4.5 Gen Problems. Possible Timing Chain. Please Help!
4.5 Gen Problems. Possible Timing Chain. Please Help!
The other morning I walked out to my car and turned it on, no problems. When I tried to merge into traffic out of my apartments, I gave it a little too much gas and the tires spun out and tapped 7400 rpms before the motor was completely warmed up. I then heard some knocking and pulled over and shut it off. Turned it back on and it was gone, so I figured I was ok. The next morning I turned it on and I could hear some loud noises coming from the belts/timing area of the motor. I let it warm up for 15 minutes and still no change. I then started driving, and after I went 10 feet with the wheels engaged it went away for the rest of the day. Every day its the same thing. Is this timing related? Or could this be something else? The car drives completely normal with or without the sound. But the sound goes away as soon as its moving, no matter what rpm the motor is at. I have been reading up on timing chain and tensioner issues but I cannot find a similar instance to my own. Can someone please help? I am getting scared she might die on me.
Thanks,
Zack
Thanks,
Zack
Last edited by mastercater7; Sep 20, 2008 at 01:30 AM.
Do you have a vacum gauge & a wideband afr gauge?
Post a vid of the start up & idle if possible.
Also remove the altenator belt & start the car to make sure its not just a bad pulley
. I hope its a very simple fix.
Post a vid of the start up & idle if possible.
Also remove the altenator belt & start the car to make sure its not just a bad pulley
. I hope its a very simple fix.
Joined: Oct 2005
Posts: 4,572
From: Middleboro/Carver, Ma
When it's cold take an automotive stethescope and find where it is coming from, and a big +1 to removing the belts, as well check the crank pulley bolt. If it turns out it's coming from the timing cover area considering it's a knocking sound (that's the impression I got) I would definitly recommend tearing the cover off to inspect since something bad could be immenent,
However, based on the cold motor + 7400, there is a possibility of a rod issue as well. Change the oil and inspect it, you can always save a little and have it analyzed as well.
However, based on the cold motor + 7400, there is a possibility of a rod issue as well. Change the oil and inspect it, you can always save a little and have it analyzed as well.
The other morning I walked out to my car and turned it on, no problems. When I tried to merge into traffic out of my apartments, I gave it a little too much gas and the tires spun out and tapped 7400 rpms before the motor was completely warmed up. I then heard some knocking and pulled over and shut it off. Turned it back on and it was gone, so I figured I was ok. The next morning I turned it on and I could hear some loud noises coming from the belts/timing area of the motor. I let it warm up for 15 minutes and still no change. I then started driving, and after I went 10 feet with the wheels engaged it went away for the rest of the day. Every day its the same thing. Is this timing related? Or could this be something else? The car drives completely normal with or without the sound. But the sound goes away as soon as its moving, no matter what rpm the motor is at. I have been reading up on timing chain and tensioner issues but I cannot find a similar instance to my own. Can someone please help? I am getting scared she might die on me.
Thanks,
Zack
Thanks,
Zack
Consensus is that the stock rod bolts are good to 7100. But the stresses to the rod bolts are cumulative. A brief, accidental rev to 7400 might not break anything, but continued use above 7100 will.
Technosquare ran a 3.5 (non rev-up) at 7200 continuously for 15 minutes before getting a rod bolt failure.
The ARP rod bolts are good to 8,000 rpm and the rev-up rod bolts (cheaper), probably to 7500.
Personally, I would not increase the stock rev limit at all without at least using the rev-up rod bolts.
From ARP's site..
Originally Posted by ARP Tech Info
Pre-Load
Finally, although not a design parameter, the subject of bolt installation preload must be addressed. It is a fundamental engineering concept that the force in a bolt in an ideal preloaded joint will remain equal to the preload until the externally applied force exceeds the preload. Then the force in the bolt will be equal to the external force. This means that fluctuating external forces will not cause fluctuating forces in a preloaded bolt as long as the preload exceeds the external force. The result is that fatigue failure will not occur.
In a non-ideal joint, such as in a connecting rod, the bolt will feel fluctuating stresses due to fluctuating rod distortions. These are additive to the preload, so that fatigue could result. In connecting rods, precise preloads are required because if they are too low, the external forces (the reciprocating weights) will exceed the preloads, thus causing fatigue. If they are too high, they provide a high mean stress that combines with the fluctuating stresses due to rod distortion. Again, fatigue is promoted. The objective, then, is to preload a bolt so that it just exceeds the external load, and no higher.
To sum up: both insufficient preloads and excessive preloads can lead to fatigue failures.
Finally, although not a design parameter, the subject of bolt installation preload must be addressed. It is a fundamental engineering concept that the force in a bolt in an ideal preloaded joint will remain equal to the preload until the externally applied force exceeds the preload. Then the force in the bolt will be equal to the external force. This means that fluctuating external forces will not cause fluctuating forces in a preloaded bolt as long as the preload exceeds the external force. The result is that fatigue failure will not occur.
In a non-ideal joint, such as in a connecting rod, the bolt will feel fluctuating stresses due to fluctuating rod distortions. These are additive to the preload, so that fatigue could result. In connecting rods, precise preloads are required because if they are too low, the external forces (the reciprocating weights) will exceed the preloads, thus causing fatigue. If they are too high, they provide a high mean stress that combines with the fluctuating stresses due to rod distortion. Again, fatigue is promoted. The objective, then, is to preload a bolt so that it just exceeds the external load, and no higher.
To sum up: both insufficient preloads and excessive preloads can lead to fatigue failures.
Thread
Thread Starter
Forum
Replies
Last Post
Lakersallday24
6th Generation Maxima (2004-2008)
14
Nov 7, 2024 07:31 PM
Finkle
4th Generation Maxima (1995-1999)
13
Sep 27, 2015 09:53 PM