368 LT5 Drinking oil - ZR-1 Net Registry Forums

Mitsumark · 01-14-2014

Ahh..As if I haven't had enough problems this week with a busted pipe in my house,my wife falling,,now my Z is drinking oil..Literally..Here's what's going on.Hopefully one of you LT5 pros could shed some light on what may be happening..My car is a 91 and has a Vette Doctors built 368 with all the other goodies(headers,flywheel,gears,Marc H tune,ect)The car has also had a very recent service including coils,FIC stainless injectors,plugs,fuel filter,and Jerry's new PCV hose assembly along with new PCV valves..About 2 weeks ago I noticed a trail of Blue taillight smoke under medium/moderate acceleration..Yesterday I'm warming up the car and noticed it is smoking lightly out of the tailpipes just idling.It seems to come and go..However the car has drank 2 qrts of Mobil 1 in the last 300 miles..It is absolutely oil as the oil light came on,the smoke is clearly Blue and it stinks to high heaven.If I blip the gas quickly 3-4 times back to back the smoke becomes heavier and heavier until I stop..I haven't checked compression but I am suspecting a burnt exhaust valve..It idles a bit rough, although it always did..If I hammer it in any gear it doesn't miss a beat.It pulls very strong..There are no CEL light on and the secondaries seem to be working fine..The car also starts without smoke cold..This progresses as it gets hot.So far I've checked for vac leaks and found nothing..I also double checked the PCV valves and there is plenty of suction present while idling.I removed the oil cap and oil dipstick to see if there was any blowby present and there was non that I can see..There are also no external oil leaks as I've checked thourally..This is definitely tailpipe smoke..So what I have is an LT5 with a working PCV system and it's dumping oil into the combustion chamber..Is there any specific entry points I can check before I start suspecting valves or rings?I did drive through a few heavy misfires a few weeks ago when it had a suspect bad coil..Maybe I hurt it then?Help me guys..

Kevin · 01-14-2014

the fact that it's a vette docs car makes me think you're in for a rebuild.

Mitsumark · 01-14-2014

Thats encouraging lol..I forgot to mention it has new 02 sensors and there is no oil visible anywhere around the header flanges..

USAZR1 · 01-14-2014

Quote:

Originally Posted by Kevin

the fact that it's a vette docs car makes me think you're in for a rebuild.

I never had any problems with my 90 that Carmen and Dennis built.

Kevin · 01-14-2014

Quote:

Originally Posted by USAZR1

I never had any problems with my 90 that Carmen and Dennis built.

I'm pretty sure Carmen and dennis didn't build your car.

USAZR1 · 01-14-2014

Quote:

Originally Posted by Kevin

I'm pretty sure Carmen and dennis didn't build your car.

Post edited by the Administrator.

Kevin · 01-14-2014

Post edited by the Forum Administrator.

Mitsumark · 01-14-2014

I wouldn't think of blaming or slamming the builder either as this car was built in 02 and has logged plenty of racetrack miles trouble free..Awhile back I was running a cooler plug that resulted in very poor gas mileage..I also had a bad coil.. I full throttled it a few times to see if I can drive it through the hiccup.Im suspecting that's when I hurt it..Probably lots of carbon buildup from idling and too cold a plug,plus the bad coil..Im not an LT5 expert by no means. Haven't even wrenched in years..I'm just thinking its valve related.As I'm typing,I'm remembering more..The car idles terrible when it's ice cold and it smells like raw fuel being dumped into the exhaust..The idle smooths out quite a bit as it warms but that's when the smoke starts..

LGAFF · 01-14-2014

Does your car have bigger cams?

Mitsumark · 01-14-2014

The original Vette Doc build sheet and receipt states "intake cams"..Don't have specifics on lift/duration but the smoke is definitely recent.

01-14-2014	#1
Mitsumark Join Date: Aug 2013 Location: NJ Posts: 117	368 LT5 Drinking oil Ahh..As if I haven't had enough problems this week with a busted pipe in my house,my wife falling,,now my Z is drinking oil..Literally..Here's what's going on.Hopefully one of you LT5 pros could shed some light on what may be happening..My car is a 91 and has a Vette Doctors built 368 with all the other goodies(headers,flywheel,gears,Marc H tune,ect)The car has also had a very recent service including coils,FIC stainless injectors,plugs,fuel filter,and Jerry's new PCV hose assembly along with new PCV valves..About 2 weeks ago I noticed a trail of Blue taillight smoke under medium/moderate acceleration..Yesterday I'm warming up the car and noticed it is smoking lightly out of the tailpipes just idling.It seems to come and go..However the car has drank 2 qrts of Mobil 1 in the last 300 miles..It is absolutely oil as the oil light came on,the smoke is clearly Blue and it stinks to high heaven.If I blip the gas quickly 3-4 times back to back the smoke becomes heavier and heavier until I stop..I haven't checked compression but I am suspecting a burnt exhaust valve..It idles a bit rough, although it always did..If I hammer it in any gear it doesn't miss a beat.It pulls very strong..There are no CEL light on and the secondaries seem to be working fine..The car also starts without smoke cold..This progresses as it gets hot.So far I've checked for vac leaks and found nothing..I also double checked the PCV valves and there is plenty of suction present while idling.I removed the oil cap and oil dipstick to see if there was any blowby present and there was non that I can see..There are also no external oil leaks as I've checked thourally..This is definitely tailpipe smoke..So what I have is an LT5 with a working PCV system and it's dumping oil into the combustion chamber..Is there any specific entry points I can check before I start suspecting valves or rings?I did drive through a few heavy misfires a few weeks ago when it had a suspect bad coil..Maybe I hurt it then?Help me guys..

01-14-2014	#2
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,633	Re: 368 LT5 Drinking oil the fact that it's a vette docs car makes me think you're in for a rebuild. __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

01-14-2014	#3
Mitsumark Join Date: Aug 2013 Location: NJ Posts: 117	Re: 368 LT5 Drinking oil Thats encouraging lol..I forgot to mention it has new 02 sensors and there is no oil visible anywhere around the header flanges..

01-14-2014	#7
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,633	Re: 368 LT5 Drinking oil Post edited by the Forum Administrator. __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B" Last edited by QB93Z; 01-15-2014 at 08:57 AM.

01-14-2014	#8
Mitsumark Join Date: Aug 2013 Location: NJ Posts: 117	Re: 368 LT5 Drinking oil I wouldn't think of blaming or slamming the builder either as this car was built in 02 and has logged plenty of racetrack miles trouble free..Awhile back I was running a cooler plug that resulted in very poor gas mileage..I also had a bad coil.. I full throttled it a few times to see if I can drive it through the hiccup.Im suspecting that's when I hurt it..Probably lots of carbon buildup from idling and too cold a plug,plus the bad coil..Im not an LT5 expert by no means. Haven't even wrenched in years..I'm just thinking its valve related.As I'm typing,I'm remembering more..The car idles terrible when it's ice cold and it smells like raw fuel being dumped into the exhaust..The idle smooths out quite a bit as it warms but that's when the smoke starts..

01-14-2014	#9
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,191	Re: 368 LT5 Drinking oil Does your car have bigger cams? __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

01-14-2014	#10
Mitsumark Join Date: Aug 2013 Location: NJ Posts: 117	Re: 368 LT5 Drinking oil The original Vette Doc build sheet and receipt states "intake cams"..Don't have specifics on lift/duration but the smoke is definitely recent.