car is running now. but have an oil problem - Page 2 - ZR-1 Net Registry Forums

Ccmano · 05-05-2009

I agree that it sounds like a restricted PCV system building excessive crankcase pressure. Are you using a zip tie to hold the PCV hoses and valves together? I've seen where the zip ties are so tight that the lower hose collapses. Make sure that lower hose is not pinched or collapsed.
H

-=Jeff=- · 05-05-2009

no zip ties.. I modded the F tube to accept clamps so the top and bottom of the PCVs are clamped

I started it tonight, I check vacuum off the metal tube at the PCV (blocked PCV)

Vacuum was 16-17"

I pulled the plug from the PCV and there was air blowing right out. I am still buying 2 PCV, but after hearing the dipstick has an outer seal at the top whil emine does not, I am thinking of either getting a replacement dipstick or a lokar like HawaiiZR1

secondchance · 05-05-2009

Quote:

Originally Posted by -=Jeff=-

no one has both PCV in stock and most show the wrong parts..

Getting them from the dealer on Thursday..

not sure what else to look at.. keep ideas coming

My experience has been, and I have logged 200,000+ miles on LT5 since 1991, dip stick is always raised by about a 1/4 of an inch whenever I check oil. It is my understanding that LT5 produces a lot of crankcase pressure, especially under full throttle.

-=Jeff=- · 05-05-2009

Quote:

Originally Posted by secondchance

My experience has been, and I have logged 200,000+ miles on LT5 since 1991, dip stick is always raised by about a 1/4 of an inch whenever I check oil. It is my understanding that LT5 produces a lot of crankcase pressure, especially under full throttle.

right, but spitting out the stick on to the headers is not a good thing.. looks like the James Bond Smoke Screen accessory..

QB93Z · 05-06-2009

Just an uninformed off-the-wall question. How far down does the dipstick tube extend inside the crankcase? Is it possible that it low enough in the oil pan to be submerged in the oil?

Jim

-=Jeff=- · 05-06-2009

Quote:

Originally Posted by QB93Z

Just an uninformed off-the-wall question. How far down does the dipstick tube extend inside the crankcase? Is it possible that it low enough in the oil pan to be submerged in the oil?

Jim

shouldn't be but I don't know

I emailed Marc h. yesterday and i got a reply on a couple things to check.. I will try to do that tonight when I get home.

secondchance · 05-06-2009

Quote:

Originally Posted by -=Jeff=-

will do, but at WOT there would be no vacuum and that is when I see the oil issue

A quick question for gurus - I always thought most vacuum would occur at WOT. Not true? Is PCV disbled at WOT?

A26B · 05-06-2009

It's the opposite. Highest vacuum occurs when the throttle is closed at higher rpm.

Think about it this way. Act like you're going to whistle, but suck hard instead of blowing, then open your mouth suddenly (WOT) & feel the vacuum drop. Same thing with an engine, trying to pull air in with throttle just barely cracked, creates high vacuum in the intake system. At WOT it makes it easier to pull air in.

PCV is not "disabled" at WOT, just doesn't work as well with low vacuum. The problem of crankcase pressure is exacerbated then because crankcase pressure is highest at high rpm under WOT conditions.

secondchance · 05-06-2009

Now that you guys explain it makes a perfecr sense.
Thanks for the education. I had it azz backwards.

05-05-2009	#11
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: car is running now. but have an oil problem I agree that it sounds like a restricted PCV system building excessive crankcase pressure. Are you using a zip tie to hold the PCV hoses and valves together? I've seen where the zip ties are so tight that the lower hose collapses. Make sure that lower hose is not pinched or collapsed. H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

05-05-2009	#12
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,169	Re: car is running now. but have an oil problem no zip ties.. I modded the F tube to accept clamps so the top and bottom of the PCVs are clamped I started it tonight, I check vacuum off the metal tube at the PCV (blocked PCV) Vacuum was 16-17" I pulled the plug from the PCV and there was air blowing right out. I am still buying 2 PCV, but after hearing the dipstick has an outer seal at the top whil emine does not, I am thinking of either getting a replacement dipstick or a lokar like HawaiiZR1 __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

05-06-2009	#15
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,689	Re: car is running now. but have an oil problem Just an uninformed off-the-wall question. How far down does the dipstick tube extend inside the crankcase? Is it possible that it low enough in the oil pan to be submerged in the oil? Jim __________________ If it isn't fun, you aren't doing it right! 1990 Black ZR-1 - sold 1993 Quasar Blue ZR-1 1994 Competition Yellow ZR-1 1995 Dark Purple ZR-1 Maryland State Coordinator WAZOO Member

05-06-2009	#18
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,394	Re: car is running now. but have an oil problem It's the opposite. Highest vacuum occurs when the throttle is closed at higher rpm. Think about it this way. Act like you're going to whistle, but suck hard instead of blowing, then open your mouth suddenly (WOT) & feel the vacuum drop. Same thing with an engine, trying to pull air in with throttle just barely cracked, creates high vacuum in the intake system. At WOT it makes it easier to pull air in. PCV is not "disabled" at WOT, just doesn't work as well with low vacuum. The problem of crankcase pressure is exacerbated then because crankcase pressure is highest at high rpm under WOT conditions. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

05-06-2009	#19
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,723	Re: car is running now. but have an oil problem Now that you guys explain it makes a perfecr sense. Thanks for the education. I had it azz backwards.