NArtissimus

Hey,

I've done alot of reading on LS1tech and other sites about checking pushrod length w/ and w/o adjustable rockers. I used the EO/IC method with a Comp pushrod tool, but what maybe throwing my measurement off is that my lifters are not pumped to 'hard'. I'm wondering if my measurements sound right and if the lifters would make that much of a difference to cause a problem

So, my setup consists of 01 LS1, stock 241 heads, Felpro factory replacement gaskets, Comp XER-281HR (232/234-.595/.598), Comp Pro Magnum 1.75 rockers (increase cam to .615/.618), PRC 199-spkit .650 dual valve spring set, & LS7 lifters.

Please I don't want to her about the cam being too big for the heads I'm looking for 243's but I can't wait, and I wanna see what the 241's will do.

My Comp tool produced best results (with a 1/2 turn preload as per Comp) with a 7.350 and 7.400 length. I would have thought with the base circle of the cam being quite a bit smaller than stock the pushrod would have been longer, but again with the LS7 lifters being .050 higher on the cup that would make up for it... I understand with the lifter not being hard, the full lift may not be achieved on the valve stem and the sweep pattern is not as wide, but the starting point should be a pretty good indication. no?

My other choice is to assemble with the stock 7.400's run the motor for a minute to pump the lifters and re-measure for the length. What do you suggest?

The other question I have is why some people call for .010 and some up to .075 of preload, and Comp calls for 1/2 turn in the Pro Magnum instructions? I'd lean towards Comp but I'm not a pro and don't know half as much as some of you have forgot.

Thanks

NArtissimus

No feedback at all from 50+ views?

Adrenaline_Z

All you need to ensure is that the lifter is on the base of the lobe. If
you don't have a degree wheel, then using the EO/IC method properly will do just fine.

You don't need to pump the lifters; that is a myth. The seat will spring up and
rest against the retainer regardless.

When you measure the pushrod length for your type of rockers, you will
adjust for zero lash (yes, lash) with the rocker tip resting on the mid point
of the valve stem.



You will require a solid lifter of equal dimensions as the hydraulic lifter to
measure lift using this method. Alternatively, find a checking spring
to continue with your current setup/ process.

I suggest that is dangerous unless you have checked all clearances and
have a close enough assembly using the current rocker/pushrod/spring.


Preload is misunderstood. You need as little as possible to take up slack
(lash). The more preload you have, the more the performance will suck.

A hydraulic lifter is a self-adjusting mechanism to take up slack in the
valvetrain as parts wear down.

IE: when the lobe wears, the lifter will use the available preload to
compensate for this loss in material.

Less Preload:
The trade off is noisier valve train when cold, and adjustments more
frequently as the valve train wears down. Fortunately for us, roller
valvetrains don't buzz down much over long periods of time and therefore
do not require much maintenance, or adjusting.

If there is not enough pre-load to account for wear, and thermal
expansion you get the 'sewing machine' sound, and possible damage of the
lifter seat on cold starts.


Run as little pre-load necessary to take up the slack with the engine cold.
To set the valves properly, you should reset them hot. Doing this will
prevent the knocking sounds (sewing machine) from improper settings.

If anyone says this procedure is for solid lifters, they are correct...but you
can do the same with hydraulic lifters to get accuracy.

Just remember that you need as little preload as possible for best performance
when all is said and done.

Feel free to quote this post and get a second opinion if you like.

vettenuts

iTrader: (4)

Pushrods on an adjustable rocker set both the wipe and the preload unlike the stock setup. I found the best way to set them up if you don't know what pushrod to use is with check springs and measurements from the top of the stud to the top of the nut. This gives you a repeatable measurement that you can use to determine how high the rocker will sit on the stud. From there you can measure for pushrod length. Unless you have a solid lifter and several pushrods the rotating the motor is not going to give good results.

NArtissimus

Hey,
Thanks for taking the time to reply.

My engine is is assembled and torqued to specs so adding a solid lifter is out of the question. I'll go pick up some checking springs and use them along with the adjustable pushrod. It's on a stand so atleast I'm not leaning over the fender all day.

