Reluctantly joining the catch can club - ZR-1 Net Registry Forums

1991 Corvette ZR-1 · 10-07-2022

have had some spirited drives in the Z and noticed I get a decent puff of smoke on an aggressive downshift sometimes. Any other time, no smoke even on WOT without downshifts. Well after a few romps to near redline on one trip and off throttle coasting down to a stop at a light, I noticed the engine was running rough. This was after I looked in my rear view mirror around 4K rpm during the off throttle deceleration and saw a big puff of oil smoke. Not constant, just a decent quick cloud almost like the engine took a teaspoon gulp of oil in the cylinders. Pulled into a parking lot and the car recovered from the rough idle. The first thing that popped in my mind was O2s or spark plugs got saturated with burned oil and this caused the rough running condition.

I have had a few more trips to the 6-7K rpm area since and no issues but I also didn?t get off the throttle completely on those for decel. Looking inside the plenum and it is the usual shiny wet appearance that is what we have come to expect from the LT5. Driver side PCV valve is new while the extremely rare passenger side valve is still the original. Both valves rattle freely. There was noticeable oil volume collected below the pcv valves when removed. As expected, the tips on the Corsa are black after a few drives. So I am going to try a catch can and see if this provides something of value.

This always felt like an LS band aid and the idea of one is not great to me. However, the idea I may be slowly strangling spark plugs or O2 readings with burning oil also does not sound great either. Did a compression check a few years ago and all cylinders were great. Also, I am wondering if the after fires I sometimes get on decel are due to oil smoke in the exhausts messing with the O2s and making them enrich the combusion.

Anyway, the can I went with was an ADD W1. They come in lots of colors but I went with black to try and not draw the eye to it versus some bright purple or blue. The internal baffle design looks good and there is no Brillo pad style filter. Even has a little dipstick to check how much oil is in it if needed. I guess I will see how this works out and follow up with results good or non eventful.

Also as a side note, Dorman makes a hood prop clip assortment with a decent replacement for the passenger side fuel vapor hard line retainer if you need a new one. Stumbled on it while at the parts store for pcv hose. Dorman 45396

1991 Corvette ZR-1 · 10-07-2022

Alright, if I remember an old diagram I found from Jerry posting on here I did this right. Inlet into the can is the hose connected to the pcv valves assembly at back of plenum. The outlet from the can is hose going to the pipe coming off the front of plenum just behind the throttle linkage. A few pics. I?ll take it for a test sometime today or tomorrow. I tried to keep this as clean an install as possible.

HAWAIIZR-1 · 10-07-2022

Thanks for sharing. Very nice and clean install. I bought a catch can years ago and it?s still in my closet waiting install. I had good results with one I installed on my 90Z. It?s amazing how much oil it caught. I hope you find it worthwhile and can?t wait to hear your thoughts.

Sent from my iPhone using ZR-1 Net Registry

dredgeguy · 10-08-2022

Been thinking of this mod for a while and looking forward to hearing your results.

DRM500RUBYZR-1 · 10-08-2022

Nicely done!
Factory looking.
Keep us posted on effect.
Thanks!

Marty

Paul Workman · 10-12-2022

The LT5 tends to need a 'BANDAID" too.

I installed mine (a Moroso) on my '90 and it seems to have cured that oil issue recovered from the PCV loop.

I used metal braded lines following the stock route and then wrapped to the catch can return line to the catch can placed in the well in front of the left front tire.

It actually looks good (once I finished routing the braided lines to the stock route, except for the detour to the catch can and back). And, the Moroso can has a dump valve on the bottom. I routed the dump outlet hose to a opening in the wheel well. Works good!

Dynomite · 10-13-2022

Quote:

Originally Posted by Paul Workman

I used metal braded lines following the stock route and then wrapped to the catch can return line to the catch can placed in the well in front of the left front tire.

