Searched still confused on Pushrod length
Thread Starter
Restricted User
iTrader: (9)
Joined: Sep 2002
Posts: 7,603
Likes: 0
From: Sierra Vista, AZ
Searched still confused on Pushrod length I read this post: https://ls1tech.com/forums/showthrea...d+length+check and many like it. But, maybe its right in front of me and I dont see it. I have a new shortblock, with Morel Hyd Roller Lifters (new), milled -.010" heads, .040" Cometics, and a custom cam (not sure but heard all cams other than factory have smaller base circles). So, I bought the CC Pushrod checker, I have a test spring available. I have the idea of turning the checker and reading its length. I understand the wiping of the valve stem to rocker for correct length. BUT, the issue is I want to use the Morel lifter, however how do I "preload" it? Soak it in oil and manually pump the lifter up or what, since its basically dry. Hate missing the finer steps.
Thanks,
Charlie
Thanks,
Charlie
TECH Resident
Joined: Dec 2004
Posts: 845
Likes: 0
From: K-W, Ontario
I can clear up one question, and that is you don't need to pre-soak the
lifter.
Seems like you're taking all of the proper steps.
I use a feel gauge, or dial to measure pre-load. Do you have either tool?
lifter.
Seems like you're taking all of the proper steps.
I use a feel gauge, or dial to measure pre-load. Do you have either tool?
TECH Resident
Joined: Dec 2004
Posts: 845
Likes: 0
From: K-W, Ontario
The dial is more accurate, but takes more time to set up.
Find zero lash, then setup the dial. Set the valvetrain (adjustable, or non
adjustable?) and observe the depth of the lifter seat on the dial.
Prime the motor. Then check the roller tip on the valve stem tip (turn over
by hand).
Find zero lash, then setup the dial. Set the valvetrain (adjustable, or non
adjustable?) and observe the depth of the lifter seat on the dial.
Prime the motor. Then check the roller tip on the valve stem tip (turn over
by hand).
Thread Starter
Restricted User
iTrader: (9)
Joined: Sep 2002
Posts: 7,603
Likes: 0
From: Sierra Vista, AZ
I wont be able to prime the engine, as its in shortblock form and will be until the new pushrods are in and the swap takes place.
I am using non adjustable. Stock rockers, TR Pushrods, Morel Lifters, Cam by EDC, Heads are PP 5.3L (will be swapping out for AFR or All Pro).
By checking seat depth, I assume you push down on the lifter to see where the seat is while in the open and closed position?
I am using non adjustable. Stock rockers, TR Pushrods, Morel Lifters, Cam by EDC, Heads are PP 5.3L (will be swapping out for AFR or All Pro).
By checking seat depth, I assume you push down on the lifter to see where the seat is while in the open and closed position?
TECH Resident
Joined: Dec 2004
Posts: 845
Likes: 0
From: K-W, Ontario
When you say short block form, do you mean the heads are currently off?
What I mean by seat depth is the value on the dial after the rocker has been
set. The lifter must be on the cam lobe baseline to set pre-load.
What I mean by seat depth is the value on the dial after the rocker has been
set. The lifter must be on the cam lobe baseline to set pre-load.
The way I understand it is after you have it all setup as described by Adrenaline, after you torque the rocker arm bolt down, it will depress the lifter plunger a certain amount and that amount will show up on the dial indicator. That amount needs to fall inline with the preload specs for the lifter you are using and can be adjusted by using different length pushrods. All this seems like a waste of time though if you are swapping the heads anyway. Why not wait to measure until after you get the heads on that you will be using?
Originally Posted by CAT3
I wont be able to prime the engine, as its in shortblock form and will be until the new pushrods are in and the swap takes place.
I am using non adjustable. Stock rockers, TR Pushrods, Morel Lifters, Cam by EDC, Heads are PP 5.3L (will be swapping out for AFR or All Pro).
By checking seat depth, I assume you push down on the lifter to see where the seat is while in the open and closed position?
