help someone else out if they run into the same questions after they install theirs.

Cal

iTrader: (1)

I doubt if the butt-o-meter is going to detect 8hp, but every little bit counts and all adds up in the end. I ordered YT's mainly for the increased reliability; with the higer load of a bigger cam and stiffer springs I don't want to worry about slinging needle bearings.

verbs

I could barely notice a difference; I could tell the car revs a bit quicker up top. Nothing dramatic or SOTP of course.

AllCammedUp

Well, I can confirm that mine revs quicker now w/ the YT's than it did with the stockers, as well. It's nothing extremely radical or anything, but it is noticeable.