It's burning oil, let's make the best of it.
 

I've isolated my oil burning to cylinder 4. My plug in that cylinder fouls weekly. I changed over to 10w-40 oil and that cut oil consumption and start-up smoke to less than a quart a month which is better than the quart a week i was getting from 5w-30. Because heavy weight oil stops the burning, it's only in one cylinder, and the car hasn't lost any power. I'm assuming it's the valve seal, although if it could be something else please tell me other possibilities. If no one can say against the valve seals I was planning to redo them with a maximum $800 budget to make the most of going into the valve covers and doing it the rope trick way. I was planning on buying the supertech valve seals, new valve cover gaskets, and the motordyne 5/6 copper isothermal plenum spacer since I have to remove the plenum anyway. If changing out the valve seals sounds good does anyone know of any other good mods or things to replace while I'm in there? Thank you for any input

I'd buy a low mileage used engine and do a swap. Swapping an engine is a lot easier than a rebuild.

Valve seals with the heads on only takes about six hours and costs at minimum $100. An engine swap would take quite a bit longer especially for me, and the best deals I've been able to find were about $1000 for a 60k engine. I only have 150k on an engine that has lasted alot longer, until I get enough money to swap for a fully built vq, I'm not really wanting to f**k around replacing stock parts with stock parts. It may well come to a full out swap being needed but like I said all I have is about $800

How many miles is "less than a quart a month?"

I'd leak down test it before anything

About 750

so you're still buring a qrt every 1000k, or sonner? yeaa, do a leak down. what motor do you have?

Going to do one soon. I have the vq35de

Based on what youve described you dont really have that big of an issue. Personally I would just run it till it dies or starts burning a lot of oil again. You said the motor has 150k?

Thats what I was going to do, but now that Im swapping new spark plugs into cylinder four every week after driving maybe 200 miles tops its becoming a massive nuisance.

Hrm, well as said do at leakdown at least to try and isolate.

Could just be the spark plug seal. I guess you will find out. Sounds feasible but I don't recall anyone posting up that they have done it... The leakdown will let you know if it's the cylinder ring vs valve seal, but u could just do a compression test and if that checks out then go on ahead.

Well the plug wouldn't be fouled on the inside would it?

+1 on figuring out if it's rings or valves.

Compression test won't tell you much. I had similar issues. Only even bigger oil consumption. Compression test was ok, but leakdown test wasn't. Piston looked like this after disassemble. So I wouldn't count on compression test results.


https://cimg2.ibsrv.net/gimg/my350z....a5cf6b1477.jpg

bump for the thread, what happened in the end?

With a piston like that it should show in a comp test, and in an oil test.

Black stone lab oil tests are cheap and they should pick up if things are getting burnt up.

Also I think every DIY car owner can afford a cheap usb borescope. They're pretty low resolution, but for $20 you would see that without a tear down.

Just food for thought for anyone else that might be in that situation. Save yourself the hassle of a teardown.