Thought valve seals, but now maybe turbo???

[MKIIIarpus]

So, if the car sits and you start it, it smokes a bit on startup. It's def oil, when you rev the motor puffs come out. Compression test was great, so I suspect either turbo or valve stem seals. Well I pull the IC hoses off the turbo and all looks good. I pull the o2 sensor out the back of the turbo looks ok... well I read on here, to turn on your car hold it at 2500 for a minute, turn it off and check for oil in the downpipe, well I tried this test today. I have not checked the downpipe but at 2500rpm it was steady smoking, let off goes away... get on it harder none... but I bet if I pull the backside off that turbo there is oil.... thing is, motor was done in last 6k turbo too. So do I still pull the valve seals out and replace them or do a different turbo... I don't wanna have to buy another turbo right now if I don't have too. I have a ct26 that was supposedly sent to drift motion and is 57trim. Any advice guys?

Thanks!

 

[7M-KDL]

I am having the same issue. After my motor rebuild it was smoking. I replaced the turbo because of oil in the intercooler and damaged fins. After the turbo replacement there was no change, still smoked. Sometimes it smokes a little on startup sometimes it doesnt. At any rate, I did a compression test after this as well and it came up good. That lead me to think valve seals. However, after replacing my valve seals a few weeks ago I found that it is still smoking. The next thing I am leaning towards is rings since the intercooler is "dry" and so is the exhaust. Just because the compression is good does not necessarily mean it is not your rings. Like I said, my compression was good too. The only thing that rules out is the compression ring. There are multiple rings so just because the compression ring is good doesn't mean that one of the other rings isn't causing excessive oil consumption/smoking. Try doing a leakdown test as it will provide more conclusive results when paired with the compression test.


Edit: Who did your rebuild? Also, smoking at steady/partial throttle(2-2500rpm) usually indicates a ring issue in my experience

 

[bioskyline]

the oil rings are suspose to be 180 from eachother, according to the tsrm http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=90

though some tend to put them only 45-90 degress, or really close togther, and they wont scrape the oil off the cyl wall as effecticly and it will end up being burnt.

 

[MKIIIarpus]

Every motor I've built sbc's and sbf's, haven't done any yotas yet, I've always 180's the oil rings and just about 180'd the compression rings as well. I just have hard time thinking rings if the compression is good and I'm not showing signs of oil on the plugs. I hope it's not the rings or the guides.. yeah the parts are cheaper but I don't really feel like doing either of those right now.. especially w/my bummed leg. Was hoping if anything the turbo even though it's more expensive.

 

[7M-KDL]

I think the first thing I would do would be valve seals. They are relatively cheap it just takes time to put them in. If it was your turbo you would probably have more oil on your plugs, in your intercooler, or in your exhaust. Yes turbo is easier and very well could be your problem it is just not the first place I would look. Some other members may disagree. Also, I see that you're in Youngsville. I just did my seals so I have all the tools to do it with the head on the car. If you think you might want to use/rent them from me send me a pm and we can see what we can work out. Depending on timing I may actually be able to help you do it(which would not require rental). Just let me know what you decide, good luck.

Edit: I'd also like to add that my issue is a little different than yours because I have visible oil on my plugs but changing my valve seals did help mine. It did not completely fix the smoking but I think that is because my motor has multiple issues because of the builder I used. If the seals are leaking bad enough then it will smoke other times(like yours) not just on startup. If some other users post here maybe they have some other ideas and troubleshooting tips for you.

 

[wardog]

So, if the car sits and you start it, it smokes a bit on startup. It's def oil,

Thanks!

Smoke on start up its defenetlly your valve stems. Smoke on deceleration will be your turbo seals, the rear one. Front one is good hint the intercooler pipe being oil free and the rear one is good too or else your O2 sensor would show sign of oil on it. So its your Valve Stems... Good luck and keep us updated...

 

[JStoked]

Fire the car up while at idle open your oil cap. If smoke puffs out like a train it's your rings.

 

[destrux]

A bad turbo will smoke whenever it feels like it, or not. Mine was acting all sorts of crazy, smoking sometimes, not smoking sometimes. It's very hard to say "a smoking turbo will do this" with 100% accuracy. It all depends why it's smoking. Broken seal? Excessive play? Excessive coking? Excessive seal wear? Clogged/kinked drain? Too much oil pressure? Bad nicotine addiction?

Valve seals are pretty straightforward, unless they were installed wrong or are so old they fell off the guides (and are just slamming around on the stems). Then the typical valve seal symptoms won't be accurate either.

