tuned55

Hi, about a year ago I had a new Comp cam, lifters,springs, and 1.6 rockers installed on my 98 LS1. It's in my 55 project and I'm about ready to start it for the first time. Comp had sent the wrong push rods so when my buddy brought the engine back from the engine shop (about 350 miles north of here) I called Comp and they sent the correct ones. Now I have to adjust the valves. Just what are the specs and proceedure for doing it?

Thanks in advance


55 Chevy Bel Air C4 IRS & IFS LS1/ T56

bigdsz

iTrader: (1)

For starters I doubt whether you had 1.6 rockers installed when the OEM rockers are 1.7. There is no adjustment for the rocker arms. just torque to 22 lb.ft. How do you know that you have the correct PR length if you haven't checked? Also have you checked the swipe?

tuned55

I'll have to check the boxes I have. Like I said it's been a while. As far as the push rod lenght I called Comp and told what they sent and the sent what I needed. How do I check tfor proper lenght and swipe?

cowboysfan

I gree with bigdsz. you need to make sure all is correct or you could have piston to valve issues. stock rockers are 1.7 . did u replace hyd lifters to solid lifters? and what about them rockers are they adj type? if yes then I recommend to get a pushrod adj so you can get the correct size. if you dont know what I'm saying/talking about have somebody check your piston to valve clearance before you crank it. plus shop that built your motor should have done all this for you. even if they have installed wrong pushrods they should tell you which one u need.. sounds like u need to be more clear on this. not sure why a LS1 would have 1.6 rockers????

tuned55

I'll do some investigating. I have all the boxes and cam specs in my shop. I wish the shop had done the whole install when they had it. I was surprised to see it come back that way but there is more to this story. It's a reputiable shop that's why I went with them. I've done all the work on this car but didn't feel comfortible with the engine mods. I'll get the info I need and get back here.

Thank for the help so far

tuned55

Ok, This is what I had installed

CAM SPECS intake duration Intake Exhaust
Duration @.050 220 242
Lobe Lift .3130 3150
Lobe Seperation 112.0

Gen III/LS1/LS6 1.75:1 Pro-Magnum Rocker Arm Kit with 3/8" Flat guide plates. Kit Includes: 1.75 Pro-Magnum Rocker arms (#1375-16), 3/8 Flat Guide plates for 3/8 pushrods (#4856-8), 3/8 Rocker Studs (#4554-16), 3/8 adjusting nut (#4654-16), and Set screw for 4654 (#465SS-16)

GM Gen III/LS1/LS6 "RPM" Valvetrain Upgrade Kit Includes: (16) #7955 5/16 7.400" Hi-Tech Push-Rod (16) #26918 Hi-Performance GM Gen III/LS1/LS6 Valve Spring (16) # 772 Ti Valve Spring Retainer for use with std locks Recommended for use with a moderate High-Perf Cam.

I have the valve covers off I brought #1 piston up to TDC (exhaust valve opened then closed and piston TDC) Thses ate adjustible rockers. Am I going to adjust by tightening rocker until I feel push rod tight then go 1 1/4 turns?

Any threads on this would be helpful. I looked but didn't find what I am after. Any help would be greatly appriciated.

KCFormula

iTrader: (4)

What lifters are you using? Stock lifters require .050" to .080" preload. Do you have a dial guage?

tuned55

You know I'm not sure on the lifters. This is what we used but it's not showing specs fot the lifters
http://www.compperformancegroupstore...Category_Code=

The reason I bought this set up was because of a dyno result I read. If we need the specs for the lifters I can call Comp tomorrow

Yes I do have a dial indicator and base.

KCFormula

iTrader: (4)

Call them and find out for sure. The COMP OEMs require close to stock preload but if the COMP "R"s only need .010-.020" preload or else they will come apart, common problem on here.

tuned55

Ok I'll give them a call tomorrow. Thanks again

bigdsz

iTrader: (1)

Those are most likely the Comp 850 lifters which are the OEM equivalent. If you are about 1 1/2 turns from zero lash to 22 lb ft on you rocker torque then you're good to go. If you multiply the lobe lift x 1.75 then the cam is a mid .500 lift with virtually no ptv issues.

tuned55

Yep, Called Comp and they are indeed 850-16 lifters. It's been years since I have adjusted valves but I think I can hadle it able a bit of guidence. When I bring up #1 to TDC and I adjusting both intake and ehaust. I was told to get the push rod snug then go 1/2 then lock (I have adjustible rockers). Move 90 degrees and move to #8.

Dose this sound correct?

tuned55

The lifters are 1.75

tuned55

I finally had the time to adjust the lifters. I called Comp Cams last week and told me to take the lash out and go a 1/4 turn. I used Comp's method and turned the motor over with the starter only to find there was no compresson on any of the cylinders. I went back and backed off the rockers to snug, (where I would start with a 1/4 turn) and tried the compresson and all the cylinder are approx. 130lbs. and they stay at that. Should I call this good or whats up?