Standard or .001 extra

[Sam's GSX]

I know this has been answered, but I can only look for about 30 minutes before getting a headache.
Just a quick question.
For my specific build, should I get .001 extra oil clearance or standard?
Eagle rods, wiseco stroker pistons, eagle 100mm crank with .010 mains, and standard rod journals.
Its has balance shaft delete kit, and I believe the oil squirters or blocked off (machine shop has the block now, and that's what he said)
Obviously will be getting .25mm for the mains, shooting for around 400-450whp.
Thanks and sorry if this is beat to death.

 

[jakelandry]

The proper way is to mic everything.

 

[Sam's GSX]

Mic?

 

[llxkevinxll]

Mic?

He is referring to micrometer, he means measure everything.

https://www.google.com/search?q=mic...nt=ms-unknown&sourceid=chrome-mobile&ie=UTF-8

 

[Sam's GSX]

Oh ok, I do already have the measurements, it's more so that I've seen people run either of these, and was wondering what is best with no balance shaft and oil squirters blocked off? And if I go with extra clearance, I'll probably need to use thicker oil, like 20w50?

 

[donniekak]

You want around .0025” clearance, use whatever bearing gets you there.

 

[Sam's GSX]

Dang, I going with king xp, and they only have .002 and .003 for standard journals.
I might go with .002
I'm not ever going to be pushing more than 500hp, was just making sure it's ok with my oil pressure.

Edit, this is still a daily driver, so I went with .002, thanks guys

 

[donniekak]

You won’t know what the clearance is until you measure the crank journals and bearing bores.

 

[Sam's GSX]

Ok gotcha, so if it measures. 0020 clearance, could I ask the machine shop to take off .0005 ?

 

[jakelandry]

Ok gotcha, so if it measures. 0020 clearance, could I ask the machine shop to take off .0005 ?

The proper method is mic the crank, check the bearing bore with a set of bearings installed (using a bore gauge), take the difference and adjust from there. More often than not, a polished crank with standard bore bearings and brand new rods gets you between .002 and .003”. It’s not as easy as just buying standard or oversized bearings and getting the right clearances.

For reference, I recently put together a motor with new rods and a polished crank near the bottom of its Mitsu-supplied spec. I bought 3 sets of rod bearings mixing oversized and undersized halves until I got the numbers I wanted. It is a very time consuming task that takes the appropriate tools and a clean environment.

The quick and dirty method with the highest probability of success assuming you don’t have all the proper tools would be to buy a set of std bore bearings and plastigauge. Since the crank mains have been cut I assume the rods have been polished so the clearance will probably be north of .002” and will do fine at 500hp.

 

[Sam's GSX]

Ok, that helps thanks so much man