I have a b18a that I am trying to go ls-vtec with. I am in the process of installing the rod bearings (ACL bearings) and I am fallowing the build article on http://articles.evans-tuning.com/200...-a-gsr-engine/ but going by the spec of an b18b from the chilton repair book. I am using plastiguage to check the clearance and I got 0.020in - 0.022in on the rods.

I thought to myself so I just need to get some smaller bearings 0.0015in is what I am trying to aim for. Smaller the bearing it will squish less on the plastigauge right. So I brought my bearings to an acquaintance since he has a digital caliper to measure the bearing thickness and it came out to be 0.056in - 0.055in on all the bearings.

Checked the the rod journals on the crank measured 1.890in
Checked inner rod diameter measured at 1.770in
Rod bearings measured at 0.056in

So I added the numbers up

1.770
0.056 top rod bearing
+0.056 bottom rod bearing

Got 1.882in

Subtract 1.890in size of the crank journal from 1.882in and I got 0.008in for my clearance right.

But when I use the plastigauge it measures .020in - .022in

Am I doing doing something wrong here? Any help is greatly appreciated.

 

you wont have these issues with OEM bearings because they have differnt sizes. so the 100 bucks or so you saved gets used up in the ever invalueable thing called time running around trying to make up for what you thought was a short cut and cheaper way to go. but with the clearance you have it will run for a while its not optimal but when your half assing things and are on some super tight budget optimal isnt really a big deal anyways.

and you need a thicker bearing to make the clearance smaller.

 

This might help you.

Info for Honda B.

A. Big End Bore of Rod range: 1.8898 - 1.8906 (typically it's in the lower end of this range);
B. Rod Journal on Crank range: 1.7707 to 1.7717";
C. Bearing half thickness. Max is 0.0591.

Vertical oil clearance = A - B - 2*C.

Looks like your B measurement is below the range.

Also is there even plastigage for 0.020? Do you mean 0.0020?

Fo-Shizzay.

 

This is my first motor build after reading and searching all these builds I finally got a little confident and went for it.

I don't get it if I use thicker bearing won't it put more pressure on the plastigauge which will smash it flatter and wider?

So if going thicker to get the clearance that I would like to go with, it should be the black 1.507-1.504 mm 0.0593”- 0.0592” bearings if my calculation is right.

 

I dont think digital calipers will be accurate enough to measure bearing thicknesses.
You should measure to the ten thousandth if you can (.0001). Measuring to the .001 is not enough when your talking about bearing clearances IMO.

Also take several measurements to help rule out bad measurements.
Are you using stock crank and rods? The codes will help you select the correct color bearings...

 

Does anyone see running rod bearings at .001 clearance vs .0015 different? More prone to spun bearing?

 

Which plastigauge are you using, or what color?. I think your reading it wrong, if possible re-do the process and take a pic., show us the plasti w/ the wrapper next to it after you remove the rod cap.
I use the green stuff when building, and I like Rock brand bearings.

 

Im using the green. Theres the .001 and .0015 measurements

 

My Fault pgpbubble that was directed at op, to answer your ? , .0013 on my D16z6 would be perfect (rod bearing oil clearance .0008 to .0015), if your within the spec the bearing should not spin because of clearance.
The way to measure clearance with a caliper is: install bearings in rod torque to spec and use a bore guage to get the diameter, then measure the bore guage with a caliper.
Measure the rod journal on the crank, then subtract the smaller # from the bigger #, that is your clearance.
Plastigage is to doublecheck those measurements and also so you can see if there is taper.
Maybe op is reading the mm side of the plastigage wrapper or using the wrong color, also the measurements for rod journal and rod are strange the rod diameter has to bigger than the rod journal with or without bearings installed.
This is a picture of the plastigage we should be using if anyone is interested, .001 to .003 inch on one side and .025 to .076 MM on the other, Honda engines are metric but the specs in a haynes or chilton are in inch.