<TECH ONLY> Lifter Preload
Nov 19, 2009 | 08:58 PM
#23
When you get close to buttoning the motor up, you should always order your pushrods last. Get a pushrod measuring tool and measure your preload. There is roughly a .050 difference in lifter cup depth in the old style lifters vs. the new ones. It's beyond me why sponsors keep pimping out the 7.4's unless that's what you really need. My heads with only .007 milled, stock gasket and LQ4 shortblock running LS7 lifters needed a way shorter than stock pushrod.
Same travel (.150") for both lifters?
Rick
Nov 19, 2009 | 09:57 PM
#24
You'd be surprised if you pulled apart a full set of 16 stock lifters. The plunger travel distance amongst all 16 will all vary. This is why it's important to measure. Also there's other variables too that people need to consider when checking for preload. Just because you measured it on one valve doesn't mean that it's the going to be the same on the next valve. There may be a slight difference in valve length from one valve to the other OR depending how many times the guy working on your heads had cut the seat or if the seat cut depth is accurate. You guys really need to measure after buttoning everything else up on your builds.........
Nov 19, 2009 | 10:29 PM
#25
Nov 19, 2009 | 11:40 PM
#26
You'd be surprised if you pulled apart a full set of 16 stock lifters. The plunger travel distance amongst all 16 will all vary. This is why it's important to measure. Also there's other variables too that people need to consider when checking for preload. Just because you measured it on one valve doesn't mean that it's the going to be the same on the next valve. There may be a slight difference in valve length from one valve to the other OR depending how many times the guy working on your heads had cut the seat or if the seat cut depth is accurate. You guys really need to measure after buttoning everything else up on your builds.........
Thanks for all the good info.
Rick
Nov 20, 2009 | 11:17 AM
#28
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PT's Slowest Truck
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I'm not surprised. I got my Comp Cam pushrod checker in the mail today. I dropped a pair of used Patriot Stage ll LQ9's (already supposedly milled .030")off at my machine shop yesterday to get surfaced and a couple chambers CC'd so I can tell Rick @ Synergy what my actual compression is for my baseline tune. I'll put it together this weekend, use the pushrod checker to get my actual preload distance on a few cyclinders, get an average and then go from there. I can handle some sewing machine noise from the Patriot Golds but lifter clatter is not acceptable.
Thanks for all the good info.
Rick
Thanks for all the good info.
Rick
Nov 20, 2009 | 02:14 PM
#30
You'd be surprised if you pulled apart a full set of 16 stock lifters. The plunger travel distance amongst all 16 will all vary. This is why it's important to measure. Also there's other variables too that people need to consider when checking for preload. Just because you measured it on one valve doesn't mean that it's the going to be the same on the next valve. There may be a slight difference in valve length from one valve to the other OR depending how many times the guy working on your heads had cut the seat or if the seat cut depth is accurate. You guys really need to measure after buttoning everything else up on your builds.........