I've battled with oil leaks on various engines and have known people with the same problems. I'm interested in learning more about how crankcase pressure affects oil leaks or what other causes will create oil leaks even if the motor is sealed up properly. I know that most of the time a motor won't leak oil when being revved up sitting in neutral, but will leak like no other once a load has been put on it. I found some interesting reading on it here
http://www.teglerizer.com/triumphstuff/emissions/index.htm
I think this would be a good discussion and one that hasn't been talked about much, what does everyone think?

My take is that much of the crankcase pressure is caused by blow-by which exists in all motors to some extent, more or less. The more you rev or load an engine, the more volume of air and higher cylinder pressures which will increase blow-by.

bump

Hey everyone, AFR heads are the suck!(will this get someone to post on this thread now??!!)

I have the occasional James Bond smoke screen thing going on, often at the most embarrassing moments. Besides twice suffering premature 1 piece oil pan gasket failure, I've popped the hood to find breathers blown off, dipstick tube up, and the chrome cover from the oil fill cap missing, leaving only the rubber insert in the valvecover, which, of course has a hole through it like a grommet.

These are usually discovered after running through the gears WOT and/or prolonged mid to high rpm freeway stints. Either way, the elevated exhaust temps, quickly alert everyone to the obvious oil dicharge.

Besides experimenting with multiple breathers, I have also incorporated the use of a PCV, as well as, a vented "catch can", all with minimal effect. Currently, I have the PCV, this only because last week during a 50 mile jaunt out of town for a fashion shoot (Italian magazine "Velvet"), I was informed of my apparent disregard towards the enviroment, as it was overheard in conversation by one of my drivers, in the motorhome (loaded with models, stylists, etc...), behind me. I pulled over, pulled the catch can and replaced it with the PCV, figuring freeway rpm would, in fact, provide adequate vacuum, which it probably does. The smoke continued, only subsiding after reducing speed (rpm), therefore reducing exhaust temp. Turned out to be tranny fluid from the vent tube, I had overfilled it.

In any case, all three methods of control seemed to result in oil drips visible on the bottom of the pan, but usually not enough to leave much more than a spot in the driveway, if that. Considering the virtual Exxon Valdez episodes that accompanied each pan gasket failure, I've come to accept a slightly lubricated underside.

Hi Rowdy, you too Cody (stop pickin' on AFR), some guys up here do have some info for many here. You might want to read the post below. It's here in the engine section. Will give you more insight of the "tough" battles with
"engineers". They're the really tough guys to convince! Thanks, Gary in N.Y.

http://www.chevelles.com/forums/showthread.php?t=153517

P.S. I've also been working on a "hidden" PCV system for some of these units. It incorporates the new Vette's design adapted under the early style intakes. I have a test unit out the field on a 396 we delivered a few months back. So far, so good, but it'll be an "after-the-winter" project, providing things slow down some.

Hey guys I am having a problem with this too. I just got my 468 in my car and the dipstick keeps blowing out. I have a breathing in one side and pvc in the other. What causes the dipstick to blow out and how can i fix it. Sorry do not mean to take over this post, just thought someone might be able to help.

Tom

Hey guys I am having a problem with this too. I just got my 468 in my car and the dipstick keeps blowing out. I have a breathing in one side and pvc in the other. What causes the dipstick to blow out and how can i fix it. Sorry do not mean to take over this post, just thought someone might be able to help.

Tom

Hi Tom, to be really honest here if you have the PCV, which we really don't require and rarely use on our units, and/or have some "excellent" breathers in the covers , the only other problem that causes your condition is a piston ring or cylinder wall condition.

If it persists you'll have to tear into it a take a look at things. Most we get in here are simply "worn" out when you have that amount of internal crankcase pressure OR have "burnt" away ring lands from detonation. I have even had some tiny holes starting to go through the piston decks, more with "cast" pistons however. Thanks, Gary in N.Y.

P.S. We install (2) 6.000" x 2.000" "standoff breathers in the valve covers. To date I have not one unit with blow-by with these breathers. But we do pay close attention to the "ring-packs" we use. I also tend to "fly-in-the-face" of manufacturer's recommendatios here and send the ring's out with "tight" second gaps. Depending on the overall unit, I still run .014" on the second ring, N/S, no "spray", and "low" compression. Our 750 HP BB's have no PCV's incorporated. As I stated in a prevoius paragraph above, I'm personally working on a "hidden" PCV system, but this is not a "cure" for a ring condition. The rings/bores must be in "top-notch" condition!
The photo here is the breathers we use with the BB covers.
http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/th_ValveCoversBBC-03.jpg (http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/ValveCoversBBC-03.jpg)

Just for ya you know, I've been running engines without PCV and they sure leaked from the rear main seal, when installing PCV the oildripping stoped.... Worth mentioning is that I neither had some good vents on the rocker covers during these tests.