coops09gxp

First off let me say hello to all of you!! My name is Tony.

First post on this board and I am coming out looking for some big answers.

I am freshening the stock bottom end on my LS3 motor. I am new to the LS series of engines but have worked with the old style sbc engine for the better part of 20 plus years. Don't say that to sound arrogant, just saying I am fairly competent with a wrench on a motor so please don't hesitate to get a little technical with me. I may ask questions or for a link for the info, I'm all about learning here!!!

While pulling my cam out I checked my cam bearings, heard of these goin bad on some of our motors. Mine don't look the greatest in my opinion. They haven't delaminated but there is a ton of the base metal showing already and it looks like GM threw the cam in there. My G8 GXP only has 24k miles on it as my daily driver. With that, I'm going to put new cam, rod, and main bearings in the motor. The bottom end is completely stock and I will be keeping it that way with the exception of ARP main studs, and possibly rod bolts as well.

On to the real questions. I have heard and read a little about coated cam bearings, can somebody please explain the pros and cons of this for a daily driver application. I have seen a number of post on this forum about the use of new rod bolts and having to resize, makes sense why it would need to be done. I see ARP makes a few different versions of rod bolts for our LS engines, what would be recommended for a daily driver with between 450-500rwhp? Also, a good source for aftermarket stock size replacement bearings for the cam, rods, and mains.

Thank you for taking the time to read through this. I look forward to spending some time on this board and learning more from you folks about the LS series of engines. Have a great evening!

Tony

slowride

iTrader: (3)

The stock cam bearings always look like poo on the front journal in every car I have been through, but they were never a problem either. ARP main studs might need a line hone to tru up everything just like the rods. Why are you rebuilding it at so low of miles?

I've always used the durabond HP cam bearings, but no experiance with a coated cam bearing. If you re-size the rods it will take oversized od bearings which I believe are not availible in a race bearing just a FYI.

Anthony Williams

iTrader: (3)

Yep.. I would put my money into the known issues LS issues like Rocker bearing, push rods, harmonic balancer etc. and throw on a set of GM cnc ported heads a good cam, deeper gears then get a good tune and call it a day, GM upgraded the rod bolts in 2002 and unless you are spinning to 7k all the time or running boost, main studs are over kill..

coops09gxp

Thanks for the input folks! Didn't want to put the whole story about why the motor is out but it may give better back ground. I will try and keep it short lol. Purchased a head and cam kit from a reputable vendor from another forum, heads came from one of the best places for heads. Heads were assembled with the wrong valve springs and the springs themselves were installed wrong, should have been installed at 1.800 height, actually installed at much shorter. With my head and cam combo it left me between .005-010" from actual coil bind on the valve train.

At the dyno for tune and first pull valve floated bad about 4000-4500. Tuner came out and said something is SERIOUSLY wrong in the valve train and that is what they found. That valve float created what turned into a latent failure, i.e. one that shows up a bit down the line. What ended up failing was a lifter do to the valve float. Trashed the pin the roller rides on and eventually broke the side out of the lifter. Forgot to mention that it took the vendor 3 attempts to get me a matching set of lifters, should have known then!!! Some of it probably is my fault for not double checking all of the components for proper assembly before installing on the car. WON'T HAPPEN AGAIN!!!! I will be assembling my onw heads this time!.

So, that is why the motor is apart. As I mentioned in my first post, I'm not all that familiar with the LS series of engines yet but I am learning. Since it was down this far I thought it might be a good time to upgrade to ARP main and rod bolts for piece of mind. Now, if the stock bolts are reusable and strong enough for my application I won't monkey with it.

My new combo will feature a Patrick G spec'd cam cut by Geoff at EPS, new PRC 250 cnc aftermarket heads, and a Patrick G remote tune. All other components will stay as they were. With a redline of 6800rpm and shift point of 6600rpm from what you said Anthony Williams the stock bottom end is might be just fine. I only visit the drag strip a couple times a year. As I mentioned, was looking to do this strictly for piece of mind and not really out of need with the main and rod hardware.

Also, thanks for the input Slowride about the mains possibly needing align honed as well, never gave that a second thought!!!! With the cam bearings it would make sense that the front bearing would possibly show more wear, this is where more tension would be seen with the cam gear right there also. From what I could see of the other cam bearings they didn't look much better. The journals on the cam don't look bad at all so this is what had me wondering. Cam had 6000 miles on it since the previous head and cam install.

Again, thanks for your input folks, if there is anymore I am all ears and would love to hear your thoughts!!! Have a great day!!!

Tony

slowride

iTrader: (3)

Since you have the newer style factory rods, etc. to not mess around with so much machining I'd just run new stock head, rod and main bolts. Some re-use main bolts and never have a problem, but I just use them to check clearance and put in new stock ones. In a low rpm hydraulic valvetrain NA setup I don't see the factory bolts having any problems. Depending on the condition of the oil pump you could just port and shim it for a little extra oil pressure unless it was great before the failure. Not sure if it had trash go through it or not though.

It's really up to you on how many things you feel you need to upgrade and pay machining costs for, etc. The stock stuff is just fine for a setup like you are doing though. I've built and had a hand in quite a few ls motors so give me a ring if you ever have any questions.

coops09gxp

Slowride, Thanks for the input. I really don't want to take the bottom end apart. The only reason I was, or am considering it was just simply I have it apart this far and thought it may be a good idea or upgrade. Still learning about the do's and don'ts with the LS engines. I have no reason to suspect anything is wrong with the bottom end at all. Just simply a precautionary or piece of mind thing. From what people are telling me though my bottom end should be more than adequate for my usage.

With the oil pump I did order a new Melling high volume pump. Now, whether it is installed or not I don't know. It sounds like the stock LS3 pumps are good pumps to begin with, it is the ones used with the VVT motors that can be a bit lacking for mild performance builds from what I have read. I will know more once I pull the stock pump apart and fully inspect it and clean it.

With the money that is being spent I am all about doing it wisely and not just spending it to say look at me I got this neat shiny part lol. My first and most important goal is a good working combo that will last. From talking with more and more folks it seems I AM starting to learn a bit more and get closer to that and also getting more educated with things. I simply love learning about these motors and what makes them work and work well. Call me a nerd lol. Thanks a lot for the offer to help!!! If I hit any snags or have more questions I will probably be hitting you up. Thanks again!!!

Tony

coops09gxp

Does anybody else have any thoughts or input on this?