Is there a fix for pushing oil with hard driving?

[AintQik]

If I drive the car hard, hard brake, hard accel, I will get oil smoke. Quite embarrassing. I’ve read that it’s a common Viper issue where oil gets past the valve cover and sucked into the air box.

Is there a good fix? Catch can? I’ve done some searching but can’t seem to find something definitive. Many performance shops I find are out of business. Chevy guy, 1st Viper so some of these things are very odd and new to me. Car is an 00 GTS.

 

[GTS Dean]

This has plagued many a Gen 2 owner since 1996. It still vexes me to this day. I have tried many, many things to fix it lately and it is much better, but not done yet. I am actively engaged in SOLVING this issue.

I can tell you that it is NOT coming from the valve covers, it is coming from copious amounts of oil getting pushed/siphoned out of the crankcase vent port behind the t-stat, up thru the orifice in the tee feeding behind the throttle bodies and filling the plenums. When you accel or turn, the oil sloshes and fills the cylinders with oil causing smoke. When you decel, the oil sloshes forward, past the throttle bodies when they open during downshifts and fill the airbox with oil that drools out the bottom.

A catch can on the valve cover vents catches NOTHING - been there, done that. The best thing I've done so far is installing a LARGE catch can between the block vent and the tee to the intake manifold. I have to drain and pour it back in every track session, and periodically on the street based on how I drive. This keeps the intake DRY unless the can overfills.

More news to follow as the story develops...

 

[AintQik]

Thank you! I’m going to look at the motor when I get home this week and see if I can figure out exactly what you are referring to. This is terribly aggravating and it is occurring on the street. I can’t imagine this car on a track!

 

[ACRric]

Don't confuse this with overfilling of the crankcase. Mine used to smoke like a smoke bomb had gone off until I realized I had too much oil in it, Your drive must be level and oil level on the line or below or it will smoke like crazy on deceleration and sitting at the light. Had no problems after I paid attention and I brake this 2001 really hard.

 

[AintQik]

I’ll take a look at that and ensure. I’ve actually not done an oil change yet.

What do the dedicated track cars do? Dry sump?

 

[GTS Dean]

They at least do the 10qt pan that I believe yours came with from the factory. You should have 3 ribs cast into the rear of the pan to confirm. IPSCO sells a trap door baffle kit for either the short or the deep pans. WELL worth the modest cost.

 

[AintQik]

Dean, I’ll look into that. I’m not surprised, but so many fewer suppliers for Viper stuff, I have a lot to learn. I build a lot of LS motors, this car has been a dream of mine for a long time. I hope I can continue to find support and info here. I call places like Rowe and they are closed.

 

[GTS Dean]

I've been in dialog with a PhD ME on this. One simple improvement he suggested is getting full port area flow in/out of the engine on the makeup air side, so I split the valve cover vents back to my airbox instead of going thru the tee and into one port, which just about doubled the cross section area. I did this in about 20 minutes last night and will test a couple different driving situations to see if it is pressure, or vacuum that is contributing most to oil accumulation.

 

[ISMarco]

Everything Dean has said, I've experienced too. It's most problematic under heavy braking at the track.

Big catch can at the crankcase vent is the best thing I've found so far. It's not a perfect solution, and the can fills up fast.

The valve cover vents don't seem to release much oil.

If there's a better solution, I'm eager to find out

 

[Bob Woodhouse]

What happens as understood from years ago and talking with SRT engineers, is under heavy braking the oil travels to the front of the pan, gets on the timing chain and climbs it. There must be enough air velocity up there at high rpm that sends oil vapor through the breather system. Back in the day I just lived with it since it doesnt hurt anything and running a quart over full was cheap bottom end insurance at the track. Yes, anything you choose to do with oil pan baffling and or the swinging sump upgrade will help. I like the suggestions here on slowing the breather air velocity by doubling the tubing or increasing the sizing. When you slow the velocity the oil vapor tends to drop out.

 

[GTS Dean]

The chain oiler is a .032" pinhole off the main oil feed galley to the camshaft. It shoots a 50+psi stream directly on the uphill chain side and the sprocket flings droplets off at the top. The lower sprocket is several inches above the windage tray (like the B-RB big blocks) which extends all the way to the front of the pan. I don't feel even under extreme negative G braking that enough other sump oil ever gets on that sprocket to matter much. If you run the trap door baffles, only the front-most portion of the sump could slosh up the outer corners of timing cover.

