Toeknee

I have a new custom build LS7 engine for my road race car. It's using a 3 stage Aviaide external oiling system.

The question is... do I still need to use the factory valley breather and valve cover breathers?

I see other people using a 4 stage dry sump blocking off both the valley and valve cover breathers.

But I am wondering if anybody here knows if a 3 stage (2 suction stages) will pull enough vacuum to do the job w/o the breathers.

Thanks in advance

TonyG

backintrouble

sorry i cant answer your question, but i would call john directly at aviaid- he would be your best source

KiwiKid

Hi TonyG,

I am very familiar with running external dry sump pumps on Ls7 engines, and in my experience by blocking off all the breathers including the valley cover, you will pull more vacuum, with two scavenge stages, than you will want to run with a standard engine.

We block off everything and weld a boss onto the rear of one of the rocker cover to accept a Peterson adjustable vacuum regulator which we set at 10 inches of Mercury.

On standard Ls7 engine this is worth 10 BHP and 10Ftlb's and will not risk starving the gudgeon pin [wrist pin] of oil or suck in the main crankshaft seal etc.

Cheers,

Mark.