Road Runner Nest

Menber Kenny posted a topic about where the 3 nipple lines goes to. I have some concerns on this now and didn't want to highjack his thread so I decided to post a related subject on it.

I just got my motor the other day, built by a Mopar guy. Some of you might have seen a few pictures I posted of the valve covers and air cleaner. I have the "Mopar performance" valve covers and air cleaner. The new motor came with a breather installed on the valve cover. Here is my delima about what to do: Planning on installing the fuel seperator behind the drivers side rear wheel, like factory and run the hard line, which I have new and in SS. Should I replace the breather from my builder and use the OE one, just plugging two of the nipples because they won't be used? That is, if the OE one will fit in the valve cover. Or not put any of that on and keep the breather from my builder? When I had him build the motor, I told him I need a vacuum source for the OE power brake booster, which he made a provision for it on the back of the intake.

What would you do? Advice? Opinions? Thoughts?

Thanks!

if i understand how that system works correctly you could run the provided breather skip the 5/16 fuel vapor return line installation all together cap that nipple on the vapor canister in the wheel well and use a vented fuel cap on your fuel tank. that would look better than trying to use the 3 nipple breather with 2 nipples capped off.

I remember, but can't remember where, that when every thing is working, the PCV system flows air in both directions depending on what the engine is doing. So, if you eliminate some of the components, will the system still work correctly? I can't remember if that was in Mopar Action or the service manual.

pcv goes to carb not the breather so it should function fine without the three nipple breather as long as it has a breather, and he said he did have one to go with the new valve covers, if i understand how the system works you need a breather to let air in and a valve to let it out the other side he would still have both just not the original style and the fuel tank doesnt need the pcv system it just needs a way to breathe, thats why i said use a vented fuel cap. although that is just my logic based on thinking how the parts work together but im not an engine builder or even a good mechanic.

IDK what to do. I have the 5/16th fuel vapor line. I have all of the lines but none are installed yet because the car is in the body shop. I also don't know about leaving a little hole in the passenger wheel well for the clamp that holds that 5/16 fuel line as well, then there's the vapor seperator in the rear wheel well too.

My goal is for the most part, mainly stock appearing, even though the motor is not. With that, I want to utilize as much factory stuff as possible. Now I'm ththinking to either cap the two nipples, cut the other two off and seal up where those two where, or see if there is a breather that has one nipple on it. Thoughts?

Again, thanks

Look on ebay, one and two nipple breathers are for sell from time to time.Usually it's harder to find the three nipple ones. Why not just hook everything up as stock? I have a 530 inch, 650 horse Hemi that will have everything hooked up, and stock looking. You could always plug the hoses, and hook them up, so they will look like they function.

71bird wrote:Look on ebay, one and two nipple breathers are for sell from time to time.Usually it's harder to find the three nipple ones. Why not just hook everything up as stock? I have a 530 inch, 650 horse Hemi that will have everything hooked up, and stock looking. You could always plug the hoses, and hook them up, so they will look like they function.

Because the air cleaner isn't stock and the carb has a electirc choke on it. I'm outting the "Mopar Performance" air cleaner and valve covers on it.

Durn, believe me I have been here before, when you deviate from standard it affects everything else down the line. Ok, lets think. Is there enough over hang on the breather base to drill a hole in the back, and put a nipple for the hose on it?

The three nipple factory breather cap can’t correctly be run with both the 3/8” and 7/8” nipples capped off. It needs the 7/8” open and preferably plumed to the air cleaner for PCV cross flow. If you are not running a carb with an enclosed bowl vent valve you can plug off the 3/8” nipple designed for that purpose.

72RoadRunnerGTX wrote:The three nipple factory breather cap can’t correctly be run with both the 3/8” and 7/8” nipples capped off. It needs the 7/8” open and preferably plumed to the air cleaner for PCV cross flow. If you are not running a carb with an enclosed bowl vent valve you can plug off the 3/8” nipple designed for that purpose.

The 7/8" nipple I don't know what do with since I'm using the Mopar performance air cleaner and valve covers. More than likely then, just leave it open. In regards to the 3/8", I think I can plug that nipple. According to the paperwork that came with the motor, the carb is a "Quick Fuel Hot Rod 850 carb". I'm assuming it has no enclosed bowl vent valve. It does have a PVC in the valve cover, so is that connected to the manifold? The manifold is a " 383 RPM intake". I left the plastic covering the motor until I'm ready to mount it to the K. With the plastic on the motor, some things are hard to see, detail wise.

The Quick Fuel carb should have a 3/8” nipple provision for the PCV at the rear of the throttle body. On a street carb, I’d be surprised if it didn’t. Most aftermarket intakes come with a 3/8” pipe threaded port, normally plugged, as did all factory manifolds, for the appropriate hose fitting to accommodate vacuum accessories like power brakes. Important to remember that unlike vacuum powered accessories that don’t flow, the PCV is considered a calibrated vacuum leak. It needs to be connected to the carb port designed for that purpose.
I’ve seen some aftermarket air cleaners with fittings for an enclosed breather cap. Should be pretty easy to fab up a connection fitting under the base plate to plum it in. Could be done in such a way it wouldn’t be visible.