I did very similar

Post 148 - Elite Engineering Oil Catch Can

Post 242 - Installation of Elite Oil Catch Can

The PCV hose connected under front of plenum (Vacuum source) is connected using SS braided hose to an Oil Catch Can external to the engine which Oil Catch Can is connected using SS braided hose to the dual PVC valves hard line located at the rear of the plenum. The Oil Catch Can is located on the drivers side under the drivers side head light.

W i l l · 10-17-2022

I've got catch cans on one of my cars, but a racer told me I should go back to PCV to get the vacuum on the inside of the motor and avoid the pressure buildup that will cause gaskets to leak, etc. I told him I didn't want to be burning oil back through the intake but he said in a street-driven car the horsepower loss is very minimal.

My catch cans were installed by Lingenfelter and have the brillo pads vents. Are the catch cans you guys are using sealed? Probably not if they have a dipstick. But why not get a baffled and sealed catch can and put the catch can downstream of the PCV valves and get the best of both worlds?

1991 Corvette ZR-1 · 10-18-2022

Quote:

Originally Posted by W i l l

I've got catch cans on one of my cars, but a racer told me I should go back to PCV to get the vacuum on the inside of the motor and avoid the pressure buildup that will cause gaskets to leak, etc. I told him I didn't want to be burning oil back through the intake but he said in a street-driven car the horsepower loss is very minimal.

My catch cans were installed by Lingenfelter and have the brillo pads vents. Are the catch cans you guys are using sealed? Probably not if they have a dipstick. But why not get a baffled and sealed catch can and put the catch can downstream of the PCV valves and get the best of both worlds?

The ADD W1 is sealed. The little knob for the dipstick is threaded to screw into its hole and it also incorporates an O ring to help seal it when fully threaded in. It is a nice little feature.

Young1 · 01-16-2023

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D8DFA2C9-3B7E-41BF-AC80-60331681E8B9.jpg
I joined the Catch Can Club to eliminate oil in plenum and octane reducing oil vapor. I experience pinging only when hot on the track and the can should fix that. I purchased one with a valve on the bottom to drain it. I made a bracket to attach it to the nut on the brake booster. The nipple under the plenum is 3/8 and I inserted a 3/8 hose barb in the pcv collector at rear of plenum. Easy.

10-07-2022	#1
1991 Corvette ZR-1 Join Date: Sep 2018 Location: Florida Posts: 294	Reluctantly joining the catch can club have had some spirited drives in the Z and noticed I get a decent puff of smoke on an aggressive downshift sometimes. Any other time, no smoke even on WOT without downshifts. Well after a few romps to near redline on one trip and off throttle coasting down to a stop at a light, I noticed the engine was running rough. This was after I looked in my rear view mirror around 4K rpm during the off throttle deceleration and saw a big puff of oil smoke. Not constant, just a decent quick cloud almost like the engine took a teaspoon gulp of oil in the cylinders. Pulled into a parking lot and the car recovered from the rough idle. The first thing that popped in my mind was O2s or spark plugs got saturated with burned oil and this caused the rough running condition. I have had a few more trips to the 6-7K rpm area since and no issues but I also didn?t get off the throttle completely on those for decel. Looking inside the plenum and it is the usual shiny wet appearance that is what we have come to expect from the LT5. Driver side PCV valve is new while the extremely rare passenger side valve is still the original. Both valves rattle freely. There was noticeable oil volume collected below the pcv valves when removed. As expected, the tips on the Corsa are black after a few drives. So I am going to try a catch can and see if this provides something of value. This always felt like an LS band aid and the idea of one is not great to me. However, the idea I may be slowly strangling spark plugs or O2 readings with burning oil also does not sound great either. Did a compression check a few years ago and all cylinders were great. Also, I am wondering if the after fires I sometimes get on decel are due to oil smoke in the exhausts messing with the O2s and making them enrich the combusion. Anyway, the can I went with was an ADD W1. They come in lots of colors but I went with black to try and not draw the eye to it versus some bright purple or blue. The internal baffle design looks good and there is no Brillo pad style filter. Even has a little dipstick to check how much oil is in it if needed. I guess I will see how this works out and follow up with results good or non eventful. Also as a side note, Dorman makes a hood prop clip assortment with a decent replacement for the passenger side fuel vapor hard line retainer if you need a new one. Stumbled on it while at the parts store for pcv hose. Dorman 45396 Last edited by 1991 Corvette ZR-1; 02-22-2024 at 10:04 PM.

