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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191160
03/04/12 07:18 PM
03/04/12 07:18 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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front main cap
At this time i don't have any pictures of the bottom caps until i go rent a harmonic balancer puller.
EDIT! Don't have any picture of the TOP bearings. Got confused with the engine upside down!
Last edited by VoodooCLD; 03/04/12 07:46 PM.
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191165
03/04/12 08:13 PM
03/04/12 08:13 PM
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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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Acid in the oil can cause the damages you see like on the rear main bearing, so can dirt  #1 main bearing gets oiled first, #5 gets oiled last  Have you looked at any of the rod bearings yet? If not look at them also, the main bearings get oil first and many times they will eat the dirt, if it is bad enough the metal and dirt from the mains will be washed into the rods also  Let us know what you find  BTW, how long has it been since the motor was built and ran for the first time years or months, not miles
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Bad Main bearing cause?
[Re: Cab_Burge]
#1191166
03/04/12 08:54 PM
03/04/12 08:54 PM
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Joined: Oct 2011
Posts: 460
Oklahoma
VoodooCLD
OP
mopar
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OP
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Joined: Oct 2011
Posts: 460
Oklahoma
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I bought the car 7 years ago. Drove it right away for about a year and a half. Sat for a year, then drove it for another year and a half. The last stint as been sitting for about 3 years. I havn't tried to start at all in the past 3 years becuase the water pump went out and the fan went through the radiator. I finally decided to just go back through the car so i pulled the engine. I'm gonna pull the crank and take it to have a machine shop check it out. I tried mic'ing it but my tools are crappy, and combined with the wobble of the engine stand, i couldn't get an accurate reading.
If its no good, i might just have to look into stroking it.
Oh ya is the number 1 bearing the front of the engine or back?
Last edited by VoodooCLD; 03/04/12 08:58 PM.
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Re: Bad Main bearing cause?
[Re: 340duster340]
#1191172
03/04/12 09:54 PM
03/04/12 09:54 PM
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Joined: Oct 2011
Posts: 460
Oklahoma
VoodooCLD
OP
mopar
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OP
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Joined: Oct 2011
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Oklahoma
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bores look good, but no crosshatching. If those bearings are dated 99 then that probably lines with his story. If i got the crank straigtened away, and put new main and rod bearings it. Shouldn't it be good to go?
My only fear is that maybee it got some shoddy workmanship. Either that or i destroyed the bearings some how.
Last edited by VoodooCLD; 03/04/12 09:55 PM.
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191173
03/04/12 10:24 PM
03/04/12 10:24 PM
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Joined: Sep 2004
Posts: 654
MN
astrobuf
mopar
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mopar
Joined: Sep 2004
Posts: 654
MN
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I would check the crank for straightness and you may well need to check the block's line bore. I'm thinking there damage seen may not be due to trash in the oil, but instead by a bent crank and/or line bore that is not true.
Astrobuf
So, are you really a Rocket Scientist?
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Re: Bad Main bearing cause?
[Re: MoparforLife]
#1191175
03/04/12 11:15 PM
03/04/12 11:15 PM
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Joined: Jan 2003
Posts: 4,323
NY NY
340duster340
master
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master
Joined: Jan 2003
Posts: 4,323
NY NY
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Quote:
Lots of engines are rebuilt on a 'budget' if it was holding good oil pressure only the rod bearings and rings are replaced. Maybe even the valves reseated.
thats what i was thinking if the bores had no visible cross hatch.
maybe the motor wiped a cam or tossed a bearing and the guy put it back together on the cheap. honestly for the time you are going to spend working on it to maybe get it right, i would either correctly rebuild what you have or get a 440 and run / rebuild that.
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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
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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
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Joined: Oct 2011
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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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Re: Bad Main bearing cause?
[Re: Dodgem]
#1191202
03/15/12 07:52 PM
03/15/12 07:52 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:
Quote:
Interesting , just did a build with a 63HP and didn't experience any of this .
You sure you have an HP and not and HV they sell 3 stock, High volume HV and High Pressure HV.
When I went to the speed shop with the HP he said I will not sell them just HV or stock. He said his book said industrial motor only with canister type filter.
And yes I checked the bypass even put a stock spring in which did not help much at all.
Put one of my used mopar high volumes on and it was fine so then got a new HV and it was fine the gears are totally different!
Well I see the melling hp is just a stock pump with stronger bypass spring??
This one years ago had tall gears like a high volume but real sharp?? may have been a Federal Mogal bin a while but it was dangerous. took out 3 140 hp oil gauges as well as filters.
I am 99% sure it was a HP , will have to check the invoice now ... I t did have a leak and I had to lap the plate the oil filter attaches to because it looked like it was surfaced with a rock. Standard height stock looking rotors , never seen one with the sharp rotor till someone posted the picture of the new style that is coming out?
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Re: Bad Main bearing cause?
[Re: rhad]
#1191203
03/15/12 07:58 PM
03/15/12 07:58 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:
dont the main caps have the number cast into them?
Yes the caps are numbered.
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191204
03/15/12 08:02 PM
03/15/12 08:02 PM
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Joined: Jul 2009
Posts: 413
Norway (old world)
Oyvind Mopar
mopar
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mopar
Joined: Jul 2009
Posts: 413
Norway (old world)
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Quote:
Quote:
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 had a 360 stroker that had same bearing issues due to 3 worn-out camlobes had sent the trash through the mains, chewed them up badly first. Rodbearings looked better.
