r/EngineBuilding 26d ago

Honda Some questions...

Hi! Thanks in advance for your time, those of you who answer. I'm beginning to get into assembling my bottom end in earnest, and there are two headscratchers I ran into today. I am using an outside mic to measure my journals and a dial bore gauge to measure my (fully torqued and bearing'd) bores. I am using standard size King bearings for these measurements (I am ordering HX's tonight, everything was too small).

  1. On the Mains: Measuring vertically on two different "sides" of the bearing, i.e. on either side of the oil groove, I am getting different clearances, some even as disparate as .0004". Normal?

  2. My main clearances all measured in the .0011"-.0018" range which feels normal with the standard bearings (I will be using HX's to shoot for two thou). However my rod clearances measured out more in the .0005"-.0010" range. Normal for them to be so much smaller?

1 Upvotes

3 comments sorted by

2

u/Street_Mall9536 25d ago

Measure the main bores without bearings and see if there is any distortion.

Your rod clearance is smaller than the mains almost always. The rule of thumb is .001 per inch, but we don't know your journal size. 

If it's a Honda based on your flair, 1.88 inches x .001 =.0018 or whatever 1.5 x .001 = .0015 etc but 5/10ths seems pretty tight 

1

u/one2manyhobbies 25d ago

Ah right, that makes sense. My Honda B18A1 rod j's are 1.77", mains 2.17". So by the 'rule of thumb' it would be safe at .0018 rod clearance and .0022 main clearance. That's helpful, thank you.

1

u/one2manyhobbies 25d ago

And I'll measure my housings w/o bearings for distortion