10-07-2022	#2
1991 Corvette ZR-1 Join Date: Sep 2018 Location: Florida Posts: 294	Re: Reluctantly joining the catch can club Alright, if I remember an old diagram I found from Jerry posting on here I did this right. Inlet into the can is the hose connected to the pcv valves assembly at back of plenum. The outlet from the can is hose going to the pipe coming off the front of plenum just behind the throttle linkage. A few pics. I?ll take it for a test sometime today or tomorrow. I tried to keep this as clean an install as possible. Last edited by 1991 Corvette ZR-1; 02-22-2024 at 10:04 PM.

10-07-2022	#3
HAWAIIZR-1 Join Date: May 2010 Location: Japan Posts: 3,538	Reluctantly joining the catch can club Thanks for sharing. Very nice and clean install. I bought a catch can years ago and it?s still in my closet waiting install. I had good results with one I installed on my 90Z. It?s amazing how much oil it caught. I hope you find it worthwhile and can?t wait to hear your thoughts. Sent from my iPhone using ZR-1 Net Registry __________________ Craig "ZR-1 NO KA 'OI" "ZR-1 ICHIBAN" 1995 #228 Black/Black with Dunn Heads ZR-1 owner since September 2003 ZR-1 Net Registry Founding Member #0074 NCM Lifetime Member #2048

10-08-2022	#4
dredgeguy Join Date: Aug 2012 Location: Ellicott City, MD Posts: 1,627	Re: Reluctantly joining the catch can club Been thinking of this mod for a while and looking forward to hearing your results. __________________ Charlie __________ Dredgeguy WAZOO Member 1992 Bright Red/Black ZR1 #246 Dana 4:10 gears Polished LT5 by Haibeck Polished Fikse FM5's with Michelin Pilot Sport 2 Stainless Works headers and cats with Corsa

10-08-2022	#5
DRM500RUBYZR-1 Join Date: Sep 2008 Location: Mullica Hill, New Jersey Posts: 2,566	Re: Reluctantly joining the catch can club Nicely done! Factory looking. Keep us posted on effect. Thanks! Marty

10-17-2022	#8
W i l l Join Date: Jul 2005 Posts: 77	Re: Reluctantly joining the catch can club I've got catch cans on one of my cars, but a racer told me I should go back to PCV to get the vacuum on the inside of the motor and avoid the pressure buildup that will cause gaskets to leak, etc. I told him I didn't want to be burning oil back through the intake but he said in a street-driven car the horsepower loss is very minimal. My catch cans were installed by Lingenfelter and have the brillo pads vents. Are the catch cans you guys are using sealed? Probably not if they have a dipstick. But why not get a baffled and sealed catch can and put the catch can downstream of the PCV valves and get the best of both worlds?

01-16-2023	#10
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 869	Re: Reluctantly joining the catch can club 01B00B52-011B-49B6-94B8-0018520A951F.jpg B9C0A583-110C-403C-885A-843111C7DB70.jpg D8DFA2C9-3B7E-41BF-AC80-60331681E8B9.jpg I joined the Catch Can Club to eliminate oil in plenum and octane reducing oil vapor. I experience pinging only when hot on the track and the can should fix that. I purchased one with a valve on the bottom to drain it. I made a bracket to attach it to the nut on the brake booster. The nipple under the plenum is 3/8 and I inserted a 3/8 hose barb in the pcv collector at rear of plenum. Easy. __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.