First look....new LSX lifters
03-05-2012, 10:11 PM
#43
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03-05-2012, 11:09 PM
#45
Over the weekend I decided to try some 7.35" pushrods after mis-measuring using my Comp pushrod length tool. It sounded like yours does. I put the 7.4" back in and it got quiet.
I paid attention when tightening them and I have over 1 3/4 turns past zero lash to 22 ft/lbs. Not sure what preload that translates too but it is definitely quiet.
I paid attention when tightening them and I have over 1 3/4 turns past zero lash to 22 ft/lbs. Not sure what preload that translates too but it is definitely quiet.
https://ls1tech.com/forums/14943159-post36.html
Main thread:
https://ls1tech.com/forums/generatio...questions.html
Another good lifter pre-load thread:
https://ls1tech.com/forums/generatio...-pre-load.html
LS7 lifters have 0.166" total plunger travel.
Last edited by ZeeOSix; 03-05-2012 at 11:39 PM.
03-05-2012, 11:30 PM
#46
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Per some recent threads on how many turns equals what pre-load, 1-3/4 turn of the rocker arm bolt from zero lash to 22 ft-lbs equates to ~0.110" of lifter pre-load.
https://ls1tech.com/forums/14943159-post36.html
Main thread:
https://ls1tech.com/forums/generatio...questions.html
LS7 lifters have 0.166" total plunger travel.
https://ls1tech.com/forums/14943159-post36.html
Main thread:
https://ls1tech.com/forums/generatio...questions.html
LS7 lifters have 0.166" total plunger travel.
03-05-2012, 11:41 PM
#47
Part of the pre-load equation is also knowing what lifters you have and their total plunger travel.
03-05-2012, 11:52 PM
#48
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I would think that bleed rate would be more of a concern than actual plunger travel. I would also think that being nearer to the TOP of plunger travel would allow for less worries related to lifter pump-up....and that if anything, LESS preload on the LS7 lifters would be more beneficial....allowing for more of a hydraulic cushion between the bottom of the plunger, and the inside bottom of the lifter body.
03-05-2012, 11:56 PM
#49
Not debating what's the "best pre-load" for a specific lifter. Just saying GM recommends mid plunger travel on every lifter I've seen from them.
My LS6 has the lifters set to mid-plunger travel (ie, stock setup), and they are quiet.
You'll find that about half the members here think that less pre-load makes them more quiet, and the other half thinks more pre-load makes them more quiet. Everyone can't be right if split in their thinking.
I think lifter pre-load is the most talked about and most mis-understood topic on any LSx chat board.
My LS6 has the lifters set to mid-plunger travel (ie, stock setup), and they are quiet.
You'll find that about half the members here think that less pre-load makes them more quiet, and the other half thinks more pre-load makes them more quiet. Everyone can't be right if split in their thinking.
I think lifter pre-load is the most talked about and most mis-understood topic on any LSx chat board.
03-06-2012, 09:00 AM
#51
I have Vortec 350 lifters. The engine was a rebuild my dad did about 10 years ago and a stray nut found an intake port with an open valve and he never even knew it. It popped a piston on start up and he pulled it to replace with another engine for the customer.
My lifters were toast and I didn't know until the last minute. Using the barely ran lifters saved me 4-5 days wait on getting the car back together so I could go back to work.
Should I be worried and try some 7.375"? I tried 7.35" and the car was useless. Geoff recommends a 7.425" with stock shortblock and his cams and the only difference is my heads are shaved .010". I used Felpro stock replacement gaskets.
My lifters were toast and I didn't know until the last minute. Using the barely ran lifters saved me 4-5 days wait on getting the car back together so I could go back to work.
Should I be worried and try some 7.375"? I tried 7.35" and the car was useless. Geoff recommends a 7.425" with stock shortblock and his cams and the only difference is my heads are shaved .010". I used Felpro stock replacement gaskets.
03-06-2012, 09:34 AM
#53
Not debating what's the "best pre-load" for a specific lifter. Just saying GM recommends mid plunger travel on every lifter I've seen from them.
My LS6 has the lifters set to mid-plunger travel (ie, stock setup), and they are quiet.
You'll find that about half the members here think that less pre-load makes them more quiet, and the other half thinks more pre-load makes them more quiet. Everyone can't be right if split in their thinking.
I think lifter pre-load is the most talked about and most mis-understood topic on any LSx chat board.
My LS6 has the lifters set to mid-plunger travel (ie, stock setup), and they are quiet.
You'll find that about half the members here think that less pre-load makes them more quiet, and the other half thinks more pre-load makes them more quiet. Everyone can't be right if split in their thinking.
I think lifter pre-load is the most talked about and most mis-understood topic on any LSx chat board.
03-06-2012, 09:38 AM
#54
Well you can understand I'm nervous about spending more money on 7.375" when the car was unusable with 7.35".
It sounded like a stock cam (no lope), sounded like 2 industrial sewing machines under the valve covers (I could hear them rattle over 3" exhaust dumped at the axle), and had no throttle response or upper rpm power.
Put the 7.4" back in and it runs good. Ran 7.54@92mph 11.92@111mph Sunday. I just don't want to break anything.
It sounded like a stock cam (no lope), sounded like 2 industrial sewing machines under the valve covers (I could hear them rattle over 3" exhaust dumped at the axle), and had no throttle response or upper rpm power.
Put the 7.4" back in and it runs good. Ran 7.54@92mph 11.92@111mph Sunday. I just don't want to break anything.
03-06-2012, 11:42 AM
#55
0.110 pre-load is kind of deep, but if he's got LS7 lifters they have 0.166" total plunger travel ... and half way (0.083) is the recommended pre-load by GM. So he's only 0.023 too deep. Maybe LS7 lifters like more pre-load and that's what quiets them down (?).
Part of the pre-load equation is also knowing what lifters you have and their total plunger travel.
Part of the pre-load equation is also knowing what lifters you have and their total plunger travel.
BTW, I believe the same lifters are used in the later SB chev.
Ron
03-06-2012, 01:16 PM
#56
You've probably already seen this chart a few times, but will be interesting to see how your measurements compare.
03-06-2012, 02:27 PM
#59
Yes, if your talking about lifter GM P/N 5234670 in the chart I posted.