ITSWILL

I have a 99 LS1 in an 89 Mazda RX-7. I rebuilt the engine about 5000 miles ago for nitrous. The ring gaps were set for a 200 shot.

The PCV system initially was not correctly connected. The PCV valve was just pushed into the rear grommet on the driver's side valve cover and everything else was left open. Every once in a while when I would get on it I would see some smoke behind me and I could smell burned oil. I believed that the open ports were blowing some oil out and getting on the exhaust. I also never saw a single drop of oil under the car.

Recently I put the PCV system back together I believe the correct way ( I say I believe because I'm not sure if there should be a check valve in the hose from the front nipple of the passenger side valve cover to the throttle body, and I am just using a plain hose). Also I do not have the ground strap on my PCV valve.

Since putting this back together the correct way I drove it a couple hundred miles without any issues even when getting on it hard. The other night however, I got on it as I had the day before and I looked back and there was a huge cloud of smoke. When I got home I popped the hood with my fire extinguisher in hand thinking it could be on fire. No fire but I did notice oil everywhere and it appears to be coming from between the engine and trans.

Yesterday I cleaned everything up and warmed the car up to check for oil leaks and there was nothing leaking from anywhere.

I took the oil fill cap off and covered it with a rag and took it for a beat run, no smoke, no oil.

So then I put the cap back on and replaced the PCV valve. No smoke and no oil again.

I'm thinking to put the old PCV valve back in and try it but I don't think there is any guarantee it will smoke and leak again since the valve didn't seem stuck when I took it out. It seems it could have been sticking intermittently.

I really want to keep things stock looking (it's amazing how many people underestimate this car), I'm wondering if an LS6 PCV system would be worth while?


Any suggestions or ideas?

Taxman20

iTrader: (11)

In my opinion the PCV will not pull enough vacuum in the engine to prevent the rear main from leaking. If you have oil from the rear main its most likely a bad seal. We run lots of stock car race engines with no PCV at all, just oil breather filters on one valve cover and do not have issues on the rear mains or any other seal or gasket. I think its bad and needs to be replaced. OR, when you installed it, are you sure it was centered well? There is a guy on here that sells a tool for making them perfect and if its off a little too much it will leak.

Mercier

iTrader: (15)

^^^What he said. I didn't realize how "off" the cover alignment could be until I got the right tools. The seal is a slight bit flexible but harder than most and will likely run fine for a short period it misaligned but then start to fail. Also easy to install it backwards..tiny, tiny writing on the seal(and black on black) that says "this side out."

ITSWILL

I'm pretty meticulous and I would like to think I installed it correctly. I seem to remember a white plastic centering "tool". With that said I am pulling the engine soon to do heads and cam and throw out bearing, so I'll have a gander at the seal to see if it's in right and prolly put a new one in.

From under the car I can see the rear main and I don't see it leaking while running. Seems to only be an issue at WOT sometimes...

Darth_V8r

iTrader: (4)

Your oil pan gasket might be bad. Bear with me here.

Right by the filter, mine cracked. At WOT it squirted oil on the headers, making a smoke show. There is high pressure oil running through the oil pan gasket to the oil filter and then back to the block.

PCV won't fix that either.

joecar

Darth_Vader,

Hiw did it get cracked there...?

Darth_V8r

iTrader: (4)

I never found out. The steel wasn't cracked, just a split in the rubber

Mercier

iTrader: (15)

I have that same problem on a LS2. Good call. Always forget that portion has pressure. And with a 10296 with the big spring it's got more pressure than before. Kept worrying it was the filter or similar like some K&N's that had welding problems with the "integrated" nut.

On the subject alignment, I was referring to aligning the rear cover, pan, front cover. You can install the rear seal right side out but if the cover is pushed one way or the other just a little, the seal opening won't be perfectly centered around he crank, and the seal won't be either.

BUT I think Darth_V8r has the likely culprit. I am now sure that is what's up with mine. Idle for years with no problem and then haul *** for 5 seconds and embarrassing burning oil smell, drip from my filter, and brown on the exhaust.

ITSWILL

I was well aware of the rear main alignment so I would like to think I was careful enough, but who knows.

I have the 10296 pump as well, added it when I did the rebuild. Seems like the oil pan gasket could be a possibility. The only weird thing is there was oil on both sides of the engine. Who knows though maybe its squirting oil back towards the bell housing? I'm doing a trap door oil pan baffle when I pull the engine too, so I will take a good look at the pan gasket.

Mercier

iTrader: (15)

I've found that an oil leak pretty much defies the laws of physics. Just because oil is somewhere doesn't mean at all that it came from there or near there. Especially if the vehicle is moving.

Also let's say oil pan is misaligned just a little to the rear--like extending past the back of the block just a tiny bit(easy to accidentally do)..the rear cover and seal will seem to go on just fine but then when you bolt on the transmission it could push on the oil pan and cause a gap. Maybe where the pressurized oil comes through as mentioned above, maybe all the way across?

Darth_V8r

iTrader: (4)

You can also get oil blowing past the dipstick tube o ring under load. Squirts all over the place on passenger side.

ITSWILL

I haven't seen any oil or smoke for the past 100 miles with the new PCV valve. I should be pulling the engine soon. I'll let you know what I find.

ITSWILL

I pulled my engine to change the throw out bearing and it turns out it was my pilot bearing making the noise.





Anyhow, I verified that the rear main seal was in the correct direction. There was no visible oil around the main seal either, I think I'm going to leave the one I have in there rather than replace it and chance messing a new one up. The oil appears to have been coming from the oil pan gasket, but I will confirm when I take the pan off tonight or tomorrow.

ITSWILL

Seems like the oil was most likely coming form the oil pan gasket. The new GM gasket has an improved design, hopefully this will solve the issue. I also went ahead and switched over to the LS6 Valley cover PCV system which since it doesn't have a PVC valve should eliminate the chances of a PCV valve failure.