rnbiker

I've got a 2001 C5 that's modded with pistons, headers, cam, heads, tune and the like. The builder/tuner put a crankcase breather behind my left head and I'm actually getting some smoke coming out from the filter at times. Not all the time, but regularly and especially after a hard pull on the street. If I pull the oil cap on the other side, the smoke stops puffing out of the filter and can be seen coming out where I pulled the cap. The smoke is a neutral color, not especially black or white, but is present. I just recently had a new cam put in the car and the builder told me the rest of the engine seemed fine, but should I have this smoke coming out? Does this mean something isn't tight below and I could have a problem?

0Paul Ruggeri

If its puffing out, that's usually blow-by problem. I'd do a compression check.

rnbiker

That's kind of what I'm afraid of.... My builder/tuner said that he checked the compression and it was fine (just a week or so ago), but seems to me there is maybe a problem....

rebelheart

Sounds like hot oil vapors escaping from an open pcv system to me.

rnbiker

Rebel..... Hot oil vapors as in probably normal....or as in blow-by from loose rings or something???

rebelheart

May be normal as you dont see those vapors in a proper closed system,but they are there!

rnbiker

So what is the best way to do a properly closed system and why does the stock setup not seem to suffice for most people with bigger mods? I don't understand why anything is ever changed from the stock setup. Now my builder has some other item ordered that goes up front somewhere because the fumes/puffs of smoke get into the cab since the filter he placed is near the fresh air inlet for the interior. I don't know why anything else is needed. Maybe because of running LS6 heads on my LS1 or something? I was just worried that something was loose below, but maybe it's normal....

rnbiker

::Bump:: Anyone have any info/advice for me? I'd appreciate it...

dougbfresh

I'd do a leak down test, a compression test isn't enough. If both valves are closed (and sealing correctly), and your leakdown is fast, your rings ain't right.

rnbiker

Not really sure how to do that myself (leakdown test) as it has been awhile since I've even seen one.... I'll have to do some homework and see if I can do it at the house.... If not, maybe a local mechanic won't charge me an arm and a leg to do it for me.... Thanks for the advice... I suppose it'll have to wait until next week if I can't do it myself....

lucky131969

I would like to see the breather setup, and the pcv setup on the other side. Post pics. You probably don't have an issue, but I need to see what you have setup.

rnbiker

I'll snap some pics tomorrow morning and post them. The "pcv" system in non-existent except for that breather. Since it was cold today, I've noticed that I can't even turn on the heat without getting wicked fumes in the car (even on recirculate), so I definitely need to figure something else out... The builder has another part ordered that is supposed to relocate the filter someplace closer to the front of the engine compartment, but if I'm getting that much in the cab, I don't know how much that's gonna help. Anyway, I'll post the pics and I'd love any inputs as to what system I could use that would eliminate the issue. I'm also going to see if I can video and catch any of the smoking on camera and see if I can post that as well... Some say it's a loose lower end/oil control issue and others say it "might" be normal and just not normally seen when the system is closed..... Who knows.... Thanks....

lucky131969

Was the oil pressure sensor changed out....by cutting a hole?

Bill Curlee

Why on earth would someone remove the PCV system and replace it with a breather. Thats early 60s stuff. If you had FI then a PCV system with a beather is in order.

I will say that a properly installed and quality catch can will aid in keeping oil out of the induction system.

If you plan on restoring the PCV system, install a 2002 + system as it was redisigned and works better than previous years. There are a few post on how to do that mod on this forum.

My 450 RWHP 02 ZO6 has the OEM PCV System and a catch can and it works just fine.

BC

rnbiker

Don't know why it was ever changed and was kinda my original question.... Why would you change it and what's wrong with the OEM system that GM designed?? As for the hole.... yes, the builder said he would have to make a hole, then was talking about closing it up when this new part comes in... As for the oil pressure sensor, I am not aware that anything was done to it.... Should this have been modded as well??

lucky131969

I was just wondering, as this is the fresh air intake. Often, when some knucklehead cuts a hole to replace the OPS, they seldom seal them up properly...if at all. Given the location of that breather, if there was a hole cut to replace the OPS, and it was not sealed up.....that would explain the fumes in the cabin.

bkel33

Many people replace the oil pressure sensor by cutting a hole in the cowl. The OPS is located behind the intake manifold.

It doesn't take long to remove the manifold (30 min or so). Remove it and check that the OPS is sealed properly. While you have it removed, install the newer style PCV mod. Check out http://www.ls1howto.com/index.php?article=18 for a full step-by-step guide.

50 cents says that will fix your problem!

bucketlist1957

Pull the fuel rail covers and please post pictures of the Driverside valve cover at an angle looking towards the back of the Valve cover. Then take a picture of the Passenger side looking at the front of the Intake manifold and Throttle Body. Just curious. You said the PCV system was removed. Your vette unless I am mistaken should have a tube coming out of the front of the Valley plate on the passenger side. That is where the PCV should be with a line going into the Front of the manifold or TB I am not real sure about the LS6 intake. In 04 they went to the fixed orfice in the valley cover that completely removed the external PCV valve. BC, Manley or one of you other guys with all the experience speak up if I am wrong. The reason I was interested is I am getting ready for different heads that require me to go to the valley cover PCV system. I went with the O4 style after calling the GM parts house. It really isn't the heads that require the different valley cover it is because I have to have the newer center bolt valve covers and the PCV system is different.

rnbiker

Good info and planning to check this stuff out more tomorrow as it is unseasonably warm right now Anyway, I'll post pics tomorrow as suggested. Thanks so much for all of the good info. I really want to get this fixed properly and not just "rigged" or "band-aid" fixed. I really appreciate all you guys with more experience helping me figure this out....

Dale002

I bet if you reinstalled the updated PCV setup the problem will go away.
Some of the old guys still don't understand how these new engines work.
They will eliminated the PCV, cause that was the thing to do back in the days.
On these new type engine you need a PCV system.
If too much oil is collecting in the inlet, then you will need a catch can.
Very simple set up. Good luck and keep us posted.