Thread: LS1 heart
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Old 09-01-2003, 03:26 AM
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Aussie Mike Aussie Mike is offline
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Join Date: Jan 2001
Location: Sunbury, VIC
Cobra Make, Engine: Rat Rod Racer, LS1 & T56
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Hi Craig,

Boxhead correct me if I'm wrong but the Oil surge problems are caused by the Holden sump design. The reservoir and pickup are at the front of the sump to clear the cross member. Under hard acceleration the baffling can't cope with the movement of oil and the pickup can find itself without oil to suck up. Holden's solution for the Commodore LS1 is to add an extra litre of oil. The Ideal Cobra solution is to run the Camaro/Firebird sump with it's reservoir and pickup at the rear or the Corvette sump which has a rear pickup but is slightly shallower and has wings for extra capacity. The Camaro sump hangs about 1" below the chassis rails on the Classic Revival and the Corvette sump should about even with the bottom of the rail. The lowest point will still be the bellhousing and the gearbox at about 1" below the rails.

The oil control problems/piston slap are related to the tension of the oil rings and the piston clearances used. In order to get maximum fuel economy I beleive GM used some low tension oil rings and run a low viscosity oil. This seems to make the break in process a bit hit and miss with some engines not properly bedding their oil rings. After reading the various LS1 forums I see some people are having good results with the right choice of oil. Part of the oil consumption can also be blamed on the crank case ventilation. The early system took the PCV from the rocker covers where there is a lot of oil mist and this gets drawn into the intake. I've seen pictures of LS1s with the manifold removed and the ports are dripping with oil. The problem has been fixed in later motors and the PCV is now taken from the valley cover where there isn't much oil mist.

I still think the LS1 is a very solid building block for a very tuff lightweight motor. It makes heaps of HP out of the box with no internal mods. Chipmaster got 251 rear wheel KW out of a stock unopened motor with just exhaust, airbox and remapping. Check out the article here Chipmaster Monaro

The bottom end is extremely strong even with the sintered metal rods that people have doubts about. Nizpro had one on thier dyno and kept feeding it bigger and bigger hits of N2O to see how it coped. I believe it got to about 650HP and 800lbs/ft torque before it burnt a valve and stopped testing. They reckon it could have gone to 750HP (Check out Volume 13 of Performance buildups).

The engine stand lookslike a ripper by the way. Much better design than the ones that bolt off the gearbox flange.

Cheers
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Mike Murphy
Melbourne Australia

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