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Re: Bad Main bearing cause?
[Re: 340duster340]
#1191176
03/05/12 12:06 AM
03/05/12 12:06 AM
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Joined: Oct 2011
Posts: 460
Oklahoma
VoodooCLD
OP
mopar
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OP
mopar
Joined: Oct 2011
Posts: 460
Oklahoma
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Ya, i don't really understand. The motor ran like hell before it threw the water pump. I almost buttoned it back up, but decided i wanted to lift the crank to properly install the rear main seal. It had good oil pressure, and didnt knock or anything. I guess i'll have to see if the line hone or crank is out of wack. What does a shop usually charge to check a crank, and line bore? I'm in stillwater, oklahoma if that helps.
Last edited by VoodooCLD; 03/05/12 12:12 AM.
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Re: Bad Main bearing cause?
[Re: Cab_Burge]
#1191178
03/05/12 11:30 AM
03/05/12 11:30 AM
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Joined: Oct 2011
Posts: 460
Oklahoma
VoodooCLD
OP
mopar
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OP
mopar
Joined: Oct 2011
Posts: 460
Oklahoma
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Ya i had the heads off last week and the cylinders look fine. The engine turnes over smooth without and grinding.I'm trying to decide what to do as of now. I'm considering doing a *cheap rebuild* by cleaning it my self. having the line bore checked,bores checked, turning the crank next size, and putting in new main and rod bearings. I'm also considering keeping my eyes open for a 383 or 440 short block that's ready to run, and reusing my 906 heads. The more i think about it, the more i wanna blame poor oiling for this.
Anyone got a fresh short block for sale?
Oh ya, I've decided I'm definitely gonna bring my crank to a machinist to have him check it out. The condition of the crank will definitely determine my final approach.
Last edited by VoodooCLD; 03/05/12 11:32 AM.
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Re: Bad Main bearing cause?
[Re: Challenger 1]
#1191181
03/05/12 12:29 PM
03/05/12 12:29 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,376
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Since when did a 383 crank have inherent weaknesses that made it unusable if it had been ground more than 10 under? NEVER. There are main and rod bearings out to at least 40 under. Racers looking for that last hundredth or two often used to grind the cranks down as much as they could get bearings to fit. The popular 3.91" stroke offset ground 440 crank, or any bigblock chevy rod stroker, has rod journals 0.175" smaller than stock. I'd say that if your main bearings look that bad, the crank needs to be reground. Period. And with that amount of bearing material circulating I'd say you need to take the engine down and clean out all the oil passages and everything else you can clean. You can check the taper in the cylinders and the piston fit at the same time. Don't buy any new parts, including the crank regrind, until you know what you have. Looks to me like the engine was starving for oil. The oil pump is on the front of this engine. The progressively worsening damage from the front of the engine to the back suggests that for whatever reason there was not enough volume of oil being pumped or else there was oil bleeding out of the system before it could get to the back of the engine. R. 
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Re: Bad Main bearing cause?
[Re: dogdays]
#1191182
03/05/12 12:39 PM
03/05/12 12:39 PM
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Joined: Oct 2011
Posts: 460
Oklahoma
VoodooCLD
OP
mopar
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OP
mopar
Joined: Oct 2011
Posts: 460
Oklahoma
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Quote:
Since when did a 383 crank have inherent weaknesses that made it unusable if it had been ground more than 10 under? NEVER.
There are main and rod bearings out to at least 40 under. Racers looking for that last hundredth or two often used to grind the cranks down as much as they could get bearings to fit. The popular 3.91" stroke offset ground 440 crank, or any bigblock chevy rod stroker, has rod journals 0.175" smaller than stock.
I'd say that if your main bearings look that bad, the crank needs to be reground. Period.
And with that amount of bearing material circulating I'd say you need to take the engine down and clean out all the oil passages and everything else you can clean. You can check the taper in the cylinders and the piston fit at the same time. Don't buy any new parts, including the crank regrind, until you know what you have.
Looks to me like the engine was starving for oil. The oil pump is on the front of this engine.
The progressively worsening damage from the front of the engine to the back suggests that for whatever reason there was not enough volume of oil being pumped or else there was oil bleeding out of the system before it could get to the back of the engine.
R.
As much as i don't want it to be true, i think you are correct. I'm definitely gonna get the crank checked first and foremost. Also gonna be looking for a ready to go 440 shortblock, or a good builder.
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191183
03/05/12 12:51 PM
03/05/12 12:51 PM
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Joined: Jul 2004
Posts: 370
beedees
enthusiast
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enthusiast
Joined: Jul 2004
Posts: 370
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Either those are full-groove bearings or the uppers are installed in the lower and vice-versa. Looking again, I see they are the lowers and are f.g. brngs, looks to be excessive oil clearnce. Maybe .010 brngs. on a .o2o under shaft? I've seen it before.
Last edited by beedees; 03/05/12 12:58 PM.
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191187
03/15/12 12:34 AM
03/15/12 12:34 AM
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Joined: Oct 2011
Posts: 460
Oklahoma
VoodooCLD
OP
mopar
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OP
mopar
Joined: Oct 2011
Posts: 460
Oklahoma
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Ok so for an update, i stripped the entire motor down and noticed that there was a chunk taken out of one of the cam lobes. I'm sure the engine was dirty however i have a strong feeling that the oiling was a problem for the bearing failure. I noticed that i have a m63hp which is a melling high PRESSURE pump. Could this have been the cause of my rear main seal leak all along?
