Death Rattle??
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Junior Member
Joined: Jul 2000
Posts: 56
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From: Bothell, WA, USA
Death Rattle??
I drove my car for the first time after a new ZZ4 engine installation. I had previously broke the cam in and changed the oil last week without any problems but today was different. Initially, I set the idle, adjusted the TPS and timing then shut it off. Five minutes later I started it up to take it on the highway but it began to rattle. I shut it off and inspected the exhaust and torque converter bolts. All looked fine and I started the engine and by using a stethescope the rattle was comming from the oil pan area but I couldn't pin point it. The knock/rattle is erratic and dissapears above 2000rpm and also dissapears when the torque converter is unbolted.
Unfortunately, I've heard a bottom end rattle before and this does not sound like a rod or main knock. As it is not consistent and there is no loss of oil pressure. (45 psi at 750rpm, 60 psi at 2000rpm)
Any help would be appreciated.
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87 IROC -
ZZ4 350
SLP T-Ram,1"3/4 SLP headers, Cat back, Hotch-kis, MSD, Iebach etc.
Unfortunately, I've heard a bottom end rattle before and this does not sound like a rod or main knock. As it is not consistent and there is no loss of oil pressure. (45 psi at 750rpm, 60 psi at 2000rpm)
Any help would be appreciated.
------------------
87 IROC -
ZZ4 350
SLP T-Ram,1"3/4 SLP headers, Cat back, Hotch-kis, MSD, Iebach etc.
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Joined: Jan 2000
Posts: 19,655
Likes: 309
DLP,
I thought the ZZ4 cam was a roller design, requiring no break-in period.
Anyway, since unbolting the torque converter from the crank stops the noise, it would appear that the noise is either generated by the transmission and is radiating through the crankshaft, or the torque converter is exhibiting some type of axial load on the crank, causing the thrust to move something enough to create interference.
Does the converter fit up well to the flexplate, or do the bolts pull the flexplate toward the transmission? Is the converter pushing against the transmission? Is the trans oil pump failing? Is the transmission acting normally? Does the noise change with the transmission in gear?
A lot of questions, I know, but it seems that the transmission may be more of a problem than the engine. It may also be possible that the transmission isn't aligned with the engine properly, causing some stress when the two are bolted together. Make sure the transmission bell is solidly bolted to the engine and there are no gaps.
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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0
[This message has been edited by Vader (edited November 05, 2000).]
I thought the ZZ4 cam was a roller design, requiring no break-in period.
Anyway, since unbolting the torque converter from the crank stops the noise, it would appear that the noise is either generated by the transmission and is radiating through the crankshaft, or the torque converter is exhibiting some type of axial load on the crank, causing the thrust to move something enough to create interference.
Does the converter fit up well to the flexplate, or do the bolts pull the flexplate toward the transmission? Is the converter pushing against the transmission? Is the trans oil pump failing? Is the transmission acting normally? Does the noise change with the transmission in gear?
A lot of questions, I know, but it seems that the transmission may be more of a problem than the engine. It may also be possible that the transmission isn't aligned with the engine properly, causing some stress when the two are bolted together. Make sure the transmission bell is solidly bolted to the engine and there are no gaps.
------------------
Later,
Vader
------------------
"Make Me Bad"
Adobe Acrobat Reader 4.0
[This message has been edited by Vader (edited November 05, 2000).]
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