Removing DOD hardware & fitting a larger camshaft

[88ls1blazer]

so should there be a change in the relief valve?

[Crazy Paul]

so should there be a change in the relief valve?

That's something we've yet to find out. We only received the tech info on the relief valve yesterday.

[Crazy Paul]

Dyno Sim Results (flywheel HP)

Yellow = 10.9 CR .......Cam 224/230 .581/.590 112 [FWHP]
Blue = 10.9 CR .......Cam 224/230 .581/.590 112 [TQ]
Red = 10.9 CR .......Cam 220/220 .581/.581 112 [FWHP]
Green = 10.9 CR .......Cam 220/220 .581/.581 112 [TQ]

10.9 CR is L92 heads milled 0.030" on a 6.0 block.




Yellow = 10.4 CR .......Cam 224/230 .581/.590 112 [FWHP]
Blue = 10.4 CR .......Cam 224/230 .581/.590 112 [TQ]
Red = 10.4 CR .......Cam 220/220 .581/.581 112 [FWHP]
Green = 10.4 CR .......Cam 220/220 .581/.581 112 [TQ]

10.4 CR is stock L92 heads on a 6.0 block.




Real world RWHP results in a 2006 GTO
LS2 6.0 Block
Cam 224/230 .581/.590 114
CR 10.4 (unmilled, untouched L92 heads)

[GeorgeInNePa]

Those 8x O rings underneath block off the previous oil supply from the L76 Lifter Oil Manifold Assembly to the Collapsible DOD Lifters. Some engine builders additionally like to tap threads into these galleries and plug them with (Qty 8) 1/8"NPT allen plugs.

Do we need to worry about this?

Additional consideration should be given to the DOD oiling system.
The L76 oil pump displaces 1.24"/rev compared to non-DOD 6.0 engines (LS2 and L98) which have 0.95"/rev oil pumps.

There is also a DOD specific oil pressure relief valve inside the oil pan. When main oil pressure exceeds 55psi this relief valve exhausts excess oil to the sump.

What about this?

[GRRRR8]

Yes you will replace that in pic 1. I already have that. Pic 2, well the jury is out, but it is a oil relief that wont let oil psi exceed 55psi. I am pretty sure I will pull the motor in mine. I will have the trans out for the converter, might as well do it all on a stand then in the car. That way I can do new rear main, upgrade oil pump, heads,cam, double roller t-chain all at once.

[GeorgeInNePa]

Yes you will replace that in pic 1. I already have that. Pic 2, well the jury is out, but it is a oil relief that wont let oil psi exceed 55psi. I am pretty sure I will pull the motor in mine. I will have the trans out for the converter, might as well do it all on a stand then in the car. That way I can do new rear main, upgrade oil pump, heads,cam, double roller t-chain all at once.

I meant going so far as to tap and plug those oil holes instead of relying on the o-rings.

[Crazy Paul]

I meant going so far as to tap and plug those oil holes instead of relying on the o-rings.

That's going to be down to the personal preference of your engine builder. Some like to do it with all Gen4 blocks. The plugs might cost eg $20 and an hour to tap the threads...so it's not a huge deal to perform for that extra piece of mind.


I was thinking about the L76 high volume oil pump (1.24in/rev) V LS2/L98 oil pump (0.95in/rev). You guys with the G8-GT wont have to worry about changing the oil pump if you remove the DOD hardware. G8-GT has an 8+ litre oil pan.

The reason it was a problem for some in OZ is because we used the L76 to retrofit into older cars. Up until the start of 2006 the Holdens and HSV's had the front sump oilpan (to clear the steering rack) which held a total of 5.7 or 6 litres.
Now with an L76 with DOD hardware removed + an oil pump which pumped about 18% more volume than normal, combined with only a 6 litre front pick-up sump......under certain conditions it was possible to pump the sump dry.
[I remember now reading about a guy who found this out while doing a really long burnout going up a hill].
I guess for burnout man, most of his oil was at the rear of the old 6L sump away from the front pick-up.......then the L76 oil pump was pumping the only available oil to the top of the engine, faster than it could drain back to the pick-up at the front of the engine.

[GRRRR8]

I meant going so far as to tap and plug those oil holes instead of relying on the o-rings.

I am contimplating doing this if I pull the engine. It will not require any further disaaembly and out of the car will make it a breeze and will eliminate EVER having a issue.

[jbradsh1]

Anyone know the specs on the LS3 hot cam?

[GRRRR8]

anyone know the specs on the ls3 hot cam?

219/228.......525/525........112