Novice needs help. lifter install
03-15-2010, 11:53 PM
#1
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Novice needs help. lifter install Heads are off and about to install LS7 lifters. Any tips on some precautionary things to do or remember while doing this? its a stock 98, stock heads, cam. Ive never done this before and dont wanna screw anything up. is it as simple as putting the news ones in the tray, bolting them down and just reinstalling the heads? Any advice is greatly appreciated
03-16-2010, 10:45 AM
#2
Throw the lifters it a bucket of oil and let them soak for a hour or so. Did you get new plastic trays for the lifters? Also before you put the rocker covers back on I like to dump oil all over the rocker arms and down the push rod holes to the lifters. One last thing, Make sure to use compressed air and blow all the coolant out of the head bolt holes in the block before setting the heads back in.
03-16-2010, 12:02 PM
#3
I would get a pushrod length checker, considering that the LS7 lifter is not the same Height as the LS1, Outside they look the same but the LS7 lifter cup is Higher/lower (cant remember which) So I am not sure that the stock pushrods will be the correct length.
03-16-2010, 02:38 PM
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ok great info. Lifters are soaking as we speak but i did not get new lifter trays. Is it essential to replace that as well or just a good idea? i'll make sure its especially clean in the holes and where the new gasket will lay. I did buy a pushrod length checker and from what i understand is i put it in the hole, torque down the rocker and unscrew the checker until it reaches the rocker and has no up and down play. Sound about right?
03-16-2010, 04:08 PM
#5
i would go ahead and get new trays. texas speed shipped them for $25 to my door last year. It's cheap insurance because you don't want those lifters having problems or falling in the hole. Not sure how many miles are on the car but being a 98 i'd imagine they are ready for some fresh ones.
Clean those holes as best as you can. Make sure you torque the heads properly also to get a good tight seal.
As for the pushrod checker never done it so can't help you there. Hope this helps.
Clean those holes as best as you can. Make sure you torque the heads properly also to get a good tight seal.
As for the pushrod checker never done it so can't help you there. Hope this helps.
03-17-2010, 09:28 AM
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It is a good idea to change the lifter trays.. They wear over time and the lifter can twist inside the tray.. It is also very important to get ALL the coolant out of the bolt holes!!!!
If coolant is left in the holes, as you torque the new bolts therer is no where for the liquid to go, And you can Crack the block!!! The other important part is to clean the head surface completely, This will enable the heads to seal better. Good Luck
If coolant is left in the holes, as you torque the new bolts therer is no where for the liquid to go, And you can Crack the block!!! The other important part is to clean the head surface completely, This will enable the heads to seal better. Good Luck
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03-17-2010, 01:02 PM
#8
Keep in mind the LS7 lifters are slightly different in length and I would measure the preload on the rocker when tightening down the rocker bolt. If you are past a turn after zero lash before the bolt gets tight, you probably have to much preload (depending on who's advice you follow on preload. Opinios range from .06 to about .1). Preload is the amount of turning past zero lash. I believe one turn is about .1. I think somebody will chime in if that is wrong.
So what's zero lash? I think this where a lot of people misunderstand the term. It is also a somewhat subjective measurement. It is where the the lifter is just before it starts to compress when tightening down the rocker arm with the pushrod installed. Inside the lifter there is a mechanical spring that keeps the lifter expanded at its full length. Oil enters the lifter during operation and acts as damper with a controlled bleed off while the engine is running. If you presoak your lifters (which is what comp cams directions tells you not to do), it is difficult to feel the mechanical spring. The lifter does not compress until you bleed off the oil. That's where the measurement get subjective. Some people spin the pushrod, others listen for the lifter by pulling down on the pushrod and letting bounce back. Personaly I don't think its that critical and either method will work.
So what's zero lash? I think this where a lot of people misunderstand the term. It is also a somewhat subjective measurement. It is where the the lifter is just before it starts to compress when tightening down the rocker arm with the pushrod installed. Inside the lifter there is a mechanical spring that keeps the lifter expanded at its full length. Oil enters the lifter during operation and acts as damper with a controlled bleed off while the engine is running. If you presoak your lifters (which is what comp cams directions tells you not to do), it is difficult to feel the mechanical spring. The lifter does not compress until you bleed off the oil. That's where the measurement get subjective. Some people spin the pushrod, others listen for the lifter by pulling down on the pushrod and letting bounce back. Personaly I don't think its that critical and either method will work.
03-17-2010, 10:48 PM
#9
Keep in mind the LS7 lifters are slightly different in length and I would measure the preload on the rocker when tightening down the rocker bolt. If you are past a turn after zero lash before the bolt gets tight, you probably have to much preload (depending on who's advice you follow on preload. Opinios range from .06 to about .1). Preload is the amount of turning past zero lash. I believe one turn is about .1. I think somebody will chime in if that is wrong.
So what's zero lash? I think this where a lot of people misunderstand the term. It is also a somewhat subjective measurement. It is where the the lifter is just before it starts to compress when tightening down the rocker arm with the pushrod installed. Inside the lifter there is a mechanical spring that keeps the lifter expanded at its full length. Oil enters the lifter during operation and acts as damper with a controlled bleed off while the engine is running. If you presoak your lifters (which is what comp cams directions tells you not to do), it is difficult to feel the mechanical spring. The lifter does not compress until you bleed off the oil. That's where the measurement get subjective. Some people spin the pushrod, others listen for the lifter by pulling down on the pushrod and letting bounce back. Personaly I don't think its that critical and either method will work.
