3 rod bearings within a year

mitecl96 · Jul 23, 2013

Alright, just like the title says, I have spun three different rod bearings with in a year. :barf:

Spun my first rod bearing a year ago, took 3 months to rebuild that motor, had that motor finally put together and within 5,000 miles that motor spun a rod bearing, still being in debt from the rebuild I chose to pull a motor from a pull a part that only had 127,000 miles on it. My girlfriend helped me with buying this motor, now maybe 4,000 miles on this motor after dropping it in It spun a freaking rod bearing, :cry:

What can cause bearings to go besides the engine, something has to be causing the bearings to wear and spun in my car.

Miasma · Jul 23, 2013

Check your clutch adjustment, if it's out. It could be dragging on the crank creating more sidewall pressure.

Do you see hot spots on the crank shaft. Hot spots are caused by a spun bearing. After you spin a bearing you need the crank redone or a new crank entirely. Along with possibly having you block realignment honed.

Example of hot spot on crank...

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mitecl96 · Jul 23, 2013

What do you mean by checking my clutch adjustment? What am I looking for?

I never noticed a hot spot on my crank.

Ghost_92TSi · Jul 23, 2013

Damn that sucks, I was going to say the first block could of been the rods being out of round. But a second block changes things. Are you reusing any parts from the old motor, IE, Oil pump, oil filter housing, head. If there was metal shavings from the first motor. All these parts would need to be throughly cleaned because it can introduce this to a new motor and start tearing into the bearings.

Cdc1221 · Jul 23, 2013

Yes reusing anything from the old engine could a crapped this one, including the turbo. Like Chris said, everything needs completely disassembled and cleaned. I made that mistake once myself...

mitecl96 · Jul 23, 2013

Only thing I used from the old motor was the intake and header. Everything else I left alone.

The first block the rods were looked at by the machine shop and two had to be replace but all where round and in spec. I really think there is something outside the motor that is causing my problem. I know a bit about cars, but this is completely stumped me. 3 motors within a year and in debt $1500 and now nothing to show for it.

Cdc1221 · Jul 23, 2013

The only external part I can think of that would cause a bearing failure would be an oil cooler, at least on a non turbo. And that's if it has one

mitecl96 · Jul 23, 2013

Don't have one, something is off here. Why all of a sudden my car is spinning rod bearings.

glowryder · Jul 23, 2013

How do you drive.. Hard turns? Any baffles in the pan/ oil control? the 420a is kinda notorious for spinning bearing if you drive the car hard in turns, starving the motor.. We accumulate too much oil in the head and our poor drain back leaves the pan oil level to be desired..

I'm assuming the machine shop put the bearing tolerances to stock, even though you've turbo'd the car? while thats not a smoking gun, it could have something to do with it..

Any way of monitoring your oil pressure?

mitecl96 · Jul 23, 2013

I don't drive the car hard, and I know about the hard right turns in these cars. I shift at 2500 rpms and never let it get below 1700 rpms when slowing down.

Not sure where the turbo came from but my car is stock 420a n/a. The machine shop made sure it was to stock specs, but that was with the old motor. The motor in the car now is the one I pulled from the pull a part with 127,000 miles on it and just put oil in it and put it in the car.

glowryder · Jul 23, 2013

Oh my bad, i thought you were boosted. Well thats defiantly a weird issue if your driving like that.

mitecl96 · Jul 23, 2013

Yeah I know, really considering selling it and looking for another 420a or maybe even a 1g

slickers111 · Jul 23, 2013

Seeing as its spinning bearings alot, Id just drop the pan, and replace the 1 bearing every 3,000 miles.

Routine Maintenance. LOL

But I have no clue as to why it would be spinning bearings like that.

mitecl96 · Jul 23, 2013

slickers111 said:
Seeing as its spinning bearings alot, Id just drop the pan, and replace the 1 bearing every 3,000 miles.

Routine Maintenance.

But I have no clue as to why it would be spinning bearings like that.

Funny I have been thinking about doing this, just to get me by for a little while.

killercolt · Jul 23, 2013

mitecl96 said:
Alright, just like the title says, I have spun three different rod bearings with in a year.

Spun my first rod bearing a year ago, took 3 months to rebuild that motor, had that motor finally put together and within 5,000 miles that motor spun a rod bearing, still being in debt from the rebuild I chose to pull a motor from a pull a part that only had 127,000 miles on it. My girlfriend helped me with buying this motor, now maybe 4,000 miles on this motor after dropping it in It spun a freaking rod bearing,

What can cause bearings to go besides the engine, something has to be causing the bearings to wear and spun in my car.

