Hi guys,

I'm in the process of installing my 1.6 Roller Rockers on my 94 LT1.
I tackled the passenger side last night since it looked like there was a bit more room to work. I've thus far replaced the valve seals, installed LT4 springs and the new 1.6 RR (lash has not been set). It wasn't difficult at all so far. The RR are the Summit house brand. I've read they are made by scorpion but I have no proof of that. They are blue anodized aluminum with a '1.6' stamped on. The LT4 springs look to be smaller diameter wire than the LT1 springs...I'm almost fearing I was sent the wrong springs, though it makes sense that the smaller wire has more room to compress before binding. I have p/n from the box at home and I'll list that later. The springs have a painted green stripe. I believe LT4 springs are supposed to be made of 'egg shape' wire. I couldn't really tell by eye. I ended up using compressed air fed through the spark plug holes to maintain cylinder pressure and keep the valves from dropping. I went with a cheapo valve spring compressor from the parts store - the kind that you turn the **** - it hasn't been a problem and its working well. I had left the car in 1st gear and the parking break was not set. I have to say I was shocked to see the car lurch a few inches forward when I pressurized a cylinder with only 90 psi!

When I quit for the night I simply put the valve cover back on to protect the top end from dust/dirt. It was difficult to get it over the rockers. The cover is seated against the mating surface of the head but it is definetly touching the rockers. I've read that some people have had to remove material from the valve cover in order to clear roller rockers. My question, is the part of the valve cover that is intefering with the roller rockers the 'cross' braces? I've read about 'drip tabs' but I'm not sure what is being referred to. The valve covers feel like some kind of composite plastic - what is the best method to trim these pieces back? I don't want to risk cracking it with snips of some kind but using a cutoff wheel is going to make a huge mess.

I also included the phrase 'setting lash' in the subject title. I'm not at that point yet and I am going to read more before asking questions on it. When the time comes I will add to this thread rather than begin a new one. I know the procedure in my FSM for setting lash will not hold true for the roller rockers. This set uses polylocks. I plan on resuming work tomorrow and will take it a few hours at a time over the next week or so to get it done.

Have a few pics of the progress, will post later. Thanks for reading!

 

If you have composite valve covers ...look at the inside and you should see 8 tabs....cut them off .....and you should have your valve cover clearance..
once I used a dremel...another time I snapped them off

As for setting lifter preload..you will be starting a Cat fight...since there are a couple of ways to do this and some folks are fanatical about the superiority of their method..


IMO google EOIC (exhaust opening intake closing) .....and you will find plenty of magazine articles on setting preload....and lash



Mike

 

Golen Engines has photos of which areas need to be removed on certain year covers. I say "certain year covers" because my son's 96 LT1 covers didn't require any mod at all when I installed his Scorpion RRs last summer.

I posted a detailed STICKY on LS1LT1.com on the LT1 Engine Tech board on how I recommend lifter preload be set; it's the EO/IC method as previously mentioned. I wrote in with "first-timers" in mind in an effort to make the procedure more understandable.

There are others to choose from on the internet, so just read them and choose which one you like best. The EO/IC method is, by far, the least prone to errors. The three main methods are with engine idling; piston at TDC and EO/IC.

Jake

My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!

 

Thanks for the feedback. The new valve seals, springs and roller rockers are all installed.

Jake, I adjusted the roller rockers based on the EO/IC method, after zero lash I added 3/4 turn preload. The motor runs but where once there was silence now there is some clatter. I know roller rockers make more noise than the stamped steel units but I don't know how much more since this is the first set I've dealt with. So I'm not sure if my lash/preload is incorrect or if what I am hearing is just the extra noise associated with the roller rockers.

Here is a video. There is a definite tapping which I think may be one or more mis-adjusted rockers.

ignore the slight smoke, it is a bit of oil burning off the headers.

found another video on youtube of what appears to be the same rockers I have in a Camaro and they are running far more silenty: http://www.youtube.com/watch?v=JzPTU_eP348

I'm thinking of trying to adjust while the motor is running. With the motor running I believe the procedure is to back the nut off until the rocker taps, then tighten it until the tapping stops. At this point am I at zero lash and still need to add my preload, or is the preload accounted for with this method?

Thanks for looking!


(here they are)

 

That sounds like the "old school" method of adjusting them all right. I'd ad another 1/8 turn or so after the clatter stops. Make sure the engine is at normal operating temp. Yes, that takes care of the pre-load as well.

 

Thanks, I'm going to give the engine running method a try in the next few days - looks like all I need is a piece of cardboard to keep oil from going all over the place.

 

I adjusted the rockers with the motor running and she is nice and quiet now. I had a brain-fart and forgot to plug in the electric waterpump while doing so and got the water temp up to around 250* before I realized my error. Seems okay though, no smoking out the tail and running ok.

Once buttoned up I took it for a spin. I'm not sure if there is any real seat of the pants gain in power but it did accomplish what I was looking to do - and that is be able rev close to 6k without the power plummeting. I can probably attribute the increased rev capability to the LT4 springs more than anything else buy I'm sure the increased rocker ratio and reduced friction do their part as well. Seems to rev smoother too, but that might be in my head.

Good mod for the time/money.

 

The power gain is mainly in the mid-range up so it may not register as noticably by your SOP meter.

Jake

My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!