Bob This is an analysis issue but also I felt I should post here first.
For all those with the GM engines LS1 and the other modular engines that develop a knock sound after just a few miles I need your help and info on the knocking sound.
I have a yet unproved theory that the sound is caused by the forward thrust bearing wearing the copper overlay out of that bearing. Once the coppper is gone the bearing stil functions but slowly wears resulting in eventual engine failure or the crank sensor not being able to receive a signal causing the engine to shutdown unexpectedly. The problem is exacerbated by unequal stress on the crank and loose tolerance of the other components and a basically unbalanced engine.
This is just a theory and I need more info to prove it . First if you have had a oil analysis drawn from 0 to 100,000 miles on any of these engines in the last 3 years please share that under "GM engines knock" header of the oil analysis section. If you are my customer you know I am already working with you.
The copper seems to be high initially and begins dissipating which is not unusual. The problem I need to verify is that upon the copper declining, I get reports from the customer that the knock is made evident by intensity and increased sound. Or in other words the first time they notice the sound being a issue.
Finally, If this results in any action by GM or you to GM under warranty or otherwise it is your business. If I am brought in in any capacity our prevaling consult fees,travel costs,and lodging expenses apply. If enough of you share data here for free it could solve a growing problem. Hopefully I am wrong and it is isolated cases only.
WARNING LS1 and GM modular engines
- Thread starter Terry
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Patman
Staff member
Terry, if you want more data on this, I suggest you post a message at both LS1.com and LS1Tech.com, both of which have thousands of members with these engines.
For all those with the GM engines LS1 and the other modular engines
Specifically can someone provide more detail on this ie: 3.8 L or 3.5 L or something else. The modular engine phrase is what I do not understand.
[ August 13, 2002, 04:09 PM: Message edited by: Spector ]
Patman
Staff member
I will post this link on both of those boards for you Terry!
Terry -
Are you familiar with the GM Piston Slap Website?
www.angelfire.com/tx5/gmpistonslap/index.html
Many there should be interested. (Sorry I can't link directly)
Terry, I can't imagine where'd you'd get an idea like that... ![[Roll Eyes]](images/icons/rolleyes.gif)
Anyway, I'll dig up a copy of tims and get it on here.
For all of you out there with ideas of people who want more info, instead of sending Terry all over, You might just goto your favorite site and have them centralize their posts and findings here as it will be easier to do that than to go there on one site, switch to another and find posts on that one and so forth.
Anyway, I'll dig up a copy of tims and get it on here.
For all of you out there with ideas of people who want more info, instead of sending Terry all over, You might just goto your favorite site and have them centralize their posts and findings here as it will be easier to do that than to go there on one site, switch to another and find posts on that one and so forth.That is an interesting idea Terry. The 3300 Buick V6 (89-93, same family as the 3800) has a TSB describing the same sort of problem and giving a fix for it in that engine. It is possible to change the bearing without removing the crankshaft on that particular engine. I have no idea if it is possible with an LS1
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