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Are you using full groove main bearings or stock? If stock maybe you should use full groove instead What weight oil and what where you doing when it spun, cold , hot, driving at normal RPM or revving the motor up? Do you know how much actual (measured with micrometers and or dial bore gauge)clearance you had on the rod to crankshaft? Bearings spin for several different reasons

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Bearings don't spin for without reason. Somewhere, somehow the bearing came in contact with the crank. Trouble shooting the cause takes some detective work. Lack of oil,detonation, aerated oil,wrong clearances, hydrauliced cylinder ,big end distortion of the rod,poor pan design. Plenty of 440 motors around running over 7000 RPM that haven't spun bearings. I would look very carefully during dis-assembly. A very knowledgeable engine builder made this statement. If your engine has to much bearing clearance you will know it. If it doesn't have enough ,everyone will know. Good luck on your diagnosis.
Doug

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Common causes are loss of oil (various reasons) and detonation beating the bearing up.

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One bottle of STP treats 5 qts. of oil. My system, 7 Qt. pan, windage tray =1 more qt. and an
HP oil filter = 1 more qt. That's 9 qts, and I just add another bottle for GP's. You can't have too much zinc.

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I am not saying STP is bad, but remember that the oil in the STP bottle that carries the additives may not be the best oil. IMO, the ZDDP additives on the market now in smaller containers (4oz) are a better alternative.

http://www.zddplus.com/

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I am not saying STP is bad, but remember that the oil in the STP bottle that carries the additives may not be the best oil. IMO, the ZDDP additives on the market now in smaller containers (4oz) are a better alternative.

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I've been using STP for 40 years. I'll probably keep using it. Here's the thing. When I pulled my engine appart, the other 6 rod bearings looked like I just put them in. Same with the mains. There wasn't any bearing left in #6 rod, and #5 looked pretty bad. This engine was assembled by me in 2004......... Again, my question is, why mostly #6 or #5 rod bearing?

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I can't truthfully say that I would pull the bottom end appart for inspection each year, because I didn't. I would pull the clutch and transmission down for inspection. I guess that from now on, pulling the engine's bottom end down will be a yearly thing also.

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How many miles on it then how many passes

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How many miles on it then how many passes

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I would restrict the passage to the rocker shafts,...

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Too little flow left over at # 4 to feed the rods enough. Doesn't matter what the gauge says, if it is leaving the main bearing so fast there isn't enough to feed the rods, they starve. I would restrict the passage to the rocker shafts, or feed them externally to keep max oil to #4 main. Also while the motor is down, check clearances on the lifter bores and lifters themselves and any other place oil can bleed off (cam bearings?)due to wear.

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My opinion exactly... its too bad we cant get a oil
pressure reading at the end of the line instead of
near the beginning

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Id assume he is talking about the passage that goes from the block to the head from the #4 cam bearing! tap it and put a set screw in there with a hole drilled in it!

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Got it. I run RPM's so drilling the block has to be the way I have to go. Will this affect street driving, as my car is mostly driven on the street?

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Too little flow left over at # 4 to feed the rods enough. Doesn't matter what the gauge says, if it is leaving the main bearing so fast there isn't enough to feed the rods, they starve. I would restrict the passage to the rocker shafts, or feed them externally to keep max oil to #4 main. Also while the motor is down, check clearances on the lifter bores and lifters themselves and any other place oil can bleed off (cam bearings?)due to wear.

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(EDIT)#6 only (my bad; thanks ModernCylinder) is going to get the least amount of oil based on the design of sending oil to the rocker shafts. Depending on what rockers/shafts you are using you may have to restrict oil to heads (usually done in the block on stock oil systems).

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Are you oiling the rockers full time? If not don't restrict the oil to rockers The reason being that the stock oiling through the cam only allows oil to the rockers around 15 camshaft degrees....

