this is my lsvtec from last year. eventually, it lost 40 psi in cyl #1 due to a scratch in the cylinder wall. it blew most of the oil out of the motor through the catchcan, so i probably drove around with half the oil in the motor for about 5-10 miles just putting around 2000 rpm.

i found this upon teardown.

just a few pieces. is this where it came from, the backing material to the bearings?



it wasnt knocking, the crank/friction side of the bearings didnt have any excessive wear, and all bearings were still properly aligned in the rod ends with the tangs. none of the rod big ends were scored/burnt/rainbowed

just want to get some clarity on this before i reassemble it once its back from the machine shop, which should be sometime next week

 

do you have a picture of the babbit material side?

 

Looks like left over debris from machining.

 

i think i found it, look around the oiling hole



ok now the bigger question, what causes that? overheating? bad oil? just trying to not have a repeat performance here

 

How did the oil pan look? Was there a lot in there? It's not too much to be worried about. Definitely looks like bearing material. Could have been from previous build and not all the oil passages were 100% cleaned out.

 

no other metal in the oil, didnt look like metallic paint either.

build only had about 13,000 miles on it. it lost some compression due to a scratch in the cyl wall #1 cyl, and blew out most of the oil out of the catchcan. i caught it quickly thankfully

 

Who made the bearings?

I've had some cheaper clevites flake before . . . its not exactly unheard of.

 

all bearings are oem. tolerences were between .0015-.0019

 

Most all the oem LS/b20 bearings I have seen exhibit some flaking around the oiling hole.

 

Hmm ok. More common than I thought. I just didnt want to have an issue with tolerance or anything and make the same mistake twice. The pieces were far to big to make it through the pickup screen and oil filter

 

Use ACL race and you won't get any of that crap

 

The tolerances dont allow for that im in the yellow and red range between the standard and hx extra clearance. I would tho otherwise

 

did you put oil on the back of the bearings when you installed them?

 

no i didnt. i dont think i usually do. they do get a healthy coat of assembly lube on the crank surface upon assembly. ive never had a problem with it in the past

 

1. the coloration on the back of the bearing indicates something. any ideas, guys

2. the contact pattern on the face indicates another. what you guys think is going on

 

how tight were the rod nuts when you removed bearings

 

nothing excessive, but i dont remember exactly as it was last fall.

the rods are oem with arp replacement studs. they were installed, did 3 on/off cycles, then retorqued to the spec i think it was 26 ftlbs with the moly lube and brought to the machine shop to be honed out.

is the breaking apart of the bearing face around the oil holes normally caused by contamination on the oil like fuel or coolant, or is it pretty normal. i cant see it being a tolerance thing.

since the motor ran low on oil im not sure how well i can accurately look at the wear on the bearings as being indicative of proper/improper tolerance. they all plasticgaged between .0017-.0019

 

were to bolts loose at the time you took apart the rods

oh, oil starvation. That will cause the bearings to become wiped

 

yeah it certainly ran on low oil.

i guess im lucky i caught it when i did before it spun a bearing or damaged the crank/rods

 

x2 on the oil starvation.