What Killed It?


Active Member
OK, here are all the bearings set next to each other. Number 1 at the top and Upper shell on the left.

This is just 5 tanks of gas and very light cruise on the first 4 tanks of gas. When I got on it I had 100 octane and about 12 - 14 PSI of boost. No Knock on the scan tool but I have had one person tell me that the upper rod bearings prove knock and that nothing could have hurt the upper shells and not the lower, period!

I found that the drivers side front oil galley plug had come out. The engine sounded and ran great but the gauge said there was a problem so I hope just a polish on the crank and also either narrow rod bearings or have the machine shop chamfer wide rod bearings - it really did not look like the bearing could get close to the radius in the crank pin.


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A few more - sorry about the quality of the pics


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The top of the bearing half being beat up without hurting the bottom is a classic sign of detonation. The other scratches ar a result of trash from the rod bearings more than likely.

Rod bearings are from lack of oil pressure and volume. #3 main cap insert==trash. I have come to believe that we need to do some more cleaning AFTER the cam bearings are installed.
The loaded sides of engine bearings are the bottoms of the mains because the crank is being pushed down. That is where you look when checking mains and the top shell on the rods because that it where the force is being applied from the rod. personally I would get new HD bearings then plastic gauge each rod and main to verify the clearances, and depending on what you find would help you figure what you need to do. BTW there are a lot of machine shops that that don't under stand the tight clearances that we run. BTW also you pry clean your crank up with some emery paper and when done be sure to clean out the oiling holes. Also do you have a oil gauge on the car? And did you either prime the motor before first run. Or how long after the build was it installed. Because some places just put a light coat of oil on bearings.

Personally I put a swipe of stp on the cap side bearing the side that touches the crank during assembly.