I'm not worried about the EO/IC method. My bigger concern is the lifters not being fully pumped up, but yes the seats do rest on the retainers and at that point it would be no different if they were solid. Is it as simple as setting zero lash to center of the valve stem for checking the length of the pushrod? Then adding 1/2 turn (as per Comp) or 3/4 turn (as per Horse Power TV) of preload for assembly.

'Vettenuts' do you mean measuring from the top of the polylock to the top of the stud with the set screw removed once the first set is properly preloaded to keep consistency. You don't think there maybe inconsistencies in the lengths of the locks and studs right from comp?

Just to clarify one more thing. The lifters did soak in Royal Purple for about a week before install into the engine, I just did not manually pump the lifters hard. But they are not dry by any means. I'm a little confused as to how stiff they are supposed to be for this. Are they supposed to be 'solid' or just not soft enough to be able to pump them with a toothpick?? I've assembled #1 cylinder with the stock 7.400 with 1/2 turn of preload and rotated the engine numerous times and I've used the adjustable rod with different lengths down to 7.300 (did not go longer, maybe I should) and had no problems with PTV clearance BUT again with the the lifters not being solid, the geometry may be different. I also don't think my cam is big enough to cause any PTV issues on a stock block and heads. I've seen other builds with more lift and duration be fine even with thinner gaskets and/or machined surfaces.

Thanks again. Any other feedback would be appreciated aswell. I've built a few SBC in the past with good results but this is my first LS, and the last full build was probably 12 years ago too. So I'm not clueless but a little uneasy getting back into the engine work instead of just bolt-ons.

vettenuts

iTrader: (4)

Exactly. I used check springs and operated the valves by hand with a dial indicator to the retainer to measure valve lift. You have to be steady when you do it, but you can obtain the wipe pattern. Once you have the distance, you can install the adjustable to measure for pushrod length. I think you will find that there is a small range that provides a good wipe pattern, take two pushrod measurements and then add in the preload. That way when you install the pushrod and adjust with the poly lock you should be in the good wipe zone as well. Just remember that counting turns on the poly lock if you want to figure out what the lifter preload is changing you have to correct for the rocker ratio as well.

Adrenaline_Z

No, there's much more involved but most people get away with this because
of conservative components.

For the most part you're doing it correct. Taking up all the lash in the assembly
then adding a bit of preload is fine. I don't agree with the 1/2, or 3/4 turn
method; I'd rather use as little preloading as necessary to keep the valvetrain
quiet and slack free. With an adjustable system, I'll set mine to as little as
0.005" after everything is warmed up.

No worries, there's no need for this. You are fine.

As long as the spring within the lifter can support the pushrod and rocker
while setting the valves, then you don't need to be concerned with the
stiffness. The spring inside the lifter is strong enough to hold up the pushrod
and rocker, and this will allow you to properly set the valvetrain.



After you take up all the 'up and down' slack in the assembly, then you
add a bit of preload. Set them cold, and then check them hot.

Setting them cold gets you very close, and in most cases no adjustment
is need after warming up the motor depending on how much pre-load you
desire.

If the lifters were "solid" at one point, rotating the motor with spring pressure
acting against the seat will almost always bleed down the lifter. Whom
ever is telling you to check pushrod length by turning the motor with hydraulic
lifters is confused.

The PR length is checked with the lifter on the base of the lobe.

It seems like you've done everything just fine. No need to lose sleep over it.

LIL SS

iTrader: (9)

I got to ask...

So what your saying is you want as little preload as possible right? What determines proper preload?

I would assume that a stiffer valve spring might require more preload as it is pushing down on the plunger with more force? In return not getting full lift?

Perhaps a motor with more oil pressure needs less preload as it can easily keep the valve at it's full lift?

These were a few things I was thinking about today. I assume the plunger depth while running will change based on spring load and oil pressure?

But I don't know for sure..

Adrenaline_Z

Yes; as little as required to keep the valve train 'loaded' and quiet.

Your desire to re-adjust valves as the parts wear down.

Proper setting is determined by removing all the 'play' in the pushrod,
rocker and valve tip... and then loading the seat with an additional amount
based on the application:

More pre-load = longer service life, but poorer performance

Less pre-load = may need adjusting more often (not really an issue with roller
parts), better performance.

