Lifters and Push rods question...
12-24-2013, 04:29 PM
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Lifters and Push rods question... Shoot me now if you want for asking such a newb question, but I'm really doing this whole build as a 'self-taught' thing. I've never messed with engine internals, so outside of what I can find on here, I'm clueless.
Building up a 5.3, I know I should replace the lifters and push rods because I'm swapping the cam and heads... but I haven't the SLIGHTEST clue how to figure out what size push rods I'll need, or what type of lifters... Hydraulic, roller, mechanical?
also, when it comes to rockers, what's the difference between 1.7/1.8 ??? What's that number even mean!? lol, yeah, total blindness here...
Engine is a 5.3 LM7 out of an 02 Silverado
Cam is a Bullet Racing 225/232 .581 114LSA if that helps or is needed...
Building up a 5.3, I know I should replace the lifters and push rods because I'm swapping the cam and heads... but I haven't the SLIGHTEST clue how to figure out what size push rods I'll need, or what type of lifters... Hydraulic, roller, mechanical?
also, when it comes to rockers, what's the difference between 1.7/1.8 ??? What's that number even mean!? lol, yeah, total blindness here...
Engine is a 5.3 LM7 out of an 02 Silverado
Cam is a Bullet Racing 225/232 .581 114LSA if that helps or is needed...
12-24-2013, 05:20 PM
#2
Ok first things first.. Pick a lifter any lifter, albeit ls7 or a morel either will suffice as long as they're hydraulic... I run GM stuff..
To measure pushrods Get a comp cam pushrod length checker, it's essentially a adjustable pushrod, use that to measure your desired length..which I go zero lash +.045 I use a caliper to measure the actual length of the checker as I've never had good luck measuring by turns..
The 1.7/1.8 is a rocker ratio, stock is 1.7.. 1.8 will give you more lift.. Make sure you have room for the extra lift in your springs, and piston to valve clearance, I'd suggest leaVing it alone...
To measure pushrods Get a comp cam pushrod length checker, it's essentially a adjustable pushrod, use that to measure your desired length..which I go zero lash +.045 I use a caliper to measure the actual length of the checker as I've never had good luck measuring by turns..
The 1.7/1.8 is a rocker ratio, stock is 1.7.. 1.8 will give you more lift.. Make sure you have room for the extra lift in your springs, and piston to valve clearance, I'd suggest leaVing it alone...
12-24-2013, 06:17 PM
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To measure pushrods Get a comp cam pushrod length checker, it's essentially a adjustable pushrod, use that to measure your desired length..which I go zero lash +.045 I use a caliper to measure the actual length of the checker as I've never had good luck measuring by turns..
The 1.7/1.8 is a rocker ratio, stock is 1.7.. 1.8 will give you more lift.. Make sure you have room for the extra lift in your springs, and piston to valve clearance, I'd suggest leaVing it alone...
12-25-2013, 12:42 PM
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The 1.7 1.8 ratio is how much the cam lift gets multiplied by by the rocker. The can might only have let's say .320 lift on the actual can lobe, but then you multiply that lift by the rocker ratio and that's your actual lift at the valve.
12-25-2013, 05:54 PM
#6
yes....
I'm also going to suggest you stay away from an LS7 lifter..they are Junk in my opinion, and they are also a shorter maximum travel than the other GM lifters.
buy yourself a Comp Lifter or a Morel Lifter....the Morels will be quite a bit better than the Comp Lifters, but they are also quite a bit more money and you may not need that level of lifter for your application.
zero Lash is basically the point at which you have no slack inbetween the lifter/pushrod/rocker...
generally, it means the pushrod is the exact length to reach between your lifter and rocker with No preload on the lifter yet
to find it, you take and adjustable pushrod, and spin the top portion of it until it just barely touches the rocker and you feel a very slight tension and it can no longer spin freely...
at that point, you take your rocker off, pull the pushrod out, and measure...
you add your desired preload to that vale and order pushrods to that total length(or order something very close that will bee close enough to your desired preload
all pushrod companies will cut you a custom length pushrod if desired, but most sell precut lengths that are close enough for 95% of applications (yours included)
the process is just a little different with an adjustable rocker, but its basically the same.
if you have an aftermarket cam, the manufacturer will tell you if you can use the the 1.8 rockers or not.
what you need to know, is the 1.8 is a more aggressive profile, combined with a cam with an aggressive profile...which means you will have shorter spring and lifter life and potentially can have other issues as well with the cam lobes and valve guides.
most people should NOT use a 1.8 rocker with an aftermarket cam unless your cam was designed for it...obviously there are exceptions to the case, but I would highly suggest you stick with a 1.7 rocker since you are fairly new to all of this
I'm also going to suggest you stay away from an LS7 lifter..they are Junk in my opinion, and they are also a shorter maximum travel than the other GM lifters.
buy yourself a Comp Lifter or a Morel Lifter....the Morels will be quite a bit better than the Comp Lifters, but they are also quite a bit more money and you may not need that level of lifter for your application.
zero Lash is basically the point at which you have no slack inbetween the lifter/pushrod/rocker...
generally, it means the pushrod is the exact length to reach between your lifter and rocker with No preload on the lifter yet
to find it, you take and adjustable pushrod, and spin the top portion of it until it just barely touches the rocker and you feel a very slight tension and it can no longer spin freely...
