Burning oil only on De-acceleration? Help!

LSVTEC 91 Civic · May 22, 2005

Curious, my car burns oil (I can see the blue smoke/smell the burnt oil) ONLY when I de-accelerate after a high RPM (8kRPMs) 3rd/4th gear pull. What usually causes this? It doesn't smoke @ WOT, only when I let off the pedal.

PCV valve is new, cylinder compression is a good 270psi in all 4.

Any suggestions?

I'm running GC

Alan · May 22, 2005

I belive if it's during de-acceleration it's the valve seals that are leaky.

Blokey · May 22, 2005

Definitely valve seals. Under deceleration, the engine pulls a lot of vacuum, the oil gets pulled past valve seals that are worn.

dickwells · May 22, 2005

According to my rough calculations your compression ratio is something over 18 to 1 so some problems might be expected

You may have a little carbon build up in the combustion chambers.

JHZR2 · May 22, 2005

at 8k rpm there is a lot of vacuum. it sucks the oil through.

Hows your cat? Are you racing the car, or what is your reason for pulling 8k rpm?

JMH

Gary Allan · May 22, 2005

Yeah, avoid engine braking after you wind it up. I have a feeling you won't see nearly as much smoke. You don't happen to get a little pinging immediately after this, do you? Your oil level is not anything over full is it?

I think that you're sucking it past the rings during high vac situation. This doesn't require that the ring have anything wrong with them ...just too much oil flying around in the presence of too much vacuum.

[ May 23, 2005, 08:51 AM: Message edited by: Gary Allan ]

LSVTEC 91 Civic · May 23, 2005

Valve seals have about 4k miles on them... head was rebuilt not too long ago.

Compression is around 12.4:1, tuned on 93 octane with stock timing... What would carbon buildup have to do with smoking? Should I seafoam?

There is no cat on the car. No pinging, oil is always at the full mark.

Would an oil catch can help me out any? I rev to 8k because thats where I stop making power.

Edit: I'm also getting around 100-110psi oil pressure at WOT past 6-7k

LSVTEC 91 Civic · May 23, 2005

**** , I can no longer edit my above post.

Would M1 0w-40 help out as well?

LSVTEC 91 Civic · May 23, 2005

Wow, I really wish I could edit my posts.. I hate making 3 posts in a row.

Anyway,

Bump for another idea.

I have a hose running from my valve cover to my intake... should I remove this and replace it with a valve cover breather?

Gary Allan · May 23, 2005

Hmm ....(pondering the different little things going through my mind here ...first thi--- nah ..well, tha--- ..nope ..hmmm)

You want to stop this from happening? Stop winding it out to 8k and then letting off the gas.

..but since that ain't gonna happen...

I think you're gonna live with it. You can stop it from ever hitting the intake ..but you won't stop the cause of it.

Since you have no cat ..have one of these

welded into your exhaust pipe. It will use the exhaust to draw a vac on your crankcase. You may still send a blue cloud out the back ..but it won't be going through your intake (if that's how it's getting into the exhaust). That's the V8 setup. Just put "evacuation system" into the Jegs search engine and you can buy one for about $13+ ..tee in the hose you attach to it to your PCV hose and life will be good. Further enhancements may be required if you end up sucking too much oil into the exhaust.

LSVTEC 91 Civic · May 23, 2005

Okay, I'll give that a shot. Still burns a little bit at WOT, but I don't really see the smoke unless I redline then let off the gas. I don't do it on purpose, but I was just curious about the blue smoke... making sure my motor is in good condition before I spray Nitrous.

I'm going to give that evac system a shot, along with a fill of M1 0w-40.

wileyE · May 23, 2005

LSVTEC 91 Civic · May 23, 2005

quote:

Originally posted by wileyE:

13.4 @ 101 , Daily driven N/A 1.8L

LSVTEC 91 Civic · May 24, 2005

quote:

Originally posted by Drew99GT:
One more thing, does it puff ANY blue smoke on cold startup in the morning? If not, then I'd say your valve seals are A-OK.

No blue smoke on startup. Valve seals are still new from the head rebuild..

Tell me what you think about this setup, I found it on Honda-Tech...

.. on this thread http://www.honda-tech.com/zerothread?id=337928

What do you think about a catch can setup like that? If that would work, I could build the setup for fairly cheap.

The excessive pressure would also explain why my seals are going to poo.

kenw · May 24, 2005

Not sure how well the baffles will catch anything other than large globules. the oil that escapes this way is pretty much vaporized anyway, baffles won't do anything. Just fill the can with a permeable / open cell foam lawn mower airfilter. And replace it when needed.

wileyE · May 24, 2005

quote:

13.4 @ 101 , Daily driven N/A 1.8L

Sounds like she runs pretty good. Sorry for the wise guy pic post.

At 8000 you may be pumping too much oil to the topend? and when you let off the pvc systems picks up some oil? I've had to resrict/redirect the flow to the topend on some motors that turn way over design rpms. Never built a honda, so just a thought.

Drew99GT · May 24, 2005

I wouldn't do the valve cover breather in a Honda cause all that does it create the world's biggest vacuum leak IF, IF you don't disable the PCV on the back side of the block. The valve cover hose is the freash air side of the PCV system. I'm thinking that with your compresion etc. and the power enhancements, that the PCV system could be the culprit. Even with a new, tight motor, your may get more overall blowby than stock simply because you have way more cylinder pressure. A closed loop catch can would be the best setup, but I see many Honda enthusiests going with the valve cover breather and taking the PCV box off the block and putting another breather in it's place while capping the nipple on the bottom of the intake manifold. By the way, that's a quick little Honda! Bet you've wiped the grin off many a Mustang owner's face

Drew99GT · May 24, 2005

One more thing, does it puff ANY blue smoke on cold startup in the morning? If not, then I'd say your valve seals are A-OK.

LSVTEC 91 Civic · May 25, 2005

quote:

Originally posted by wileyE:

quote:

13.4 @ 101 , Daily driven N/A 1.8L

Click to expand...

Sounds like she runs pretty good. Sorry for the wise guy pic post.

At 8000 you may be pumping too much oil to the topend? and when you let off the pvc systems picks up some oil? I've had to resrict/redirect the flow to the topend on some motors that turn way over design rpms. Never built a honda, so just a thought.

I'm just going to go ahead and build my own PCV system with an M1 0w-40...

Drew99GT · May 25, 2005

A setup like that drawing is perfect. Just keep the valve cover hose to your intake pipe; you could actually put another catch can there as well because excessive crankcase pressure is relieved through the fresh air side.

Burning oil only on De-acceleration? Help!

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