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Ya, my blocks are all stock oiling systems. So I have to live with what I got, and do the yearly tare down and inspection from now on.
Thanks to all for good info,
Larry

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#5 main feeds #8 rod
#4 main feeds #7 and #6
#3 main feeds #5 and #4
#2 main feeds #3 and #2
#1 main feeds #1

it would appear to me that you have a volume issue if you hurt #5 and #6 since they are fed off two different mains,,, what did #7 look like?

what kind of filter did you have on it,, ive seen restrictive filters hurt rods in th eback of the motor

the "typical" rod that gets hurt in a bb mopar is #3 usually

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Maybe this is old news and I didn't get the memo, but why is it that these rod bearings,especially #6, are the first to spin on a big block? Also, is there a remedy to fix this issue?
Thanks for any good input.

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There are many reasons bearings spin as stated. There is a good remedy for more equalized Rod bearing oiling posted in the Moparts Power Adder section. I Bumped it to the top for you. Its Feets post on "Any Crank Failures On Boost" Its a good read.

And No, Its not a Fail safe remedy for spun rod bearings. Its just another step in the right direction, IMO

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Wow, three bottles of STP . Is that the super thick STP? I run Hughes oil additive in my Rotella, two years so far with no issues.

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That`s EXACTKY what I was thinking plus, 9 quarts of oil AND the stp........I wonder whats going on inside the pan.

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That`s EXACTKY what I was thinking plus, 9 quarts of oil AND the stp........I wonder whats going on inside the pan.

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What's this mean? I don't get it!

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That`s EXACTKY what I was thinking plus, 9 quarts of oil AND the stp........I wonder whats going on inside the pan.

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What's this mean? I don't get it!

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Are you oiling the rockers full time? If not don't restrict the oil to rockers The reason being that the stock oiling through the cam only allows oil to the rockers around 15 camshaft degrees....

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Ya, my blocks are all stock oiling systems. So I have to live with what I got, and do the yearly tare down and inspection from now on.
Thanks to all for good info,
Larry

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Have you made any of the oiling system changes like that listed in the tech archives?

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I agree with the excessive stp deal. 3 in a burned out /6 maybe...
The only additive you may need is zinc, and there are better versions of it out there now.

I put my engine into an "extreme over-rev" condition in the spring and it bent # 5+6 exh valves.

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That`s EXACTKY what I was thinking plus, 9 quarts of oil AND the stp........I wonder whats going on inside the pan.

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What's this mean? I don't get it!

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You may have gotten a little carried away with your use of an additive, I can see one bottle, but 3???

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Yes that and the excessively THICK 98 cold psi and 65 at idle doesn`t seem ideal to me personally. With fairly large bearing clearances in my motor I still run 5w30-10w30 oil and even though I have an 8-quart pan, I run bet 6-7 quarts and have about 70psi cold and 30-40 at idle/cruise.

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Yes that and the excessively THICK 98 cold psi and 65 at idle doesn`t seem ideal to me personally. With fairly large bearing clearances in my motor I still run 5w30-10w30 oil and even though I have an 8-quart pan, I run bet 6-7 quarts and have about 70psi cold and 30-40 at idle/cruise.

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Cool, you're entitled to your opinion, but tell me this, how many cases of rod bearing failure have you heard of, that was attributed to too high of oil pressure? I'm guessing that I'm allot older than you and I've NEVER heard of high oil pressure causing bearing failure. Granted it robs horsepower, but this is my choice to have higher pressure......... I've heard of many, many more failures due to too low of oil pressure, rather than too high.

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kinda think there is a possibility that high pressure and loose oil viscosity may cause a bearing to spin, it comes down to physics. IF the clearances are to loose, the thick oil circulating at high pressure, may cause such a "drag", no idea what to call it in English, but the forces at play get so high, that it rotates the bearing?

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Bearings are "indexed" so they won't rotate. One reason of what causes a spun bearing is metal to metal contact, or, lose of oil pressure. Your theory may be valid, I'm no physisist, but I'd have to see documented proof.
My bearing clearances are .0025", which is in line for my type of engine usage. Nothing exotic, here.