As for the bearing failure, it had that high pressure pump, no windage tray, and an el cheapo stock oil pan with baffling. Also i noticed the pickup tube measure like .6" or something, and the inlet was .56". Is this the measurements of the hemi oil pickup? I thought 383's had the smaller pickup tube. Did someone drill and tap out the oil pickup (if they did, they did a pretty good job)?
Can anyone determine if this oil set up could have been the cause of my bad main bearings? I looked around and it seems not too many people run the high pressure pumps. whats the deal with them on a semi hot street motor?
I dont remember what oil pressure it was running at, but its a 383 bored .40 over, pretty stock bottom end with speed demon 750 carb, holly street dominator intake, headman long tube headers, and full 2.5" exhaust. Yes i ran it very hard on the street.
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191188
03/15/12 03:16 AM
03/15/12 03:16 AM
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Joined: Aug 2003
Posts: 43,127
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,127
Bend,OR USA
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Quote:
Ok so for an update, i stripped the entire motor down and noticed that there was a chunk taken out of one of the cam lobes. I'm sure the engine was dirty however i have a strong feeling that the oiling was a problem for the bearing failure. I noticed that i have a m63hp which is a melling high PRESSURE pump. Could this have been the cause of my rear main seal leak all along?
As for the bearing failure, it had that high pressure pump, no windage tray, and an el cheapo stock oil pan with baffling. Also i noticed the pickup tube measure like .6" or something, and the inlet was .56". Is this the measurements of the hemi oil pickup? I thought 383's had the smaller pickup tube. Did someone drill and tap out the oil pickup (if they did, they did a pretty good job)?
Can anyone determine if this oil set up could have been the cause of my bad main bearings? I looked around and it seems not too many people run the high pressure pumps. whats the deal with them on a semi hot street motor?
I dont remember what oil pressure it was running at, but its a 383 bored .40 over, pretty stock bottom end with speed demon 750 carb, holly street dominator intake, headman long tube headers, and full 2.5" exhaust. Yes i ran it very hard on the street.
3/8 National pipe thread,NPT, is the stock oil pump size on the 361 to 440, 1/2 inch NPT is stock for the M.W.426 and the 426 Street and race hemi motors. Not sure of the O.D. on either, sorry  Take the pump apart and look at the gear and rotor, if not tore up you can reuse it  , cut 1 to 2 coils off of the high pressure spring and reuse it, if you want more pressure after trimming the spring get some very small flat washers that will fit ino the bypass plug that holds the bypass valve and spring in the oil pump cover and install them one at a time until you get the oil pressure you want Always check it(pressure) with hot oil, not cold oil, at idle and wound out  
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191190
03/15/12 12:18 PM
03/15/12 12:18 PM
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Joined: Aug 2006
Posts: 2,499
God's Country Maryland
GODSCOUNTRY340
top fuel
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top fuel
Joined: Aug 2006
Posts: 2,499
God's Country Maryland
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Looks like the bearings get worse toward the rear of the engine. Did you ever throw a lifter from the lifter bores? This would cause a loss of oil pressure and would cause the bearings at the rear to sustain more damage than the front as they are oiled from the front to the rear. Also by the looks of the front bearing the line bore is out and needs corrected before building it again.
I love the smell of Deer guts in the morning, it smells like... VICTORY!
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191192
03/15/12 01:20 PM
03/15/12 01:20 PM
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Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem
master
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master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
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You don't want a 63HP they will put out huge pressure 140 + you want a 63HV gives volume at way less pressure. Think the Hp is for industrial motors like water pumps that run 24/7 at 4000 rpm. with a canaster style filter. took one off a friends 440 would blow the filters up and off sometimes and buried the 140 oil pressure gauge. Sharp pump gears as opposed to the rounded ones 
Last edited by Dodgem; 03/15/12 01:24 PM.
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Re: Bad Main bearing cause?
[Re: Dodgem]
#1191193
03/15/12 01:59 PM
03/15/12 01:59 PM
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Joined: Jan 2003
Posts: 74,978
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,978
U.S.S.A.
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Quote:
You don't want a 63HP they will put out huge pressure 140 + you want a 63HV gives volume at way less pressure.
Think the Hp is for industrial motors like water pumps that run 24/7 at 4000 rpm. with a canaster style filter.
took one off a friends 440 would blow the filters up and off sometimes and buried the 140 oil pressure gauge. Sharp pump gears as opposed to the rounded ones
Interesting , just did a build with a 63HP and didn't experience any of this .
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Re: Bad Main bearing cause?
[Re: GODSCOUNTRY340]
#1191195
03/15/12 02:57 PM
03/15/12 02:57 PM
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Joined: Oct 2011
Posts: 460
Oklahoma
VoodooCLD
OP
mopar
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OP
mopar
Joined: Oct 2011
Posts: 460
Oklahoma
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Quote:
Quote:
I don't think i threw a lifter at any point. Do you think maybe the line bore is screwed up due to the previous owner not replacing the main caps back in their original spot?
ABSOLUTELY- The main caps have to be installed in their original position. They're line bored from the factory with the caps installed in their respective mains and can NOT be mixed.
Right, i understand this. I was just wondering if the wear patterns indicate this could have been the problem, since i didn't build the motor.
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