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I should clairify that the main and rod bearings all showed that debris
had gone thru them but the didnot look like the ran without oil and when
I dissasembled the engine both the rods and mains had a normal amount of oil on them. My question is was the debris there before the
spun bearing? And yes I did remove all the case plugs when I cleaned
the case Thanks Palmer
Old 05-10-2005, 02:54 AM
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I will try to post some pictures of the bearings.Palmer
Old 05-10-2005, 03:04 AM
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debris normally just damages the bearing surface, and if it's coarse enough, the crank gets scored too. unusual for the bearing to actually get loose in the rod and spin, just from debris.
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Old 05-10-2005, 08:53 AM
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Bearing pictures


THANKS Palmer
Old 05-10-2005, 05:12 PM
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The Bearings in the center were the spun rods.Palmer
Old 05-10-2005, 05:13 PM
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To listen to your description and to see the bearings, I would venture to guess that you have a problem in your oil pump, or somewhere in the oil return system that is not allowing the oil to drain from the tank.

AFJuvat
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Old 05-10-2005, 07:22 PM
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Yup, that looks like lack of lubrication to the rod bearings to me.
Old 05-10-2005, 09:14 PM
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If you had proper oil pressure, you could not have an oil return problem, could you????

If you had proper oil pressure (and thats a mininum of 10 lbs per 1000 rpm) then you must have had a restriction. This again assumes all the oil clearences were proper, ie 0.0015" up to 0.0025" possibly 0.003" max). By the way any track only car should run only Red Line oil, straight 30 wt, race oil prefered for track only. Any lesser oil is taking chances and ALL oils are lesser than Red Line. You say you measured rod diameters and crank journals, which are the most accurate way of doing things, but do a double check using plastiguage, ie a sanity check, its worth the couple bucks.

OR the oil was way overheated. What was the oil temp???

REMOVE ALL OIL PLUGS, ESPECIALLY in the CRANK and mechanically clean all passages out.

At this point, just for s and gs replace the oil pump. Clear or replace all oil lines in the car.

Remember, there is NO such thing as black majic, keep checking and you Will find the problem.

Best of luck

Jack

Last edited by snowman; 05-10-2005 at 09:45 PM..
Old 05-10-2005, 09:39 PM
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There are a bunch of problems that can cause oil delivery restrictions. Case plugs sometimes can become dislodged, affecting the rising and falling of the oil pressure pistons in the bores - check those first.

John's right - this sound like an oil pressure / delivery problem, and it's probably something wrong with the case that didn't get fixed the first time around...

-Wayne
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Old 05-10-2005, 10:25 PM
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Oil temp was fine I did notice that after the engine thermostat opened
I could feel the front cooler and hoses get warm I dont have a front cooler thermostat. so I think there was good flow Its hard to see in the pictures but the mains look to me like they were fine except for debris and the intermedate bearings show almost no wear (picture makes them look copper color but there not) but the rods show all the wear
thats what made me think I over or under streched the bolts I remeshered them and they are not over streched and I did re mesher
the good jornals on the crank the are fine so were the rods. thanks Palmer
Old 05-11-2005, 02:46 AM
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A few years back a well-known race team lost (I think) three engines due to sudden oil starvation. In the end they found that some portion of the combination rubber/steel oil lines between the engine or oil tank and the oil thermostat had delaminated on the inside. If you recall the rubber part is spiral wound. Apparently at some point the oil flow would cause the loose rubber to work as a flap, which would stop or severely restrict oil flow.

Scott
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Old 05-11-2005, 09:34 AM
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how could the crank be fine with a spun bearing? doesn't happen!

read it again, and you said the "good" journals were fine. sorry.
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Old 05-11-2005, 09:58 AM
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Sorry I ment the main jornals and the rod jornals not spun meshered
in spec. thanks Palmer
Old 05-11-2005, 07:39 PM
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Palmer.
Based on what you have said, the problem should be inside the crankshaft, ie an internal blockage.
Old 05-11-2005, 08:53 PM
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Wayne. If there was a problem with the case would the mains get oil
and the rods not. I did pull all the case plugs and the oil press pistons
the pistons were free. What if I mixed up the springs on those? I dont
think I did but just wondering. I did notice the oil pressure fluxuating
right after the engine thermostat opened the first time I added more
oil and it stoped (I have a very large front cooler).Could I have damaged the bearings then? Thanks for the help Palmer
Old 05-12-2005, 03:06 AM
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Just to add to the last. it took 17 quarts to bring the oil to the full level
when the engine was warm idling and on the first start up I only had
10 in it. I am thinking I must have ran it out of oil when the engine thermostat opened and #2 and#5 rod bearings would have been the last to get oil does this make sence? Palmer
Old 05-12-2005, 04:50 PM
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The mains would have been toast as well.
Old 05-12-2005, 04:56 PM
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Not necessarily. Its possible to lightly toast a rod, especially those in the middle on a non center drilled crank, without burning up the mains.

The rod bearings are more heavily loaded and the centrifugal forces fling out whatever little oil makes its way there.
Old 05-12-2005, 06:14 PM
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Maybe so, but the rods look an order of magnitude or more worse and I would suspect at least something happening to the mains at that point.

On second look, it looks like some main damage as well. Wish the photos were better.

Last edited by snowman; 05-12-2005 at 07:59 PM..
Old 05-12-2005, 07:56 PM
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