Really need help finishing my rebuild. Rod Bearing Issues

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JesterX18
Posts: 28
Joined: Sun Dec 14, 2008 1:26 pm
Car: 1991 240sx SE

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Ok, I just got my engine back from the machine shop and brought my engine over to my buddies to take all the bearing measurements. Im using the eagle rod and wiseco piston combo on my engine. When the crank was in the machine shop i had it polished which the machinist said it only takes of a few ten thousandths off the crank journals. I verified this with the measurements i took and found that the main bearing journals hadn't changed enough to change their grade so i know which main bearings to order. My problem is the rod bearings. I didn't have the oem SR rods on hand to measure at my buddies house and nissan doesn't list a spec of the rod bore in the fsm, merely colors., i did measure the eagle rods bore and it matches the spec they gave on the website http://www.eaglerod.com/index....id=32

So basically what i found is that my rod journals and eagle rod bore nearly match the websites spec. I know oil clearance is between 8-17 ten thousands if i recall. housing bore: 2.0080 in. - rod journal: 1.889 in. =.119 in. .119in - oil clearance of lets say .001 = .118 bearing thickness convert to mm you get 3.0226 mm of bearing thickness to achieve an ideal oil clearance. Now i was looking a tomei, acl, and other bearing companies and there bearings tend to run between 1.5 to 1.7mm in thickness. Because i dont know the factory rod bore im wondering if the eagle rods are a bigger bore or something. The rods were torqued properly when measurements were taken. I understand i need to remeasure the journals because the micrometer i used didn't have ten thousandths which is crucial for oil clearance but im not even close. The eagle website has nearly identical values so my math cant be that far off. Does this all make sense? Am i missing something in my calculations. If anyone thats has gone through this process or has properly matched eagle h beams rod to some kind of bearing i would appreciate your take on the situation. I mean a 3mm bearing?


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the converted
Posts: 2767
Joined: Wed Feb 21, 2007 7:14 am
Car: '99 BMW M3 6.0
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Location: Boston

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Forgot to divide by two :-) That said, your looking for a bearing that is ~ 1.51mm. I think that the FSM lists the thicknesses for the bearings.

Actually just found this:Connecting Rod Bearings (Std from Nissan)Grade Thickness in mm Identification0 1.500 - 1.503mm No Color1 1.503 - 1.506mm Black2 1.506 - 1.509mm Brown

JesterX18
Posts: 28
Joined: Sun Dec 14, 2008 1:26 pm
Car: 1991 240sx SE

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Oh man thats awesome! So i needed to divide by 2 because the bearings are halves. Is that all it was. Thanks a lot man i really appreciate it..


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