LS1-450

iTrader: (33)

Am talking about adding a slot connecting the round holes above the cam bore; the top end oiling holes. On pre-04 blocks the oiling groove that connects those holes is machined into the rear cover only. Am asking if anyone has machined a groove into the block, just like an LS6 or 04 & newer block, in order to help top end oiling. Can see in the pic where I'm talking about. Those whom have timed the top end oiling know that it takes minutes for oil to reach all of the rockers in a pre-04 engine.

Have you done it & what size groove, how deep did you go? Thanks

LS1-450

iTrader: (33)

Hmmm...I understand, ya'll want to keep it to yourself. That's cool. We're gonna go with a 3/16" wide x 1/8" deep slot between the holes, making sure to keep the slot inside the sealing area of the rear cover gasket. The groove will follow the exact same path as the groove in the rear cover that it will mate with. Basically, we will be transferring the cover groove into the block to give the oil galley more area. This will allow a higher volume of oil to flow to the top end @ the same pressure. We'll keep this thread for the archives.

Arc00TA

iTrader: (17)

I wondered about the same thing looking at my 98 block. In for pics!

Steve - Race Eng

iTrader: (1)

I wrote a CNC program a few years ago to take care of machining the back of the early LS1 and iron blocks which also lack the oiling groove.

I charge $75 to set up the block and machine the groove.

Steve

LS1-450

iTrader: (33)

I knew there had to be guys who had done this. Looks great. Too bad I'm a gazzillion miles away or you'd have the block first thing Monday. Nice work & thanks for the pic.

butler

I have a 98 block. And did it. I spin mine to 7100 and have no issues.

LS1-450

iTrader: (33)

High RPM is not the issue. The problem that it solves is the time it takes oil to reach the top end @ start up. Once it's there, there is no issue. Oil starvation related high RPM issues are caused by slow oil drain back or prolonged g-forces. There are other solutions to these.

At start up it takes several minutes for oil to reach the top end. Oil reaches the driver's side first & passenger side second. The delay is caused by the restrictive oiling passage @ the back of the block, as you know. Guys who ruin there valve train, do it by starting the car & not waiting a few minutes before romping on it. Dyno sessions are a good example of this. Without oil having reached the valve train, there can be damage.

Isolde

iTrader: (4)

Thank you for sharing! Is this a good idea for everyone? Is there any application where this should NOT be done? Towing with a Silverado?

NHRA4MULA

iTrader: (29)

I'm in the middle of a engine build and have done a bunch of work on the block just some minor stuff cleaning up some casting flash ect and I'm going to do the coolant holes just round them out it will improve flow some but this is a worth while thing to do can I just cut a grove and open it up fron one side to the other is there any special way to seal it or will the rear cover take care of it

LS1-450

iTrader: (33)

The groove needs to follow a path that remains inside the rear cover seal that surrounds it. Otherwise, you're gonna have a f'cked up block. The pick that Steve Race - Eng posted shows the ideal path.