Well I was just wondering. I searched and read like 30 posts on spun rod bearnigs. Last spring, i was boosting on 5psi and spun 2 rod bearings. My oil light would always flciker when at idle, never while driving. I searched to see what causes spun bearings and the most I read was, its because of lack of oil and low oil pressure. I ALSO read that it could be from the vortech FMU???? I guess my question is, if I was full on oil ALL THE TIME like i was, how was I lacking oil and my oil press gauge barely reading anything? Is it because my stock oil pump went out, or what the hell? Can the FMU really cause something like this? when going WOT, my a/f gauge read the last bar on the rich side so i was deff running super rich on stock injectors and only on 5psi but i never got the black poof of smoke going WOT. I am rebuilding this winter as we speak with howells bottom end kit and planning on 12-16psi next year, but i wanna make sure i dont spin any more bearings! i got a new crank that is in factory specs now and am gonna use factory sized rod and main bearings and im getting the cyl walls bored, but what can i do to make sure this wont happen again?

FMU only has to do with fuel, not oil.
sounds like low oil pressure to me.

even so, what causes low oil pressure?
a shot oil pump?

A failed pump, or failing pump could most definitely cause low or no oil pressure. The FMU, SFMU will not cause low pressure because as stated /\/\/\/\/\/\ it deals with fuel NOT oil.

Good luck.

well ya shit, i knew the FMU was straight about fuel, but it was mentioned in a post when i searched, dont know why, but the dood said his fmu caused a spun bearing, lol. so, ONLY a oil pump going bad or bad already could cause a bearing to spin due to the low oil pressure?
its weird that this hapened liek a month into boosting on 5psi, never when i was n/a!

definetely the oil pump.

The oil pump failure has nothing to do with boosting. Post Hoc isnt always true.

Did you take out all the shavings after drilling out the oil pan?

How many miles on your car? Was the oil pump ever replaced? I know some memebers here have had bad mellings like 3 times in a row.

I was on the stock pump. Ya I took out all the shavings when i drilled it. Um no it was never replaced of my knowledge unless the previous owner had to. Car has 47k on it.

Who knows, guess it was the oil pump. doesnt make sense though, but oh well, hopefully my melling will help me out with this shit, lol.

i was pretty sure that they spun due to low oil pressure becuz of lack of oil and i figured it was from the oil pump going bad, just wanted to make sure the pump could be the only prob.

the oil pumps on our cars are very unreliable for such a small engine

-EE

:(

Originally posted by THEBALLIN1
the oil pumps on our cars are very unreliable for such a small engine -EE :(

Actually, our oil pumps are very, very reliable..they consist of only 2 moving metal rotors, driven by the crankshaft. The only real way for one of these to fail would be to have a rotor actually break. There is also a pressure relief spring and plunger, but I've never heard of any issue with them, unless a larger metal particle gets the plunger stuck, which can cause pressure problems. First thing I would do, is to get an actual oil pressure gauge, and don't rely on the idiot light on the dash. The sending unit could be going bad, and giving false information. Normal oil pressures when cold, is around 60-70 psi at idle, and aroun 25 psi at a fully warmed up idle. Around 60 psi off idle fully warm.

The main reason for spun bearings is lack of oil. That is for the most part user error, for not keeping the pan full of good, clean oil. Combine a boarderline full oilpan, and a long, sharp turn(esp right hand turns)then that can create a short amount of time that no oil is getting through the pump and into the bearings.

So first thing I would do is to get an actual pressure reading. Then, second step would be to inspect the pressure relief spring/plunger. They are under the large bolt, right on the oil pump cover, near the oil filter area.

My brand new melling pump failed on me causing me to spin a rod bearing. Any other after market high performance pump for the 420A?

Originally posted by XtremeRS

Originally posted by THEBALLIN1 the oil pumps on our cars are very unreliable for such a small engine -EE :(

Actually, our oil pumps are very, very reliable..they consist of only 2 moving metal rotors, driven by the crankshaft. The only real way for one of these to fail would be to have a rotor actually break. There is also a pressure relief spring and plunger, but I've never heard of any issue with them, unless a larger metal particle gets the plunger stuck, which can cause pressure problems. First thing I would do, is to get an actual oil pressure gauge, and don't rely on the idiot light on the dash. The sending unit could be going bad, and giving false information. Normal oil pressures when cold, is around 60-70 psi at idle, and aroun 25 psi at a fully warmed up idle. Around 60 psi off idle fully warm. The main reason for spun bearings is lack of oil. That is for the most part user error, for not keeping the pan full of good, clean oil. Combine a boarderline full oilpan, and a long, sharp turn(esp right hand turns)then that can create a short amount of time that no oil is getting through the pump and into the bearings. So first thing I would do is to get an actual pressure reading. Then, second step would be to inspect the pressure relief spring/plunger. They are under the large bolt, right on the oil pump cover, near the oil filter area.

well i have an oil press gauge now, but back then i did have a shitty one. i guess i should get a crankscraper especially when turbo, so in hard turns, i keep in the whole pan and keep the journals oiled up! this hapened a long time ago and i was just checking to make sure it was most liekly the pump that failed so i could know what it was in case this seems to happen during the current rebuild

but thats what i mean even if you have a gauge to monitor your oil pressure, taking those hard turns is still pontentially harmful....
HARD RIGHT TURN = Rebuild
that has happened to me twice.....
what can i do? :shrug

-EE

Baffled pan + crankscraper

..thats the answer to the spun bearring problem