DaveJackson

iTrader: (5)

So it looks like I have bad valve seals in one cylinder. The car is burning quite a bit of oil but the leak-down test shows that everything is within 15% so it's not like it's something catastrophic. One of the plugs was fouled with oil (on the electrode IN the combustion chamber, not from a leaking valve cover gasket). I've found this thread: https://my350z.com/forum/engine-and-...-question.html and it looks like a pretty ugly job.
To me, the leak-down test proves that it is not rings and not a burnt valve. I don't think it rules out valve guides, but it is most likely valve seals. If someone knows of a way to rule out one of these, please let me know!
So, based on the job that the other thread details, what would you do? (Refer to the poll.) Replace all 24 of the valve seals, or, just do the ones in the affected cylinder? It's not about being cheap with money on this one, it's about being cheap with time. This sounds like an extremely time consuming job and I don't really want to cook an entire weekend on it. What if I finished and found out it was valve guides after? That would suck, non?!
It's a 2003 with fewer than 60,000 miles on it, so I hardly think that the rest of the seals are "about to go." It's most likely that a couple of them failed very prematurely just due to bad luck. I don't think this is like leaving a worn out front tire on and replacing the one with the nail in it. Perhaps the lion's share of the work is removing stuff to where you can actually get at them in which case you might as well do them all.
Who thinks that this could have anything to do with test pipes that I recently tried out?
Also, if anyone like JohnWigs or others who have taken on a valve seals job (with the heads still on) can offer some more details, please do! I'm going to phone a shop to get a hilarious quote at some point, too.
Thanks for voting and for any advice!

ericjackson

iTrader: (2)

tell me this, i am having similar issues. Will this cause the car to smoke as well? if it gets bad enough

DaveJackson

iTrader: (5)

Mine is smoking quite a bit on take off after an idle (at a traffic light), so yes.

ericjackson

iTrader: (2)

what about high rpms as well?

i just spent about $800 on rebuilding an engine that i had and turns out its leaking coolant from the block deck because it is uneven from having the motor mount welded. so that was money wasted. so if this is all that was wrong with my original engine, that is going to suck...

i recently saw where this was an issue with our cars. I have never seen anyone discuss it before so i guess i just did not pay attention. I also have looked at this thread https://my350z.com/forum/maintenance...seal-time.html

I see that you say it is the valve seals where others are just talking about the the valve covers. did you try and replace the cover first or no? I have some that i can throw on the original engine with that issue, but like you, i have oil all over the spark plug on the combustion chamber side.

I hope im making sense here, because im getting slammed at work and this whole engine rebuild is killing me at night + a 7month old. hah.

basically, im asking if just the new valve covers could be my issue, or should i take the new(er) heads i have and put them on the old block that i thought was blown? the new(er) heads i have, the guy i got to do the welding told me a way i can see if the valves needed any work by filling the ports up with water or gas and look for leaks. i did that and all was good. but this was while i had them off the engine. i just hate to buy a 3rd set of head gaskets plus another set of head bolts if i replace the heads.

thanks for your help

ericjackson

iTrader: (2)

so i saw your other post in that seal time thread. i guess i should just put my heads on the old block.. that sucks i just spent ~$180 to have the gaskets and bolts overnighted. now i cant re-use them

konrad

iTrader: (15)

If its valve seals you would get lots of smoke when the car is cold and no smoke or less smoke when engine is hot. I had to replace 2 seals and its quite a job. Cams have to come out which means front timing cover and timing chain has to come out. Most shops take the head off to remove the valve spring. What I did was I got the JWT valve spring compressor . Pushed a nylon rope into the cylinder through the spark plug hole. Than rotate crank to tdc of that cylinder which caused the nylon rope to press and hold the valve in place. That's the best way to swap out springs or do valve seal swap without taking the heads off the car .

DaveJackson

iTrader: (5)

Well, mine is smoking when hot in two main instances.
1) After a long idle.
2) After a deceleration (using tranny, not brakes, to slow down).

If that somehow indicates that it's valve guides, someone tell me!

10-E-C-350Z

iTrader: (9)

most of you guys sound like you need valve guide seals. I had the same exact symptoms ar most of you, but unlike Konrad stated, mine smoked when hot too. I used the nylon rop trick as well, which was awesome because I was in no rush to get this done and could stop whenever I wanted. I wouldn't just replace the affected cylinders seals. IMO it's like brakes or plugs, just do them all and get it over with. Once you get the block broken down to do one cylinder, you will have access to do that whole bank. Then the only thing needed to get the other bank done is pull the cams. It's actually pretty simple looking back on it, just stay organized. Make sure you do a leakdown test before staring this project as you would probably become suicidal or spouse beater if you went through all of this and realized your rings are shot instead. Also, I have the JWT spring compressor as well. When I am home next month, if anyone needs it I will happily make a classified ad on here and sell it.

ericjackson

iTrader: (2)

Will the leakdown test not be affected by the valve seals at all?

10-E-C-350Z

iTrader: (9)

To my knowledge, no. It checks the seal between your piston rings and valve seats. The valve guide seals do not have anything to do with compression since they are out of the combustion chamber. They just keep oil from running down the stems and into the cylinders.

ericjackson

iTrader: (2)

thanks. i bought a leakdown tester yesterday.

10-E-C-350Z

iTrader: (9)

Not a problem. If there's anything else I can help with, let me know. If you need the tool I can help there as well.

ericjackson

iTrader: (2)

thanks. i dont know if it would be better or cheaper to replace the heads with some i have from another engine, or replace all the valve seals.

DaveJackson

iTrader: (5)

Yeah, my leak-down test is done and it's fine. I should have worded the poll differently since you have to remove a cam. I'm pretty sure I won't just do the one cylinder, but just doing one bank seems tempting, particularly if I don't even have to remove the valve cover on the other side...
Sorry I haven't read enough about the procedure, yet, or got a quote from a shop but I'm away right now.

10-E-C-350Z

iTrader: (9)

Life will be a lot easier if you do both banks. This engine has 3 timing chains, one for each set of cams and the main connecting them all. If I'm not mistaken (I don't have my car right in front of me) You need to pop both valve covers just to get to the chain, so you might as well just knock them all out. doing one extra bank will be the least of your worries throughout this process.




besides, right now it's 6-0 on doing the whole thing.

ericjackson

iTrader: (2)

would you just replace heads from another engine or replace the current seals?

10-E-C-350Z

iTrader: (9)

current seals. once you get to them they are super easy to replace. just twist/tug them off with a pair of pliers being careful not to nick the top of the valve stem, and gently tap the new ones in with an appropriate sized socket. You will feel when they bottom out and are set.

DaveJackson

iTrader: (5)

No. The ides is that you can replace these and leave the heads on. If it was a car that the heads were less of a hassle to remove, I'd look at swapping heads.

ericjackson

iTrader: (2)

well i tested today and my leakdown test was about 10-11psi which i read is decent. my crank case is open so i hear the air coming from there. im guessing that is normal as long as the leakdown test is in range?

thanks for all your help too. never meant to hijack the thread.

DaveJackson

iTrader: (5)

Yep. I think 11psi is great IF you did the test at 100psi.