 

[InTheZoneAC]

This has plagued many a Gen 2 owner since 1996. It still vexes me to this day. I have tried many, many things to fix it lately and it is much better, but not done yet. I am actively engaged in SOLVING this issue.

I can tell you that it is NOT coming from the valve covers, it is coming from copious amounts of oil getting pushed/siphoned out of the crankcase vent port behind the t-stat, up thru the orifice in the tee feeding behind the throttle bodies and filling the plenums. When you accel or turn, the oil sloshes and fills the cylinders with oil causing smoke. When you decel, the oil sloshes forward, past the throttle bodies when they open during downshifts and fill the airbox with oil that drools out the bottom.

A catch can on the valve cover vents catches NOTHING - been there, done that. The best thing I've done so far is installing a LARGE catch can between the block vent and the tee to the intake manifold. I have to drain and pour it back in every track session, and periodically on the street based on how I drive. This keeps the intake DRY unless the can overfills.

More news to follow as the story develops...

Would this be resolved with a better designed oil pan and ensuring your oil levels are correct?

 

[GTS Dean]

No. It's pretty much all about alternate crankcase venting to overcome very poor Gen 2 CCV design. Post #8 was an incremental improvement, but not a cure. The Gen 1 cars were largely immune to this problem with a standard PCV system and that's what I'm using as an improvement guide right now. I won't know for sure if it fixes the issue until this fall when I hit COTA again. However, I have a very high level of confidence in what I have ready for that test.

 

[GTS Dean]

This combination WINS! No oil escaped the crankcase and the plugs are beautiful!

This combination takes full advantage of the HUGE baffle area and volume above them in the G1/2 valve covers. Big hoses slow the flow velocity down and let the oil vapor coalesce on the internal surfaces and stay in the engine. I put caps on the block outlet and stock valve cover nip-ples. It also retains a full, closed PCV system. You can run the stock PCV valve for '96/'97, or '98+ cars retain the orifice PCV in the tee feeding the manifold behind the throttle bodies. I'm running an aftermarket, tunable PCV valve that can either function conventionally, or in orifice mode.

Props to JonB at PartsRack for supplying a Gen 1 drivers side and late Gen 2 passenger side for testing!

 

[GTS Dean]

For 90-95% of owners, this is a non-problem. But for the rest of us who use these cars much harder, then venting the valve covers is the ONLY sure way to cure this issue.

For dual purpose street/track cars, the intake (makeup air, clean side) should breathe filtered air from the airbox like the Gen 1. This hose should be at least 1/8" larger diameter than the outlet hose. The outlet hose (dirty side) should have a PCV valve or orifice in it. It is a good idea to have the catch can in this circuit. I'm running a -12AN (3/4") intake hose and a -10AN (5/8") outlet hose to the can. Then, 1/2" to the PCV and 3/8" to the motor. This is a CLOSED "vent to engine" catch can setup and maintains the emissions system.

For a full time track car, you can run both valve covers to a single top-vented "vent to atmosphere" catch can using at least -10 hose.

None of this is high pressure and push-lock fittings work fine. Use fittings and adapters to point the hose in the right direction at each end. Keep bend radii generous if required. Valve cover fittings can be AN bulkhead, o-ring boss swivel, or purpose built for the job. Some of the cleanest hardware I've come across are from Motion Race Works https://www.motionraceworks.com/collections/catch-can-pcv?utm_adname=Video+-+Catch+Can+Short+Cleetus. You cannot use aluminum welding bungs on the valve covers because they are made from cast magnesium.

One big reason people go to Gen 3 valve covers and spacers is to make room for adjustable rockers that can otherwise hit the baffle plates. You can keep the G1-2 covers and have the mounting bosses milled down about 5/16" to gain the clearance you need to keep the baffles.

Gen 1s (pictured below) run a conventional PCV valve in the passenger side (rear) valve cover and rarely, if ever have these oil control problems. I'm thinking the Gen 2 engine team just wanted to clean up the look of the motor (they did so) but FAILED BIGTIME in the performance side of things.