408 lq4 bearing clearances

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Jun 13, 2015 | 02:07 PM

HISS

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From: Corpus Christi Texas

408 lq4 bearing clearances

Gonna be starting assembly on the 408 over the next month or so. Wondering what the clearance range should be.
Specifics
Early lq4 block
Bored .030 line honed deburred etc at SAM
Box stock Lunati Voodoo forged crank
Box stock scat I beams
Wiseco -8 cc dish pistons with reliefs for l92/ls3 valves k394x3 with wiseco pins and rings
Clevite h main bearings
King x Rod bearings
Durabond cam bearings
Here's what I need
Cam clearance
Main clearance
Rod clearance
Crank and camshaft endplay
Ring gap 90% street/10% street raced...small shot 200 or less.
Rod side clearance
If anyone has a similar setup or a good weath of experience and knowledge I'd appreciate the response. Only want to build this once I'm on a super tight budget and can't afford to build it twice.
Thanks in advance.

Last edited by HISS; Jun 13, 2015 at 02:42 PM.

Jun 14, 2015 | 12:29 AM

Blown06

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I run an iron 408 and the crankshaft takes a major beating as it is turning a cog drive F2 procharger. It turns into a wet noodle when the power is wicked up, but is staying together rather well, considering.

My main and rod bearing clearances are both .0027".

Jun 14, 2015 | 11:10 AM

HISS

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Quote:

Originally Posted by Blown06

Thank you for the response. I doubt I'll be putting near as much load on mine as you are. I'd like to keep the clearance a little tighter to promote better oil pressure when street driving. Car gets driven to the track 300 miles round trip or so. I think if my clearances were that loose I'd have low oil pressure. What's your pressure like at hot idle, and cruising if it's street driven?

Jun 14, 2015 | 02:02 PM

HISS

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Also forgot to mention I am going to use the melling high pressure (not high volume) pump. Thinking that might allow me to open up the clearances a little more as well without suffering a major drop in pressure. After all loose is fast right?

Jun 15, 2015 | 12:53 AM

Blown06

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I run the Melling 10296 pump with the heavy spring they supply. I have been running 20w50 synthetic oil, but plan to drop that down as I think I have some room to loose a little oil pressure and pick up a bit of power.

My pressure at idle hot is about 47 psi
My pressure at 4500 rpm hot is about 80 psi
It will generally make 95-100 psi anything over 6000 rpm if stationary on a dyno
Durning a run the pressure will spike around 95-100 psi as soon as I let go of the transbrake, but will fluctuate between 95 and 75 psi throughout the run. Likely due to acceleration forces and the general design limits of the ls pump.

Jun 15, 2015 | 12:56 AM

Blown06

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To help you get a visual of my oil pressures during a run, here is a screen shot of a data log of only showing rpm and oil pressure. You can see the scale for each on the right (y-axis).