|
Re: #6/#5 spun rod bearing ?
[Re: gregsdart]
#1069276
09/05/11 12:17 PM
09/05/11 12:17 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
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.
My opinion exactly... its too bad we cant get a oil
pressure reading at the end of the line instead of
near the beginning
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: moderncylinder]
#1069283
09/05/11 01:48 PM
09/05/11 01:48 PM
|
Joined: Oct 2003
Posts: 4,003
South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,003
South Park, Pa.
|
Quote:
#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
#7 looked like I had just installed it, like I previously stated. #6 wasn't there. #5 was there but burnt. ALL other rods and ALL mains looked like new. I usually use either a Fram HP1 of K&N hp filter. This time it had a Fram on it. I run a deep sump oil pan and a HV pump. Cold start up it sets on 98 psi. All warmed up and at idle it sets on 65 psi.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: 68LAR]
#1069284
09/05/11 02:41 PM
09/05/11 02:41 PM
|
Joined: Sep 2007
Posts: 258
Stockholm, Sweden
TomsCharger70
enthusiast
|
enthusiast
Joined: Sep 2007
Posts: 258
Stockholm, Sweden
|
This thread came at a perfect time  Lost the oil pressure in my Hemi and it started to knock.. This is what I found when I opened it up. (Sorry for bad picture quality)  Its the # 6 Rod bearing (I think) that is sticking out... Havent removed the rods/pistons/crank yet. Is the Hemi block oiling system the same, refeering to.. #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 and would the Hemi oil system also be better off with restricting the passage to the rocker shafts. Oil system is a external Milodon Dual Line system with a Melling HV pump. No windage tray. I guess in my case I think the spun bearing happened because of low oil volume in the pan.. Ive also been messing about trying to get the E85 carb to run right. Had to change the oil a couple of times because of carb running excessively rich in the beginning. Typical luck for me, the loss of oil pressure happened about the same time I managed to find a nice carb tune.. Though I think the bearing had been messed up longer than that, but it let go right then... /Tom
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: TomsCharger70]
#1069285
09/05/11 03:01 PM
09/05/11 03:01 PM
|
Joined: Oct 2003
Posts: 4,003
South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,003
South Park, Pa.
|
Sorry to hear about your damage. Maybe WE all can get some good info from this post.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: 68LAR]
#1069286
09/05/11 03:08 PM
09/05/11 03:08 PM
|
Joined: Oct 2003
Posts: 4,003
South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,003
South Park, Pa.
|
Here's a question for you. What about a rev limiter or 2 step? Could these have an impact on #6 rod bearing going prematurely? MY 2 step was raised toward the end of last year from 4800 to 5400-5600 for my launch.   After re-reading some of the replies, how about restricking the oil to the rockers by 1/2. If the existing hole is 1/4", drill and install a 1/8" restrictor. What are the thoughts about this working on a street/strip engine?????
Last edited by 68LAR; 09/05/11 06:39 PM.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: 68LAR]
#1069287
09/06/11 12:00 AM
09/06/11 12:00 AM
|
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Sport440
master
|
master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
|
Quote:
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.
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
Last edited by Sport440; 09/06/11 12:15 AM.
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: 68LAR]
#1069290
09/06/11 11:46 AM
09/06/11 11:46 AM
|
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
JohnRR
I Win
|
I Win
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
|
Quote:
Quote:
That`s EXACTKY what I was thinking plus, 9 quarts of oil AND the stp........I wonder whats going on inside the pan.
What's this mean? I don't get it!
You may have gotten a little carried away with your use of an additive, I can see one bottle, but 3???
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: 68LAR]
#1069291
09/06/11 11:49 AM
09/06/11 11:49 AM
|
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
JohnRR
I Win
|
I Win
Joined: Jan 2003
Posts: 74,937
U.S.S.A.
|
Quote:
Quote:
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....
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
Have you made any of the oiling system changes like that listed in the tech archives?
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: Sport440]
#1069294
09/06/11 01:20 PM
09/06/11 01:20 PM
|
Joined: Oct 2003
Posts: 4,003
South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,003
South Park, Pa.
|
Thanks for the bump Mike, good info. I'd like to try that mod, but have 2 questions. How would street driving be affected, and how would I block the oil feed from the cam bearing to the head after the new cam bearing had been installed? Would plugging the holes in the cam work?
Last edited by 68LAR; 09/06/11 02:49 PM.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: #6/#5 spun rod bearing ?
[Re: RemCharger]
#1069295
09/06/11 01:21 PM
09/06/11 01:21 PM
|
Joined: Dec 2009
Posts: 1,074
detroit, mi
POS Dakota
super stock
|
super stock
Joined: Dec 2009
Posts: 1,074
detroit, mi
|
Quote:
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.
What is it about STP? Is it the thickness that is to much and causing the bearings to spin? I used it in an engine for a while that had bearing wear and low oil pressure and it bought me another year.
But I would think too high a viscosity could be a problem, no?
|
|
|
|
|
(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).
The reason being that the stock oiling through the cam only allows oil to the rockers around 15 camshaft degrees at the most, I have not taken the time to measure that so that is a less than a SWAG 
Remember that the cam goes around only once for every two crankshaft revolutions 
BTW, I use a lot thinner oil , 5W20 wt. in my motors and more bearing clearances than yours, .003+ on both the rods and mains with no oiling problems so far. I don't like STP either but I do use a zinc additive in all the non roller lifter motors I build. I feel your pain on what happened, I have had it happen more than once,especailly in factory motors. I'm not sure what causes it but I'm almost sure it is NOT the loss of oil supply when oiling the rockers with the stock system 