I am using non adjustable. Stock rockers, TR Pushrods, Morel Lifters, Cam by EDC, Heads are PP 5.3L (will be swapping out for AFR or All Pro).
By checking seat depth, I assume you push down on the lifter to see where the seat is while in the open and closed position?
Trending Topics
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
You are now .024 shorter on a stock LS1 cam add to that the difference in cam circle between yours and a stock one. That will give you the total difference in pushrod length needed Vs stock length.
What is your custom cam base circle difference?? VS stock cam
>.024 shorter would require 7.375 p-rod.
So I would bet that 7. 375>7.40 is what you need. (reasoning by deduction)
Unless you base circle is .050+ less (huge lifts) then 7.425
To help you :
The stock intake lobe has .281" of lift at the cam so if your cam has .xxx lift at the cam, the difference would be (.281-.xxx = Y)
Now take:
(.024 + Y) = Z (the p-rod length difference you need).
Since the increments on Comp Cam p-rods are by .025 get the closest one to Z on the negative side (meaning do not go bigger, but smaller).
The lifters will absorb the minute difference.
Hope this helps.
What is your custom cam base circle difference?? VS stock cam
>.024 shorter would require 7.375 p-rod.
So I would bet that 7. 375>7.40 is what you need. (reasoning by deduction)
Unless you base circle is .050+ less (huge lifts) then 7.425
To help you :
The stock intake lobe has .281" of lift at the cam so if your cam has .xxx lift at the cam, the difference would be (.281-.xxx = Y)
Now take:
(.024 + Y) = Z (the p-rod length difference you need).
Since the increments on Comp Cam p-rods are by .025 get the closest one to Z on the negative side (meaning do not go bigger, but smaller).
The lifters will absorb the minute difference.
Hope this helps.
Last edited by PREDATOR-Z; Jun 18, 2005 at 09:43 AM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
Thread Starter
Restricted User
iTrader: (9)
Joined: Sep 2002
Posts: 7,603
Likes: 0
From: Sierra Vista, AZ
Predator, got the shorter vs. longer. Will see if I can find the base circle.
Adrenaline....I think I know how I am confusing myself, check this:
Lifter has a spring inside it, and relies on the oil inside to stabilize the springs action, bleed down. I am used to using a solid lifter, so I had some crosschat going on in my headpiece...but since I am using a super soft test spring on the valve, I need get the measurement with dial indicator at zero lash. Zero lash being, I adjust the prod out to remove any verticle movement, leaving it so the prod spins feely in the lifter socket when rolled b/w the index finger and thumb! Then take the measurement of how far the dial indicator moves down after torqueing the stock rocker to 22lbs., which will give me the amount of preload, and ensure I am not bottoming out the lifter cup, or not preloading it all.
Next, I need to do the wipe test:
Using a marker, mark the tip of the valve stem, and cycle the cam through a rotation to check for proper alignment. Which will have the wipe in center or valve stem, not rolling off the outside edge (too long) or inside edge (too short) as well as side to side improper alignment.
If the above is correct, cool, if not kick my in the happy sack.
Now, question is using the valve test spring, how is the lifter going to get preloaded, since the lifter spring has more pressure then the valve test spring?
Adrenaline....I think I know how I am confusing myself, check this:
Lifter has a spring inside it, and relies on the oil inside to stabilize the springs action, bleed down. I am used to using a solid lifter, so I had some crosschat going on in my headpiece...but since I am using a super soft test spring on the valve, I need get the measurement with dial indicator at zero lash. Zero lash being, I adjust the prod out to remove any verticle movement, leaving it so the prod spins feely in the lifter socket when rolled b/w the index finger and thumb! Then take the measurement of how far the dial indicator moves down after torqueing the stock rocker to 22lbs., which will give me the amount of preload, and ensure I am not bottoming out the lifter cup, or not preloading it all.
Next, I need to do the wipe test:
Using a marker, mark the tip of the valve stem, and cycle the cam through a rotation to check for proper alignment. Which will have the wipe in center or valve stem, not rolling off the outside edge (too long) or inside edge (too short) as well as side to side improper alignment.
