Blue smoke with engine braking - ZR-1 Net Registry Forums

Dime · 07-20-2015

Took the car out yesterday for the first time in a few months.
I usually start it up every other weekend regardless of whether or not I drive it, and I let it get up to operating temperature. This was the first time I'm driven it really hard this year more than likely.

Everything was fine, and there was nothing worth mentioning or noticing. Maybe a very slight miss that I'll look into. Plenty of oil. The top of the oil met the top of the fill line on the dipstick. Basically as full as can be. The car had been sitting two weeks, so everything that could drain back had.

I ran the car up to 5,500 to 6,000 a handful of times in third, got off it, and stayed in third. Car seemed fine and dandy. Looked back behind me and saw a trail of what looked like blue smoke. Nothing crazy, but you could definitely see it. I did it a few times more, and seemed to have dissipated, but maybe still a little smoke here and there.

The oil temp gauge also went higher than I've seen it before. Again, nothing crazy. I'd say about half way between the end of the second 0 of the "100" and half way up the gauge. It went back down below where it normal sits after she's warmed up completely after cruising for a bit. I was trashing on her harder than I usually do though.

Just porting, flywheel, headers, and exhaust as far as power goes. And, NO cats.

Caused by sitting, started and idled, and not being run hard for several months? The fact that she was as full of oil as she could be?

Thanks in advance

Fully Vetted · 07-20-2015

Anytime I fill mine to the top it smokes on decel. There's just to much frothing going on at high engine speeds and these LT5's create so much vacuum it just sucks it right into the plenum. I always run mine at the lower end of the safe zone. I can make it smoke a little if I want to but it has to be at pretty high rpm's on decel to do it.

RussMcB · 07-20-2015

Bobby, I've seen several folks have installed aftermarket catch cans, I believe to address this inherent issue with the LT-5 engine. A search here will give you more details.

Fully Vetted · 07-20-2015

UPDATE: I do have a catch can, BTW. I empty it every couple thousand miles.

07-20-2015	#1
Dime Join Date: Feb 2011 Location: Vicksburg, MS Posts: 135	Blue smoke with engine braking Took the car out yesterday for the first time in a few months. I usually start it up every other weekend regardless of whether or not I drive it, and I let it get up to operating temperature. This was the first time I'm driven it really hard this year more than likely. Everything was fine, and there was nothing worth mentioning or noticing. Maybe a very slight miss that I'll look into. Plenty of oil. The top of the oil met the top of the fill line on the dipstick. Basically as full as can be. The car had been sitting two weeks, so everything that could drain back had. I ran the car up to 5,500 to 6,000 a handful of times in third, got off it, and stayed in third. Car seemed fine and dandy. Looked back behind me and saw a trail of what looked like blue smoke. Nothing crazy, but you could definitely see it. I did it a few times more, and seemed to have dissipated, but maybe still a little smoke here and there. The oil temp gauge also went higher than I've seen it before. Again, nothing crazy. I'd say about half way between the end of the second 0 of the "100" and half way up the gauge. It went back down below where it normal sits after she's warmed up completely after cruising for a bit. I was trashing on her harder than I usually do though. Just porting, flywheel, headers, and exhaust as far as power goes. And, NO cats. Caused by sitting, started and idled, and not being run hard for several months? The fact that she was as full of oil as she could be? Thanks in advance __________________ [B][U]1991 No. 519[/U][/B]

07-20-2015	#2
Fully Vetted Join Date: Sep 2012 Location: Rockwall, Tx Posts: 1,510	Re: Blue smoke with engine braking Anytime I fill mine to the top it smokes on decel. There's just to much frothing going on at high engine speeds and these LT5's create so much vacuum it just sucks it right into the plenum. I always run mine at the lower end of the safe zone. I can make it smoke a little if I want to but it has to be at pretty high rpm's on decel to do it. __________________ _________________ 1994 AB/Grey #141 430 RWHP/392 RWTQ FBI Lyposuction / Secondaries relieved of duty / SW Long Tube Headers / Corsa Exhaust / FIC SS Injectors / MSD Coils / Lightweight Pulleys / Corey tuned B & M Shifter / Aluminum Flywheel / Samco Hoses / Shelby Series One's / C4 No Flex Frame Stiffener BBC - Bling By Carter: Custom ZR-1 Center Caps / Custom Plenum Plate / Air Box Knobs / TB Cover / Oil Filter Cover

07-20-2015	#3
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,160	Re: Blue smoke with engine braking Bobby, I've seen several folks have installed aftermarket catch cans, I believe to address this inherent issue with the LT-5 engine. A search here will give you more details.

07-20-2015	#4
Fully Vetted Join Date: Sep 2012 Location: Rockwall, Tx Posts: 1,510	Re: Blue smoke with engine braking UPDATE: I do have a catch can, BTW. I empty it every couple thousand miles. __________________ _________________ 1994 AB/Grey #141 430 RWHP/392 RWTQ FBI Lyposuction / Secondaries relieved of duty / SW Long Tube Headers / Corsa Exhaust / FIC SS Injectors / MSD Coils / Lightweight Pulleys / Corey tuned B & M Shifter / Aluminum Flywheel / Samco Hoses / Shelby Series One's / C4 No Flex Frame Stiffener BBC - Bling By Carter: Custom ZR-1 Center Caps / Custom Plenum Plate / Air Box Knobs / TB Cover / Oil Filter Cover