hardcore97

Like the title says, spun a bearing on the old setup, not exactly sure what happened. Never lost oil pressure, and it spun when I was driving around like a grandma about 3k rpms. Anyway, waiting to get my new crank micro polished at the machine shop and debating on clearances. Car made 481whp on 20 pounds of boost and I plan on turning it up more. Car is on running e85. This is a mostly street driven car that will see a bit of track time as well. Should I go to the loose end of the oem tolerances? Or try to stick in the middle?

ojasia

Oem tolerances are for a stock Oem setup. If it was me rods would be .020" mains 1245 .017"- maybe .018" main 3 .020"
If you had Oem tolerances that's probably why you just spun a bearing out of nowhere lol

hardcore97

I don't know what tolerances were before, purchased the bottom end assembled a couple years ago. I can check when I get it apart I suppose.

blackeg

ill stand behind those tolerances as well. I would not run any bearing less than .016 or so, and there really isnt a need imo to go much bigger than .022ish.

the last motor i built was .020 on the rods and right about .018 +/- a thou or 2 on the mains

KevinEF7

+/- a thou or 2....???

You guys have your decimal places wrong, you must mean plus minus 2 tenths. or .0002"

.020" clearance and youd being having nightmares.

I typically run ACL race bearings which are on the looser side of the spectrum but Ive never had a problem with them on daily high boost cars and there coatings/treatments still look superb on the few engine Ive torn down before sleeve failure.

Right out of the box on a stock crank acl race have always put me in the .0024" on both rod and main. Perfect oil pressure with 5W-40oil

ojasia

:O forgot a Zero. . . Thnx. Kev. Taking a quick glance at my notes and then switching pages from bearing clearances to ring gaps got me thinking thousands.

Mains 1,2,4,5 .0018" Main 3 .002" Rods: .002"

KevinEF7 - Are you DD'ing the ACL's? How long? // Power output? // You run the same clearance all the way across on your mains?

KevinEF7

Yup daily driven, every single say it doesnt snow for about 4 years on this engine, has been through multiple turbo setups in the 275-400whp range. Main clearance mic'd @ .0025/.0026 according to my engine log book

My buddies motor with ACL race and a crank that has been polished twice is very close if not spot on .003" on the rods and has been together for 2 daily seasons and he beats the crap out of it. I personally think .003" is a little much on the loose side though.

No spun bearings though, much better than running to tight and hearing that nightmare of a noise

blackeg

yeah my decimals were off as well. i meant .002.

i like the acl race hx's on my rods. from the few sets ive used they spec out between oem pink and red. the upper rod bearings usually see a good amount of wear and i feel the acl's hold up better than the oem bearings.

hardcore97

Thanks for the input guys. I'll probably check it on the old crank/rods just to see where they were before.

hardcore97

Another question also, what weight oil should i be running with those clearances? trying to find some info on google as i type this

1HGEJ2

iTrader: (1)

5w40 or 5w50..

KevinEF7

With the .0025" clearance figures I gave above running 5w-40 rotella, fully warm/hot I get 15psi @ 800rpm idle , 50psi @ 4k , 80+psi @ 6k and above

hardcore97

i was running rotella before, but will be switching to brad penn or VR1

TomCat39

Since the topic of oil came up with the bearing clearances, I am curious....

Is there a table or formula for oil viscosity vs bearing clearances?

I am aware your clearance determines your viscosity however, I have no idea what clearance means what viscosity.

What's the general rule of thumb with this?

PyroProblem

I think it all depends on what pressures your shooting for. I think 10 psi minimum per 1000 rpms is what's generally recommended. Up until max pressure when the relief valve opens.

If 30W oil isn't giving you the pressure your after, try a 40w oil. In planning on running a 40w oil with pretty much the same bearing clearance listed.

ojasia

Hope I can jump into this convo. Real quick I have like 80+ psi to 100 by 2500-3k rpm my gauge only goes to 100psi. Is this robbing power? Should I go to a 0w-20. Application: NA h22 Built.

PyroProblem

That seems on the high side. What is the max pressure supposed to be before the relief valve opens on h22s?

What's your bearing clearances at and what oil do you use?

ojasia

Rods are .002" main 1,2,4,5 .0018" Main 3 .002" I'm not sure what the relief valve is suppose to open at. running 10W-30 conventional oil in it right now. The only difference I see in psi is hot idling from the old 140k oil pump and engine it would idle at like 15-20 psi, and now with the KS BS delete, new oil pump, new fresh block. it hot idles psi at 29-35psi but once I get on it, it shoots up to the 80's-100 oil pressure gauge stays pegged. was wondering what ya'll think. its sounds healthy everything else is normal. I'll do some testing down the road. Maybe check my psi at the head with another gauge to see if its in the same ball park.

PyroProblem

There are car manufacturers that have variable output oil pumps so apparently there is some benefit to not running high pressures when it's not needed. Load? Rpm?

I think anything over 80 -90 psi is excessive and the relief valve is most likely/should be open dumping oil back in the pan and doing work for nothing. So its wasted energy. Idk how much, but it's something.
You have really good pressure. But I wonder if it's a bit too much.
You said you basically doubled your oil pressure at idle, right? So since the oil pump is driven off the crank, the increase in psi should be directly proportional to rpm.
So if you had 80 psi max before the new oil pump and before the BS delete kit, you could be seeing really high pressures. As indicated by your oil pressure gauge.

At what rpm do you see 100 psi oil pressure?
Nevermind, I just saw you posted it. 2500-3000 rpms.

PyroProblem

Get a 0-200 psi gauge!
I'm curious now lol.
Then again goes that saying go... "If it ain't broken, don't **** with it" . that's all I have.

ojasia

I'm just gonna get a higher pressure gauge and test at oil test port on head. Then I'm gonna talk to my buddy that assembled the short block and see what he thinks, most modern 2.0 liters are recommending 0w-20 these days so ill see what he thinks about the hole thing. I re-confirmed today psi reading at fully operating temps. In fith gear 2500 rpm had 80 psi and hot idle 32 psi 1000 rpm. Thanks for the input.

blackeg

your readings seem more than fine.

the thin oil is a result of much tighter clearances. not sure how this really plays out if you can get away with those tight clearances on a high performance motor and not have issues. ive seen excessive bearing wear at .0014. also think about it like this, at 500 whp the hp per cylinder you are making is much more than any factory car shy of a lambo etc..

Runnerdown

How are you guys measuring clearance

hardcore97

I'm a machinist so I have access to some nice equipment if I wanted. I will be measuring the crank with micrometers and recording them, I could use one of our CMM's to measure the rods if I chose lol and then plastigauge once bearings are here to verify. If you have old bearings you can assemble and use plastigauge to check them and then order the correct size bearings. I have almost a full set of acl standards sitting around which are equivalent to greens IIRC so I could use those to test if I wanted to as well

ojasia

Black I'm not the OP and im not making 500 hp. I have a built h22 NA, thank for the tighter clearances idea tho. Off to some service manuals.