When setting the valves
This is a discussion on When setting the valves within the Internal Engine forums, part of the LSx Technical Help Section category; When setting the valves. You set them them to zero then is it a half turn or a full turn ...
04-22-2010, 05:49 PM #1
- Join Date
- Apr 2010
When setting the valves
When setting the valves. You set them them to zero then is it a half turn or a full turn or nothing at all.
04-22-2010, 06:28 PM #2
if your talking about an ls1 engine then i tourqued all of mine down to 20 ft lbs then rotated the motor 360 degrees and checked them all again.
04-22-2010, 06:52 PM #3
Do you have adjustable or non adjustable?? Because your question sounds as if you have adjustable.
Non adjustable just gets torqued and that's it, preload is set by pushrod length.
Adjustable is a bit tricky. I have a crane adjustable setup on my wifes car. A member here informed me that the preload is a bit different on the LS motors as compared to gen 1 sbc or bbc's.
I found that LS1 lifters prefer somewhere in the .080 to .100 preload range. Since the screw in studs on my adjustable valve train have a very fine thread (finer than studs found in most sbc's or bbc's) A simple half turn or full turn wouldn't give the correct amount of preload. So I did this.
Set up dial indicator on back of rocker assembly. Adjust for zero lash and reset dial indicator to "0". Turn adjusting nut until I had between .080-.100 preload while I counted the revolutions I was turning the wrench. To get a baseline so to speak.
I think I found that mine took 1 1/2 turns or 1 3/4 turns. Once I had that figured, I could simply go through the rest of the rockers with the same amount of turns and I was done.
Keep in mind, other brand manufacture assemblies might be slightly different, so I would recommend the dial indicator method on yours as well just to be certain they get the correct preload.
04-22-2010, 07:19 PM #4
- Join Date
- Apr 2007
- 2057 Bugatti
This is the best/easiest method to use for the weekend wrencher....
The EO/IC method. Get all your pushrods in, make sure they're pressed down in the lifter so the lifter is out of the retainers, then run all your rockers down finger tight. As soon as the rocker is tight enough that it won't wiggle, you're right around zero lash. Now spin your cam until your exhaust valve starts to open, at this point your intake lifter will be on the base circle of the cam and you can get an accurate TQ reading. TQ down your rocker but pay attention to the amount of turns needed to achieve 22 ft lbs. 1 1/4 - 2 turns is the acceptable range to achieve proper preload. If you're under 1 1/4 turns, then you need a longer pushrod. If you're over 2 turns, you need a shorter pushrod.
Once the intake valve is TQ'ed, spin your motor until the intake valve opens and then begins to close again. Right when the intake is closing, then your exhaust side will be sitting on the base circle of the cam. You then repeat your procedure I just listed above.
This method isn't going to be exact to the integer like using a dial indicator, but for 99% of the street setups everyone uses it works just fine. I've been building engines for YEARS using this method and never had any problems, and my valvetrains are always quiet.
Last edited by Damian; 04-22-2010 at 07:23 PM.
04-23-2010, 03:39 AM #5
Yep... Stock rockers, just tighten them down to 20 ft lb's...
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