I installed a catch can. Here is a pic of the set up.[IMG][/IMG]

 

Very cool and doesn't look too difficult. I'm going to call the builder today and see what's up. Why he chose to pull everything off is anyone's guess for now, but I plan on asking him and will update. I'm really pissed and find this to be pretty shodddy work from someone with this guy's reputation. In any case, I'm going to insist on the LS6 conversion. I think he owe's me the time after this. It's just not right.

 

Oil consumption...yes

 

im not a genius so take this with a grain of salt! i have the same problem just not in a corvette .its caused by the cylinder pressurizing as the piston is being pulled back down also compressing air and puffing through the vent. or thats what ive been told

 

Yes, from internal engine pressure.... That's normally what the pcv system regulates...which I'm missing on my car. Hopefully after I talk with the builder today, I'll get it fixed...

 

well you should probably get one lol not to familiar with a pcv system but sounds like it would fix you up! good luck

 

That is not the function of the PCV valve. No offense, but I suggest you buy a service manual. You can read the full description and operation virtually all systems on a C5, and gain an understanding of how everything works.

 

From the Wiki.... Was trying to keep it simple since the guy noted he wasn't an expert.. Neither am I, but I know this much...

A crankcase ventilation system is a way for gases to escape in a controlled manner from the crankcase of an internal combustion engine. A common type of such system is a positive crankcase ventilation (PCV) system, the heart of which is a PCV valve—a variable-restriction valve that can react to changing pressure values and intermittently allow the passage of the gases to their intended destination (which nowadays is the engine's intake stream).

 

We used to refer to the PCV system as an "engineered controlled leak"...

 

.......Wiki, huh? There is a difference between "reacting".....and "regulating".

 

Symantics, but sure.... Wiki was pretty close though.... Again, keeping it simple...

 

No, it's not....but no biggie.

Good luck with your issue

 

It regulates by reacting to changing pressures.

 

LOL!! That's funny and a great way to put it to satisfy both.. Are you a politician??? LOL... Too funny...

 

Rnbiker, all this talk about pvc systems and catch cans is hiding the fact that if you have aftermarket pistons and they used good pistong rings you should have NO blowby, regardless if there is a pvc system or not. The only time I had smoke coming out the oil filler neck was when piston #7 (unlucky 7) broke a piece of the ring gland off. Good piston rings that have sealed correctly should not have that problem...period. I rebuilt the motor, used good rings, broke them in correctly, and have had zero bowby issues. A good motor should not need a catch-can. I have a pvc system but still use a breather on the valve cover. Remember you should have vacuum, not pressure. I'd say you have a ring or rings that arent fully sealing. Btw a pvc is just a check valve, thats it. Your builder might have been fine but if you drove the car slow or at low rpms to "break it in" then the rings wouldnt seal right. Correctly breaking in rings includes a couple of hi rpm passes to help them seat correctly. Sorry to say but puffs of smoke (any color) from the valve cover is never good. On a stock motor its common because stock rings are crap, on a built motor its a no no.

 

I disagree.The whirling mass of the crank and rods act just like a fan and create pressure,just as the simple act of the pistons moving down the bore displaces air inside the crank case and also creates pressure.If he has no vacuum source directed to the crankcase,he will have positive pressure.

 

Sorry bud that not correct. You want vacuum if the rings have sealed properly. Some guys even run vacuum pumps. You can always research the topic.

http://nutterracingengines.com/racin...uum_facts.html
HOW IT WORKS

The reduced pressure ("vacuum") in the crankcase is generated by having a substantial excess of scavenging capacity with respect to the engine's oil flow rate. The "vacuum" increases the pressure differential across the ring package, producing an improved ring seal. The improved ring seal allows the use of a low-tension (reduced friction) ring package, yielding a power increase as well. Further, the reduced crankcase pressure dramatically reduces windage losses at high RPM.
Here are a few observations we have made over the years of developing winning race engines. First of all, in most engines, the expected power gains will occur with 8 to 10 inches HG crankcase vacuum. Beyond that point, more vacuum does not generally produce any measurable power gain until (a) you get more than 20 inches HG of vacuum AND (b) you are operating in excess of approximately 8300 RPM.
However, we generally size the systems on our engines to produce around 14 "HG when the engine is fresh. That provides sufficient capacity so that as the engine wears and blowby increases, there will still be sufficient scavenging capacity to achieve the 8"HG minimum, and power does not drop off noticeably.
If you want to run a high level of crankcase vacuum (18 inches HG or more), there must be provisions in the engine to supplement the lubrication that used to occur when oil was being thrashed about by the moving parts ("windage"). There will likely be problems with at least wristpin and cam follower lubrication. The best solution will be the addition of piston oilers and, if your engine has a flat tappet cam, provisions for extra lubrication of the cam lobe-to-lifter interface will certainly be required. If you are trying to achieve over 18 "HG, you will need to install special crankshaft seals (front and rear) which have the sealing lips reversed to hold that higher level.

 

Thats not a totally correct statement. The DISPLACEMENT inside the engine block (even when the parts are rotating and moving) NEVER physically changes. When one piston comes DOWN in it cylinder, another one goes UP the same amount. There is turbulence but, just the crank, rods and pistons moving DO NOT produce any pressure.

The later GM engines took care of this turbulence (ZO6 LS6 and later model LS1 blocks) by designing windows in the block to allow the air flow inside the block to move more freely. The pressures in the block comes from blow by. The PCV system maintains a vacuum in the block to evacuate this blow by and remove the gasses, and moisture and also (as C5Natie stated) aid in ring sealing.

If your piston rings are so bad that they overwhelm the PCV system, your ALWAYS going to have out gassing (pressure) coming out of a crankcase opening (ie oil fill pipe ) when the engine is running.

Recommend that you conduct a leak down test on each cylinder and make sure your rings are not defective.

BC

 

So then, I should NOT have positive pressure or air blowing out of the filler port unless there is a problem with the engine internally, correct? So, the one that I saw that had a vacuum when removing the cap while running is the CORRECT condition that I should be seeing in my car...yes? I wonder because the builder who built this car for the previous owner is my current guy and he said he "pulled and checked" the pistons on the cylinders that were giving problems with oil-fouled plugs (before the valve guide fix on my heads) and that "they looked fine"... Sounds like he should maybe have checked ALL of the cylinders because it sounds like I have a problem... One that would have been a lot cheaper to fix with the engine out and the heads off a couple of weeks ago So...let me finally ask this question of you kind forum folks.... Would a proper leakdown test on all cylinders finally and conclusively, answer whether or not I have an internal problem...or are there other tests I can do? I'm considering having someone else do the tests and go back to the builder if the engine "fails" whatever test conclusively points to an internal failure, if there is one... And to this end, is there any other reason that I could have the air puffing out of the valve cover or can this ONLY be blow-by from loose internals? Sorry for the long post and thanks so much for everyone's help...

 

Your very first concern should be to restore your PCV system. I CAN NOT tell you what amount of of if any pressure should come out without the PCV system being functional. I will tell you that it shouldnt be much if any.

That being said, the LEAKDOWN test has measureable limits and YES,,, it will identify any defective rings and cylinder bores.

Just GOOGLE it

http://www.aa1car.com/library/leakdown.htm

http://www.carcraft.com/techarticles...ter/index.html