I have a boosted b20. I can go down the road and let off the gas pedal then press the pedal to accelerate an my car will smoke only in gear.. I can be rolling down the road in neutral an press the gas pedal an dnt get any smoke.. I let it set over nite an went out to start it an car did not smoke @ start up. any suggestions????? Thanks...

 

My bet is worn valve seals, seems to usually be the case when you have smoke on deceleration.

 

I thought that to but wouldnt it do it when i let it set over night an start it in the morning?

 

I had a similar smoking problem. Turned out to be the oil rings not working properly. Made power just fine and had good compression + leakdown numbers but still burned oil like crazy. I don't think the decelerating in gear and then giving it gas can really distinguish between valve seals and rings....I am speaking from personal experience. A good hint as to whether it is rings or seals is by the amount of oil being burned ie. miles/qt. If it is pretty significant it is probably rings.

 

I duno what it is i was thinking if it was rings it would smoke more then it does... I really wana find this out,,, Any help is better then none... Thanks...

 

how much oil are you burning? miles/qt?

 

when you let off the gas the motor builds a vacuum and suck the oil past the valve seals when worn....next time you do a oil change before you drain it let the motor cool off pull the plugs and spray a **** load of pb blaster down on the tops of the pistons...I have been lucky several times to losen up bound up rings and have had motors restore their compression and non-oil burning habits...just a tip from a old timer...

 

Just got car runin havent drove it enough to tell really how much oil i have burned.. I will deff try the pb blaster... Thanks for all the help and pointers keepem coming... thanks.....

 

ok i have searched all i can and people with my same problem have got anser as of bad valve guide seals and seals in the turbo.. Whats the best way to eleminate the two of these to find this problem.. How do i check these problems To find the source.... Thanks..

 

Stem seals are dirty cheap. You can get a whole set of Vitons off ebay for $18 shipped... and yes, they are good quality seals also. I just changed mine since I was having the same issues as you. I can't SEE the smoke, but people behind me can. I was seeing a pretty good drop on the dipstick with minimal mileage. I don't think the stem seals solved the problem, but I will be monitoring it over the next few days. My engine is realatively new also... I might try thicker oil. What weight oil you using? I've got 5w-30 in there now.

 

A good way to eliminate the turbo seals as being the problem is to put a NA header on the motor. This is what I did and the oil burn did not stop so I knew it had to be either valve stem seals or oil rings. I changed the valve seals first and this did not solve the problem so I rebuilt the bottom end. Information on this website and others suggest varying driving tests to determine whether it is a ring problem or a valve stem seal problem: decelerating in gear from high rpm and then accelerating etc. The argument is that this high vacuum situation pulls oil past the valve stem seals and then gets combusted when you give the motor gas. I have read others say that this test could also be pulling oil past faulty oil rings. In the end, I think the best hint is the rate of oil burn, miles/qt. If you are in the range of 1000-3000miles/qt. this leans more towards valve stem seals while less than 1000miles/qt. you might have a ring problem.

For the thicker oil comment, Car Talk has an interesting article about this on their webpage. They argue that using thicker oil can make the problem worse if the rings are to blame because a thicker oil creates a thicker film on the cylinder wall. If the oil ring is not working properly it won't scrape the whole film off. Just some food for thought. I have provided the link below:

http://www.cartalk.com/content/puzzl...29/answer.html

"RAY: Butch is twice as dense and that's why sometimes using heavier oil, although it seems intuitively like it should reduce your consumption, will in fact increase the consumption because it's leaving that thicker film on the cylinder walls, it isn't getting scraped off and then when the combustion hits that film of oil that should be in the oil pan but is not, it gets burned up and comes off the tail pipe as these pretty billowy blue clouds that, it's so lovely."

I think a big part of why newly built motors start to burn oil is that they are not broken in properly. I don't believe my motor was broken in properly the first time by the original engine builder and that is why I had to put new rings in. I follow this break-in procedure on my new build and my motor doesn't burn a drop now:

http://www.mototuneusa.com/break_in_secrets.htm

Essentially just put the motor under significant load in the first few miles to seat the rings and use some 30 weight non-detergent oil for the first 100 miles.