Few causes:
-Poor crank prep
-7bolt bearings in 6 bolts block (seen this before)
-debris from oil pump. Usually from not deburring
oil pump gears and oil pump case. Helical oil pump gears can cause shaving in the oil pump after bs elimination too.
-excessive detonation
-bad crank of rods
-not cleaning out engine after turbo bearing failure
-recycling oil cooler after bearing failure

Note: Do not trust the oil filter to filter the oil complete. Debris can bypass the filter.

mitecl96 · Jul 23, 2013

killercolt said:
Few causes:
-Poor crank prep
-7bolt bearings in 6 bolts block (seen this before)
-debris from oil pump. Usually from not deburring
oil pump gears and oil pump case. Helical oil pump gears can cause shaving in the oil pump after bs elimination too.
-excessive detonation
-bad crank of rods
-not cleaning out engine after turbo bearing failure
-recycling oil cooler after bearing failure

Note: Do not trust the oil filter to filter the oil complete. Debris can bypass the filter.

Most of these or the 4g63 motor I'm a n/a 420a.
The motor in the car has had no work done to it.

Miasma · Jul 23, 2013

[ame=http://www.youtube.com/watch?v=vYJxQyjIhUw]Proper Clutch Adjustment - YouTube[/ame]

How to adjust your clutch, might have something to do with it might not...

Other than that all I can think of would be oil starvation, journals being out of round. Could you measure your crank and rod journals?

mitecl96 · Jul 23, 2013

I watched that when I replaced my slave and master cylinder.

Would bad motor mounts do this. I have a jerk a little when I give it gas and when I let on the gas.

dacowgod · Jul 23, 2013

A long long time ago when I first met a good friend of mine he had the exact same issues as you .... He spun bearings in 2 freshly rebuilt motors(One SBR, one Locally built) and a long time running used motors withing 500-1000 miles every time..

I took one look at his tune..and told him he was running wayyyy to rich..i have no idea how the car was not breaking up/missing it was still pretty damned fast actually (Ran 12.3's back then) ..

His oil smelled like pure gasoline...

He got a wideband I dialed the car in for him and low and behold he has never had bearing issues since... now the car runs 9.20's w/ an hx40 ;-)

Your tune can be either too rich or too lean and wipe out bearings ..Rich will cause the oil to lose its film strength.. Lean will cause knock which will force the crank to make contact w/ the bearing surface and beat them out that way.. Either way its bad news....This logic also applies to your NA motor as well... Not saying its the problem..but just something else to check is all..

slickers111 · Jul 23, 2013

mitecl96 said:
Funny I have been thinking about doing this, just to get me by for a little while.

Id do it. But it can just cause more failure of other parts from the metal shavings.

mitecl96 · Jul 23, 2013

dacowgod said:
A long long time ago when I first met a good friend of mine he had the exact same issues as you .... He spun bearings in 2 freshly rebuilt motors(One SBR, one Locally built) and a long time running used motors withing 500-1000 miles every time..

I took one look at his tune..and told him he was running wayyyy to rich..i have no idea how the car was not breaking up/missing it was still pretty damned fast actually (Ran 12.3's back then) ..

His oil smelled like pure gasoline...

He got a wideband I dialed the car in for him and low and behold he has never had bearing issues since... now the car runs 9.20's w/ an hx40 ;-)

Your tune can be either too rich or too lean and wipe out bearings ..Rich will cause the oil to lose its film strength.. Lean will cause knock which will force the crank to make contact w/ the bearing surface and beat them out that way.. Either way its bad news....This logic also applies to your NA motor as well... Not saying its the problem..but just something else to check is all..

All this sounds good if I had done anything to my car, It is the stock motor, with stock ECU, I was getting 34 to 36 mpg. I had a lot of carbon build up on my old motor. Looked like it had 200000miles on it and it was only less than 5,000.

If it is the tune how do I go about looking at it with it still running the stock ECU.

YZFR1 · Jul 23, 2013

On a stock 420a it might just be bad luck. But if you wanted to be certain, look up Blackstone Labarotories. They can test your oil sample for $25. You should also take apart the motor and check all crank clearances.

mitecl96 · Jul 24, 2013

I'm not doing engine work on this motor ha I call it quits on this car. It is up for sell as much as I don't want to. Just wish I knew why its throwing rods with-in 5,000 miles

But still have a question will bad motor mounts do this. My car jerks a little when I shift, accelerate, and decelerate.

tylerbrunkhart · Jul 25, 2013

I just spun a bearing in mine after 4000 miles on mine

daniel dee · Jul 25, 2013

I am a ex muscle car V8 guy....Rod bearing failure is oil film breakdown..
Solution is having adequate oil pressure ,(don't like zero weight oil for bearing protection).. Bearing crush and bearing clearance...
For V8 motors I ran .003" bearing clearance...Not sure if this is too much for our tuner motors but it works fantastic in big V8 motors.
Did many 1/4 miles runs with no bearing failure.

I am currently running .002 in my built stroker motor and the bearings look like crap to me.

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3 rod bearings within a year

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