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Yes that and the excessively THICK 98 cold psi and 65 at idle doesn`t seem ideal to me personally. With fairly large bearing clearances in my motor I still run 5w30-10w30 oil and even though I have an 8-quart pan, I run bet 6-7 quarts and have about 70psi cold and 30-40 at idle/cruise.

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Cool, you're entitled to your opinion, but tell me this, how many cases of rod bearing failure have you heard of, that was attributed to too high of oil pressure? I'm guessing that I'm allot older than you and I've NEVER heard of high oil pressure causing bearing failure. Granted it robs horsepower, but this is my choice to have higher pressure......... I've heard of many, many more failures due to too low of oil pressure, rather than too high.

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I have heard of it "washing" the bearings, That was in an 8500rpm dirt latemodel engine. It would accually just force the oil out of the bearing, I dont understand it for sure either, but the engine im talking about ran 20w50 with .003 rods, and mains, and he had 95+ psi oilpressure, and had a bearing failure on his small block, when he changed the pump to no more than 65psi at the same rpm the bearing issue went away.

so from that I honestly dont know why...

Kasey

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Are you oiling the rockers full time? If not don't restrict the oil to rockers The reason being that the stock oiling through the cam only allows oil to the rockers around 15 camshaft degrees....

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Ya, my blocks are all stock oiling systems. So I have to live with what I got, and do the yearly tare down and inspection from now on.
Thanks to all for good info,
Larry

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the reality is that the engine needs to come apart completely now anyway, so it's a good time to do the oiling mods and get it over with.
there's no reason a street/strip combo should have that much oil pressure. pressure is a result of restriction, keep that in mind.
when the engine was built, was each rod checked for size and roundness? oil clearance doesn't mean much if the bearing lacks themproper crush to hold it in place. those index tabs you speak of are just that, a way to locate the bearing. they're in not intended to keep one from spinning in the housing bore.
as far as restricting oil to the top end, hogwash. it's a driver, not an all out race car.
do the oiling mods in order to get the volume of oil to the places it needs to be. use due diligence in checking housing bore sizes and other standard engine building practices and move on. engine failures are costly, doing it any way but the right way the 2nd time around is even more costly. best of luck.

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DUDE, you have two different kinds of rod nuts. or am i hallucinating?

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the reality is that the engine needs to come apart completely now anyway, so it's a good time to do the oiling mods and get it over with.
there's no reason a street/strip combo should have that much oil pressure. pressure is a result of restriction, keep that in mind.
when the engine was built, was each rod checked for size and roundness? oil clearance doesn't mean much if the bearing lacks themproper crush to hold it in place. those index tabs you speak of are just that, a way to locate the bearing. they're in not intended to keep one from spinning in the housing bore.
as far as restricting oil to the top end, hogwash. it's a driver, not an all out race car.
do the oiling mods in order to get the volume of oil to the places it needs to be. use due diligence in checking housing bore sizes and other standard engine building practices and move on. engine failures are costly, doing it any way but the right way the 2nd time around is even more costly. best of luck.

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the reality is that the engine needs to come apart completely now anyway, so it's a good time to do the oiling mods and get it over with.
there's no reason a street/strip combo should have that much oil pressure. pressure is a result of restriction, keep that in mind.
when the engine was built, was each rod checked for size and roundness? oil clearance doesn't mean much if the bearing lacks themproper crush to hold it in place. those index tabs you speak of are just that, a way to locate the bearing. they're in not intended to keep one from spinning in the housing bore.
as far as restricting oil to the top end, hogwash. it's a driver, not an all out race car.
do the oiling mods in order to get the volume of oil to the places it needs to be. use due diligence in checking housing bore sizes and other standard engine building practices and move on. engine failures are costly, doing it any way but the right way the 2nd time around is even more costly. best of luck.

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My clearances were checked prior to the build in 2004, as stated, rods and mains WERE all at .0025".
The increase in oil pressure is done by me adjusting the pressure relief spring in the oil pump, up a tad. With the relief spring untouched, my pressure was at 65 psi cold and 45 hot. I wasn't comfortable with that.
Again, a question of what oil mods I should make, IF any, still has to be anwered. Remember, this is NOT a dedicated race engine. Most of the time it is street driven. DO I NEED TO MODIFY THE OILING SYSTEM????? Right now, to tell you the truth, I'm confused and getting mixed opinions as to IF I do need any mods at all.

