Lifter Preload? How to measure? I don't get it.
03-31-2013, 10:28 PM
#21
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Why are you running the Morel 5294s in a street motor? I would advise against that. If you get any kind of particle of dirt in the oil and it makes it into that lifter. It'll seize up. Erik @ HKE recommends the 5206 on a street application, because of that.
Now, 7.5" would be find with an LS7 lifter in that motor. Since the Morel/Lunati lifter needs less preload ~ .050" less and has a .050" taller body/cup, you need at least a .100" shorter pushrod. But you also have a smaller base circle cam, so that adds back .025" and a milled head, so that's about .020" closer. So .100" would get you close, but still might be off for the preload. Without measuring, you can't tell.
Now, 7.5" would be find with an LS7 lifter in that motor. Since the Morel/Lunati lifter needs less preload ~ .050" less and has a .050" taller body/cup, you need at least a .100" shorter pushrod. But you also have a smaller base circle cam, so that adds back .025" and a milled head, so that's about .020" closer. So .100" would get you close, but still might be off for the preload. Without measuring, you can't tell.
It has a 6 gallon 3 stage dry sump, with a twin disc ceramic clutch, T101 4 speed dog box transmission, 1988 Mazda Rx7 .... racecar.
Oil filter gets changed every race.
03-31-2013, 10:30 PM
#22
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You need to measure with a SOLID lifter. Shim up an old one as I described to bring the pushrod cup to the top of its travel. At this point the lifter is imcompressible. From there you set your push-rod length checker to zero lash (0 preload). Your desired pushrod length is the length of the checker at this zero lash value, + your desired preload. When you install your actual lifters that have push-rod cups with available travel, you will get the preload you need. Trying to "pump one up" for measuring would be pretty unreliable when you're trying to hit what is likely a 0.030"-0.060" window.
03-31-2013, 10:33 PM
#23
Getting that ASSumption out of the way. You can still measure using the Morels. Just get a checker spring and soak them in oil. Just don't collapse them.
Or you can buy the 7.375s and see what happens.
03-31-2013, 10:34 PM
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If the lifter is indeed full of oil and it is all the way at the top, with the way to long of push rods, wouldn't it have pushed the lifter down, especially when it was on the base circle (and there was still tons of pressure from the valve being open)? If not.... what is the point of having hydroponic lifters if it never goes down? O.o
03-31-2013, 10:35 PM
#25
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I just spend a lot of money on racecar. 
03-31-2013, 10:39 PM
#26
I'm just giving you hard time. A lot of folks on here don't know what they are doing.
And even if it's full of oil, if the pushrod is .100" too long (or longer), there isn't that much range in the lifter from what I recall. So it was probably sitting at the bottom of the lifter cup. Which is why it was still hanging open. 7.375" is a good bet for what you need since with a 7.4" pushrod application (243 heads), a 7.275 ends up being pretty close.
And even if it's full of oil, if the pushrod is .100" too long (or longer), there isn't that much range in the lifter from what I recall. So it was probably sitting at the bottom of the lifter cup. Which is why it was still hanging open. 7.375" is a good bet for what you need since with a 7.4" pushrod application (243 heads), a 7.275 ends up being pretty close.
03-31-2013, 10:40 PM
#27
if you know the difference (if any) between pushrod cup heights at the top of travel between the stock lifters and the ones you're using, there is no reason this method couldn't work for you.
03-31-2013, 10:41 PM
#28
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03-31-2013, 11:53 PM
#29
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If I take the dry sump belt off and turn the engine over a few times, it would let the pressure out of the lifters, right? I can take two of the push rods out of the engine before I do that to see if the others fall down further compared to them?
04-01-2013, 04:09 AM
#30
There is no need to disassemble or go through major changes to measure. One thing I found with the new Morels was the plunger was very easy to depress. Use the adjustable pushrod and turn it out so it is just loose, or the rocker when gently lifted will provide a "tick" "tick". Then use a feeler gauge to measure between the valve stem and the rocker until you just take out the "tick" "tick" when gently lifted. Once you have that measurement, multiply by 1.54 (assuming stock rockers and noting they are not 1.7 on the seat). This is the lenth of increase you need to get the pushrod to zero lash. So if the feeler guage is 0.020", then you need to open up the pushrod by 0.031". Remove the pushrod and open up the required turns then re-try.
You need to slowly creep up on zero lash without depressing the plunger. You can try opening half the measured feeler gauge turns and then re-check with the feeler gauge. The point is you want to just get to where you have removed the "tick" "tick" without depressing the plunger.
Also. if you lift the rocker tip too hard you will easily depress the plunger.
You need to slowly creep up on zero lash without depressing the plunger. You can try opening half the measured feeler gauge turns and then re-check with the feeler gauge. The point is you want to just get to where you have removed the "tick" "tick" without depressing the plunger.
Also. if you lift the rocker tip too hard you will easily depress the plunger.
04-01-2013, 08:00 PM
#32
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I'm just giving you hard time. A lot of folks on here don't know what they are doing.
And even if it's full of oil, if the pushrod is .100" too long (or longer), there isn't that much range in the lifter from what I recall. So it was probably sitting at the bottom of the lifter cup. Which is why it was still hanging open. 7.375" is a good bet for what you need since with a 7.4" pushrod application (243 heads), a 7.275 ends up being pretty close.
