Offshoreonly.com - Main/Rod Bearing Clearances

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automobili_v12

03-12-2019 09:39 AM

Main/Rod Bearing Clearances

Hi, Im building a 454 Stroker, what Main & Rod Bearing Clearances would be recommended.

beaver 3

03-12-2019 11:15 AM

I built mine to .0025 - .003. I run 20/50 oil oil pressure is always good. Only about a season and a half on the motor now though probably around 20 hours.

getrdunn

03-12-2019 12:22 PM

Going off memory and not manual but .0027-.003 on rods and .003-0035 on mains. Some shops run slightly more clearance or the rear main. Closed or open cooling? I've always went by marine engine speed shop and seems like we always ran on the higher side due to the cooler water and oil temps. BUP should be able to get you spot on if he chimes in.

flashgordon

03-17-2019 11:06 AM

i have 0028 on rods and 0035 on the mains

automobili_v12

04-18-2019 07:40 PM

Can anyone else chime in,

Thx

sutphen 30

04-18-2019 09:13 PM

Quote:

Originally Posted by automobili_v12 (Post 4682862)

Can anyone else chime in,

Thx

why,,how tight are yours?

Rookie

04-18-2019 09:31 PM

Quote:

Originally Posted by automobili_v12 (Post 4682862)

Can anyone else chime in,

Thx

Those are the proper tolerances. What more are you looking for? I run on the higher end. Cooler engines (120°F) and oil 165°F, 15/50 Mobil 1 oil.

automobili_v12

04-19-2019 09:21 AM

Should I run the bearings -.001 extra on the clearances for more Lubrication?

ph1971

04-19-2019 10:34 AM

.0028 main and .0025 rods in my 540

Rookie

04-19-2019 10:20 PM

Quote:

Originally Posted by automobili_v12 (Post 4682946)

Should I run the bearings -.001 extra on the clearances for more Lubrication?

No, you should run within the tolerances given. Lubrication is a little portion of oil. More importantly it works as a hydraulic stabilizer when the charge is set off in the combustion chamber. The oil is a non-compressible fluid and creates a cushion between the journals and crank so they don't slam into one another. Tolerances are critical and no need for you to try to engineer new tolerances. Between the given tolerances is personal preference and build design specific.

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