Thanks for any input,

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Yes that and the excessively THICK 98 cold psi and 65 at idle doesn`t seem ideal to me personally. With fairly large bearing clearances in my motor I still run 5w30-10w30 oil and even though I have an 8-quart pan, I run bet 6-7 quarts and have about 70psi cold and 30-40 at idle/cruise.

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Cool, you're entitled to your opinion, but tell me this, how many cases of rod bearing failure have you heard of, that was attributed to too high of oil pressure? I'm guessing that I'm allot older than you and I've NEVER heard of high oil pressure causing bearing failure. Granted it robs horsepower, but this is my choice to have higher pressure......... I've heard of many, many more failures due to too low of oil pressure, rather than too high.

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Settle down skippy...............wasn`t refering to the spun bearing just damn thick oil that`s all and another thing, older DOESN`T make you smarter. Now where were we?

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i'm just trying to help. did you ever check the housing bores for size and roundness? frankly, most home builders don't because they don't have the proper tools or experience to do it. 65 psi cold is a smidgen low on a cold motor, but not what i would be concerned about. what was the pressure hot at 6000 rpm? that's way more important in my book.
i'm just saying, IMO you should do the oiling mods. it's not voodoo, it helps. the basic mods are fine although i still prefer the 1/2" oil pickup.
are you running a std or high volume oil pump?

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I know you are trying to help. It's hard to show feelings with a key board. I appreciate all of the replies so far, really!
I did not check bore size because of the reason you mentioned. 65 psi was cold idle. At 2200 rpm it was at 75 rpm. I didn't take it up higher than 3500 and it remained at 75. When I raced it with the engine at temp. my oil pressure sets, or sat at, 75-80 psi at 6500 rpm.
With that, what mod would you recommend? I'm leaning toward the one that blocks the oil from #4 to the cam bearing and drill and tap in a restrictor into the main oil galleies for rocker lubrication. If any mods, to me, this one as described in the "Power Adder" section, would work best on a street/strip engine like mine.

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Considering the preference for high viscosity oil/additive, that stp adds a whole bunch of viscosity....but if you like it, go ahead and use it....I also think it's a good candiate for the old direct connection "hemi" 1/2" oil pickup, radius and blend the pickup passage modification. SAE 50 and 40 weight were commonly used back when the books detailing those mods came out.

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Settle down skippy...............

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I'm just a dumb old man, but I am settled.

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Checking the passages from the mains to the gallery is the most important step. I've learned this lesson the hard way on a couple of engines. If one of the passages is partially plugged then the engine will spin rod bearings every time you lean on it.

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Agreed............when I started the big-block journey years ago, Pettis did the oiling mods to my block and I`ve ran 6-quarts of oil at 7000+ rpm`s for 11+ years w/out issues.

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I know you are trying to help. It's hard to show feelings with a key board. I appreciate all of the replies so far, really!
I did not check bore size because of the reason you mentioned. 65 psi was cold idle. At 2200 rpm it was at 75 rpm. I didn't take it up higher than 3500 and it remained at 75. When I raced it with the engine at temp. my oil pressure sets, or sat at, 75-80 psi at 6500 rpm.
With that, what mod would you recommend? I'm leaning toward the one that blocks the oil from #4 to the cam bearing and drill and tap in a restrictor into the main oil galleies for rocker lubrication. If any mods, to me, this one as described in the "Power Adder" section, would work best on a street/strip engine like mine.

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i wouldn't block any oil to the top end. the pressures you listed above are fine. we run similar pressures on engines that regularly see 7000+ rpm at the track and get driven hard on the street. it's all about volume, not pressure. open up those main passages so the volume gets to the bearings. you'll be surprised how small some of them are as cast. having the 1/2" pickup is great, but by itself it doesn't help much. you need the other passages opened up for it to be effective. one other thing, replace the rod that spun the bearing, don't repair it. if the one next to it got hot, make sure it's checked out preperly or replace it too. hopefully the rest of the damage isn't too bad.

