ACL Rod/Main Bearings Extra Oil Clearance?
Dec 4, 2008, 11:15 AM
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ACL Rod/Main Bearings Extra Oil Clearance?
I am in the market for ACL coated bearings, and they seem to have two different types of standard size bearings.
One with standard oil clearance and the other with an extra 0.001" oil clearance.
I know a good oil clearance is for the main and rod bearings to be about 0.002". What is the advantage and disadvantage of running 0.003" oil clearance? 0.003" is still within the factory manual limit for both the rod and main bearings.
One with standard oil clearance and the other with an extra 0.001" oil clearance.
I know a good oil clearance is for the main and rod bearings to be about 0.002". What is the advantage and disadvantage of running 0.003" oil clearance? 0.003" is still within the factory manual limit for both the rod and main bearings.
Oct 25, 2018, 05:03 PM
#3
There are a couple of reasons for tighter or looser clearances, but the main focuses are oil weight, high rpm safety, temperature, and journal distortion. The end goal is to not spin a bearing. Choosing the right size bearing also helps keep bearing crush pressure in check!
In short, your rod and crank journals ride on top of an oil film that is held by your rod and main bearings when oil pressure is present. You want to maximize this oil film strength, but it can vary based on total power output and RPM.
This article contains more detail if you are interested.
http://www.enginebuildermag.com/2013...ng-clearances/
In short, your rod and crank journals ride on top of an oil film that is held by your rod and main bearings when oil pressure is present. You want to maximize this oil film strength, but it can vary based on total power output and RPM.
This article contains more detail if you are interested.
http://www.enginebuildermag.com/2013...ng-clearances/
Oct 25, 2018, 11:28 PM
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Very good read, thank you. So say I have a stock bore Evo 8 block with clean honed cylinders. Have a brand new 88mm manley crank, standard forged Manley pistons, Manley h beans, and plan to make about 550whp on an fp black. For main and rods do I go with the standard acl bearings or the standard acl’s with .001 oil clearance?
And for which decision I chose what oil weight is preferred?
Of course all clearances will be double checked when assembled
Seems to be a tough thing to research because there are so many different opinions with so many different types of builds.
And for which decision I chose what oil weight is preferred?
Of course all clearances will be double checked when assembled
Seems to be a tough thing to research because there are so many different opinions with so many different types of builds.
Last edited by stunna2o1; Oct 25, 2018 at 11:39 PM.
Oct 26, 2018, 12:05 AM
#5
Very good read, thank you. So say I have a stock bore Evo 8 block with clean honed cylinders. Have a brand new 88mm manley crank, standard forged Manley pistons, Manley h beans, and plan to make about 550whp on an fp black. For main and rods do I go with the standard acl bearings or the standard acl’s with .001 oil clearance?
And for which decision I chose what oil weight is preferred?
Of course all clearances will be double checked when assembled
Seems to be a tough thing to research because there are so many different opinions with so many different types of builds.
And for which decision I chose what oil weight is preferred?
Of course all clearances will be double checked when assembled
Seems to be a tough thing to research because there are so many different opinions with so many different types of builds.
Everyone is going to tell you something slightly differen as to what oil weight corresponds to what bearing clearances.
My main bearing clearances average 0.0026" and I use 10w30 VR1 synthetic. My rod bearing clearances are slightly looser than that. I tried 20w50 and found that I was making too much oil pressure for my turbo, but that's a different issue all together.
Oct 28, 2018, 11:50 AM
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I’m still pulling the old motor apart. Have to see if the crank is salvageable. Threw a rod and shot a hole the the motor and oil pan. Would you say even a turned oem crank over a brand new Manley crank? Was hoping might even just need a polish. From what I can see it might have only smacked where the rod broke in the center of the rod.
Last edited by stunna2o1; Oct 28, 2018 at 02:26 PM.
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