I been searching the forum but can't find what I am looking for. I checked my rod bearing clearances last night using a mic and mitutoyo bore gauge. I was able to play the shell game and get all rods to .0022" -.0023" I am concerned based on what I am finding on-line that for a mild performance build this may be border line tight. This is a 454 .030 over about 10-10.6 :1 CR depending on heads on a forged crank and Scat rods with 7/16 ARP Bolts. Plan on about 6K Max RPM I am considering some X bearings. Using one shell "should" get me to .0027 -.0028". That seems borderline too Loose? Just wondering if it is worth getting the X Bearings. or living with the clearance I have. They are King HP Series Bearing BTW.
Another Rod Bearing Clearance question
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If you're not planning on running a heavy oil you should be fine.
I am going to check the Mains tonite. I am not sure what weight oil to run... That was going to be a separate question at some point. 5w-30 or 10w-40 is what I figured it would be.. Does .0022" on the rods for a 550Hp big block turning 6K scare anyone?
No need for 40wt oil so I'd stick with the 5-30 or 10-30.
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A Metutoyo bore gauge with ridged fingers is not very accurate for checking bearing clearances.
it's fine. find something real to worry about. Or just take a nap, conserve mental energy for the next over-think coming up. 
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That's perfectly fine clearance. A bit on the loose-ish side actually IMO but entirely within the range.
Run it. Use normal oil in it. (10W-30 Mobil1 or the like)
Run it. Use normal oil in it. (10W-30 Mobil1 or the like)
Well I found the next item of concern this evening. I checked the Mains and they don't look so good.it's fine. find something real to worry about. Or just take a nap, conserve mental energy for the next over-think coming up.
1 & 2 = .0024
3 = .0022
4 = .002
5 = .0036 - .0045 with pump mounted
5 = .0032 - .0042 without pump mounted Yes it is tapered.. Big in front and small near seal..
WTF?? I had it lined honed.. Actually all the mains are tapered a couple tenths, all bigger in the front. The dimension listed is the smallest size I recorded. I know I need to open up 1-4 but is the thrust acceptable like this?
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What do the housing bores measure with out the bearings?
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That, I would NOT run.
What do the crank journals mic?
What do the crank journals mic?
I just finished up checking the Main Housing Bores without the bearings and here is what I found.
1= 2.9271
2= 2.9270
3= 2.9271
4= 2.9268
5= 2.9272 - 2.9278 w/out pump mounted
5= 2.9277 - 2.9280 with pump mounted and ARP Stud torqued to 55ft lbs.
Was supposed to be alingn honed with pump mounted so it looks like it was.
I had stud torqued to 63ft lbs when i posted # 5 clearance yesterday.
Rechecked with bearing and pump torqued to 55lbs and got better results:
# 5 bearing clearance now is .0035 - .0042 bigger in front.
I swaped # 2 shells with # 4 but # 4 still is only .002"
Crank mains are: ( ground 0.010 under)
1= 2.7388
2= 2.7390
3= 2.7390
4= 2.2398
5= 2.7385
I think I am looking some .001 x bearings and using half shells on 1,2&3 and the full .oo1 on # 4.
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What's tapered; the crank or the bores?
The # 5 bore is only .0002 without a bearing in place. Put the shells in it reads about .0007 tapered. Bigger to the front.
Yes it was a typo.. add .010 to those numbers. Is .007 to .008 taper on the thrust main clearance a problem. I know it is not desirable. If I used a half shell on that one too it should end up at about .003 to .0037 ish, bigger to the front. Thoughts on this?
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