I'm currently in the process of installing some roller rockers on my 99. I've got everything else done, and I'm ready to put the rockers on and set them up for zero lash.

What is the best way to turn the engine over one cylinder at a time to set up the zero lash? On my LT1 I just used a rachet on the crank bolt, but it doesn't look like I can get to it on the vette.

What meathod do you guys recommend to turn the engine? I'm thinking about just using the starter and hoping that I don't turn the engine over to far.

Any recommendations? Thanks.

 

 

Remote starter is how they showed me to do it up at the vette doctors. If you google or even search on here you can find info on how to build yourself one, or there are some good ready made ones.

If you need instructions on how to do it, you have several options:

1) wait for someone here to chime in with more specifics
2) go to your local trusted mechanic (any, corvette experience not really necessary, except to know firing order), pay him to do it once and show you how.
3) Call comp cams help line, they always help, don't think they ever even asked me if I was using their product.

The one thing I never got straight was, and this may vary depending on setup, is whether the lifters should be pre-loaded (with oil) or not. I originally did my lash while I was buttoning up the heads and cam, turning the crank bolt, but it ran fairly rough after. Had Dennis adjust them for me, the lifters now being preloaded and shazaam, smooth runner.

Not an expert, hope that helps... Good Luck!

 

Below is a "how to" that is posted on LS1Tec.
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Checking Lifter Preload (non-adjustable rocker arms)
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1. Turning the engine, bring one of the cylinders to TDC on the compression stroke. Both valves will now be fully closed on that cyl.

2. Now, fully loosen one of the rocker arm bolts on that cyl.

3. Then start turning the rocker arm bolt down until the lifter is at "zero lash". You will be able to tell it is at zero lash when the rocker bolt gets very hard to turn. It gets hard to turn because the valve spring starts to compress. Again, stop turning the bolt as soon as you feel resistance to turning. You can also spin the pushrod with your fingers while turning down the bolt. You will feel resistance to spinning when you are at zero lash.

4. Then mark the bolt with a marker.

5. Now count how many turns it takes to completely tighten the rocker bolt to 22 FT/LB.

The bolt should have turned between 1 3/4 to 2 turns for the acceptable GM lifter peload. This is how much preload a bone stock LS1 will have.


NOTE: You really only need to do this on one cylinder. The rest will be the same.

NOTE: If you have aftermarket Comp Cams “Type R” lifters, I understand that those like less preload than stock lifters. Instead of 1 3/4 to 2 full turns as indicated above, about 3/4 to 1 turn may be more acceptable.
Yella Terra rockers may also use less preload too. Just remember, no matter what hyd lifters or rocker arms that you have, you must have [some] preload.

NOTE: Allways run the engine prior to checking the preload so as to get the lifters pumped up. This is important if you just installed new lifters or had the old ones out while installing a new cam.
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I'm using the Crane Cams quick lift rockers, they are adjustable so I can't just torque them down. (I wish I could!)

Has anyone used the starter method and just turned the key super quick?

I would like to just turn the crank pulley, but I don't know if there's any room to get in there. Anyone done this? I might have to try jacking the car up a bit and seeing if I can get in there.

 

This would be so much easier if it was an fbody.

 

FYI if you get the right kind of angled wrench you can turn the motor over w/ the PS rack in place.

I have yella terras... I did it when installing my cam so I had everything out. Followed their instructions and the ones on ls1howto.com. I didn't need to run a shim.

 

I made a wrench with 1/8" flat bar and a sliced off socket welded to it. You can sneak it into place and turn the motor over with the rack in place. Careful finding zero lash, that is where a lot of guys make a mistake. Pick up the roller tip gently until the "tick" "tick" just disappears as you gently between the thumb and fore-finger turn down the adjusting nut.

 

I was just checking out the situation. A ratchet wont fit, and regular box end wrench wont fit either because the crank pulley sticks out to far. I'm heading out the door right now to go to sears! I figured I could get one of those extreme angled wrenches and it would fit between the crank pulley and the ps rack just fine. Hopefully this works.

 

New wrench worked great. I finished setting the rockers to zero lash, and now I'm in the process of setting up the lifter preloads. Should have her running by later this evening.

 

Tighten the tensioner and turn the Alt nut. I forget what size it is but it will work fine. Remove spark plugs for a easier time(one person). If you leave the plugs in your friend will have to hold the tensioner tight and drink as many beers as he can with his other hand.

Randy

 

Does the friend need to do this at the same time?

 

Ok, so the directions for the rockers say go to zero lash, and then go another 1 1/2 - 2 turns for the preload.

I just went to 1 turn, and I don't think I can go any farther. It looks like the rockers are touching the guideplates!?!?

Everything I've found says I need 1 1/2 - 2 turns for preload. One guy told me to go 1/2 a turn past zero lash.

Anyone know how these things are really supposed to be? I'm tempted to just go 1/2 past zero lash.

Please help! I need to drive this thing to work in the morning. Thanks.

 

I just took another look, and one of the springs looks like it's coil bound! LPE said the cam is 308 lift or .525 with 1.7 rockers, so with the 1.8 rockers, I should be looking at about .562. I'm using comp cams 918 springs which are supposed to be good for .600 lift.

When I was setting up my zero lash, I bet I turned the motor over 10 full turns tightening the nuts finger tight each time trying to make sure that they were just tight enough that the rockers didn't have slack before touching the valves.

Is it possible that I went way past zero lash and that's why I can't set up my lifter preload and why I'm coil binding? Please help. Thanks.

 

Just for clarification for everyone, I'm using the Crane 1.8 quick lift kit, it came with the pushrods and guide plates, etc.

 

I used a large rubber belt wrench on the crankshaft pulley to turn over the motor by hand. It seemed to work fine.
John

 

1.5 to 2 turns is with the thread for the stock rockers. I have no idea what the pitch is on your aftermarket studs.

Install your old setup and get to work

Randy

 

It looks like I didn't get the zero lash set right. I'm guessing I got them way to tight somehow. I only finger tightened them, and only to the point where the rockers wouldn't leave the valves. Should there be some play?

I can't think of why my springs would be coil bound though, unless the rockers are just that tight.

 

A very important geomety check is the location on the end of the valve stem where the rocker arm contacts. It should be in the center so as not to side-load the valve. Use a felt tip marker to apply a little ink on the end of the rocker arm, bolt it down, and turn the engine over to cylcle the valve. Remove the rocker arm and look at the "wipe" on the end of the valve stem: it should be centerred in the middle. Off to either side and your overall geometry is off. Adjustments can be made by longer/shorter push rods or shimming the rocker arm pedastel. Once one valve is set, they all should do the same thing.

 

Well... I'm pretty sure I've found my problem. I believe I went way past zero lash to start with. I took all the rockers back off and started over. I've already reset them to the correct zero lash. (Suprisingly, it took me about 1/10 as long to do it the right way). I'm currently setting up the preloads, so hopefully she'll be back up and running within a few hours.

Thanks for the help guys. I'll give you an update soon.