at that point, you take your rocker off, pull the pushrod out, and measure...
you add your desired preload to that vale and order pushrods to that total length(or order something very close that will bee close enough to your desired preload
all pushrod companies will cut you a custom length pushrod if desired, but most sell precut lengths that are close enough for 95% of applications (yours included)
the process is just a little different with an adjustable rocker, but its basically the same.
what you need to know, is the 1.8 is a more aggressive profile, combined with a cam with an aggressive profile...which means you will have shorter spring and lifter life and potentially can have other issues as well with the cam lobes and valve guides.
most people should NOT use a 1.8 rocker with an aftermarket cam unless your cam was designed for it...obviously there are exceptions to the case, but I would highly suggest you stick with a 1.7 rocker since you are fairly new to all of this
Last edited by soundengineer; 12-25-2013 at 05:59 PM.
12-25-2013, 08:38 PM
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yes....
I'm also going to suggest you stay away from an LS7 lifter..they are Junk in my opinion, and they are also a shorter maximum travel than the other GM lifters.
buy yourself a Comp Lifter or a Morel Lifter....the Morels will be quite a bit better than the Comp Lifters, but they are also quite a bit more money and you may not need that level of lifter for your application.
zero Lash is basically the point at which you have no slack inbetween the lifter/pushrod/rocker...
generally, it means the pushrod is the exact length to reach between your lifter and rocker with No preload on the lifter yet
to find it, you take and adjustable pushrod, and spin the top portion of it until it just barely touches the rocker and you feel a very slight tension and it can no longer spin freely...
at that point, you take your rocker off, pull the pushrod out, and measure...
you add your desired preload to that vale and order pushrods to that total length(or order something very close that will bee close enough to your desired preload
all pushrod companies will cut you a custom length pushrod if desired, but most sell precut lengths that are close enough for 95% of applications (yours included)
the process is just a little different with an adjustable rocker, but its basically the same.
if you have an aftermarket cam, the manufacturer will tell you if you can use the the 1.8 rockers or not.
what you need to know, is the 1.8 is a more aggressive profile, combined with a cam with an aggressive profile...which means you will have shorter spring and lifter life and potentially can have other issues as well with the cam lobes and valve guides.
most people should NOT use a 1.8 rocker with an aftermarket cam unless your cam was designed for it...obviously there are exceptions to the case, but I would highly suggest you stick with a 1.7 rocker since you are fairly new to all of this
I'm also going to suggest you stay away from an LS7 lifter..they are Junk in my opinion, and they are also a shorter maximum travel than the other GM lifters.
buy yourself a Comp Lifter or a Morel Lifter....the Morels will be quite a bit better than the Comp Lifters, but they are also quite a bit more money and you may not need that level of lifter for your application.
zero Lash is basically the point at which you have no slack inbetween the lifter/pushrod/rocker...
generally, it means the pushrod is the exact length to reach between your lifter and rocker with No preload on the lifter yet
to find it, you take and adjustable pushrod, and spin the top portion of it until it just barely touches the rocker and you feel a very slight tension and it can no longer spin freely...
at that point, you take your rocker off, pull the pushrod out, and measure...
you add your desired preload to that vale and order pushrods to that total length(or order something very close that will bee close enough to your desired preload
all pushrod companies will cut you a custom length pushrod if desired, but most sell precut lengths that are close enough for 95% of applications (yours included)
the process is just a little different with an adjustable rocker, but its basically the same.
if you have an aftermarket cam, the manufacturer will tell you if you can use the the 1.8 rockers or not.
what you need to know, is the 1.8 is a more aggressive profile, combined with a cam with an aggressive profile...which means you will have shorter spring and lifter life and potentially can have other issues as well with the cam lobes and valve guides.
most people should NOT use a 1.8 rocker with an aftermarket cam unless your cam was designed for it...obviously there are exceptions to the case, but I would highly suggest you stick with a 1.7 rocker since you are fairly new to all of this
Thanks again. If anyone else has 2 cents to throw in, that'd be great too!
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12-26-2013, 11:01 AM
#10
12-26-2013, 02:00 PM
#11
a 5/16 .120 wall thickness would be better
11/32 is even better and will fit with the stock heads...
3/8 gets better yet, but you would have to have the heads machined for them
I highly suggest ordering your pushrods from Manton...
if you call them, they will talk with you and discuss options with you and explain why certain things are better than others for your setup.
12-26-2013, 09:10 PM
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its spelled "Chrome Moly"...LOL
a 5/16 .120 wall thickness would be better
11/32 is even better and will fit with the stock heads...
3/8 gets better yet, but you would have to have the heads machined for them
I highly suggest ordering your pushrods from Manton...
if you call them, they will talk with you and discuss options with you and explain why certain things are better than others for your setup.
a 5/16 .120 wall thickness would be better
11/32 is even better and will fit with the stock heads...
3/8 gets better yet, but you would have to have the heads machined for them
I highly suggest ordering your pushrods from Manton...
if you call them, they will talk with you and discuss options with you and explain why certain things are better than others for your setup.
12-26-2013, 10:29 PM
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Along with spending some time on this site i would suggest buying a book on rebuilding ls1 engines. I bought How to build and modify GM ls series engines by Joseph Potak and it has helped me tremendously