cr250r

iTrader: (4)

Doing a turbo lh6 forged rods pistons street strip motor 10.5 compression fully ported 862 heads tsp e85 fuel 19-22 lbs of boost twin turbo what main bearing clearance should i have my machinest set up the block for? Max 6900 rpm usually 67-6800 dont want oil pressure to tank on cruises

Gray86hatch

iTrader: (83)

.002 on the mains.
.0025 on the rods

Schumann dynamic pump from Car Shop Inc

Tim

D9HP

+1

Building an ERL sleeved 5.3L block now.

Read dozens of opinions. This is what I'm doing.

cr250r

iTrader: (4)

Okay ill talk to my machinest if if im a little over such as .0022 will that be okay or should i try to run tighter .0018-.0019 if i can't get .002?

Gray86hatch

iTrader: (83)

Mine would idle with 30 psi 210 oil and 190 engine temp.

With heat in the engine it will be .0032 that is a lot for a small dia main
Mix a match bearings to get it where you need it.

Tim

LsF-150

iTrader: (2)

What would you consider not enough idle psi? You plan to run yours harder than I do, so the larger clearance's are probably in order but I just got an ERL 427 running that started life as an aluminum 5.3. According to the build sheet the mains are at .0018-.0019, using the Melling 10296 with the red spring shimmed "a little" I have to run 20/50 to carry 30psi hot idle pressure, idle speed is 750. It will live for years like this, I know that, but I would prefer it to be 35-40. It just makes me feel better to see a little more than that. The same pump in the iron 6.0 that it replaced did over 40 hot idle with 10/30 and 100 less rpm. The aluminum motors definitely open up more warm, about .0010 from everything I've read. This is in my daily driver, something I plan on using for years and not opening up every couple years.

Gray86hatch

iTrader: (83)

With 20-50 and that tight on the mains I would not load the motor until it had 180 degree engine and close to 200 in the oil.

I ran 5-30 ls30 in mine and always waited for 175 oil temps and it would still make 100 psi at wot.

Tim

cr250r

iTrader: (4)

I would like to see at least 25psi idle hot and 70 psi at 6800 using rotella 15-40 or a 20-50 amsoil

cr250r

iTrader: (4)

My only fear is that the twins will cook the oil and i will see it plummet after a pull or while cruising if i hit traffic

Gray86hatch

iTrader: (83)

You have to have a oil cooler.
If you had erl doing the engine I would go with what they recommend they build a bunch of them.

Having enough oil pump is key. All oil gets thin with heat. Alum block will gain more main clearance that. Iron. I would not worry about 20 psi at idle.

Tim

KCS

iTrader: (20)

For builds like this, I like to use coated bearings. I'll use a bearing that may normally give me .0025"-.0030" or so, and then have PolyDyn here in Houston coat the bearings. Clearance will be about .0015"-.0020" with the coating. Oil pressure will be good and if something bad happens, the coating is wiped away and the bearings will still be undamaged.

cr250r

iTrader: (4)

Alright i dropped the crank off so i should know the clearances soon

Whistler

iTrader: (46)

I assume you meant "bearing clearances on an aluminum block 5.3" and not "aluminum (bi-metal) bearing clearances on a 5.3" , right?

cr250r

iTrader: (4)

Clearance with my hx bearings was .0028 my machinest has a set of p series that he through in got .0019 im going to buy them for 100$

cr250r

iTrader: (4)

Tim what does the schuman set cost??? Truck pan here