RedRascal

I am installing a GenIII engine into my old pickup. I used a 2007 5.3L LC9 as a donor engine. This is my issue: I have three EGR outlets: one on each valve cover and one coming out of the valley cover. The donor intake manifold has plumbing to accommodate one of those outlets which is the valve cover on the rear driver side. The manifold has no other ports that could accommodate the remaining two ports. I want to keep those functioning to properly vent the engine. I suppose I could plumb all three together; however, there may be a more elegant and useful solution. Has anyone else had and solved this problem? Thanks in advance!

tfi racing

iTrader: (2)

That would be PCV, not EGR. Vacuum will go typically to one side valve cover,the others can be vented to the atmosphere with a small filter or use a catch can set up from any of the LS vendors.

RedRascal

Thanks TFI Racing! When you explain it like that it makes perfect sense. Thanks for the fast reply!

RedRascal

I have one other question that I would like to throw out there. In the rear of the Intake Manifold is a ~5/8 inch rubber hose, approximately 2 feet long with a stubby right angle fitting that appears to have been designed to push fit into some sort of grommeted receptacle. Does anyone know it's purpose and if not needed on a replacement engine for an old truck, can it be removed/plugged? Thanks in advance!

Floader

iTrader: (32)

Brake Booster line

RedRascal

Floader:
Yep, that's what it is. I recognize the booster fitting now. Mr Obvious might say, "Huh, I never made the connection." Thanks again!!

Fast355

GM makes a plug that goes there for vans and trucks that use hydroboost instead of vacuum power brakes.

Michael Yount

iTrader: (1)

Is there an orifice to restrict flow in the valve cover connections?

I realize my engine is different (new LS3), but on mine the "vacuum" connection occurs through a short hose that connects the intake (right behind the throttle body) to the lifter valley. The connection to the valve cover is for make up air -- pulled from the air inlet tube downstream of the mass air sensor - so that the air pulled from the crankcase into the intake manifold to be part of the combustion air is metered. I only need make up air on one side or the other -- the other valve cover vent can be capped.

FWIW

Since the PCV restrictor is in the valve cover for the 5.3L LC9 (I think) -- shouldn't the make up air into the other valve cover come from air inlet tube downstream of the mass air meter instead of from atmosphere (through a "filter")? Won't make up air from atmosphere essentially be a vacuum leak? Trying to learn...

G Atsma

I would think ANY air to be burned in the engine should be metered, to keep air/fuel ratio consistent.