SBC Engine Bearing wear help.
#1
Senior Member
RACING JUNKIE
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Join Date: Dec 2004
Location: austin texas
Posts: 729
SBC Engine Bearing wear help.
Can someone help me figure out what happened here. Eagle rotating assembly, show 1.5 thou on all rods and mains. Engine has 500 miles on it. It showed great oil pressure until it got warm ,160* or after 20 mins of diving. Then oil pressure dropped to 10-20 lbs. THe bearings show to be starving for oil, correct, especially the three center main caps? I thought the front oil galley plugs could have been leaking, which would have blead off oil pressure as soon as the 20/50 got warm, but they look fine.
383 sbc roller hyd cam.
Wix oil filter
Castroil 20-50
Engine was built with assembly lube and i primed the engine before installation.
The problem was not that the engine was dirty or contaminated.
I cleaned the block flawlessly, installed cam bearings and re cleand. All oil plugs where removed.
I tried it with a melling stock pump first, drove 100 miles and changed to hv pump, same problem?
Thanks for any help!!!!!!
383 sbc roller hyd cam.
Wix oil filter
Castroil 20-50
Engine was built with assembly lube and i primed the engine before installation.
The problem was not that the engine was dirty or contaminated.
I cleaned the block flawlessly, installed cam bearings and re cleand. All oil plugs where removed.
I tried it with a melling stock pump first, drove 100 miles and changed to hv pump, same problem?
Thanks for any help!!!!!!
#3
Senior Member
RACING JUNKIE
Thread Starter
Join Date: Dec 2004
Location: austin texas
Posts: 729
#4
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RACING JUNKIE
Join Date: May 2006
Posts: 2,044
Glad you found the problem, screw in plugs are the way to go.
My buddy had a similar issue with his BBC that he built, might have been the same problem plug leaking or something who knows it's gone now.
But anyways, he had all new lunati H beams, Eagle forged crank, new pistons, pressure was low after warm up, around 15/20 idle, didnt last long 2 passes later it spun a couple rod bearings and snapped 2 of them H beam rods like they were tooth picks. :shock:
I tried to check your video out, didnt work for me.
Cp
My buddy had a similar issue with his BBC that he built, might have been the same problem plug leaking or something who knows it's gone now.
But anyways, he had all new lunati H beams, Eagle forged crank, new pistons, pressure was low after warm up, around 15/20 idle, didnt last long 2 passes later it spun a couple rod bearings and snapped 2 of them H beam rods like they were tooth picks. :shock:
I tried to check your video out, didnt work for me.
Cp
#5
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RACING JUNKIE
Thread Starter
Join Date: Dec 2004
Location: austin texas
Posts: 729
Yes i agree, i knew all my clearances where good and i was loosing oil pressure some where. The three plugs went in nice and tight, i dissasembled the engine and taped them for 1/4 pipe plugs tonight. I imagine this problem happens to alot of people and never now the problem!!!
#7
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RACING JUNKIE
Join Date: Sep 2007
Posts: 4,137
Glad you figured it out. Have you measured that crank in the middle and the ends of each journal? It looks like the journals are hourglass shaped.....Just my opinion but I'd want closer to .003 on the rods and .0035 on the mains.
#8
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Join Date: Aug 2005
Location: Tell City, IN
Posts: 356
#10
Originally Posted by DrivingMissDD
Now THAT is a 'teachable moment'
Good catch!
Dave