pipe on drivers side of plenum - ZR-1 Net Registry Forums

Belsy · 06-23-2010

In looking at various ZR-1 engine pics I notice an alum style pipe mounted on the drivers side along the plenum? My 95 does not have this! Does anyone know what it's for and how or why I can be without it?? Mystery to me.

Thanks,
Gene

rebelz · 06-23-2010

It is the Crankcase Vent Valve pipe. Connected to the PCV system at the rear of the engine. I'm not sure if it was still done that way by 95, but if it was it could have been modified by introduction of a Catch Can or in some other way. I have an earlier model and it is there on mine.
Rich

phrogs · 06-23-2010

show us a picture of your motor.

Belsy · 06-24-2010

It's all apart now searching vacuum problem & closing coolant passages to plenum. It has the standard Y connector from each I/H to rear but they are hoses and I like the the hard pipe I have seen, where can I get that? Also had a lot of oily passages when tore down, any C/V mods or improvements out there? Again I do not have the small hard pipe bolted along the plenum (drivers side) as seen on so many.
Thanks as always for the responses

Belsy · 06-24-2010

In looking further in the FSM I see the pipes & connectors with the F connector with both PCV valves at the F (behind the plenum). Mine is routed with a PCV valve at each I/H to a T behind plenum with supply (all rubber hoses) going to front of plenum (behind T/B on drivers side) does this suffice or has someone butchered the system?? Either way how much effect does the system have on overall drivability??
Again this is a '95.
Thanks as always,

tccrab · 06-24-2010

Quote:

Originally Posted by Belsy

In looking further in the FSM I see the pipes & connectors with the F connector with both PCV valves at the F (behind the plenum). Mine is routed with a PCV valve at each I/H to a T behind plenum with supply (all rubber hoses) going to front of plenum (behind T/B on drivers side) does this suffice or has someone butchered the system?? Either way how much effect does the system have on overall drivability??
Again this is a '95.
Thanks as always,

Most assuredly someone has modified the PCV system.
Likely because they discovered how expensive the replacement hoses are.
If it's plumbed correctly, and the correct PCV valves are used, it shouldn't negatively affect the performance of your car.

TomC
'Crabs

bdw18_123 · 06-24-2010

This is how the PCV system should look stock (mocked up with my '90 Z parts):

I am also missing the hard line on the driver's side of the plenum. It's the one that would connect to the rubber connector on top of the PCV's and go to the very front of the plenum just behind the throttlebody. I don't want to spend the money on it though, so I plan to install a oil catch-can on that side so I won't need that piece.

If you do want one though, Jerry's Gaskets site has one.
Link here: http://jerrysgaskets.com/store2/root...roducts_id=358

Someone here might also have a used one floating around they might sell you.

Belsy · 06-24-2010

Thanks for the great pics!! Looking at it it seems like 1 source to draw 2 PCV valves together? Why not 1 valve at each I/H joining at a T (junction) at almost any equal point with same point of draw from front of plenum? Similar routing and if done with alum pipe or braided line could look & work fine!! Any thoughts or advice appreciated.
Thanks

bdw18_123 · 06-24-2010

Quote:

Originally Posted by Belsy

Thanks for the great pics!! Looking at it it seems like 1 source to draw 2 PCV valves together? Why not 1 valve at each I/H joining at a T (junction) at almost any equal point with same point of draw from front of plenum? Similar routing and if done with alum pipe or braided line could look & work fine!! Any thoughts or advice appreciated.
Thanks

Like tccrab said, if it's done correctly (i.e. hoses not too long and similar inside hose diameter to originals), I'm sure it will work fine. If your car runs and drives fine like it is, you can probably leave it that way. But if you want it to look better, like you mentioned, you could get some kind of nice looking hard lines or braided lines.

VetteMed · 06-25-2010

Quote:

Originally Posted by Belsy

Thanks for the great pics!! Looking at it it seems like 1 source to draw 2 PCV valves together? Why not 1 valve at each I/H joining at a T (junction) at almost any equal point with same point of draw from front of plenum? Similar routing and if done with alum pipe or braided line could look & work fine!! Any thoughts or advice appreciated.
Thanks

There are 2 different PCV valves, which I believe have different specifications for the vacuum required for opening, and this difference is intended to provide something of a dual-mode operation of the PCV system. We had a discussion on here about this, a while back, If I recall correctly.