 

I am runniing 5w30... Thanks for all the help guys.. I will try the header thats a really good way i didnt think of that..lol... I also got a new pcv to install... I will keep you guys posted this is my dd thats what sucks.. If any thing else is thought of please feel free to speak it i wana hear what everyone has to say this is the first time going thru this... Once agin thanks for all the info you guys have provided....

 

Ok i did a compression test today an its consistant all the way across.. Thank god... Installing a friends turbo 2moro hopefully to get a fix...

 

Compression tests will not show the condition of the oil control rings. Keep this in mind. If your turbo was "Bad" in the way you are thinking, it would smoke all the time. Not only under decel.

 

Agree. A compression or leakdown test won't give insight into the condition of the oil control rings. Swapping out turbos with one that is known not to be leaking/burning oil is a good test.

How many miles are on the motor? Was it recently rebuilt? If so, how was it broken in?

 

True. If the turbo is bad it will smoke all the time. When my turbo blew smoke would pour out under boost, much less under decel.

I've also experienced bad oil rings. I thought it was valve stem seals, so I replaced them and it turned out to be oil rings. If it's seals, generally the car will smoke more when cool and go away when its warm. My motor showed good compression and it was rings...

 

ok turns out my turbo seems to be ok.. The warmer it gets the more it smokes.. I just dnt get it.. I would think if it was oil rings it would do it all the time... like when i get on it....

 

What size is your return line? I have the same problem and I think it is because my return line is way to small and oil is backing up.. I don't know it may be it or it may not be I am going to look into it further though..

 

Again, this problem wouldn't replicate itself in the fashion the OP describes. If the oil return line was inadequate then you would see excessive smoke under higher RPM pulls, when oil pressure/volume is greatest. His issues arrises when manifold vac is at a high level. The oil is being pulled past something. I would honestly look into the PCV system or the stem seals.

Like I said, stem seals are REAL cheap and can be changed with the head still on the car. I just did mine on my Y8 in about 1 hour start to finish and that was taking my time. For $18, you can't go wrong.

 

Pull the charge pipe off turbo and see if there is any oil in it. If so then you have bad seals in turbo.

 

The valve stem seals are inexpensive but I seriously doubt it will take 1 hour even if you have done it before. It is all the work of changing the timing belt and then some because you have to take the cam(s) out, pressurize the cylinders, remove the valve springs, pull the old seals, put the new seals in, and then reassemble the head/timing belt.

However, I still agree that replacing the valve stem seals after ruling out the turbo and PCV system is the route to go. I just didn't want people to think that changing the valve stem seals takes 1 hour start to finish. My first stem seal change took a full weekend.

 

Im a mechanic and I have a single cam. I think people tend to forget the simplicity of the Honda single cam engines. I am well aware of what is involved and yes, it took approx 1 hour. You can compress the springs on a single cam engine by hand. Remember, no dual springs here.

 

That's all fine and dandy but if you are really trying to help the guy who started this thread you should have considered that he is not working on a single cam motor and he is probably not a professional mechanic like you. You should gauge your comments to your audience. I was just making a comment that your labor time estimate for an amateur mechanic to replace his/her valve stem seals on a b20 motor for the first time seemed low. I did not want the author of the thread to get the impression that replacing his valve stem seals is going to be as easy as changing his oil or spark plugs.

At any rate, valve stem seals could be the problem but I still think the biggest clue the author has yet to provide is how much oil (miles/qt) the motor is burning. There is only so much oil burn that can come about from old valve stem seals and/or worn guides.

 

I have never heard of the pb blaster trick but sounds promising. But one thing I use to do go to autozone and buy a can of Engine restore. Be sure you get the 4 cylinder can.

 

I agree... valve stem seals are a pain in the ***. I went there first and was wrong. I wish I didnt waste my time and money. Like the guy above said, have you pulled the charge pipe off turbo yet? That's an easy way to check the seals in the turbo.