main oil clearance question?

[TurboV6Sonoma]

Is 3 thousands vertical oil clearance ok for the mains? Or should the crank be cut to get it tighter?

Thanks in advance
Ryan

 

[Dominic]

Is 3 thousands vertical oil clearance ok for the mains? Or should the crank be cut to get it tighter?

Thanks in advance
Ryan

If you grind/polish the crank it will have less clearance. Unless you turn it down another .010 and your machinist stays on the high side. Childs & Albert used to sell +.001 bearings but i'm not sure if the do anymore. If you could get them you could buy a std. set and a +.001 set and mix & match the two sets untill you have your desired clearance. You could also have the mains align honed and have your machinist stay a lil' tighter too.

HTH.

 

[TurboV6Sonoma]

3 thousand is the final number after being polished, so is this to much to use a standard bearing? The bearing paperwork says anything up to 3.5 thousands is good but I thought I rememer seeing 2.5 thousands or tighter on the board before.

 

[Dominic]

3 thousand is the final number after being polished, so is this to much to use a standard bearing? The bearing paperwork says anything up to 3.5 thousands is good but I thought I rememer seeing 2.5 thousands or tighter on the board before.

Everyone has there own opinion on this subject, and just like anything else if you ask 10 different people the same question you will get different awnsers.

My .02 cents.....I think you will be fine. I have run them that loose without any problems whatsoever. Oil psi is good and steady too. Now you have to check the rods.

 

[DMan]

What is 'vertical oil clearance'? Is this main bearing clearance?

 

[DMan]

Assuming you're talking main bearing clearance, there is much discussion about this. I rebuilt my motor in the fall, and had a lot of back and forth with my machinist, who advocated loose, and my GN-colleague, who said tight.

Factory specs are believe it or not, 0.0003 to 0.0018.

I didn't want to cut my crank, so I gave it a light polish. Using that, and 1-under bearings (Clevite) my clearances came out to 2.0 to 2.2 thousandths.

While this is above factory spec, oil pressure is fine. The gauge read 37 psi at the end of the 20 minute cam break session (hot idle) with a standard oil pump.