LT1 tapping when warm!!
12-13-2011, 05:10 PM
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LT1 tapping when warm!! My 93 z28 developed a tapping sound on the driver side .. Sounds like a classic lifter tap. It only does it when the engine is warmed up and it does it at around 1000-1500 rpms. Oil pressure is around 60 under load and 40 at idle. The interesting part is, I took off the valve cover and use a screw driver to locate the tap and I found it on the #3 cylinder and I think intake valve.. So I loosened the nut on my rocker arm( which are crane cam 1.50 roller rockers) about a half turn then tighten it a half turn and the taping would stop. Then It would come back in about a minuet later.. So I thought maybe it's the lifter since the car has 240xxx miles on it... push rod and rocker arm seems fine. So I buy two lifters and just replace the two for #3 cylinder. Put her all back together and the tapping is still there. And when you loosen the nut a half turn and tighten it real fast it goes away but then comes back... Any body know what it could be? Here's a video of it from YouTube..
http://www.youtube.com/watch?v=PWPWC...e_gdata_player
http://www.youtube.com/watch?v=PWPWC...e_gdata_player
12-13-2011, 05:26 PM
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When you say Poly lock, are you talking about a nut inside the main bolt down nut? Because it looks like in other pols videos there is a lock down nut but none of mine have that... I bought this car from someone who has rigged it all up so it's hard to say what they have done to it, as far as a cam and what not.
12-13-2011, 05:59 PM
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What grade oil are you using? Perhaps replacing the poly-lock since everything else checks out. You can also check side load slop on the rocker shaft to see if the bearings are bad and in need for a rebuild.
All that work for replacing just 2 lifters??? Should have done them all bro...
All that work for replacing just 2 lifters??? Should have done them all bro...
12-13-2011, 06:11 PM
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5w 30 mobile
5w 30 is what I always used bust since then I've put some Lucas in there and it didn't help... I know I feel dumb for not doing all the lifters but Christmas and bills I didn't have much to spend... It only Took 4 hrs anyways but your right... Lots of work!
5w 30 is what I always used bust since then I've put some Lucas in there and it didn't help... I know I feel dumb for not doing all the lifters but Christmas and bills I didn't have much to spend... It only Took 4 hrs anyways but your right... Lots of work!
12-13-2011, 06:52 PM
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#3 intake looks like it is barely moving. Could be a collapsed lifter. When you tighten down the rocker it tightens up until the force collapses it more.
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12-13-2011, 09:01 PM
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Can you validate that the #3 intake rocker is barely moving? I would love to see a close up video of the drivers side bank running at idle then at about 2000 rpms.
12-14-2011, 02:13 PM
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Did u soak them in oil to pump up the plunger in the lifter, before u popped them in? If yer going back in, please replace them all!! I know it's Christmas, but sometimes we have to bite the bullet. Fix once, fix right!
12-14-2011, 02:32 PM
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Gotta change that oil bro... Waiting for 3,000 miles is NOT for everyone. On average, I change mine about every 1700 miles.
Soaking can take more than a few minutes. I let mine soak the day before...
Soaking can take more than a few minutes. I let mine soak the day before...
12-14-2011, 02:58 PM
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Im the same way about my oil I change it before it hits 3000... Plus my oil pressure after about 1000 miles on an oil change drops to zero every time I stop... Ever experienced that? The sending unit is new.
And btw I soaked em for thirty min or so:/ was that a bad thing?
And btw I soaked em for thirty min or so:/ was that a bad thing?
12-14-2011, 03:01 PM
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Whaaaaa....OK. Do u have oil pressure to begin?? Do check immediately and report back pressures. This could be the culprit of yer problems...
Depends if u still see air bubbles coming out, they r not done siphoning....
Depends if u still see air bubbles coming out, they r not done siphoning....
12-14-2011, 03:18 PM
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Yes...pm'd!
Beginning to suspect your pick-up screen on yer pick-up is partially blocked..... New doesnt always mean it's gonna work by the way. Testing new and old does..
RTV silicone and other garbage dropped into engine during cleaning can create issues like this. It clogs up the intake screen and chokes off pressure and damages bearing journals eventually. Lifter clatter is usually a sign...
Ya got a stethescope camera? Those come handy here. Allows u to see whats on the pan or screen pickup.
I am hoping your oil viscosity just thinned out when u went to 0 pressure, then climbed back up! Sounds like to me that perhaps the plunger in the new lifters arent geting enough oil to create a lash, creating the tapping noise. Lash down the rocker again so that it no longer clatters. Then, try changing the oil again and keep an eye on the oil pressure. Note when clatter returns: ie...outside temps, engine temp, oil pressure.
Hope the new locks work for ya. Text me on yer progress Troy...
Beginning to suspect your pick-up screen on yer pick-up is partially blocked..... New doesnt always mean it's gonna work by the way. Testing new and old does..
RTV silicone and other garbage dropped into engine during cleaning can create issues like this. It clogs up the intake screen and chokes off pressure and damages bearing journals eventually. Lifter clatter is usually a sign...
Ya got a stethescope camera? Those come handy here. Allows u to see whats on the pan or screen pickup.
I am hoping your oil viscosity just thinned out when u went to 0 pressure, then climbed back up! Sounds like to me that perhaps the plunger in the new lifters arent geting enough oil to create a lash, creating the tapping noise. Lash down the rocker again so that it no longer clatters. Then, try changing the oil again and keep an eye on the oil pressure. Note when clatter returns: ie...outside temps, engine temp, oil pressure.
Hope the new locks work for ya. Text me on yer progress Troy...
12-14-2011, 06:00 PM
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With 240,000 miles, it maybe time for a good olde fashion rebuild. Main and rod bearings, rings and cam bearings, weak oil pump or a combination of all could cause your oil pressure problems. A collapsed lifter is more than likely the tapping issue. I don't think a lobe on the cam has been wiped out because of the roller lifters, unless the roller on the lifter you changed was seized then cam could be bad.