what exactly is the cause of this? and what's the difference between stock bearings and aftermarket bearings (i.e. clevite)...

 

why people are spinning bearings? simple - ls1 owners are greedy with rpm. guys run big cams and ls1 owners think 7000 rpms is no big deal

untill they cry about a rod bearing that didnt have any oil!

 

so are you saying the larger the cam, the more likely to spin a bearing?

or is it more spinning it to 7000 rpms...

 

He's saying both. It's EASY to throw big top end cams into LS1s and spin the motor to make good numbers... Factory bottom end tolerances begin to fall short of acceptable the higher you wind the motor... Boom.

 

Thats why you want good bearings and rod bolts to hold it together.

 

Change your oil more often,like every 1000 miles or less if your running extremly hard all of the time and save your motor.My car has over 750 runs on it,I change oil after every 30 -40 runs.Also do not hot lap,let it cool at least 15- 20 min,or longer in extream heat.

 

Better bearings aren't really the solution at all. The factory bearings are fine for 90% of the people on this site. It's the RPM that's causing this. Stock rod bolts are not meant to be spinning 7k plain and simple. Some people throw a large cam like the MS4 or Trex in their car and need to spin pretty high to get the most out of them, so they turn the limits up to mid to high 6,000 rpm. Some get away with it, others (some of the spun bearings you're seeing) do not. You can spin the LS1 shortblock to 7k, you just need to take a few precautions. New rod bolts are the biggest.

However, I've read quite a few where it was just the crappy oiling systems in some of the pre 2000 LS1's that have lead to spun bearings as well. So it can't all be blamed on the high RPM, but a good deal can...

 

thats why i went custom with my cam, to be shifting at 6500 and that melling oil pump and gc and k&n oil filter

 

The cam has no physical effect on the actual spinning of the bearing.

Is is the rpm and oil starvation that do the damage.

 

Just curious but if we wanted to spin it that high, what would we need to replace and buy new better parts?

 

ARP or Katech connecting rod bolts would make it a lot safer to spin higher.

Of course upgraded pistons and rods would be better, it just depends on how much you want to spend.

 

hmmm id say because there to cheap to pay the extra 100 bucks for better rod bolts.....

 

any difference between the ARP or Katech rod bolts?

 

Katech ones are designed to be direct replacements w/o having to resize the rod. Some ppl put in the ARP's w/o issue, but there is more risk to that - although many have gotten away with it.

 

RPM's can be a killer.

 

Street cars are not designed for 7K RPM. If you want a race car, go buy a race car. I mean its simple. Street applications are designed for reliability on the long term if treated properly. I can't get over how people complain and gripe about spinning a bearing running their stock bottom ends to 7K.

If you want to do it all the power to you. Either suck it up when you puke your motor, or spend the money, do it right, and build a race motor.

 

I spun a bearing on 1st dyno pull after the cam. Spun at 6200 RPMs, so it isn't merely the RPMs. and the oil pressure was good the entire time. I think it has to do with the stock rod bolts expanding under high temp/friction. Moral of the story, SPRING FOR A SET OF ARP ROD BOLTS (and new bearings) when you do the cam.

 

The rod bolts will only help guard agains a spun bearing due to bolt stretch. Thats only one issue. Improper or worn tolerances is another. Poor oil pump volume is another. Low oil pump relief valve spring tension is another. Crank side loading can also dump oil. And of course running dry. Theres a great many parts to the equation. Unless you live at 7000+ rpm, theres a lot of different things that can get you. Stock rod bolts are just as likely to break and send a rod through the block as they are to stretch. Im not convinced theyre the sole cause of spun bearings as it seems people are claiming here.

 

Not sure what it is , but I know 2 people that have spun bearings. One was doing a burn out. The other was a old man, drove it like a old lady and changed oil every 3k so I don't think high rpm's was his issue.

 

Aluminum is a softer metal is it not? Just my thoughts.