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Pulling The Lq9. Spun Cam Bearing


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Went to do a cam swap this weekend and had trouble getting the old cam out. Finally after what seemed like an hour Cody was able to get it out. The 4th journal on the cam, second from the back was black, like the bearing was getting really hot. We took a chance and put the new cam in hoping it would be ok, started it up, and the oil pressure was at 6 maybe 7. So we're pretty sure its a cam bearing. Going to get the motor out this week and look at my options.

 

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You can see where this lobe was excessively worn. Cam has 30k on it. Maybe a bearing in the lifter? Or To much spring pressure? Running Patriot Duals. This is the only lobe with wear like this.

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o man that is never any good. i had to mod my driver header a little to get it to clear the front drive shaft.

 

Mod it for what? I'm pulling the motor and if the header does lean far enough for the motor to come ill take the driveshaft out.

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  • 4 weeks later...
  • 4 weeks later...

Not sure if this will help you as I'm replying late, but my machinist has seen a few of these engines with this problem. I'm 99% sure mine has the same problem (oil pressure dropped one night after a little bit of play) ;-D.

 

Anyways iirc, he said around mid 2004, GM changed the cam bearing part #. Basically, the newer cam bearings have a larger OD. Consequently, he has been able to machine the cam bore out to fit the newer bearings rather than scrapping the block. His thinking is that there wasn't enough crush designed into it from the factory or some other weird issue and that they resolved it with the new design.

 

Hope this helps----good luck!!!

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Not sure if this will help you as I'm replying late, but my machinist has seen a few of these engines with this problem. I'm 99% sure mine has the same problem (oil pressure dropped one night after a little bit of play) ;-D.

 

Anyways iirc, he said around mid 2004, GM changed the cam bearing part #. Basically, the newer cam bearings have a larger OD. Consequently, he has been able to machine the cam bore out to fit the newer bearings rather than scrapping the block. His thinking is that there wasn't enough crush designed into it from the factory or some other weird issue and that they resolved it with the new design.

 

Hope this helps----good luck!!!

 

 

 

 

 

so your truck is still making noise? I thought it was a cat? I hoped it was a cat...

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No, my issue with the cam bearing happened late last winter and I've put 15-20,000 miles on it since. There is a tad more valvetrain noise (ever so slight), but nothing really obvious. My knock was/is the catalytic converter which is causing a severe exhaust restriction. I'm still driving it unfortunately for now. I'm in the process of figuring out what exhaust I'm going to run. Right now, I have (2) 3" catalytic converters (Magnaflow) and a set of pacesetter headers with the v-bands welded on. They are 1 3/4". My plan is the run 3" from them to an x-pipe, then dual mufflers and finally out the right rear with a pair of 3 1/2" tips from Magnaflow.

 

The muffler is the only question mark right now. Must be fairly quiet so that narrows my choices a lot. I am leaning towards some huge magnaflows, or maybe flowmasters or even possibly some edelbrocks. Considered Dynomax too. Basically, I have no clue which muffler I'm going to run....LOL!!!

 

Sorry to hijack this thread and thanks for the concern.

 

so your truck is still making noise? I thought it was a cat? I hoped it was a cat...

 

Sorry to hear about this, that totally blows. :(

 

Mr. P.

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No, my issue with the cam bearing happened late last winter and I've put 15-20,000 miles on it since. There is a tad more valvetrain noise (ever so slight), but nothing really obvious. My knock was/is the catalytic converter which is causing a severe exhaust restriction. I'm still driving it unfortunately for now. I'm in the process of figuring out what exhaust I'm going to run. Right now, I have (2) 3" catalytic converters (Magnaflow) and a set of pacesetter headers with the v-bands welded on. They are 1 3/4". My plan is the run 3" from them to an x-pipe, then dual mufflers and finally out the right rear with a pair of 3 1/2" tips from Magnaflow.

 

The muffler is the only question mark right now. Must be fairly quiet so that narrows my choices a lot. I am leaning towards some huge magnaflows, or maybe flowmasters or even possibly some edelbrocks. Considered Dynomax too. Basically, I have no clue which muffler I'm going to run....LOL!!!

 

Sorry to hijack this thread and thanks for the concern.

 

 

 

 

 

There is a thread on LS1tech where they directly compared a bunch of mufflers on an engine dyno back to back and the Hooker Maxflow were the 3rd most power (less than 1hp difference) and the 2nd quitest behind the Borlas. I'm running one on my truck and even with no cats, ARH LT headers, dual 3" Yd into single 4" and a single 4" Hooker Maxflow dumped in front of the axle it's quieter than the stock setup with a drop in Flowmaster. Now at WOT this baby SCREAMS but under 4krpm it's deep and smooth.

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