06-23-2010	#1
Belsy Join Date: Nov 2006 Location: DeBary , Fl. Posts: 119	pipe on drivers side of plenum In looking at various ZR-1 engine pics I notice an alum style pipe mounted on the drivers side along the plenum? My 95 does not have this! Does anyone know what it's for and how or why I can be without it?? Mystery to me. Thanks, Gene __________________ Gene in Fl. :handshak: ______________ 95 ZR-1 #399 Dunn heads X-pipe w/3" misc. mods

06-23-2010	#2
rebelz Join Date: Jul 2007 Location: Anchorage, AK Posts: 106	Re: pipe on drivers side of plenum It is the Crankcase Vent Valve pipe. Connected to the PCV system at the rear of the engine. I'm not sure if it was still done that way by 95, but if it was it could have been modified by introduction of a Catch Can or in some other way. I have an earlier model and it is there on mine. Rich __________________ REBelZ '92 ZR-1 Yellow/Black #031

06-23-2010	#3
phrogs Join Date: Jul 2004 Location: Kalamazoo MI Posts: 1,758	Re: pipe on drivers side of plenum show us a picture of your motor. __________________ JOHNNY P Currently own 90 ZR-1 #845 DRM 500 engine package 90 #226 Parts car Hit me up if you need anything.

06-24-2010	#4
Belsy Join Date: Nov 2006 Location: DeBary , Fl. Posts: 119	Re: pipe on drivers side of plenum It's all apart now searching vacuum problem & closing coolant passages to plenum. It has the standard Y connector from each I/H to rear but they are hoses and I like the the hard pipe I have seen, where can I get that? Also had a lot of oily passages when tore down, any C/V mods or improvements out there? Again I do not have the small hard pipe bolted along the plenum (drivers side) as seen on so many. Thanks as always for the responses __________________ Gene in Fl. :handshak: ______________ 95 ZR-1 #399 Dunn heads X-pipe w/3" misc. mods

06-24-2010	#5
Belsy Join Date: Nov 2006 Location: DeBary , Fl. Posts: 119	Re: pipe on drivers side of plenum In looking further in the FSM I see the pipes & connectors with the F connector with both PCV valves at the F (behind the plenum). Mine is routed with a PCV valve at each I/H to a T behind plenum with supply (all rubber hoses) going to front of plenum (behind T/B on drivers side) does this suffice or has someone butchered the system?? Either way how much effect does the system have on overall drivability?? Again this is a '95. Thanks as always, __________________ Gene in Fl. :handshak: ______________ 95 ZR-1 #399 Dunn heads X-pipe w/3" misc. mods

06-24-2010	#7
bdw18_123 Join Date: Apr 2009 Location: Prather, CA Posts: 808	Re: pipe on drivers side of plenum This is how the PCV system should look stock (mocked up with my '90 Z parts): I am also missing the hard line on the driver's side of the plenum. It's the one that would connect to the rubber connector on top of the PCV's and go to the very front of the plenum just behind the throttlebody. I don't want to spend the money on it though, so I plan to install a oil catch-can on that side so I won't need that piece. If you do want one though, Jerry's Gaskets site has one. Link here: http://jerrysgaskets.com/store2/root...roducts_id=358 Someone here might also have a used one floating around they might sell you. __________________ [IMG]http://i13.photobucket.com/albums/a292/bdw18_123/_zr1netforumsigphoto.jpg[/IMG][B] 1990 Corvette ZR-1 [/B][I] White/Flame Red, #2299, mostly stock, 144K miles.[/I] -Cams timed to the '93-'95 405HP LT5 stock timing. -IAT sensor relocated to below front bumper. -Haibeck hoops installed in airduct. -OBX cat-back exhaust. [COLOR=DarkRed][B](SOLD - December 2012 [/B][/COLOR][COLOR=DarkRed][B]:hello:)[/B][/COLOR] 1993 Corvette Coupe Black/Black, 6-speed (SOLD - October 2009 :hello:)