This is between 3 different motor builds at once. I have hit the point where my machine shop and myself are becoming GREATLY acquainted.
H22a, J35a3, and LSVtec

Per his advice, .002in clearance on bearings is not such a bad idea. I personally thought that oem bearing clearances would apply. On the LS it has a KMS modified oil pump to flow more (30 psi at warm idle and 80 @7k). im questioning this mod on the other motors, so i am waiting. the LSv will be the first built and ran in early Feb, so i am witing on that decision until the motor is broke in then ran hard.

On all 3 cranks, they were only in need of a polish as they were readily driven at the time of teardown. but they will all be knife eadged.

Rods,
For the h22 and LS were I beam sourced from eagle.
The J35 will be using shot peined oem rods.

Pistons -
Using a ycp type R piston for the LS stock bore as the cylinder walls were not out of round and were simply deglazed.
The J35 was a lower mile bottom end that came from a friends mishap. im replacinthese with OEM pistons from a diferent motor (13010-RJA-000) along with matching cams from the 07 RL as well.
The h22a was a great deal s i picked it up, ran it for 10k and pulled it out. im looking to source a forged piston (either K572M87 from wiseco or 166035 from JE).
My main question is clearance (both ring and piston to wall)for Forged vs cast as far as experiance. i have talked to wiseco and they recoment about .005in clearance total (.0025in a side). the LSv and J35 ar both measured t about .003in (.0015 a side)
.001 for the first ring and .0025 for the second ring on the piston rings. i have been given way bigger numbers from guys just talking bu willing to take advice from anyone who has had theirs built by a shop before.

 

You have to get that h22 sleeved if you're running pistons from Wiseco or JE; only Mahle has FRM compatible pistons. Also, clearances on forged pistons will depend on what alloy they are made from.

 

As far as bearing clearance A general rule of thumb for an engine that will be making more power than stock or be driven aggressively .001" per inch of diameter of journal. As in the rod journal on a b18 is 1.7707-1.7717 so the rod clearance then would be .0017+/- a tenthousandth or two, depending on actual measured diameter.

The piston to wall clearance from the manufacture is a minimum recommendation. The more power you make the more clearance you need. The clearance is also dependent on the fuel that will be used. 700hp on race gas would need more clearance than 700hp on ethanol or methanol.

The ring gap outlined by the piston manufacture is also a minimum recommendation. More power more gap.

 

Can you explain the difference between ethonol and gas (understanding that one fuel is more combustable than the other) and how that directly effects the clearance between ring and piston to wall clearances? This will help me take into account purchasing pisyons later. Im already aware of the frm issue in the c series and h series.

 

and to the top? no one?

 

The gap is a reflection of coefficient of expansion of the metals involved, and the expected operating temperatures they will experience in your engine.

Looking around I see both 'leave it the same' and 'you can reduce the gap a little because it runs cooler'.

I'd stick with 'leave it the same' unless I'd extensively monitored engine and combustion temperatures under all anticipated operating conditions and could guarantee you wouldn't reach the higher temps.

Running out of ring gap is catastrophic; so, possible mild upside .vs. radically bad downside.