If the above is correct, cool, if not kick my in the happy sack.
Now, question is using the valve test spring, how is the lifter going to get preloaded, since the lifter spring has more pressure then the valve test spring?
TECH Resident
Joined: Dec 2004
Posts: 845
Likes: 0
From: K-W, Ontario
Damn, a solid roller in a street car.
No pre-load for solid cams, it's all lash adjustments and they must be set
hot.
You can get a preset lash using a feeler gauge during cold settings just to get
in the range.
After the motor warms up, and all of the components, heads, block, gaskets
set/expand, redo the lash...but if I recall you're using a non adjustable valve
train.
I'd hate to be the one tuning that motor
No pre-load for solid cams, it's all lash adjustments and they must be set
hot.
You can get a preset lash using a feeler gauge during cold settings just to get
in the range.
After the motor warms up, and all of the components, heads, block, gaskets
set/expand, redo the lash...but if I recall you're using a non adjustable valve
train.
I'd hate to be the one tuning that motor
TECH Addict
Joined: Nov 2001
Posts: 2,003
Likes: 0
From: Live Oak, FL - in the woods where the creatures lurk.
I believe he is saying he is USED to solid lifters and adjustments but is confused about determining prod length for valvetrain with hydraulic lifters.
TECH Resident
Joined: Dec 2004
Posts: 845
Likes: 0
From: K-W, Ontario
Oh sorry, I'm getting lost now!
CAT3, you are correct in your logic then. I'll leave your happy sack alone.
I have never set pre-load on a non-adjustable valvetrain, so I'll bow out.
My guess is that you'll need the valve train components which will be used
in the real world to set the pre-load.
IOW: get rid of this valve test spring and install the "real springs".
CAT3, you are correct in your logic then. I'll leave your happy sack alone.
I have never set pre-load on a non-adjustable valvetrain, so I'll bow out.
My guess is that you'll need the valve train components which will be used
in the real world to set the pre-load.
IOW: get rid of this valve test spring and install the "real springs".
Thread Starter
Restricted User
iTrader: (9)
Joined: Sep 2002
Posts: 7,603
Likes: 0
From: Sierra Vista, AZ
Yes, I used to setup solid rollers, but this one is a Hyd Roller.
So, if I use an actual valve spring, then I am thinking I will have to modify the technique:
1) base line dial indicator (DI) at zero lash.
2) tighten rocker to 22lbs, which will force the lifter cup down, since there is no oil in it to resist the higher valve spring pressure.
3) measure the DI at 22lbs, compare to desired "pre-load"
4) wipe test, and adjust prod length until the wipe is correct and has acceptable "pre-load" on the lifter cup.
Does that make sense, since with a valve test spring, I am sure the lifter cup would not pre-load but rather it would just push the valve open (test spring has too low of a tension)?
So, if I use an actual valve spring, then I am thinking I will have to modify the technique:
1) base line dial indicator (DI) at zero lash.
2) tighten rocker to 22lbs, which will force the lifter cup down, since there is no oil in it to resist the higher valve spring pressure.
3) measure the DI at 22lbs, compare to desired "pre-load"
4) wipe test, and adjust prod length until the wipe is correct and has acceptable "pre-load" on the lifter cup.
Does that make sense, since with a valve test spring, I am sure the lifter cup would not pre-load but rather it would just push the valve open (test spring has too low of a tension)?
You really only need the checker springs for checking you P/V clearence. The amount that the lifter is going to absorb will be minute and shouldn't affect your pushrod decision. For the combo you listed above, I'd use 7.350 pushrods. If you figure the .024" for the base circle, the roughly .010" for the thinner gaskets, and .010" for the milling, your looking at .044" total taken away from the stock height. A 7.350 should get you right close to the stock pre-load, which in my opinion is to high. I would try the the checker on 7.325 and 7.350 and see how the wipe looks. My car with .024" milled heads, .024 smaller base circle, and .045 gaskets was fine with the 7.350's, but I wish I would have used 7.325's for a little less pre-load. You can use the checker springs for checking the number of turns it takes to get to 22 ft/lbs. With the checker spring in place, run the rocker down till the spring starts to move. This should be zero lash. You can then check how many turns from there it take to get to 22ft lbs with your TQ wrench. Don't forget the the theads are finer in these heads and the amount of turns can't be compared to the old school 1/4 or 1/2 past zero.