You can also check the MFG data for the specific lifter. Some will say
the seat should never rest against the retainer and at least some pre-load
is required.

There are many race setups that use small amounts of preload to make the
lifter act like a solid type.

No, not at all. The preload has nothing to do with spring pressure. More spring
pressure will bleed the lifter down faster. The lift is determined by the
lobe, and rocker ratio.

Oil (fluid) is not compressible; therefore once the lifter is pumped by the
oiling system, it will be able to lift the valve.

Don't relate pre-load, and oil pressure to valve lift. Have a read here:

http://www.ratwell.com/technical/HydraulicLifters.html

http://www.youtube.com/watch?v=lorANZ1Tptw

I took a quick look through this article and it seems pretty good. I'll try to
find better references.

Yes both spring pressure and oil pressure will effect how and when the lifter
"cycles" to prime itself.

LIL SS

iTrader: (9)

I haven't read the article you posted yet, perhaps some of my questions will be ansered. With your last comment, you are contradicting yourself IMO..

Think about a spring loaded check ball. When you put pressure against the ball it compresses the spring. The more pressure you put the farther the spring is compressed until it goes in to coil bind. Raising the spring pressure would require more psi to compress the spring. Lowering the spring rate would allow for less psi to move the same distance.

If your putting force on the lifter plunger with no oil pressure it will bleed down correct? But when you put pressure to it from an oil system, it is raising the plunger only to the point the spring is stronger than it's pressure force.

With less oil pressure would the lifter not pump the plunger up as far during it's cycle? (Not enough pressure to overcome the spring rate) Less oil pressure to push against the bottom of the plunger meaning less pressure against the spring? (Assuming the same spring rate and preload is available)

With a heavier spring and the same oil pressure, would the lifter plunger raise less?

I understand the characteristic of the oil becoming a hyd liquid and is hard to compress, but your still applying a pressure force (30psi, 60psi). That pressure force is now raising the lifter plunger.

LIL SS

iTrader: (9)

Let me add this real quick..

Let's say you had a 300lb rate spring on the head and .050 preload would allow the valve to lift full at .500 at 30psi of oil.

If you went to .100 preload, the valve might stay open at that oil pressure right? Your now raising the plunger higher due to the oil pressure.

Now let's say you had a 400lb spring with the same .050 preload and 30psi. Perhaps that 30psi would would not overcome the added force of the sping. But at 60psi it might.

That's the point I was trying to make. Is that assumption correct?

Adrenaline_Z

If you are talking about the spring inside the lifter, the amount of pressure
required to compress the spring in relation to the valve spring is miles apart.

We're talking a pound vs. a couple hundred pounds.

The oil is used to take up slack in the system. In other words, when the
oil is pumped into the lifter, the seat rises and tightens all the loose play
between the lifter and rocker tip including everything in between.

I'm confused. Are you referring to the valve spring at all here? The spring
inside the lifter is used to hold the check ball in place and the plunger
assembly so that oil is locked inside the chamber.

Once the oil is locked inside, the internals become 'solid'.


Which spring do you mean? The valve spring?

The plunger is only moving up to remove slack. It is not raising the valve.
60 PSI over that small area is no match for a valve spring * the rocker ratio
acting against it.

Have a look at the video and read through the article to understand what
is happening.

http://www.autoeducation.com/rm_preview/valve_train.htm


Here is an excellent video. Notice the lifter fills with oil and then the lobe
raises the lifter. The internals are solid at this point:
http://www.kohlerengines.com/differe...valveswork.htm

Adrenaline_Z

No, sorry.

The lifter is not designed to allow the system pressure to raise the valve.

Watch the videos again and observe when the oil is let into the chamber.

Once the check ball is in place, and the oil passage is no longer aligned with
the oil entry hole, the pressure within the lifter is static...or disconnected
from the oil pump pressure.

While the lifter is raising in the lifter bore, it's not receiving the 30, or 60 PSI
from the pump. The fluid is simply locked in there and cannot be compressed.

Think of it like this:

- the oil system pressure determines how fast the oil gets into the chamber
when the oiling holes are aligned, and the check ball is allowing flow.

