C5 piston slap?
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I took the car out for a drive and made a video when i got home. You can slightly hear the noise still but its much less noticeable than when the engine is cold. It sounds the same from both sides of the engine which makes me believe its a lazy lifter since the cam is in the middle of the engine.
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Just from the video I do think I hear a very very slight noise which I imagine in person it’s easier to distinguish. It’s not severe so I really encourage you to check for pushrod straightness. As the oem pushrods aren’t very tough
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Ok, when I get a chance I will pull the valve covers and rockers and check the push rods. I wonder if one is slightly bent and the lifter doesnt have enough preload so it ticks.
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That’s what happens usually bud. If they are severely bent they will be louder than that. But I’ve seen them bend bad enough to wear the pushrod hole in the top of head. Lifter lost all preload so it actually would “loft” off the cam and it was all fubar for that lifter bore lol a simple repair became a pita
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That’s what happens usually bud. If they are severely bent they will be louder than that. But I’ve seen them bend bad enough to wear the pushrod hole in the top of head. Lifter lost all preload so it actually would “loft” off the cam and it was all fubar for that lifter bore lol a simple repair became a pita
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If slightly bent I believe they would still be centered in the lifter and rocker cup. It may not be your issue but for the ease of checking them it helps to cross out the possibilities for diagnosis. A failed lifter sometimes causes your oil pressure gauge to flutter when oil is good and hot.
Burning Brakes
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From: Regina Sask
Thanks for all the replies fellas. I finally got a chance to make a cold start video for you guys to see what you think. Definitely sounds 90% better once its fully up to temp.
https://youtu.be/c0Pb-Fnxek0
https://youtu.be/c0Pb-Fnxek0
Russ Kemp
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Melting Slicks
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From: Virginia
Yep I believe you did. Glad it wasn't something more serious, I expected to find this on mine, but have yet to figure mine out.
How did you know which one to check? Or did you just pull them all?
How did you know which one to check? Or did you just pull them all?
Last edited by bwill03z; Aug 20, 2018 at 08:23 PM. Reason: Added comment
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Im glad too. Hopefully the cam and lifter are ok since i know its been driven like this for a while. I figure if I replace the pushrod and it runs quiet its probably fine.
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OP if you physically pushed on the rocker cups when checking them for vertical “slop” then I’d imagine you didn’t lose all of your preload and lifter SHOULD be okay. Just be certain when you get your new pushrods you verify length/preload. Ls motors lifter preload is set by pushrod length. Comp has a pushrod length checker that works okay. Also I’m glad I could help and you didn’t take the noise as normal. Get er fixed up and let it rip. Also if you measure I have a new set of chromoly tick performance 7.400s id sell you for cheap. Either way good job on being proactive on maintenance of your ride 
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OP if you physically pushed on the rocker cups when checking them for vertical “slop” then I’d imagine you didn’t lose all of your preload and lifter SHOULD be okay. Just be certain when you get your new pushrods you verify length/preload. Ls motors lifter preload is set by pushrod length. Comp has a pushrod length checker that works okay. Also I’m glad I could help and you didn’t take the noise as normal. Get er fixed up and let it rip. Also if you measure I have a new set of chromoly tick performance 7.400s id sell you for cheap. Either way good job on being proactive on maintenance of your ride
Melting Slicks
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From: Virginia
So you replaced the bent pushrod in your pic but the noise didn't go away?? That sucks, maybe you have multiple ones bent a little?
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Yeah i put a new one in the passenger side to replace the bent one. Pulled the others and they were straight. I still have to pull the drivers side ones though. I just figured id try it and see how it sounded first.
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typically they bend on a manual from the good old money shifts. Springs lose control of valves due to mechanical over-rev and the valves kiss the pistons then stuff the pushrods into the lifter. Stock pushrods are weak so they usually bend first before damage to lifter but not always. However you probably have more than one bent one. If so I do recommend getting the comp cam pushrod length checker. They aren’t much and figuring out what length you need. The 7.400s are close to stock replacement length. Also if you suspect a mechanical over-rev be sure to inspect the stock crap rockers as they like to puke needle bearings
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typically they bend on a manual from the good old money shifts. Springs lose control of valves due to mechanical over-rev and the valves kiss the pistons then stuff the pushrods into the lifter. Stock pushrods are weak so they usually bend first before damage to lifter but not always. However you probably have more than one bent one. If so I do recommend getting the comp cam pushrod length checker. They aren’t much and figuring out what length you need. The 7.400s are close to stock replacement length. Also if you suspect a mechanical over-rev be sure to inspect the stock crap rockers as they like to puke needle bearings
Last edited by Millhousemx; Aug 20, 2018 at 10:44 PM.
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I’m at work so it’s a bit hard for me to hear. What is your oil pressure cold/hot? Also I would not drive it like this. If it is a lifter and it turns in the bore or fails then you are very likely to be looking at some damage. It sounds like a lifter tick at idle. I don’t like that sharp squeaky knock noise when you first rev it though it may be my phone speakers lol. You’re looking at topend tear down I’d say. I don’t think it sounds really deep like a rod knock/ they chirp sometimes as well. I don’t think it’s a spun bearing. You’d probably be seeing a lot of gold stripper glitter in oil and filter if it’s a spun bearing. I’d bet you have a seized lifter wheel and if I’m actually hearing a squeak at first rev is the wheel not rolling but sliding across the cam lobe. But It’s not hard to replace lifters though if you’re a bit mechanically inclined. I’d get the morel drop ins or Johnson’s. Johnson’s are a step up. But I think morels are the only lifter who use a wire lock axle shaft at oem wheel size The rest are swedge lock and they can walk out when valvefloat occurs if ever. It’s a shame you can’t rev the motor while camera is right there. If you plan on modifying in the future. Now is the time to get a build list going if you verify heads gotta come off. If you need help I would be happy to help fellow ls owner. You MIGHT be able to verify by pulling all rockers and spinning motor several times. This SHOULD cause lifters to stick up in lifter trays. Then you can manually seat each lifter on its lobe with a pushrod. One may be very hard to seat back down but I’m just spitballing here. I’m sorry I can’t help much more than give you an estimated guess. I know how it feels. Stuff like this makes me sick to my stomach when it’s my own ride.
Last edited by Lt1slowerbird; Aug 21, 2018 at 02:40 AM.
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Oil pressure is in the 40s at idle cold, at full temp it sits around 30 at idle. When i blip the throttle it rattles a bit when cold. Doesn't make any squeaks though must be your phone speakers. Once the engine reaches full temp the rattle goes away fkr the most part. I figure I'll tear it down this winter and do some upgrades. With my luck I'll do heads cam and lifters and it will sound exactly the same haha.