Hello everyone. I am installing a gm crate engine ls3 with the t56 package deal in my friends nova. Right now, I am in the paint stage of the car. The engine is in the box still. I have had the lid off and have been studying all the connections. I have all the paperwork from GM about the install, but they don't tell me what to do with all the open ports. I am aware of the steam lines at the front of the engine that need to goto the radiator. They are tied together already, ready to be run to the radiator. I will be removing it and installing braided lines for them. But here are the questions I have with the rest(sorry for no pics yet.......not near the engine, and I just joined the forum)/

1) The capped hose fitting on the rear of the drivers valve cover..........what do with it?

2) there is a metal line snaking out of the passenger's valve cover under the coil bracket in the middle.........what to do?

3) the capped line at the back of the manifold(large 3/8 or 1/2 fitting)......vacuum?.......something else?

I know there are more to list, but I know I should have pics. I am just surprised that GM didn't give any info on this stuff.

I need to give a little background about myself. I am really quite good with engines. I have a 363 supercharged mustang(foxbody) making around 650....all built by me. I am just old school engines. I have rebuilt many 1st gen 350 chevys and a lot of ford 302's. I have never even touched a lt-1 or ls engine till now. Well, I changed a power steering pump on my 2000 Silverado....does that count? I only did exhaust work on it.....never modded it. So, all these questions I have are because of my newness to this arena.......especially in a car that is as old as me. It'd be different if it were going in a car that already had one of these in it.

So, if you guys can even talk me through some of this stuff without the pics........I'm very appreciative. I will try and get pics posted soon.

I already have all the swap stuff necessary(hopefully). I have the crossmember, motor mounts, exhaust, oil pan, radiator, pulleys etc. I will be tying my brand new car harness into the gm wiring harness for the engine.

 

That is the fresh air inlet for PCV. It needs to connected to a the intake tube AFTER the MAF and BEFORE the throttle body. It allows fresh metered air to enter the crank case.

I am not sure what line you're referring to. Can you take a photo?

That is a manifold vacuum connection, usually used to connect to a power brake booster.

 

 

This thread might help a bit more

https://ls1tech.com/forums/conversions-hybrids/1092371-ls3-picture-reference-connections.html

 

That thread helped out tremendously. I now understand to connect the metal fitting out of the passenger valve cover to metered air in front of the TB. I have just two questions still.

1) i'm sure my harness will have the connection to the evap fitting on the passenger's side right behind the TB. But what do I do with the open fitting on that same evap sensor? It is already attached to the manifold with a hose, but the one side is not attached to anything, just like it showed in that thread.

2) Do I need to attach the capped off line at the drivers side rear to anything?

Again thanks to everyone. This is a very different system for me compared to what I am used to.

 

(1) That is an evap solenoid. You can completely remove the solenoid and cap off the vacuum line that goes to it, then eliminate the connection on the wiring harness or just leave it dangling.

(2) Which line are you referring to?

 

Thanks for the reminder. I forget that the older throttle bodies had that port to get fresh metered air.

 

Sorry for lack of clarity. I meant to say the valve cover in the post........I missed that. It's the other valve cover vent. Would it hurt anything to leave it capped? Or should I connect it with the other and run it to the intake tube(which I still need to design and build for the nova).

I just went and put my freshly powdercoated valve covers back on and got to thinking about the "DEXOS" oil writing on the fill cap. What is a good dexos rated crude oil that I can get anywhere till I break the engine in? I will be switching to synthetic oil at 3000 miles. I just want to run crude for a short bit for everything to "seat".....so to speak. The instruction manual has me changing the oil twice by 500 miles. I don't want to be wasting my money on synthetic for that stuff.

 

Usually on an LS3 the driver's side valve cover is capped off. The passenger side valve cover is connected to fresh metered air. The valley cover fitting near the front is connected to vacuum.

Sorry I think I switched passenger/driver in one of my posts above.

 

No problem. Thank you for replying.

Anyone got any feedback on startup of a brand new crate engine as to what kind of oil to use? I just realized that a dexos rated oil is at least a synthetic blend or better. Won't a synthetic blend affect the seating of things during start-up......meaning too slick? I just would like more knowledge on it. To my understanding from the past, synthetic oil was not to be used on start up because it prevented rings from sealing etc. Is that still the case or is it an old wives tale? I fully intend to run synthetic. I have seen the benefits of it first hand on an engine tear down.

If anyone has some insight on this, I would sure like to hear it.

 

Just synthetic Mobil 5w-30, just make sure oil prime the engine prior.

This is a video I did,

 

LS3 crate went in mine 2 years ago -- as stated above - I capped the PCV makeup air valve cover vent on the driver's side, and connected the passenger side to the maf tube in between the maf and the throttle body - so make up air is metered.

Evap - that would normally be connected to your charcoal canister that the fuel tank vents into. The ecu will open the evap purge valve from time to time which will allow engine vacuum to pull from the canister. I had that function removed in the ECU, removed the valve/rigid hose, and capped the port on the intake. I connected the charcoal canister directly to the air inlet piping UPSTREAM of the maf, so that anything that might move into the inlet air pipe from the canister would be metered. If you need pics, lemme know.

 

Thank you both, gentlemen. I appreciate your input.

Michael, I would love some pics of the evap system you fabbed up. I am installing a new charcoal can for the car since the other one was 45 years old.....doh!
Do you spend anytime over at the Corral anymore? I still have my 363 supercharged foxbody. I am building this car for a friend. I keep saying "my" but its really his......I'm just doing all the work and getting a great education on an amazing engine(the LS platform). So, I just say "my" and "mine" to keep it simple in the chatroom. I am quite thankful the engine is plug and play with the ecu however!

 

Happy to take a pic - Vacuum line from the "outlet" of the canister to a brass/barbed fitting that's installed in the air inlet pipe upstream of the MAF. Pics to follow....

Overview of compartment for orientation....

Attachment 712560

PCV line going from fitting on air inlet DOWNSTREAM of MAF to valve cover fitting with orifice in it to control flow. Be sure your valve cover connections have the orifice or you'll suffer a big vacuum leak. Finger pointing at the clamp where this line connects to the valve cover fitting (between the first 2 injectors). Next pic shows that clamp a bit better - between #2 and #4 injectors.





Next - pic of the canister connection on the bottom of the air inlet pipe UPSTREAM of the MAF. The second pic I'm pointing to where the fitting is on the bottom (180 degrees off of my point).