After hearing the stories about OE rockers that spill their needle bearings, I'm paranoid about any noise that my engine makes that's abnormal, even if it's for a couple of seconds.

A couple of days ago, there seemed to be a bit of valvetrain clatter, and the 'Vette has been parked until this weekend, when I plan to give it a look over. My plan is to first drain the oil, and see if any needle bearings appear.

Should this happen, either new rocker arms, or a rocker arm rebuild will be happening. But, to be honest, I'm a bit confused as to what to do. I've read about installing replacement rockers, but there seems to be a lot of concern about getting the "pre-load" set correctly. I understand the need for this, of course, but did the workers at GM go through all of this when our engines were initially assembled?

There are several detailed explanations both here and "LS1-how to", that detail the task. Although all the procedures are fairly similar, there are some small differences, and each author says the others are incorrect. Who's right?? Is it possible that the machining/assembly tolerances for the LS engines are that loose, that in the field, such jobs as replacing a non-adjustable rocker arm with a similar part requires such a detailed process?

Assuming all that detail is required, here's my question...What rocker arm is the easiest to install and get set-up? My car is a "driver", not a track car, auto-x er, or drag racer. I'm looking strictly to either repair damaged parts, or replace potentially troublesome parts. I'm considering either the Yella-Terra or Harland Sharp rockers, and I really don't need the adjustability or cost of the Crane rocker conversion. I know that H-S can rebuild the stockers, but there's down time involved, and seemingly, for a few bucks more, a full roller rocker can be purchased.

One other thing.....I e-mailed Harland Sharp early yesterday, asking whether their OE rebuild or their full roller rockers would be a better deal. They said either would be OK, but yes, their fully rollerized rocker would free up a few ponies. BUT, I repeat, BUT, they didn't recommend their rockers for a "daily driver".........

Tell me, guys, what do you think?

 

GM is able to get away with a cookie cutter application because they manufacture every engine with strict tolerances not "loose" ones. This makes it repeatable. The difference is that people change or modify heads, cams and other things that make the need for different length pushrods exist in order to achieve the proper preload. Rocker arm geometry is another story. Proper rocker arm geometry must be achieved before the proper pushrod length is determined. Not sure why Harland Sharp didn't recommend their rockers for a DD. I would have asked them and still would. There is only 1 way to do rocker arms properly, but possibly few ways to achieve it. Make sure you know the difference between different techniques to achieve the same goals and different goals. Attention should be paid to what modifications existed to an engine prior to rocker arm failure. Many mods will cause additional load on the needle bearings. Lack of sufficient quality lubricants can contribute to the failure as well. GM designed their rockers for a very long life and I don't consider them a weak point until major mods such as cam and tighter springs are added to the equation. Not sure why you are so paranoid about this. Sounds like possibly a little OCD is running through your veins. The easiest rocker to install is the factory ones. After that, I dunno. I have the Cranes and like them. Stay away from Scorpions. They have great geometry, but break more easily that factory.

 

Based on how you drive the car, you may have three options. HS, Yella Terra or simply new GM. As for setting up the GM rockers, the way I see it there is one correct procedure (not LS1howto), which is GM's (See below). Yella Terra's are nice, but once again LS1howto is wrong and the YT instructions cover all their rockers and are confusing. If you don't want to bother with detailed setup, I would say stick with stock as any aftermarket setup needs to be verified during installation.

 

"Blownblue", I appreciate your comments. The reason for my "paranoia" is because I'm now at the age where I enjoy driving my cars more, and fixing them less. In years gone by, I "modded" just about everything I owned, and while most of what I did worked out reasonably well, other things did not.

As corny as it may sound, one of my neighbors had an "old saying" that went like this..."The more you're under the hood, the more you're under the hood". As much as that saying caused the hair on the back of my neck to bristle, age has caused me to realize that there's more than a grain of truth in that statement.

My 'Vette's engine is stock, has 15,500 miles on it, and has always had Mobil 1 in it. It sees some "high speed cruising" from time to time, but for the most part, has been driven rather conservatively.

Having heard that there have been rocker arm problems reported, I'd rather deal with it sooner rather than later, such as 40 miles from home, out in the country.....

 

I understand your concern, however keep in mind the circumstances of the failures that you are reading about. Those folks were probably "under the hood" beating on their cars with much more aggressive cam profiles and springs.
Since you are not and take reasonable care of your vehicle and only have 15.5kmi on the car, I would advise you to relax and enjoy your car a very long while before worrying about the rockers.

 

That seems very low mileage for a rocker arm to let go. Hopefully its nothing.

 

That's what I'm hoping!



BTW, thanks for your input also. If it turns out to be a bad rocker arm, in terms of ease of replacement, anyway, maybe I would go with the H-S rebuild....But then again, having a roller tip, as well as fulcrum, would be nice.

 

If you go full roller, between the two I would prefer the YT's.

 

the yt's 1.8's needed the .050 shim but if you stay stock with 1.7 verify your wipe pattern.

Preload differences are negligable because of the roller hyd lifters make up a lot of any difference.

If you were using solid lifters with adjustable rockers, it would be a different story.

I like my yt's

 

A shim that is 0.050" will result in a pushrod length change of 0.080", which is quite a bit.

 

Well, I just drained the oil, and then "dragged" the oil pan with a magnet, and nothing came out. I guess that's good, except when I started it up and let it run for a minute, I still heard a little noise, kind of like lifter clatter, at one point.

 

What you might be hearing is carbon build-up rocking the pistons. I had this issue with mine after a ling trip where I spent most of it in 6th gear. Have you considering using some Seafoam to get rid of carbon? Does it clatter when hot?

 

Yeah, it does do that when it's hot. I'll have to consider either the Seafoam, or the "old-fashioned" de-carbonizing method....

 

would that "old fashion" method be ..hold about 2500 rpm and give it a fine spray of water ??...I remember it was alot easier with carberators

 

That IS one of the "old fashioned" methods...The other one, the one I was thinking about, is to go for a ride on the expressway and "lean on it!!"

 

oh yea.....like back in the 60's...
had a few mopars that loved that "treatment"...

 

I used the set from comp cams and I am very happy with them. Also installed springs guide plates and hardened push rods last summer. No issues yet