LS7 lifter preload, .066" or .091"?
01-21-2009, 07:59 PM
#22
I dont mean to highjack your thread JMM but im about to go head first on a head and cam swap next friday!
I ordered from Vengeance a set of Trickflow as cast heads milled to 60cc's and am gonna slide in a VRX5 cam. Vengeance told me I will need a 7.5 PR and will be tied to a set of Harland Sharp 1.7's non adjustables and new Ls7 lifters. Now my question is, what do I have to check for?
I thought all I had to do was turn the motor over by hand and torqueing the rockers down to 24ft lbs with some locktight?
Thanks and sorry about the Jacking!
I ordered from Vengeance a set of Trickflow as cast heads milled to 60cc's and am gonna slide in a VRX5 cam. Vengeance told me I will need a 7.5 PR and will be tied to a set of Harland Sharp 1.7's non adjustables and new Ls7 lifters. Now my question is, what do I have to check for?
I thought all I had to do was turn the motor over by hand and torqueing the rockers down to 24ft lbs with some locktight?
Thanks and sorry about the Jacking!
01-21-2009, 09:56 PM
#24
I have LS7 lifters, a 232/234 646/612 112 cam, Dart 225's, stock rockers, and stock length pushrods and have daily driven mine for almost a year with no issues. They said they checked my preload during install, so I can only guess mine's ok, but I've lately been wondering what there is to gain by shooting for the specs above with YT6645's installed as well. I am planning on a custom cam from Ed Curtis with much less lift and duration, so I guess I should just wait til then.
06-01-2009, 07:52 PM
#27
preload. . . I'm still kinda new to the whole cam and valvetrain conundrum, i'm building an iron 5.7L out of a 5.3L, stage II 5.3L 706 heads with 04' ls6 stock pistons. i'm also installing a custom cam at 220/222 .581/.581 114LSA. with 1.75:1 rockers. so if i manage to figure all that out and not break any springs or bend pushrods, i have faith that you can do the same. besides, mines a bastard motor, yours is still pretty much the same engine it was from the factory.
Oh yeah, i used AutoCAD to build a two lobe cam model with pushrods, rockers, valves, and lifters floating in space. its a super easy way to test pushrod lengths if you have all the measurements.
Oh yeah, i used AutoCAD to build a two lobe cam model with pushrods, rockers, valves, and lifters floating in space. its a super easy way to test pushrod lengths if you have all the measurements.
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fbodysetc (11-07-2019)
04-17-2015, 01:31 AM
#29
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One lifter in my LS3 did some noise occasionally and i got
https://www.texas-speed.com/p-309-gm...e-lifters.aspx
These from TSP, seem to give abot 0.09" preload on stock 7.4" puhrods.
Also tried to measure total travel of lifter, seems to be bit over 0,2", shouldn´t this be in 0.17 range?
But is that 0.09 too much or not, isn´t this lifter that GM uses as drop in lifter also for LS3 as warranty cases or am i wrong?
My engine is FI, aiming for 800whp, will not be spinned more than 6500rpm, but sees that 6500rpm a lot and rpm is stayin at around limiter constantly bit longer times. Cam is:
Duration @ .050 (Int/Exh): 227/238
Gross Valve Lift (Int/Exh): .583"/.600"
https://www.texas-speed.com/p-309-gm...e-lifters.aspx
These from TSP, seem to give abot 0.09" preload on stock 7.4" puhrods.
Also tried to measure total travel of lifter, seems to be bit over 0,2", shouldn´t this be in 0.17 range?
But is that 0.09 too much or not, isn´t this lifter that GM uses as drop in lifter also for LS3 as warranty cases or am i wrong?
My engine is FI, aiming for 800whp, will not be spinned more than 6500rpm, but sees that 6500rpm a lot and rpm is stayin at around limiter constantly bit longer times. Cam is:
Duration @ .050 (Int/Exh): 227/238
Gross Valve Lift (Int/Exh): .583"/.600"
Last edited by Mikko; 04-17-2015 at 07:43 AM.
