#6/#5 spun rod bearing ?
#1069256
09/04/11 08:19 PM
09/04/11 08:19 PM
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Posts: 4,013 South Park, Pa.
68LAR
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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.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: #6/#5 spun rod bearing ?
[Re: dodgeboy11]
#1069259
09/04/11 10:36 PM
09/04/11 10:36 PM
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Bob_Coomer
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Thats the rods I smoked, when the engine run low of oil, before I knowned to put oil restrictors in the oil lines up top. HV oil Pump + Stock Oil pan + Indy heads turning 6800 rpms + spin bearings!
[color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]
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Re: #6/#5 spun rod bearing ?
[Re: 68LAR]
#1069264
09/05/11 10:41 AM
09/05/11 10:41 AM
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dvw
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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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Re: #6/#5 spun rod bearing ?
[Re: justinp61]
#1069266
09/05/11 11:11 AM
09/05/11 11:11 AM
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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. I run a solid lifter cam, with 1.6 roller rockers. I agree that something had to cause the bearing to spin, my question was, why does it usually happen to #6 or #5 rod, mostly #6? And what can be done to prevent it in the future?
Last edited by 68LAR; 09/05/11 11:15 AM.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: #6/#5 spun rod bearing ?
[Re: dvw]
#1069267
09/05/11 11:14 AM
09/05/11 11:14 AM
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440Jim
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Quote:
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
Common causes are loss of oil (various reasons) and detonation beating the bearing up.
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Re: #6/#5 spun rod bearing ?
[Re: 68LAR]
#1069268
09/05/11 11:18 AM
09/05/11 11:18 AM
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440Jim
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Quote:
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.
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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Re: #6/#5 spun rod bearing ?
[Re: 440Jim]
#1069269
09/05/11 11:27 AM
09/05/11 11:27 AM
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Quote:
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.
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?
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: #6/#5 spun rod bearing ?
[Re: 440Jim]
#1069270
09/05/11 11:28 AM
09/05/11 11:28 AM
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Mopar-Al
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Your HP computed from your vehicle ET is 483.36 rear wheel HP and 537.06 flywheel HP. Your HP computed from your vehicle MPH is 500.81 rear wheel HP and 556.46 flywheel HP.
Running a 4 speed and launching at that weight to run those times takes a beating. You really need to do some deep checking to see if you have a main cap issue, thrust bearing clearence incorrect or bent crankshaft. Other issues can also cause your dilema.
Just noticed you say engine has been together for 7 yrs. Did you do any anual inspections? If it went 7yrs of racing on the same build without checking the bottom end, then you actually did very excellent. Parts do go bad after abuse
Last edited by Alyerpal2; 09/05/11 11:32 AM.
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Re: #6/#5 spun rod bearing ?
[Re: Mopar-Al]
#1069271
09/05/11 11:47 AM
09/05/11 11:47 AM
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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.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: #6/#5 spun rod bearing ?
[Re: 68LAR]
#1069272
09/05/11 11:54 AM
09/05/11 11:54 AM
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MR_P_BODY
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Quote:
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.
How many miles on it then how many passes
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Re: #6/#5 spun rod bearing ?
[Re: MR_P_BODY]
#1069273
09/05/11 12:01 PM
09/05/11 12:01 PM
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Quote:
How many miles on it then how many passes
Just a guess, based on approximately 1500 miles a year with usually 4 trips to the track thrown in, something less than 11,000 miles, with more than 140 passes. All just guesses, nothing documented.
Last edited by 68LAR; 09/05/11 12:09 PM.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: #6/#5 spun rod bearing ?
[Re: Mopar-Al]
#1069274
09/05/11 12:04 PM
09/05/11 12:04 PM
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gregsdart
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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.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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