Another internet myth bites the dust... LS7 vs. LS1 lifters
06-27-2011, 07:59 PM
#43
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Nope... You'll need a pushrod ball end to check. See Havoc40's post above, the oil holes are different and the dial indicator will slip into the lifter differently... Also, install both lifters on the same lobe of the same cam and check lifter preload. You will get the same measurment.
Shane
Shane
Last edited by XtraCajunSS; 06-27-2011 at 08:05 PM.
06-27-2011, 08:17 PM
#44
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Most lifter manufacturers (me being one of them) have extended and collapsed lengths measured from the tip of the roller to the tip of a ball bearing sitting in the radius of the pushrod seat. The standard is a .375 or .3125 diameter ball, my prints spec lengths using both. I don't have an LS1 lifter in front of me, but I do have an LS7. My extended length measurements are about 2.647 over a .3125 ball. I'm going to get an LS1 lifter tomorrow and see what I find.
FWIW, I just double checked my measurements using a stock GM pushrod... 5 measurements per lifter averaged only .002" difference between the two.
You can take it or leave it. In practice, the lifters are virtually identical.
Shane
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Hey_Allen (05-14-2023)
06-28-2011, 10:05 AM
#48
Ok, so after having hundreds of customers calling me asking about pushrod length with LS7 lifter, I have finally decided to stop everthing today and take some actual measurments of the 2 lifters...
First of all, I already knew this was a myth based on actual preload measurments I've taken over the years since the "LS7" lifter came out. Secondly, since GM has superseded the LS1 lifter with the LS7 lifter I knew they wouldn't have been able to do that without making a pushrod length change as well...
If you take a look at each lifter from the pushrod side, the LS7 pushrod cup appears to be approximately .025" higher in the lifter body. HOWEVER, if you take the actual measurment that matters which is the distance from the tip of the roller to the base of the pushrod cup, the lifters are virtually identical. Overall, the LS7 lifter body is slightly shorter overall vs. the LS1 lifter hence the illusion of pushrod cup difference.
I hope this helps end the debate. If anyone is interested in performing this measurment I would greatly appreciate it so that I will have some outside verification of my measurments.
Thanks for reading.
Shane
First of all, I already knew this was a myth based on actual preload measurments I've taken over the years since the "LS7" lifter came out. Secondly, since GM has superseded the LS1 lifter with the LS7 lifter I knew they wouldn't have been able to do that without making a pushrod length change as well...
If you take a look at each lifter from the pushrod side, the LS7 pushrod cup appears to be approximately .025" higher in the lifter body. HOWEVER, if you take the actual measurment that matters which is the distance from the tip of the roller to the base of the pushrod cup, the lifters are virtually identical. Overall, the LS7 lifter body is slightly shorter overall vs. the LS1 lifter hence the illusion of pushrod cup difference.
I hope this helps end the debate. If anyone is interested in performing this measurment I would greatly appreciate it so that I will have some outside verification of my measurments.
Thanks for reading.
Shane
I've never worried about any difference between the two because I always measure for pushrod lengths in my engines. Also, never knew that there was a debate regarding that there may have been a difference. Regardless, most people who post information do so in an effort to help. So, if it has been posted that there was or was not a difference, am sure that the poster had good intentions.
"Internet myth" is a term that I don't like, personally. If someone posts something with good intentions & the information is incorrect, eventually, someone else will correct it & the poster will learn from it. There's really not more to it.
06-28-2011, 02:28 PM
#50
I just checked myself for the hell of it and came up with about the same thing, .002-.005" difference. Which is nothing. By the time a mass produced lifter is machined and assembled, the tolerance stack-up is around +/- .025" on extended lengths. So, even with the exact same lifter, it could require a different pushrod. ALWAYS MEASURE!
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Hey_Allen (05-14-2023)
06-28-2011, 03:02 PM
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I just checked myself for the hell of it and came up with about the same thing, .002-.005" difference. Which is nothing. By the time a mass produced lifter is machined and assembled, the tolerance stack-up is around +/- .025" on extended lengths. So, even with the exact same lifter, it could require a different pushrod. ALWAYS MEASURE!
Shane
06-29-2011, 12:41 PM
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Just to be clear, I'm not advocating guessing pushrod length or not measuring for proper length. I'm just saying that LS7 lifters are a DIRECT replacement for ANY roller lifter GM has used in a small block since 1987.
Shane
Shane