Had to regrind the crank etc. after a full tear down. Same has happened with other engines that ruined camlobes. Just to let you know. Hope it works out for you!
So you think i'll be alright with just turning the crank down and installing new bearings? (i'm also gonna hone, and put new rings in)
And what did you do to fix this, just install a higher quality cam? Mine looks like the original.
I do not know how to check the material quality of the cam and lifters. It is a gamble when using stock type parts. I used another block, bored it and put in the old pistons, after removing all iron particles stuck in the skirts. Then new rings. And, using a high Zn / Ph oil and the comp cams additive as well.
The old 360 block can be reused (have it for another project) after honing, it cleared out quite well with only .001" removed. Only a few tiny stripes left.
I changed the block because of a low oil pressure issue, and suspected the lifterholes to be too slack. They were no worse than the other, but I did not take chances. The hivolume oilpump was destroyed by all the debris going through.
The engine was run for some time with the damaged lobes, and I think this extended running with the debris destroyed the engine. Camwear did not stop on the broken lobes, and finally the engine started misfiring on the cylinders with low lift. Then it was all detected when I got the vehicle in for service/troubleshooting.
I hate this situation with the cams, lifters and oil. In the past I never take chances with the oil, and use the sloppiest valvesprings possible for the cam and max rpm for these street engines.
You could use lifters with lube holes, and nitrided cams (I thought they all were nitrided, but obviuosly not good enough, so extra cash is needed to avoid being cheated) and you end up with something approaching a roller in cost. Still this could be better than a roller failure in a high mile/useage street engine.
I also had an engine with a 590 cam broken in at the dyno, checked/adjusted valves, OK, and after the dyno session one lobe and lifter was gone. I guess the oil used was not good enough, and the quality of the parts is questionable.
I am so afraid of this stuff that I rather buy a slightly used cam with lifters in sorted order, to be sure it has survived the first runs. I build engines for a living, and the profit gets negative when such things happen.
Good Luck!!!
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Re: Bad Main bearing cause?
[Re: Oyvind Mopar]
#1191205
03/15/12 08:52 PM
03/15/12 08:52 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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Finally some real news. I took a second look at the caps, and while they were in the correct numerical order. THEY WERE NUMBERED BACKWARDS! The number 5 cap was at the front of the engine. (i believe this is backwards right?)
In any case, if i were to just get new bearings and put it back together in the correct order (1 being at the front of the engine) would it work alright? I'd really like to not have it line bored since no one here in town does it, but i don't want to be tearing down the engine again. Also are the numbers on the main caps supposed to go on the driver or passenger side?
Another thing, when i was at the shop i measured the rod journals and after machining they measured 2.354. I asked why they were 6 thousands under a .020 over, and he showed me a book that said stock journals were 2.374. I assumed that the book was right, but now every where i'm reading says that stock journals are 2.380, and .020 under would be 2.360!!!!
WHAT IS THE STOCK ROD JOURNAL SIZE ON a (cast 1970) 1971 mopar 383?
and what would a .020 under be. No websights selling bearings show the exact size.
EDIT: I have found even more sources that state the stock rod journals are 2.375". So maybee his book was right after all (in don taylors big block mopar engines, he states 2.380" and that was the first book i grabbed). And even more, they actually measured about 2.3545. So i now feel he might have done a really good job.
Last edited by VoodooCLD; 03/15/12 09:03 PM.
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Re: Bad Main bearing cause?
[Re: VoodooCLD]
#1191208
03/16/12 12:24 AM
03/16/12 12:24 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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Number one main cap is in the front of the motor by the oil pump, the rod journals should be 2.375 stock, Mopar allows +.0005 or - .0005 for the factory tolerances, 2.3745 to 2.3755, .020 under should be 2.7555 tp 2.37545 Get the new main bearings and fix the crankshaft and then install the upper main bearings(the ones with the oil holes) in the block and then lay the crankshaft in them,use oil on the main bearings and crankshaft and then spin it, install the main caps so that two bearing retaining tangs are facing each other and then tighten the mains down to 85 Ft lbs, I use three increments, 30 lbs, 60 lbs and then 80 lbs. ,except number three,leave it loose until your ready to set the end play, and spin the crank. No main seal or timing cover seal yet. It should spin very easily by grabbing the crank snout with one hand and spin it If it doesn't spin easily find out why. You can also try spinning the crank on each main bearing as you tighten them down, just in case Let us know what you find, BTW, the main caps should not fall into the main saddles, they should have to be tapped in or push in very hard by hand I use a soft faced mallet to tap them into place
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Bad Main bearing cause?
[Re: 6PakBee]
#1191211
03/16/12 10:50 PM
03/16/12 10:50 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:
Cab thank you for the info. 6pak i don't understand how checking the runout on the crank will determine if my block is still in line. Seems like that would only check that the crank isn't warped?
You are absolutely correct. If you check the crank and the crank is true (straight), then you can use it as a try bar to check the alignment of the main bearing bores. Look at it this way, if you assemble the bottom end with new bearings and the crank is hard to turn; do you have a bent crank or does your block need to be line bored because the main bores are out of alignment? If you check as I have indicated you'll know the answer.
Gotcha, so as far as checking the line bore you basically just make sure the crank spins freely..
thanks
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