Small block bearing clearances

[megacab]

Just had to pull down my new motor for little problem that luckily was avoided.But now that its got the pan off,i was thinking about the clearances.The last time i had the motor apart it went back together with the rod bearings at .0026-.0028.When i pulled it apart this time to go through it the bearings had some scoring.Probably from 7200rpm blast and slight cap walk.I put a girdle on it this time,and a local engine builder had me put -1 bearings in,meaning now their at .0036-.0038.My oil pressure is fine,80 psi cold,40-45 hot at idle,and climbs up to 75-80 when you whack it.But everything i read says .0025-.0028 is the sweet spot,.0028 being max.Should i swap these bearings out?If it wouldnt have been for another non related problem that caused me to yank it i would have left them in.But now its on the stand with the pan off im wondering if its going to be a problem.The motor was rebuilt about a month ago with these new bearings.I was running 15/40.The motor turns 7200 regularly.Its a 14.1 W5 roller cammed 416.Thanks.

 

[ramcharger]

I have my machinist shoot for .0015" clearance on the mains for a street engine and .0025" for a high rpm engine. Don't forget to check end play. It should be between .002" & .007". Make sure that the bearing are correct for application. Most HP crankshafts have a large radius on the bearing surface to crank transition and may require special or machined bearings.

 

[bOb shingler]

spinning your motor passed 7000rpm's it's a perfect idea you machinist has to keep the clearance that way. i'd recommend losing the 15/40wt stuff and go to a straight weight oil like valvoling racing in the 40-50wt range. i trust you have an oil pan that holds 8-10 quarts?

 

[moper]

With your rpms, as was said... looser is faster so long as you have the volume. Are the bearings showing any signs of heat? Pressure is one thing, but it can be misleading. You want to make sure they are getting enough oil at that pressure I would leeave it as it was. I would also be running straight 30wt racing oil in it. VR1 or equivilent.

 

[megacab]

Actually this time the bearings dont show any signs of heat.last time at the tighter clearances they were looking kinda rough.The bearings right now are a hard,coated race bearing.Also narrow.Last ones were wider and champfered.These are just narrow.So am i hearing leave them as they are,that being the larger clearances,and just run a better oil?The coating is starting to wear very sightly,and under that it looks chrome.I would rather not have to replace a 300 dollar set of rods and mains if they live as is.It sees very little street duty