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i have a 2001 pontiac trans am m6 i just recently did a ms3 cam swap in my car and also did luntai dual valve springs with seats, retainers, locks, seals, locators and tsp hardened 7.4" pushrods, ls7 lifters, a melling high volume oil pump and a ls2 strengthened timing chain. about a week after i did this it started making a really bad ticking noise sounded like a lifter and a teacher at my school (uti) said i had a collapsed lifter so i replaced them again and its still making the noise. ive checked the lifter pre load multiple times, checked the cam bolts to make sure they werent backing out, ive checked my header bolts multiple times and none of it fixed the problem. friday night i pulled the valve covers back off to check the rocker arm geometry and when the rockers where off i went ahead and pushed on the pushrods to see if the lifters would plunge and both the lifters on cylinder 7 would plunge. im not sure if this is from them bleeding down too fast or not getting adequate oil to them. any help is greatly appriceated since i have been going at this for about 3 weeks now and havent figured out whats wrong.
How much lifter preload are you running, and how did you measure it?
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If the valve wipe pattern is good, there is no problem. Lifter noise (sounds like a sewing machine) is common. The more you load the rockers, the more noise you're gonna get. I believe that it's the heavily loaded needle bearings in the rockers. Others will claim that it's the dual springs. Personally, I've never heard a spring make a noise from compressing & unloading. It's the higher spring force from the dual springs applied to the needle bearings in the rockers that makes the sound, IMO.
#7 is last to get oil & first to drain. Don't worry about being able to push the pushrod into the lifters there. Again, if the valve wipe pattern is good, there is not issue.
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i have 1/2 a turn of pre load after zero lash to 22 ft lbs and ive been told that is in the range of what you want to have. ive also checked to see if one of the trunions where just taking a crap on me from this high lift cam and spring pressure but they hardly had any side to side movement when bolted down and also didnt feel like they had a bind in them when i checked them with them off the car. and will cylinder 7 lifters bleed down 30 mins after the car has been off? i didnt know they would bleed off that fast
The method that specifies preload based on the number of turns (aka Shane's method) assumes 0.047" to 0.049' of preload for each turn, which is 0.024" of 1/2 turn. This "flat-rate per turn assumption" is a little off, but usable within the applicable range. (Corrected numbers are contained in the other thread I referenced.)
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