ok..muy f22b1 vtec engine has 22222 stamp on crank and ccbcc stamped on block which comes out to y/g,y/g,y,y/g,y/g. (that's yellow and green.)with yellows in the block and greens as well..(I know it meant one half yellow one half green, but I wanted to see the difference in the bearings...)the yellow had a clearance of .0020, which is the service limit for journals 1,2,3 4...here are muy books' readings-oil clearances-# 1 4 standard .0005-.0015 service-.002# 2 standard .0008-.0018 service-.002# 3 standard .0010-.0019 service-.0022# 5 standard .0004-.0013 service-.0016 I also tested browns and acl bearings.these are the clearances I got with a dial bore gauge.....green bearings- .0019yellow bearings- .0020brown bearings- .0015acl bearings- .0025at this point im not sure which way to go, go with stamps or clearances...any suggestions would be great... thanks
Honda uses this system to get extremely close tolerances on bearings/journals from the factory. After it has been run 100,000 miles (or 250,000); when it is time for overhaul, the crank gets turned to fit .010, or .020 under-size bearings. The clearance is determined by the machinist turning the crankshaft. Be careful, many machinists go for big clearance, like .003 because they are used to building race engines that last 3 races and get rebuilt again (short life). Better have a shop manual on hand and ask him to shoot for the smaller side of clearances.
The deciding factor is clearance! But if you need new bearings- the crank should be turned to the next size. Now this might seem like a needless expense. But it is not! For one thing it makes sure there is not too much play at the mains and rods. The second is that turning the crankshaft smaller reduces friction. That means that the engine will rap out faster! Now while you have the crank in the shop- ask about getting the flash removed and peened. Also have take the piston and rods in for a finer tolerance balance. Reducing internal engine resistance is what a performance rebuild is all about- not just slapping new parts in a worn block.