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Will do! I did ordered 2 new rods and a new piston for #6, as it hit the head. I also had to order another crank, mine showed a couple of cracks. I get carried away with things from time to time. The STP thing is one of those times. Maybe it contributed to the failure, maybe not, remember this engine was built in 2004.....
Thanks to ALL for your input, believe me, it is appreciated. Thanks again.
Larry

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I know you are trying to help. It's hard to show feelings with a key board. I appreciate all of the replies so far, really!
I did not check bore size because of the reason you mentioned. 65 psi was cold idle. At 2200 rpm it was at 75 rpm. I didn't take it up higher than 3500 and it remained at 75. When I raced it with the engine at temp. my oil pressure sets, or sat at, 75-80 psi at 6500 rpm.
With that, what mod would you recommend? I'm leaning toward the one that blocks the oil from #4 to the cam bearing and drill and tap in a restrictor into the main oil galleies for rocker lubrication. If any mods, to me, this one as described in the "Power Adder" section, would work best on a street/strip engine like mine.

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i wouldn't block any oil to the top end. the pressures you listed above are fine. we run similar pressures on engines that regularly see 7000+ rpm at the track and get driven hard on the street. it's all about volume, not pressure. open up those main passages so the volume gets to the bearings. you'll be surprised how small some of them are as cast. having the 1/2" pickup is great, but by itself it doesn't help much. you need the other passages opened up for it to be effective. one other thing, replace the rod that spun the bearing, don't repair it. if the one next to it got hot, make sure it's checked out preperly or replace it too. hopefully the rest of the damage isn't too bad.

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There are different reasons for restricting oil to the top end. The cam itself is a "Pulse oil restrictor" to the top end.

In a race engine, a additional restrictor will also help to prevent to much oil from pumping to the top end at high RPM draining a insufficient pan.

Some will groove the cam journal for a constant oil supply to the top end vs a Pulse cam supply. That would need a restrictor to the top end.

The Mod in the Power Adders section has a restriction too. As does All the above situations.

But, The Power Adders Mod addresses the #4 main Oil supply drain of the valvetrain that Robs the oil supply to #6 and #7 rod journals that get the First hit of a weak oil supply.

All the other mods wont! They will still pull/rob oil from the #6 and #7 rod bearings to feed the upper valvetrain.


At minimum while your block is apart drill the angled oil galley feeds from the mains to the oil galley to make sure they are clear "all the way through".

The "Power Adders Mod" is alittle extreme for your ride IMO. But, I would still consider a Jet restriction in the block or head for your ride. Lighten up on the STP too a little.

Your car is Mostly a street car. But with the 11.sec. trips down the 1/4 it still thinks its a race car. If and when any bearings run out of oil @ 6000 RPM, Does it care??

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Rod bearing issues are very common with stock block engines. Most of the failures I've seen were caused because people didn't take the time to open up the passages from the main gallery to the mains. The factory did a poor job on those passages. What works for years in a street engine doesn't last very long in a drag motor.

#4 main usually causes the most problems because it also sends oil to the top end. So those rod bearings get smoked first if oil volume or pressure isn't up to par.

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More simply put on the #4 main problem.

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I know you are trying to help. It's hard to show feelings with a key board. I appreciate all of the replies so far, really!
I did not check bore size because of the reason you mentioned. 65 psi was cold idle. At 2200 rpm it was at 75 rpm. I didn't take it up higher than 3500 and it remained at 75. When I raced it with the engine at temp. my oil pressure sets, or sat at, 75-80 psi at 6500 rpm.
With that, what mod would you recommend? I'm leaning toward the one that blocks the oil from #4 to the cam bearing and drill and tap in a restrictor into the main oil galleies for rocker lubrication. If any mods, to me, this one as described in the "Power Adder" section, would work best on a street/strip engine like mine.