- if you had low oil pressure, the lifter would not fill as fast with oil when
cycling. This could cause the lifter seat to sink down ... because the chamber
did not fill 100%

- if you had high oil pressure, the lifter will fill faster and push the seat
against the rod faster ... so that when the cam lobe starts raising the
lifter everything starts opening the valve sooner

Does that make more sense?

Adrenaline_Z

I just noticed that if you hover the mouse pointer over the labels, you
will get an explanation of function for each part of the lifter:

http://www.kohlerengines.com/differe...valveswork.htm

NArtissimus

I actually was thinking of the same theory as LIL SS but only pertaining to my 'non pumped' lifters for measuring pushrod length. I'm glad he could put it into less words than the novel I was going to confuse everyone with. I too haven't watched all the vids yet but your explanation makes sense.

I guess in my case of checking wipe pattern, the fuller the lifter is, the less initial compression there is to lose rocker movement to... hence not gettin full wipe pattern. With the checking spring, it is weaker than the plunger spring inside the lifter which will allow for valve movement without compressing the lifter...? I've never had a checking spring in my hand and pictures only a show so much. Not 100% sure what the theory behind it is, but maybe now I get it heh.

Also, sorry maybe I missed it but I just worked a 12hr graveyard and I probably shouldn't be thinking of this right now. But what is the accurate way measuring preload since '1/2 turn after zero lash' isn't exactly a scientific method. Using a dial indicator... but measuring where? Not on the lock, or the valve, but would have to be at the end of the pushrod on the rocker?

Adrenaline_Z

You can use this method within to measure pre-load:

http://www.holley.com/data/Products/...al/INST150.pdf

If you're not into scribing stuff, I've used a clip and wire ties to make
reference points on the rod. Feeler gauges, or verniers work well to
take the actual measurement between your reference points.

It only takes a few seconds to get the info you need.

NArtissimus

Cool, thanks. I got lots of reading and watching to do. Think I'll pick up the springs tomorrow too just so I can do it right. I'd rather not take the springs off again but atleast it's only one set to check for the pushrod length.

LIL SS

iTrader: (9)

Let me see if I can articulate this a little better now that I have had some sleep

Aren't there a ton of people on here preaching you don't want too much lifter preload as it can hang a valve open? So answer this for me. How or why then would too much preload hold a valve open if it is not bottoming out the lifter plunger? One would think the only way that would happen is through the oil pressure that is filling the lifter body, putting resistance on the plunger lifting it, aplying a force to the push rod, opening the valve.

I understand what you are saying about the lifter filling with oil to take the slack out. But, if that's all it is doing than what's the issue of running more preload assuming you are not bottoming out the plunger? IE if a plunger can go max depth of .200, why run preload at .050 vs .150.

How is preloading a lifter causing you to loose performance if filling the lifter with oil (regardless of pressure) is only making it a solid unit at what ever height your preload has put the plunger at?

See, I'm not trying to argue anyones theorey is wrong, but I am finding holes in the theorey that oil pressure has no effect on lifter plunger depth when preloaded. Again, If oil pressure did not have any affect on preloaded plunger depth, then you should in theorey be able to run any amount of preload you wanted assuming you do not bottom out the lifter plunger. But it's argued that too much preload will hang a valve open, something that I agree with.

vettenuts

iTrader: (4)

I know of two engine builders who have told me they set the lifters deep, they have seen more power with that setup.

LIL SS

iTrader: (9)

And why is that.. My theorey is this.

With less preload in the lifter your are in a sense colapsing the lifter plunger height through a lift cycle. As spring pressure goes up when the cam lobe starts to lift, you are pushing the lifter plunger deeper in to the body due to the higher pressure put to the plunger (or lack of oil pressure to fill the body fast enough, with enough pressure). With out more oil pressure in the lifter, the plunger can't substain full lift as RPM increases. Top end power suffers from the lack of lift.

This is what has driven me to ask if more preload would make up that difference. The oil that is inside the lifter may not be able to be compressed, but if the body only has 30psi of oil in it, it is only applying that much force on the plunger pushing on the push rod. At 60psi of pressure though there would be more force seen from the plunger to push rod. Perhaps having more preload is allowing the body to fill with less volume but building more pressure faster (since you have a smaller void), keeping you at full lift.

Again, this is an idea, not proven fact by me.