You could also have a breather or PCV problem, try disconnecting them from the valve cover and see if it makes the smoke stop.

 

[7M-KDL]

A bad turbo will smoke whenever it feels like it, or not. Mine was acting all sorts of crazy, smoking sometimes, not smoking sometimes. It's very hard to say "a smoking turbo will do this" with 100% accuracy. It all depends why it's smoking. Broken seal? Excessive play? Excessive coking? Excessive seal wear? Clogged/kinked drain? Too much oil pressure? Bad nicotine addiction?

Valve seals are pretty straightforward, unless they were installed wrong or are so old they fell off the guides (and are just slamming around on the stems). Then the typical valve seal symptoms won't be accurate either.

You could also have a breather or PCV problem, try disconnecting them from the valve cover and see if it makes the smoke stop.

Disconnecting the pcv will not make it stop, only change the reason its smoking if anything. Without suction from either the turbo or the throttle body port it will not put "vacuum" on the crankcase and potentially cause the rings to temporarily not make a good seal and thus cause smoking for that reason. I'm pretty sure of this theory/fact. If not feel free to correct me, preferably with some good reference material

 

[jonahs_supra]

i would do as destruxand jstoked said
i have ran my mk3 with no hoses or vaccum applied to my valve cover pcv tubes for 8 months now
daily driven 80 miles a day and 5 days a week...my oil rings are still in good shape

postive crank case pressure will find a weak spot to release...
which would flow up through the oil drains on head and the big hose on drivers side of the block
only difference is the positive pressure air in the crank wont move out as fast but will still make its way out

i dont think its your turbo
if the front seal of turbo was leaking then your car would smoke mainly in boost
since your starting your car up after sitting and revving to 2500 which isnt enough to make your intercooler pressurize to push puddles out oil out
now if the rear seal is leaking...well its going to leak whenever it feels like it and mainly leak when its hot or after a hard pull/ then will smoke a lot at idle

when engine was rebuilt was the head redone or valve seals replaced?

 

[7M-KDL]

i would do as destruxand jstoked said
i have ran my mk3 with no hoses or vaccum applied to my valve cover pcv tubes for 8 months now
daily driven 80 miles a day and 5 days a week...my oil rings are still in good shape

postive crank case pressure will find a weak spot to release...
which would flow up through the oil drains on head and the big hose on drivers side of the block
only difference is the positive pressure air in the crank wont move out as fast but will still make its way out

i dont think its your turbo
if the front seal of turbo was leaking then your car would smoke mainly in boost
since your starting your car up after sitting and revving to 2500 which isnt enough to make your intercooler pressurize to push puddles out oil out
now if the rear seal is leaking...well its going to leak whenever it feels like it and mainly leak when its hot or after a hard pull/ then will smoke a lot at idle

when engine was rebuilt was the head redone or valve seals replaced?

Without getting into a pissing contest I respectfully disagree. I do not know your background or knowledge but you might want to do some searching about the PCV system if you haven't already. Unless I am missing something(which is very possible) disconnecting the PCV proves nothing. Even by your logic(not just yours, others too, some even in this thread) a clogged or malfunctioning PCV will not cause excessive oil consumption(since you don't need PCV anyway right). I do think that some of the gases will escape without help but not all of them, especially if there is a ring problem or excessive blow-by. You are right about it finding the easiest path out, which is typically the dipstick if the PCV isn't functioning. If the PCV was pulling too much oil out of the crankcase, which I assume is what you are trying to rule out by disconnecting it, it could push it into the intercooler(possibly making it look like a turbo problem) and then into the combustion chamber, however, if this happens you likely had another issue to begin with(rings, extremely restrictive air cleaner). If the purpose of disconnecting it is to see if its blocked or clogged then I don't think that really gets you anywhere either. If it was clogged and not letting gasses out then it could/would also cause the dipstick to blow out. As I stated before, this is merely the way I see and process it, if I am wrong please direct me to the correct information so that I know for future reference. I think that is all for now, hopefully I was able to explain my reasoning sufficiently.