TECH Resident
Joined: Dec 2004
Posts: 845
Likes: 0
From: K-W, Ontario
1) base line dial indicator (DI) at zero lash.
2) tighten rocker to 22lbs, which will force the lifter cup down, since there is no oil in it to resist the higher valve spring pressure.
3) measure the DI at 22lbs, compare to desired "pre-load"
4) wipe test, and adjust prod length until the wipe is correct and has acceptable "pre-load" on the lifter cup.
Does that make sense, since with a valve test spring, I am sure the lifter cup would not pre-load but rather it would just push the valve open (test spring has too low of a tension)?
2) tighten rocker to 22lbs, which will force the lifter cup down, since there is no oil in it to resist the higher valve spring pressure.
3) measure the DI at 22lbs, compare to desired "pre-load"
4) wipe test, and adjust prod length until the wipe is correct and has acceptable "pre-load" on the lifter cup.
Does that make sense, since with a valve test spring, I am sure the lifter cup would not pre-load but rather it would just push the valve open (test spring has too low of a tension)?
extra time and measure the valve heights, and pushrod lengths, etc.
Doing this will keep a tighter balance on pre-load across all lifters. I'm not
so sure how much difference a few thousandths will make on a daily driver,
but hey...this is the Internet and we have to cover all bases!
Thread Starter
Restricted User
iTrader: (9)
Joined: Sep 2002
Posts: 7,603
Likes: 0
From: Sierra Vista, AZ
Ok, so consensus says to use planned: valvetrain to include springs, and heads w/ gaskets. Then simply adjust prod to zero lash (right before the valve opens, or reduce the prod vertical movement) then torque rocker to 22lbs, wipe test, adjust as necessary then order appropriate length prods?
So theres no real need to use the test springs, or the dial indicator?
I have a friend that can order the prods to specified length from Comp, at no additional charge so thinking I might go that route.
So theres no real need to use the test springs, or the dial indicator?
I have a friend that can order the prods to specified length from Comp, at no additional charge so thinking I might go that route.
TECH Resident
Joined: Dec 2004
Posts: 845
Likes: 0
From: K-W, Ontario
Then simply adjust prod to zero lash (right before the valve opens, or reduce the prod vertical movement)
If you set zero lash anywhere else, you risk placing the lifter on the ramp
of the cam lobe which will totally screw your process.
I would still use the DI, or feelers...something to gauge the pre-load depth.
At least that way, you'll know if you're "in the window" , or not.
I also am doing a cam swap and need two differnt length pushrods (intake/exhuast) I went to my local speed shop and picked up a pushrod length checker (adjustable rod)...
Their machine shop guy told me to "PRE-LOAD" The lifter to .060" then adjust to what length would be correct.. [.060"] seems a bit much and I would like to confirm this??...
PLEASE HELP....
I asked him also about measuren the base-circles and subtracting the difernce and he told me not to chance ordering pushrods based on that method....
HOW MUCH SHOULD I PRE-LOAD LIFTERS?????
Their machine shop guy told me to "PRE-LOAD" The lifter to .060" then adjust to what length would be correct.. [.060"] seems a bit much and I would like to confirm this??...
PLEASE HELP....
I asked him also about measuren the base-circles and subtracting the difernce and he told me not to chance ordering pushrods based on that method....
HOW MUCH SHOULD I PRE-LOAD LIFTERS?????
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
I asked him also about measuren the base-circles and subtracting the difernce and he told me not to chance ordering pushrods based on that method....