Main/Rod Bearing Clearances

Reply Subscribe

Thread Tools

03-12-2019, 09:39 AM

automobili_v12

Registered

Thread Starter

Join Date: Oct 2009

Location: Miami, FL

Posts: 222

Likes: 3

Received 2 Likes on 2 Posts

Main/Rod Bearing Clearances

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

03-12-2019, 11:15 AM

beaver 3

Registered

Join Date: Apr 2013

Location: Lagrange ky

Posts: 309

Likes: 0

Received 0 Likes on 0 Posts

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.

03-12-2019, 12:22 PM

getrdunn

Registered

iTrader: (7)

Join Date: Feb 2009

Location: NW Michigan

Posts: 8,302

Likes: 1,176

Received 1,491 Likes on 806 Posts

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.

03-17-2019, 11:06 AM

flashgordon

Registered

Platinum Member

Join Date: Sep 2012

Location: new baltimore mi

Posts: 523

Likes: 37

Received 38 Likes on 32 Posts

i have 0028 on rods and 0035 on the mains

04-18-2019, 07:40 PM

automobili_v12

Registered

Thread Starter

Join Date: Oct 2009

Location: Miami, FL

Posts: 222

Likes: 3

Received 2 Likes on 2 Posts

Can anyone else chime in,

Thx

04-18-2019, 09:13 PM

sutphen 30

Registered

Join Date: Jan 2006

Location: taxachusetts

Posts: 3,093

Likes: 537

Received 699 Likes on 353 Posts

Quote:

Originally Posted by automobili_v12

Can anyone else chime in,

Thx

why,,how tight are yours?

04-18-2019, 09:31 PM

Rookie

Registered

iTrader: (4)

Join Date: Jan 2003

Location: Grand Rapids, MI

Posts: 5,698

Likes: 438

Received 1,206 Likes on 579 Posts

Quote:

Originally Posted by automobili_v12

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.

04-19-2019, 09:21 AM

automobili_v12

Registered

Thread Starter

Join Date: Oct 2009

Location: Miami, FL

Posts: 222

Likes: 3

Received 2 Likes on 2 Posts

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

04-19-2019, 10:34 AM

ph1971

Registered

iTrader: (1)

Join Date: Apr 2014

Location: North Florida

Posts: 649

Likes: 83

Received 121 Likes on 58 Posts

.0028 main and .0025 rods in my 540

04-19-2019, 10:20 PM

#10

Rookie

Registered

iTrader: (4)

Join Date: Jan 2003

Location: Grand Rapids, MI

Posts: 5,698

Likes: 438

Received 1,206 Likes on 579 Posts

Quote:

Originally Posted by automobili_v12

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.