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i wouldn't block any oil to the top end. the pressures you listed above are fine. we run similar pressures on engines that regularly see 7000+ rpm at the track and get driven hard on the street. it's all about volume, not pressure. open up those main passages so the volume gets to the bearings. you'll be surprised how small some of them are as cast. having the 1/2" pickup is great, but by itself it doesn't help much. you need the other passages opened up for it to be effective. one other thing, replace the rod that spun the bearing, don't repair it. if the one next to it got hot, make sure it's checked out preperly or replace it too. hopefully the rest of the damage isn't too bad.

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One bottle of STP treats 5 qts. of oil. My system, 7 Qt. pan, windage tray =1 more qt. and an
HP oil filter = 1 more qt. That's 9 qts, and I just add another bottle for GP's. You can't have too much zinc.

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I am not saying STP is bad, but remember that the oil in the STP bottle that carries the additives may not be the best oil.

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As a matter of fact, you CAN also have too much zinc in the motor oil. Too much zinc increases the formation of sludge and pitting of metal surfaces.

STP is also containing additive called Viscosity Modifier and they are polymers. By using an additional STP bottle, you are also pouring more plastics to the crankcase. Certain aftermarket oil additives are also containing chlorinated paraffin that one type of an active chemical ingredient. It is causing bearing weight loss. The lubricant industry is using a bench test ASTM D5119 to evaluate an oil's ability to control copper/lead/tin corrosion of bearings. Using aftermarket additives you most often improve the chemical corrosion of the bearings. Read the attached pdf file copied from a lubricants professional journal a few years ago

The US Federal Trade Commission has had a few cases against aftermarket motor oil additive sellers

STP Engine Treatment
http://www.ftc.gov/opa/1995/12/stp.shtm

Valvoline Engine Treatment
http://www.ftc.gov/opa/1997/10/valve.shtm

Slick 50 Engine Treatment
http://www.ftc.gov/opa/1996/07/slick.shtm

Dura Lube Super Engine Treatment
http://www.ftc.gov/opa/1999/05/duralub2.shtm

Motor Up Engine Treatment
http://www.ftc.gov/opa/1999/04/motorup5.shtm

Prolong Super Lubricants
http://www.ftc.gov/opa/1999/09/prolong.shtm

Make your own conclusions from the above, but as a lubricants professional and formulator of lubes I would prefer to use high quality lubes instead of making own mixtures with aftermarket additives. You can't necessarily improve an oil by pouring in more additives from an expensive little bottle. As a matter of fact, you even can make things worse. Overdosing STP may not have been the one and only reason for the spun rod bearings, but sure it has had it's own negative reactions to the motor oil

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As a matter of fact, you CAN also have too much zinc in the motor oil. Too much zinc increases the formation of sludge and pitting of metal surfaces.

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Not trying to start an argument here, but 2 things come to mind.
1. Why did the other bearings, rods and mains, look like new?
2. There ain't no sludge in my engine, or pitting, for that matter.

Thanks for your input though!

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One bottle of STP treats 5 qts. of oil. My system, 7 Qt. pan, windage tray =1 more qt. and an
HP oil filter = 1 more qt. That's 9 qts, and I just add another bottle for GP's. You can't have too much zinc.

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As a matter of fact, you CAN also have too much zinc in the motor oil. Too much zinc increases the formation of sludge and pitting of metal surfaces.

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Not trying to start an argument here, but 2 things come to mind.
1. Why did the other bearings, rods and mains, look like new?
2. There ain't no sludge in my engine, or pitting, for that matter.

Thanks for your input though!

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I am not going either to start arguing here clear issues, but someone stated here that you can't have too much zinc in motor oil. That is NOT the truth and it has been a very long time well known issue among people who are working with the R&D of lubricants.

Like said, your bearing failure may not have been a direct result of overdosing STP, but statements here won't renew the basics of science like chemistry and tribology. Too much zinc in the oil causes problems. Period

This is the end of this discussion from my side.

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This is the end of this discussion from my side.

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Me too!