Gage Old Bearings - Buy New

After spending a few months going over and over Honda's main and rod bearing color code system, I think I finally kind of understand it. Why not just numbers!? ...anyway

So, now I'm ready to size the original bearings with some plastigage, double check the wear with a set of digital calipers and order the new bearings. Step one is to buy some "green" plastigage. The green is the appropriate clearance range, .025-.076mm (...or as we like to say at work "25 to 76 microns") for the standard tolerance on the F23 (by the book, mains are 21-45microns for #1,#2 and #4; 25-49microns for #3 and 9-33 microns for #5. Rods are all 21-49 microns).

After some online shopping and asking around I ended up finding the best availability and a decent price from Summit Racing's website. It was also convenient that their warehouse is in GA and my order arrived at my doorstep (in SC) in less than 36 hours! of course I ordered 5 packs of it (enough for 5 engines they say. I say enough for 7 or 8) to put that shipping cost to work for me. When my order came in I got things set up for measuring...

The white and green strip of paper between the block and the crank is the plastigage "envelope." You may also notice I'll be working inside... lighting and heat in the garage are inadequate so if I can be clean about it I work in the office.

A closer look at the gage strip. you can see the test range on the edge of the package. The thin green plastic thread is folded inside.

 

Here is a bit of gage cut to length and delicately placed on the journal. This stuff is pretty small and if not handled carefully can disappear into small cracks or carpet fibers... I lost at least three before getting them all in place. 

 

After some incremental and patterned torquing of the mains (to 51 lb ft) it all comes appart again to reveal the crushed gage strips. 

Oddly enough the oil-flow groove in the bearing makes for a handy comparison of before and after widths of the plastigage. The indication bars on the package are held up to the crushed gage and in this case showing a clearance of about 38 microns. Accounting for wear as measured by the calipers this figure becomes 30 microns for new bearings. In range for all specs. I repeat the process for the rods and fresh bearings are now on the way from hondapartsunlimited.com.

Psych! bearings made it to the door step before I finished this post.

The color codes are yellow and green for both rod and main bearings. Interestingly equal count of each color for both sets. From the left, in the green bags ironically are the yellow rod bearings then green rod bearings, then green mains, yellow mains and at the bottom the "shims." These handle any axial load on the crank. You can see the slot that they fit into in the journal bearing in the previous picture. The reflective face of the crank counterweight/web is the mating surface.

So the bearings will be checked as before to confirm clearance. Once the block is honed and the ring gap checked (posts coming for both), final assembly of the bottom end is only a free afternoon away.