blackeg

just trying to get my turbo block up and running, but i ran into an issue with the rod bearings. With the acl race HX bearings im at .0015. I also checked it with oem yellows and it was about .0013. Both tolerances are consistent across all 4 journals, but a bit too small. the rods are brand new manley h beams for b18b's because the crank is an oem 89mm with the rod journals all marked as "B". The motor itself is a sleeved 83mm gsr with cp's and the manley rods, with an intended power goal of 525-550whp on c12 and right about 400whp on 93. I am not comfortable running .0015" for those levels, and i guess my target is .0018-.0020. Suggestions?

Pro-SeriesFab

Take it to a good machine shop and have them take .0003-.0005" off (for what you're doing, I'd err to the larger side).

The hardness layer on the rod journals is considerably deeper than that, crank will be fine.

JRCivic1

The hardness layer is typically only six to seven thousandths deep on a "B" series crankshaft... taking a few tenths off likely will not cause any issue, however, wouldn't it be better to resize the rods and leave the crankshaft virgin ??? Micro-polishing the crankshaft could get you where you want to be, but you still have rods that are "small" on the big end... and would still be small on the big end if you needed to replace the crank in the future... or move the rods to another shortblock combination. I guess what I am saying is if the rods are the problem, why "fix" other parts to accommodate the troubled part ??? Then again, the OP has not specified what the original rod journal markings are, so unless they are originally on the LARGE side dimensionally... I think I would leave them alone.

Pro-SeriesFab

Opening up the rods decreases the amount of bearing crush, additionally machine shops are more likely to screw up the ovality of the big end than taking the rod journal down a few tenths of a thousandth.

1HGEJ2

iTrader: (1)

or use red oem bearings

motoxxxman

when honing a mere few ten-thousandths out of the rod big end bores, it's pretty difficult to oval it out. It's also not going to affect crush considering it really sounds like the rods are simply too small and not in factory spec for bore size. I vote get the rods honed out and leave the crank alone.
I've also heard a lot of not so good things about manley rods, one of them being the sizes they machine bores to. go figure...

blackeg

the rods are all evenly sized and would be great for a build with oem spec oil clearances....

I know when you install arp rodbolts in oem rods you get the big end honed back to round. Ive had it done before numerous times without issues. All i need here is .0003-.0005 more.

How deep is the nitride coating into the crank journals? Ive heard conflicting reports ranging from .01 to .001"

Pro-SeriesFab

The deep gas nitride layers on crankshafts are usually .010-.020" deep.

It's the pulse/ion stuff that is considerably shallower . . . often only .004-.005" deep.

Either way, a half of a thousandth isn't enough to break through the nitride layer even on the top fuel stuff which has ultra shallow case depths.

blackeg

well the crank is now at a specialized crank shop getting the mains taken down .0003 since #3 main was a bit tighter than the others when it should be bigger. I have to order the oem bearings so ill use different colors per journal to get the mains like .0017 and .002 for the #3. I had .0004 honed out of the big end of the rods, which should put all my rods at .0019 with the acl race hx's i already have.

rings are all gapped, set to .020 to .0208 top and .024 second, with ptw set at .004. the motor is 83mm, 9:1 cp/manley's with golden eagle sleeves. I will probably run it up to 400whp on sunoco 93 pump and 500-525 on c12. I just need enough to click off a 10.9 1/4 mile. I think the specs are all reasonable. lmk if you guys see anything that looks out of whack.

motoxxxman

those ring gaps and ptw clearance are a hair on the loose side for 525hp at that bore. it'll work fine, it'll just make a bit of noise before fully warmed up, and sometimes even after fully warmed up when just driving around normally. if you drive on the street a decent amount, it'll blacken the oil a bit faster than normal too. just stay on top of oil changes and it'll be good.

h1tman

What oil grade are you planning to use?

blackeg

most likely castrol gtx conventional 10w-40. Ive been using it for years never really had any issues. the current motor in the car is pretty much .002 for all the mains and rods, and i have 22psi at idle and 65 +psi by 2500rpm @210 degrees oil temp. I usually change the oil a few times a year, but since i dont drive it often its only maybe 1500 miles per change at most.

h1tman

I have about 0.38 mm on mains and ~0,45 mm on rods and with oil Valvoline VR1 5W50 i have also 65 +psi & 2500rpm as you have but my idle is ~12-14 psi & 550-600 rpm (i still have to work on the idle a bit) .
Do you have balancing shafts on or you have deleted them?
My BS are still on.
Do you think it is ok?
It an H23A Blue Top

blackeg

you idle is a bit low for both rpm and oil pressure. whats the pressure at like 800-1000 rpm? my motor is b series it doesnt have balance shafts. i think you would find the most help by starting your own thread that can have all your details and specs in it. help us help you lol