And even if it's full of oil, if the pushrod is .100" too long (or longer), there isn't that much range in the lifter from what I recall. So it was probably sitting at the bottom of the lifter cup. Which is why it was still hanging open. 7.375" is a good bet for what you need since with a 7.4" pushrod application (243 heads), a 7.275 ends up being pretty close.
04-02-2013, 02:46 PM
#33
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Came up with 7.375. We will see how it goes I guess. 10.7 turns (6.8+ .535 = 7.335 + .04 = 7.375 )
Hopefully because I have milled trickflow heads, it needs that extra .1.
Hopefully because I have milled trickflow heads, it needs that extra .1.
Last edited by tweakgames; 04-02-2013 at 03:41 PM.
04-02-2013, 04:47 PM
#34
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How many thousandths did you have milled off the heads? I know stock ls2 block, stock lifters, and those TFS heads, I had to run a .100 longer push rod. I believe you said 61cc head, and that should be .300-.400 milled (depending if you have the ls1 or ls2 TFS heads) according to Seth@HSC, these lifters need a .050 shorter pushrod if everything is stock. The preload on that lifter is suppose to be .010-.030.
Factory preload is usually between .050-.100. To get you in the ball park we will use the extreme ends of the measurements.
Stock rod/factory preload/new preload/height reduction/milled amount.
7.500-.100+.030-.050-.300=7.17
7.500-.100+.030-.050-.400=6.98
7.500-.050+.030-.050-.300=7.13
7.500-.050+.030-.050-.400=7.03
7.500-.100+.010-.050-.300=7.06
7.500-.100+.010-.050-.400=6.96
7.500-.050+.010-.050-.300=7.11
7.500-.050+.010-.050-.400=7.01
So you need a push rod in the 6.960-7.170 range. I'm betting you will need the 7.000 pushrod.
To come up with the new preload figure and the -.050 length requirement, I googled that lifter part number and found several threads stating that info from reputable vendors. The factory preload amount is a assumed figure, depending on what engine you are coming from. Truck lifters can have more preload then .100. Also this is assuming the head gasket you are using is the same. If it is not, you will need to add/subtract the difference.
When using the pushrod length checker, I would full depress the lifter until it bottoms out, take your reading from there. Then find the plunger travel speck from lunati and subtract that from your measurement and then add the preload specs (you will end up with two numbers) and find the closest length pushrod that fits within that range of numbers. Ideally you want to measure this before final assembly and use a solid lifter, but everything can't be ideal all of the time.
Factory preload is usually between .050-.100. To get you in the ball park we will use the extreme ends of the measurements.
Stock rod/factory preload/new preload/height reduction/milled amount.
7.500-.100+.030-.050-.300=7.17
7.500-.100+.030-.050-.400=6.98
7.500-.050+.030-.050-.300=7.13
7.500-.050+.030-.050-.400=7.03
7.500-.100+.010-.050-.300=7.06
7.500-.100+.010-.050-.400=6.96
7.500-.050+.010-.050-.300=7.11
7.500-.050+.010-.050-.400=7.01
So you need a push rod in the 6.960-7.170 range. I'm betting you will need the 7.000 pushrod.
To come up with the new preload figure and the -.050 length requirement, I googled that lifter part number and found several threads stating that info from reputable vendors. The factory preload amount is a assumed figure, depending on what engine you are coming from. Truck lifters can have more preload then .100. Also this is assuming the head gasket you are using is the same. If it is not, you will need to add/subtract the difference.
When using the pushrod length checker, I would full depress the lifter until it bottoms out, take your reading from there. Then find the plunger travel speck from lunati and subtract that from your measurement and then add the preload specs (you will end up with two numbers) and find the closest length pushrod that fits within that range of numbers. Ideally you want to measure this before final assembly and use a solid lifter, but everything can't be ideal all of the time.
04-02-2013, 05:14 PM
#35
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I spoke with Lunati this morning, he said to put my dry sump belt back on, crank it over for a bit until oil comes out of the rockers, then measure it up. Measure a intake and exhaust for a cylinder, then crank it over again until oil comes out and measure the next cylinder. I was getting the same readings from 3 lifters, so I "should" be good to go. We will see I guess.
Before when I put the 7.4 in before the lifters pumped up it built a bit or compression on that one cly. After the lifters pumped up it went back to no compression, so it must have been pretty close at 7.4.
Before when I put the 7.4 in before the lifters pumped up it built a bit or compression on that one cly. After the lifters pumped up it went back to no compression, so it must have been pretty close at 7.4.
04-08-2013, 05:38 PM
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Valve Lash Adjustment Hey guys, if you're looking to adjust your valve lashes, here's a tool that will really help you do that. It's simply a magnetic vinyl strip with graphics that wraps around your harmonic balancer or pulley that shows you exactly which valve to adjust while you manually rotate the crankshaft. Cheap and real easy to use as I have one for my Camaro and my Corvette.
www.valvetrax.com
Anyway, just thought I would let you know that something like this actually exists to make your valve lash really easy.
www.valvetrax.com
Anyway, just thought I would let you know that something like this actually exists to make your valve lash really easy.
