Need info on adjusting rocker arms.
#1
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Just replaced all the lifters in my engines. Found 3 retainers that hold the top of the lifters together half way up the push rods. Now I need to get some info on how you guys adjust your rockers, what cylinder banks to do @ TDC and the next @ 180. Do you tighten the rocker down till you see the valve move after it has compressed the the lifter all the way down and then back off a 1/2 turn, 3/4 turn?
I have done this before on allot of SBC's and V6's but that was always with the valve covers off and engine running until the they were quiet, this is not an option on my boat and I would like to get it right the first time, I hate having to tear the exhaust off to remove valve covers.
Hopefully if things go right the engine shop can do them in the next couple of days and I will not have to do them, but Memorial weekend is here and I would like to get out in it.
The engines are 454's, Scorpion roller rockers, 1.7 ratio, hydraulic non-roller lifters.
I have done this before on allot of SBC's and V6's but that was always with the valve covers off and engine running until the they were quiet, this is not an option on my boat and I would like to get it right the first time, I hate having to tear the exhaust off to remove valve covers.
Hopefully if things go right the engine shop can do them in the next couple of days and I will not have to do them, but Memorial weekend is here and I would like to get out in it.
The engines are 454's, Scorpion roller rockers, 1.7 ratio, hydraulic non-roller lifters.
Last edited by Rookie; 05-27-2004 at 07:12 AM.
#4
MarineKinetics
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Rookie,
The reason you pounded out the retainers in your lifters was to little preload.
Setting valve lash accurately requires that each lifter be on the base circle of the camshaft to ensure it's fully closed when you adjust the rocker arm. The foolproof method is to remember "EO/IC", which stands for Exhaust Opening/Intake Closing. Rotate the engine, while observing the exhaust valve. When the exhaust valve just starts to open, stop cranking and adjust the lash on that cylinder's intake valve. Then, rotate the engine again, observing the intake valve of the same cylinder. After it's fully open, and the rocker tip is at the bottom of its travel, crank it over slowly until the valve is about 2/3 closed. Stop and adjust the exhaust valve on that cylinder. Repeat on each of the remaining cylinders.
Bob
The reason you pounded out the retainers in your lifters was to little preload.
Setting valve lash accurately requires that each lifter be on the base circle of the camshaft to ensure it's fully closed when you adjust the rocker arm. The foolproof method is to remember "EO/IC", which stands for Exhaust Opening/Intake Closing. Rotate the engine, while observing the exhaust valve. When the exhaust valve just starts to open, stop cranking and adjust the lash on that cylinder's intake valve. Then, rotate the engine again, observing the intake valve of the same cylinder. After it's fully open, and the rocker tip is at the bottom of its travel, crank it over slowly until the valve is about 2/3 closed. Stop and adjust the exhaust valve on that cylinder. Repeat on each of the remaining cylinders.
Bob
#5
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Bob,
That makes sense. Now when you say adjust what is the point I am looking for? When the pushrod just starts to make conact with the lifter and rocker, or when the lifter is compressed halfway, or when the valve is just startin to open.
Jason
That makes sense. Now when you say adjust what is the point I am looking for? When the pushrod just starts to make conact with the lifter and rocker, or when the lifter is compressed halfway, or when the valve is just startin to open.
Jason
#6
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You tighten them until there is no slack (just makes contact) and then an additional 1/2 turn down. (Zero lash plus a 1/2 turn).
If you are not clear on this, you should enlist the help of a friend that knows what they are doing!
If you are not clear on this, you should enlist the help of a friend that knows what they are doing!
#7
MarineKinetics
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Jason,
Read this very carefully and print out
http://www.cranecams.com/?show=faq&id=3
I agree with Tom, if you have never done this before it would be wise to get someone who has to oversee your effort. It's not difficult, but you can do severe damage if done incorrectly.
Bob
Read this very carefully and print out
http://www.cranecams.com/?show=faq&id=3
I agree with Tom, if you have never done this before it would be wise to get someone who has to oversee your effort. It's not difficult, but you can do severe damage if done incorrectly.
Bob
#8
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I have done this before on smallblock Chevy's I haven't ever had a problem. The only thing is I am now using roller rockers on a big block and I was wondering if there was any difference.
I'm sorry for sounding real ignorant but that is the best way to get the full answer. The guys on this forum really care that you do not hurt your equiptment and help out. But I have seen people with the attitude that they know how to do something half right post a how to queston and then start disagreeing with the helpful input people are trying to give. This in turn upsets some people and the important things to answering the question at hand are skipped. I find that alot when I research the tech. section.
So if I do it like I've been w/ a SBC I should be fine. Also I researched the tech archives, I agree with the do not soak in oil or prime lifters.
Thanks
Jason
I'm sorry for sounding real ignorant but that is the best way to get the full answer. The guys on this forum really care that you do not hurt your equiptment and help out. But I have seen people with the attitude that they know how to do something half right post a how to queston and then start disagreeing with the helpful input people are trying to give. This in turn upsets some people and the important things to answering the question at hand are skipped. I find that alot when I research the tech. section.
So if I do it like I've been w/ a SBC I should be fine. Also I researched the tech archives, I agree with the do not soak in oil or prime lifters.
Thanks
Jason
#9
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Is it Ok to use loc tite on the locking set screws? I ask this because one of the set screws was laying in the valley of my head when I pulled the valve covers off. This in turn allowed my rocker nut to back off and then blowout the lifter retainer, and ruin my rocker stud. The last 3 threads are all that were holding it on. This is why all of the lifters were replaced. (I did not do the work, I bought it like this.)
Ran great last year for 30 hours before lifter started making noises. So I decided to investigate before major damage occured.
Jason
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Jason
#10
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The reason the set screws back off or loosen is because the top of the rocker stud is not flat. When installing roller rockers it is necessary to pull the studs and flatten the top so the set screw has a flat serface to seat on. This can be done with bench grinder using a rest or a belt sander witha rest. Just make sure the surface is flat!
(Not to throw a wrench in the works)
Another thing you need to check for is the proper length push rod. Simply check by rolling over the motor (with valve adjusted) and observing how the roller moves across the top of the valve as it opens and closes the valve. The full open and full close positions should be equal distance from the edge. if it varies slightly, that OK so long as it's not too close to the edge.
Hope this helps!
Jim
(Not to throw a wrench in the works)
Another thing you need to check for is the proper length push rod. Simply check by rolling over the motor (with valve adjusted) and observing how the roller moves across the top of the valve as it opens and closes the valve. The full open and full close positions should be equal distance from the edge. if it varies slightly, that OK so long as it's not too close to the edge.
Hope this helps!
Jim