ok, heres something interesting. I measured the rod bearing with the snap gauge again and measured snap gauge with mic, I then 0 bore gauge in the mic with that measure(I think 2.225) and then inserted bore gauge in rod bearing and bore gauge reads .0095 reading gauge clockwise. I then measure rod journal with mic and 0 bore gauge in mic and then insert bore gauge in rod bearing and bore gauge reads .0061. if you subtrack (.0095-.0061=.0034)you get .0034. can you do it that way?
I also tried 3 others dial indicators and get .004 with two of them and .0038 with the other reading to left of 0.
If I read the shars indicator from the left of 0 or counter clockwise I get .0039.
so now my question is would .0035"-.0039" be too much rod bearing clearance? sorry to confuse anyone here. Thanks guys

My head hurts.

Perfect if you running blown alcohol with 70wt oil. .0025" is plenty. Depending on what your building.

LOL! I hear ya. I'm sick of it myself.

Snap gages are not precise enough for this. Put them back in the box. Correctly measure the journal with a mic and lock it down. Use the mic to set up the dial bore gage. Use the anvil that will spin the indicator half a turn or a turn. Clamp the mic down or in a vice. Rock the dial bore gage in the mic to find the square spot and zero the indicator. Drop the dial bore gage into the bearing bore and rock it to find the square spot (smallest dimension making certain you're on the exact centerline of the bore). The distance from zero is the clearance. All measuring tools should have a .0001 resolution and cost more than $19.99. Don't trust your tools or yourself until you can go through the procedure 3 or 4 times and come up with the same number to the .0001th. No calculator or math needed.

ok, enough confusion. I called the dial company(shars). they tell me if the needle is on the left side of the gauge while reading your clearance that you count counterclockwise from 0 and if needle is on right side of gauge you count clockwise. so at that I remeasured crank and being careful to not crank down on the mic with the clutch(just get the air gap out) I reset mic, re 0 bore gauge insert in rod bearing, read the left side of gauge I get .0033"-.0034". I think that's the most accurate I can get.
take a look at the pic of the gauge and you will understand.
rod bolts are tq 30ftlb and clocked 60* Thanks guys

No one said snap gauges are precise, but when the OP is questioning between .0026 and .026 then a snap gauge can help him find his way.

Sometimes you have to look at other options to get your numbers correct. No body said use a snap gauge to finalize bearing clearance. Damn.

That is a bit loose for my taste. A .001 under bearing would be nice. Or, if the rods are on the high side, you can size them to the low side, or a bit under and get it to .0026-.0028ish.

I think it's time to take it to your machinist so you really know what you have!
Maybe take your gave n if he's nice n has time he can school you how to read your gages

i believe the measures. The bearings are +.001 bearings. Ill just have to get another set. Standard bearings would put clearance at .0025 zone. I ordered +.001 because all the other engines i put together had tight clearances.

Let us know what clearances you find with the new bearings Is this a BB Chevy journal rod size? If so anything from .0020 to .0028 should work fine with non thick oil

ok. Be working in the basement. Do you think cold tools might show wide clearances.

As long as everything is at ambient it should be ok.


I worked in a shop that had a huge roll up door on the east end. During the winter, when the wind was blowing, the office retards would open that door and in a minute you could start to see ambient temp starting to tighten up the bores while I was honing the blocks.


Keep everything the same temp.

paid a visit to my machinest today. I took two rods with me with bearings torqued up to spec using angle method.I set my mic to a journal, 0 bore gauge and measured rod bearing at .0033 before I left the house. He measured .0033 with his bore gauge 0 ing it in my mic. so I am reading the gauge correctly and my gauge is accurate enough IMO. something he showed me though was the bearings have taper in them. .0033 in middle and .0036 off to each side. said to get new bearings, should not have any taper. as far as the .0033 rod bearing clearance, he told me not to get caught up in .0001 of an inch measures. he would run that clearance with heavier oil if that's what he had. these are King bearings, thought they were suppose to be perfect accuracy?

Vertical oil clearance is what matters, so the extra clearance won't hurt a thing. In fact, I'm not so sure even the best rods get out of round at higher RPM, regardless of bob weight.

I also disagree with running a heavy oil. There is ZERO reason to do it any more. Unless you are running alcohol or nitro. I'd get the right bearings and have the clearance .001 less and run a 30 grade oil.

all measures were vertical.

I ran .0035+ rod and main bearing clearances on my old 518 pump gas stroker motor, it would idle at 18 to 25 lbs at 650 RPM with 5W20Wt oil at 180F + oil temps, 30 lbs at 1200 RPM, 65 lbs at 6500 RPM
Your fine with .0035 clearnces on the rods I had to use the King rod bearings on the B1 motor I built last year to get the clearances oI wanted,(.0025+ to .0030) every other brand was to tight If your going to use a motor with 2.200 rod journal sizes and want to safely rev it up past 5500 RPM reguraly your way better off with .0030+ bearing clearances, no matter what weight oil, than having .0020 oil clearances

ok, I now have the new King standard rod bearings and I torqued one up in a rod and measured. .002". its looking like I will need the other .001" larger bearings which measured .0033". better too loose than too tight.

Dave,
Use one std shell, and one +.001 shell, and you should be right around .0026". It's common practice.

That's what I did on my mains.