So what's zero lash? I think this where a lot of people misunderstand the term. It is also a somewhat subjective measurement. It is where the the lifter is just before it starts to compress when tightening down the rocker arm with the pushrod installed. Inside the lifter there is a mechanical spring that keeps the lifter expanded at its full length. Oil enters the lifter during operation and acts as damper with a controlled bleed off while the engine is running. If you presoak your lifters (which is what comp cams directions tells you not to do), it is difficult to feel the mechanical spring. The lifter does not compress until you bleed off the oil. That's where the measurement get subjective. Some people spin the pushrod, others listen for the lifter by pulling down on the pushrod and letting bounce back. Personaly I don't think its that critical and either method will work.
Last edited by chrs1313; 03-18-2010 at 01:00 PM.
03-18-2010, 09:54 AM
#10
03-18-2010, 12:59 PM
#11
I zero lashed my morel lifters then added .030 for preload...and when installed it took just a slight hair over 1/2 a turn...
also thread pitch is 1.25mm or .049"...both seem to add up to me
03-18-2010, 01:45 PM
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One question from me, did you have the heads milled. Not to take off material but at least flattened? They tend to get a little crooked from age and can benefit from a trip to the machine shop. I had my local machine shop mill mine flat and do a complete valve job for $150 out the door. Not a bad price IMO. Also here's some info on checking pushrod length.
FWIW, EVERY cam install I have done using the LS7 lifter with a cam with greater than .600" lift (read smaller base circle) AND stock heads w/GM MLS gaskets has taken 7.425" pushrods for ~.050"-.060" preload. We measure lifter preload on each and every cam install we do. I have never had a lifter failure nor do we end up with the dreaded "sewing machine" noise.
Its very simple, If you change ANY of the following:
valve sizes, valve job, head milling, thinner/thicker head gaskets, decked block, cam with an altered base circle, etc... YOU MUST CHECK FOR PROPER PUSHROD LENGTH.
I have helped countless numbers of individuals with this process over the phone, via email, and PM's. I've posted the process on at least 3 occasions.
Here it is again in a nutshell:
1. Using the EO/IC method, get the lifter to the base circle of the cam.
2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn wtih a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.
For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...
I might not know everything but I will tell you that this method has worked for me year after year cam swap after cam swap. We average 3 cam swaps a week here so you can do the math.
If you are not familiar with the EO/IC method for determining valve events in a 4 stroke engine, its very simple:
For a given cylinder as the Exhaust valve is Opening, the intake lifter will be on the base circle of the cam and lash/preload should be checked for that intake valve.
For a given cylinder as the Intake valve is Closing, the exhaust lifter will be on the base circle of the cam and lash/preload should be checked for that exhaust valve.
THIS METHOD ALWAYS WORKS!!!
I hope this helps someone. I have explained it so many times I think I do it in my sleep!!!
Shane
Its very simple, If you change ANY of the following:
valve sizes, valve job, head milling, thinner/thicker head gaskets, decked block, cam with an altered base circle, etc... YOU MUST CHECK FOR PROPER PUSHROD LENGTH.
I have helped countless numbers of individuals with this process over the phone, via email, and PM's. I've posted the process on at least 3 occasions.
Here it is again in a nutshell:
1. Using the EO/IC method, get the lifter to the base circle of the cam.
2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn wtih a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.
For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...
I might not know everything but I will tell you that this method has worked for me year after year cam swap after cam swap. We average 3 cam swaps a week here so you can do the math.
If you are not familiar with the EO/IC method for determining valve events in a 4 stroke engine, its very simple:
For a given cylinder as the Exhaust valve is Opening, the intake lifter will be on the base circle of the cam and lash/preload should be checked for that intake valve.
For a given cylinder as the Intake valve is Closing, the exhaust lifter will be on the base circle of the cam and lash/preload should be checked for that exhaust valve.
THIS METHOD ALWAYS WORKS!!!
I hope this helps someone. I have explained it so many times I think I do it in my sleep!!!
Shane
03-18-2010, 03:12 PM
#13
That's true, but the rotating point during preload is the rocker on the valve. The travel on the outside of the lever (the movement at the pushrod on the lifter) is going to be greater than the base of the rocker (bolt travel). The distance of the outside of the movement of the arc is going to be greater than the inside of the arc. I'm not sure that paints a clear picture so I'll take some measurements. I wish I had two dial indicators to so this or at least an engine that was magnetic.
03-18-2010, 07:57 PM
#14
That's true, but the rotating point during preload is the rocker on the valve. The travel on the outside of the lever (the movement at the pushrod on the lifter) is going to be greater than the base of the rocker (bolt travel). The distance of the outside of the movement of the arc is going to be greater than the inside of the arc. I'm not sure that paints a clear picture so I'll take some measurements. I wish I had two dial indicators to so this or at least an engine that was magnetic.
03-19-2010, 09:40 PM
#15
That is harder then hell to finally come up with consistent measurement. Too loose and rocker slides all over the place. Too tight and you can push a valve down (if you're not on the base circle), but in the end a half turn is approximately .03 travel on the pushrod end. That stressed me out and I'm going to drink beer now. Guiness anybody?
