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LS1 Bottom ends

General engine tech -- Drag Racing to Circle Track

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Walline
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LS1 Bottom ends

Post by Walline »

I started working a LS1 5.3 liter. My first one :D :?: :D We are trying to decide between nitrous or blower. What can we expect the short block (stock)to handle in the way of HP. With what I think we can get out of the heads, it should make a lot of power, with just a little nitrous. 500-600 HP. I have heard from some 1000hp with stock crank and rods. The pistons and head gaskets being the weakest link. Anyone working with these. We don't want to waste money on crank and rods, if stock will work. During the research stage, we would rather brake stock parts, then high$$$ one. LS1 short blocks are pretty cheap. Thanks ALL!!
SStrokerAce
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Post by SStrokerAce »

Is it a Al or Fe block?

The small bore of the 5.3L block does limit you.

The weak spot in the LS is the bolt pattern, but that's only if you have a thin deck on the head castings and a LOT of cylinder pressure.

The stock cranks are very tough, and the rods are not bad, but with the cost of replacements I dont see a point in pushing them.

The blower is going to be easier on parts in the long run reguardless of what you run it on.

Bret
automotive breath
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Post by automotive breath »

Most people here are using the iron 6.0L block for high HP applications. The heads look great, except for the big bump in the roof of the intake port, I wonder if it can be safely removed?

read this:

viewtopic.php?t=1544&highlight=ls1
pdq67
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Re: LS1 Bottom ends

Post by pdq67 »

Please answer the question because I would like to know too.

Well then, how much Hp will an iron LS 5.3 block stand??

pdq67
jed
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Re: LS1 Bottom ends

Post by jed »

JMO-A stock LS short block will live at 500/600 hp with any power adder if the tuneup is right. You can even hit those
600hp to 1000hp occasionally and stay together if the tune is right.
I just took apart a high mileage LS7 (50K+) it had a 300 shot of nitrous. It lost some oil pressure. Number 2 main was almost to
the steal back but had not spun. Rod bearings looked good except for scratches from all the trash.
Again JMO LS blocks have main bearing problems 2/3/4 will go away first 1 & 5 have little to no problems. Don't really
know why.
But I can tell you what I know for sure LS bearings have little to know eccentricity. If you have .002 vertical clearance usually
the clearance at 60/70' from vertical will be maybe .0025 or less and 25% of the time less than .002.
This is with King or Clevite bearings ACL has the most eccentricity. In my opinion you have to have the eccentricity to help create the hydrodynamic oil wedge necessary for the bearing and crankshaft to survive.
To help with the problem we have started line honing all blocks to the max housing bore size. If you check LS blocks they
have a tendency to pull in at the parting line. A line hone cures this LS problem. Then I run no less than .003 main clearance.
There doesn't seem to be a main problem with LSX blocks or dart blocks. I've ran .002 main and rod clearance on LSX blocks
with 5/20 oil at 1300/1500 wheel hp and the beatings look good. The after market blocks are all priority main oiling
which helps a bunch.
Thats all I know and it comes from experience.
There is a oiling modification that can be done to stock blocks that I think will help oil the mains but no one will take me up in trying it.
pdq67
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Re: LS1 Bottom ends

Post by pdq67 »

^^^^^^^^^^^^^^^^^^^^^
"There is a oiling modification that can be done to stock blocks that I think will help oil the mains but no one will take me up in trying it.".

You talking about piping the three center mains for priority high pressure lubing all the time? If not, then just what?

I don't think the 1st Gen. SBC engine ever had any sort of oiling problems outside of using a good pan and windage tray...

But I digress back to the old 1st Gen. engine.

pdq67
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