Why do I see so many people in LT1 tech with spun bearings? 95% of them have done cam swaps in the last year or so. What is it that causes them to do this? Should I be worried about this in my LS1?

 

main cause is probably dirt getting in during cam swap

use the search button, this has been discussed before, and isnt really "advanced" tech.

 

I would say coolant in the oil after the swap, gotta get that stuff outta the pan, its a bearing killer.


David

 

For my part it was gas in the oil. I had my headers welded (leaking) and I left the sensors on. I think they didn t like the heat and stuck on LEAN. So the computer once in closed loop was seeing a lean condition so it was dumping fuel like crazy. I changed the sensors. then it was ok. Went for a test drive and spun the rod bearings.
Mistake 1: did not remove sensor.
+
Mistake 2: did not change oil and filter after replacement of sensor, even though I knew it was really running rich.
=
rebuild.

may this experience help you

 

Installer error.
One big reason is putting in a new cam to roll on some 100k mile bearings. Most of the time it's because of the cam getting nicked on the bearings, dirt and coolant getting in, all this is just a result of installing a cam in a tight engine compartment.

-Shannon

 

besides the formentioned..sometimes even the most reputable cam manufacturers coresare not true or not handled in the best way when its shipped to your door ... if you install a cam and you feel any drag when you rotate it in the block..most likley needs some pinging to starighten her out..good machine shop usually will catch that and resolve the problem..but something to keep in mind next cam install...

 

If it did not get pruned there was a good post on it here a whilr back.

Try searching to see it had some good info

 

i had the same problem,an hour after cam install knock,knock.i thought it could be the shop that installed it for me until i read an article in gm high tech.lt-1 engines can have misaligned main bearing bores from thermal fatigue,the torque from head bolts being tightened can disrupt the block.this is an exact quote that Jayson cohen from motorsport technologies agrees with.he recommends the replacement of main an rod bearings,with cam and or head installation.

 

There is absolutely nothing about an LT1 as compared to any of the zillions of Gen I SBC's out there with respect to how the block would respond to a cam change. The LT1 cam change/spun bearing association is a myth. If the cam is installed properly there is no more (or less) reason for an LT1 to spin a bearing than any other SBC.

Rich Krause

 

Just lots of inexperienced people trying to tackle a project like that for the first time. Leave 1 thing out and it could lead to disaster..I remember my first time I followed step-by-step instructions to the T. I can just about do it in my sleep now though

Its all about preparation/cleanliness/taking your time!

Cody

 

listen to rich on this one!

 

Oh yeah !!!!!!

And Rich is dead nuts on this

 

How about the fact that the first thing many people do after installing a bigger cam is to raise the rev limiter to use the cam to its full potential? A few hundred RPM can make a big difference on engine life. Going from 5800 to 6200 can mean roughly a 14% increase on internal stresses as forces increase with the square of engine speed increase.

 

I think Lonnie is onto something here!

 

except if they spin a cam bearing.....

RPM will kill some things, but most likely it's because they screwed up a bearing or got some dirt in the motor too.

He is right on the math on that, and yeah it's got a lot better chance of going BOOM!

Bret