Initial Start Up Noise
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Initial Start Up Noise I finally finished my valve spring upgrade to PAC 1518s on my '02 Z06 ... and while in there also installed the Comp Cams trunnion kit and some Manton pushrods. I lubed/flooded everything real well with engine oil before reinstalling the valve covers.
Fired it up for the first time today and there was lots of pretty loud valve train tap/rattle, which took what seemed like forever to go away. I'd say it took a good 5~10 min at idle before it got quieted down significantly.
I'm assuming this happens because the lifters where collapsed some from turning the engine over by hand many times with the new springs installed? Does it take that long for the lifters to pump back up? Oil pressure was entirely normal during this time.
Most importantly, I'm hoping this was just rocker noise due to the hydraulic lifters trying to pump back up, and nothing was really getting damaged during this initial 10 minutes of running?
Is this normal behavior of the valve train after the work I did?
Fired it up for the first time today and there was lots of pretty loud valve train tap/rattle, which took what seemed like forever to go away. I'd say it took a good 5~10 min at idle before it got quieted down significantly.
I'm assuming this happens because the lifters where collapsed some from turning the engine over by hand many times with the new springs installed? Does it take that long for the lifters to pump back up? Oil pressure was entirely normal during this time.
Most importantly, I'm hoping this was just rocker noise due to the hydraulic lifters trying to pump back up, and nothing was really getting damaged during this initial 10 minutes of running?
Is this normal behavior of the valve train after the work I did?
Last edited by ZeeOSix; Oct 14, 2011 at 07:05 PM.
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After it ran for 10+ min it sounded quiet like it did before I worked on it, so I'm assuming it must have been the lifters pumping up. Can't believe it takes that long though ... kind of freaked me out for a bit when it didn't quiet down right away.
Can this cause any real damage?
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Just started it again for heat cycle #2 on the valve springs and it sounds pretty quiet this time ... maybe even quieter than before I did this work. With my head a foot above the engine, all I can really hear are the fuel injectors, with maybe a hair of valve train under valve covers - very hard to detect. With the hood closed, you'd think it's a Lexus ... 
Could be the Comp Cams trunnion kit helped a bit (?), as there was much less side-to-side slop of the rocker arms with the kit installed.
Also, the oil pressure is exactly the same at the same engine RPM and oil temperature check points as before. The Manton pushrods have smaller oiling holes (0.065" dia hole) than the stock pushrods (0.100" dia hole). Thought they might increase the oil pressure a tad due to more restriction, but apparently not enough to detect with the on board readouts.
Could be the Comp Cams trunnion kit helped a bit (?), as there was much less side-to-side slop of the rocker arms with the kit installed.
Also, the oil pressure is exactly the same at the same engine RPM and oil temperature check points as before. The Manton pushrods have smaller oiling holes (0.065" dia hole) than the stock pushrods (0.100" dia hole). Thought they might increase the oil pressure a tad due to more restriction, but apparently not enough to detect with the on board readouts.
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So what's making all the noise until the lifter pumps back up? Is it the plunger bottoming out in the lifter body?
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Mobil 1, 5w-30 full synthetic. Ambient temperature was 55~60 deg F ... so I'd say the oil flow was good during cold start-up. Oil pressure came up to 45 PSI in a couple seconds.
Don't know why it took so long to get the lifters pumped back up ... maybe they had a lot of air in them (?).
Don't know why it took so long to get the lifters pumped back up ... maybe they had a lot of air in them (?).
Mobil 1, 5w-30 full synthetic. Ambient temperature was 55~60 deg F ... so I'd say the oil flow was good during cold start-up. Oil pressure came up to 45 PSI in a couple seconds.
Don't know why it took so long to get the lifters pumped back up ... maybe they had a lot of air in them (?).
Don't know why it took so long to get the lifters pumped back up ... maybe they had a lot of air in them (?).
True. Once I had a car that took like almost 20, just ticking and ticking and thought the engine was no good. Till it went away.