 

[jonahs_supra]

If the PCV was pulling too much oil out of the crankcase, which I assume is what you are trying to rule out by disconnecting it, it could push it into the intercooler(possibly making it look like a turbo problem) and then into the combustion chamber, however, if this happens you likely had another issue to begin with(rings, extremely restrictive air cleaner).

my back ground is with diesel engines(mainly cummins ism and isx)
wasnt trying to rule out a clogged pcv system
i was trying to see if there is a problem with blowby(in which you stated and jstoked stated)
pcv is there to help crank case pressure and gases release(we both a agree here correct? lol)and help draw in fresh air
if he's having a problem with blowby(excessive oily gases being released into pcv system) then going through intake...then removing pcv hoses and a test drive will tell him if he has a problem with blowby(agree?)

from my experience with my mk3...not having pcv hoses connected has not once given me a problem(inwhich you stated could possibly make problems for the oil rings temporarily not seating)

no need for a pissing match lol
just stating my opinion just as you did
everybody has different logic and ways of performing diagnosis

 

[7M-KDL]

Yes, we do agree on a few of those things lol. I'm still not quite understanding, I must be over thinking but wouldn't removing the PCV only exaggerate the blowby? Obviously some blowby is acceptable and perhaps with the way your motor is setup it can handle being disconnected and still be at an acceptable level? Also, if excessive gasses were/are being taken into the PCV then the oil would deposit in the intercooler which would say turbo or PCV(blowby) problem. I guess for me, the only advantage to the PCV disconnect would be to distinguish between turbo seal depositing oil in the intercooler vs PCV(blowby) depositing the oil. However, I didn't see that he said he had oil in the intercooler piping. If he doesn't then that rules out PCV sucking out too much oil without the need to disconnect it, right?(unless he has a catch can full of oil instead of his intercooler lol). It certainly appears that your experience with the PCV has been entirely different than mine. My experience with the MKIII PCV did give me problems but I don't know. I guess the bottom line is the OP needs to do some tests, I personally recommend, more or less in this order, oil cap trick, compression test, leakdown test....then PCV disconnect?

PS, sorry my posts are so long I just want to make sure I get my thoughts explained.

 

[gsxr141]

soooo. my mk3 smokes after i decel with it in gear. if i take it out of gear while i come to a light, no smoke. i was told it was either valve seals or rings.
also, it got worse after i did an oil change the other day.
any ideas?

 

[7M-KDL]

soooo. my mk3 smokes after i decel with it in gear. if i take it out of gear while i come to a light, no smoke. i was told it was either valve seals or rings.
also, it got worse after i did an oil change the other day.
any ideas?

I'd point at valve seals for you

Although, it could be a combination of any number of things but since it occurs at high vacuum....

 

[gsxr141]

that's what i thought. i just need it to last for a couple months, till winter. i have a spare motor, but i want to wait till i can build it right.

 

[jonahs_supra]

Also, if excessive gasses were/are being taken into the PCV then the oil would deposit in the intercooler which would say turbo or PCV(blowby) problem.QUOTE]

he didnt state which piping he pulled off from intercooler piping
didnt say if there was a small film of oil inside of piping or not...
for me i always pull the lowest piping off(where its most likely to puddle up)

this is what im trying to prove for OP...
if there is a blowby problem(from what i read with above post you understand as well but to a different extent lol)

 

[7M-KDL]

Also, if excessive gasses were/are being taken into the PCV then the oil would deposit in the intercooler which would say turbo or PCV(blowby) problem.QUOTE]

he didnt state which piping he pulled off from intercooler piping
didnt say if there was a small film of oil inside of piping or not...
for me i always pull the lowest piping off(where its most likely to puddle up)

this is what im trying to prove for OP...
if there is a blowby problem(from what i read with above post you understand as well but to a different extent lol)

I gotcha. Yeh, I guess I just assume that you(the general public) would pull the lowest pipe when looking for oil pooling. It doesn't do you any good to pull the upper one, it will always have oil film on it(unless your PCV is disconnected lol). Before I replaced my turbo I pulled the lower intercooler pipe off and had .75 qt of oil come running out.

 

[jonahs_supra]

thats a lot of oil lol

ATTENTION OP I WOULD NOT RECOMMEND LEAVING PCV HOSES OFF(even though im doing it lol)
leaving them off will cause oil coking etc...

 

[7M-KDL]

thats a lot of oil lol

ATTENTION OP I WOULD NOT RECOMMEND LEAVING PCV HOSES OFF(even though im doing it lol)
leaving them off will cause oil coking etc...

Oh, one other thing i meant to mention, I know you are running without your PCV which is probably working because you (must) have a fairly healthy motor that doesn't have issues and can handle it. This may be why mine couldn't handle being disconnected. I think that being re-routed helps but it is also done partially to help the environment. Thanks for the banter? debate? conversation lol. Hopefully the OP has read some of the stuff not just posted a new thread and not been back to it since haha.