what are the main causes of rod bearing failure?

Iv been researching this a little bit and Iv been told running too much timing may be an issues. my first ls-t motor spun a rod bearing the 3rd day after it was dyno tuned and my last ls-t just spun rod bearings 2 and 3 and number 1 was all eaten up. Im wondering if its just because these motors are unknown miles and it was a coincidence or if its due to my tune?

I can post maps if needed. at 18lbs Im at 13 degrees total timing at 7krpm. only revving to 7200. first motor made 314/280 my current setup is around 330whp.

I just put all new rod bearings in my new motor along with a b16a oil pump and a s2000 oil filter. I also want to do water methanol injection just to keep things safe.

 

i say dont even worry, if you put new rod bearings in and a oil pump you should be fine. adding boost to a 150k motor with original oil pump, i'd say is the cause most of the time.

 

Detonation can flatten bearings pretty quickly. Oil starvation (for whatever reason) would be the other cause.

 

what are your rod bearing clearnces and what oil are you using

 

The main cause is friction :D

 

are you doing measurements on your bearings? or your just guessing?

 

I runt castrol gtx 10w 30 and idk on clearance I just replaced them with the colored honda bearings the crank and rods called for.

 

You did measure up for these bearings being used correct?

 

no, but your not being helpful. when the other rod bearings went out they were stock. Id like to know why my rod bearings went out. if its because of the tune or just a coincidence.

 

Are you just slapping in new bearings and calling it a day? You need a new crank and rods first, If you didn't know that already...

 

My bet is oil pressure. do you have an oil pressure gauge?

 

again, Most likely because oil pressure and do to the motor prolly had alot of miles on it correct. I dont messure my bearing clearances either, if using the same block that the crank came out of. and everything is stock. std bearings shouldnt need clearance. unless there was other issuses, Then clearances should be checked.

 

When you tuned it did you use det cans or pulling plugs after each pull or what? Also are yot tuning on crome free? If so if you go into your edit advanced table tab in the upper right of the window then click base ignition table. What dose that slope look like? Is that trowing a bunch of timing in on top of it?


On second thought your running hyundata arnt you?

 

ur bearings went out and you just replaced them? that's probably where your problem lies. The guy asking if you measured wasn't trying to be a jerk, he was wondering if you measured it. You can do that easily with plastigauge to see if clearances are within specification. it's possible that it was too long and the crank was rocking around. also if you spin a bearing, you'd want to redo the crank and run oversize bearings or get a new crank. It wouldn't hurt to line hone everything as well to make sure the mains are good to go.

 

i would also check the main to make sure that the crank isnt walking

 

Haha, I'm never TRYING to be a jerk but I just am :D In all seriousness though, it's not too wise to put together an engine without measuring things up. The amount of money and time saved by doing so makes so much sense to me. Sure you can just 'toss' some bearings in there and they may hold up for a bit or forever but this is one of those better safe than sorry situations. If you've already had bearing issues in your engine it's even more critical that you measure things because there can some serious damage in there. I must say admit that I'm too afraid to even MEASURE things up myself because I'm afraid my numbers would be off and I'd blow up an expensive engine. I need to learn on a throw-away block.

 

yes I know the proper way to build a motor. again this is just a $200 ls motor so im not gonna put a whole lot of love and time into it when I can just throw in another longblock and start over. what I want to know isn't how to build a motor I want to know if maybe my tune is eating rod bearings or its just a higher miles motor.


no det can, we dyno tuned it and since Iv made some changes and just modified the tune on the street. I have a wideband in the car along with s300 so its easy to make adjustments.


I know tons of people who don't plasti-gauge honda motors when they assemble them and its never been an issue. we aren't building small block chevy motors, hondas bearings are sized specifically to the crank and rods.


eh to each his own. if this was a built motor it would be a different story. but its not, its a cheap longblock with 80 bucks worth of new bearings. thats about all.

 

The problem is that your crank and rods probably are no longer stock spec. Unless of course they're fresh from Honda.

 

the only time i have ever spun rod bearings was when i had a journal out of round. That, and detonation are the main causes other than the obvious water contamination or no oil pressure.

 

Have you inspected the bearings yet to see exactly what caused the bearing failure from the marks on them and the stuff that is on them?

I spun a bearing when I put the wrong cap on the rod haha. I would def get the clearances checked. The person I had do mine is Hatch performance engine shop in stayton.

You can just colorcode a bearing, but please tell me you went with a new rod/ crank. With the bearings spinning they will get hot and the rods will become discolored and i believe warped.

The main cause would be either oil starvation, as previously (someone) stated, or something contaminating you oil. If you are almost hydro-locking you rods, via coolant or water in you oil, that will cause the bearing to spin.

Maybe because it is the ls and it has the bad rod/stroke ratio, the extra compression added ontop of the poor old motor and the bearings that have unknown miles on them, they just fail under strong load. You do drive your motor hard, so you got to make sure that motor is fresh!

MAJOR CAUSES OF PREMATURE BEARING FAILURE
Dirt ......................................... 45.4%
Misassembly .......................... 12.8%
Misalignment .......................... 12.6%
Insufficient Lubrication.............11.4%
Overloading .............................. 8.1%
Corrosion ................................ .3.7%
Improper Journal Finish ............ 3.2%
Other ....................................... .2.8%
(http://www.engineparts.com/publications/CL77-3-402.pdf)

 

i find that chart extremely hard to believe

 

yeha id assume it might have been oil starvation since the stock ls pump is pretty weak and ur taking the old motor pretty high hp

but again thats just me

 

The OBD2 pumps are the same as GSR/Type R

 

werd
i thought he had an obdI ls

 

it is. the motor is a 92 b18a1. so far so good. Iv beat on it quite a bit and I guess Ill just see how long she will hold up