Burning oil like it's a tank of gas
 

So my car has been taking oil for quite some time now, but lately it's really eatin it up. I'm pretty certain it's my rings, but I didn't do a comp / leakdown test yet. Today I went up a pretty big hill, and then when I came down, I was off the gas, and my car was pulling like 24-26inHG vacuum. I arrived near the bottom of the hill and pressed the gas a little bit, and looked in the rear view mirror to see a HUGE cloud of white and blue smoke. I got home and parked it. A few minutes later I started it up to take it out for a beat, and it ran really lean. I drove it pretty hard for about a mile and then it seemed to run fine. Could it be possible that this this burns so much oil than it F's with the O2 sensor? I got in boost for like 1/4 mile and it seems to blow it out. It burns about 1 quart every 700 miles! It's awesome! (I am using Castrol GTX 10W-40)

yeah you'll toast your O2 sensor(s) with oil like that.

PCV? My car drank oil before my turbo install. Now its got the 323gtx pcv and isn't burning shit for oil so far (knock on wood).

How does that vacuum measurement translate to kpa? I get like 17kpa vacuum (3k mile engine). If you're burning oil in vacuum, its likely valve stem seals.

Similar to what's happening to me, except i'm at 1qt. every 100 miles.
If it's not your rings it is going to be your valve guides.

Artie? Shouldn't you be chiming in?

I burn lots of oil too. =( I think I'm just about at what you are. 1 quart every 700 miles. I think I'm gonna drive the car to work tomorrow, then come home and check my plugs. I was working on a Toyota today and it was smoking like crazy. It actually turned out that one of the injectors was stuck open. I was running my 550's over 90% DC before so I'm thinking this might be the case with mine too. I run stupid rich while idle (12s, but mostly 13s now). And the damm car backfires quite often too. I mainly notice it after I start moving from a light and I shift. After the shift I get a backfire ( no load). Also, I notice that my AFR's spike rich every time I let off the gas ( in gear or out).

/ thread hijack.

so stuck injector = use of oil?

I tested my PCV and it seems fine, especially since it's brand new. I should run the 323GTX one though instead of the stock 99 one. I have a compression tester and I pulled my plugs out when I got home this morning. Once the wife gets home, I'll have her turn the key while I check the gauge. Should have my answer around 4PM.

you cant turn the key, wait a few seconds then get out and check the gauge?

Yeah, I guess it would work that way, but she likes to get involved. Plus I don't feel like getting in and out of the car that many times. Ok, I'll admit it...I am a lazy POS.

i hear you... :giggle:

Napa sells a tool w/ two aligator clips and a push button.

One clip to the starter solenoid, one clip to negative terminal on battery, hold button and engine cranks.

I can't think of what it's called but it's like $15 and routinely saves me tons of time/energy/needing someone else.

IDK about my miata because it doesn't run.... haha but my Saturn gulps up 2 quarts every 300 miles. Gotta love pistons w/ no oil relief holes. OEM FTW.

- Harbor Freight Tools - Quality Tools at the Lowest Prices

http://www.harborfreight.com/cpi/pho...5499/35448.gif

I just bought my compression tester at Garbage Freight. So today I did the test. My Haynes Manual says on a 1.8 liter, standard compression is 182psi. Minimum is 128psi. I tested each cylinder twice, turning the engine over for about 7 compression strokes, and this is what I got.
Cylinder 1: 170psi
Cylinder 2: 160psi
Cylinder 3: 170psi
Cylinder 4: 150psi

I didn't squirt oil in the cylinders and compression test it that way yet, should I? What do you guys think about those numbers/

You are getting close to the differential limit between cylinders, 28psi. you are at 20.


Did you warm up the engine first?
Did you pull all the plugs in the beginning before starting test?
Did you hold the throttle open?
Did you disconnect the CAS(so you don't get fuel/spark)?


I think your numbers are a little low for a 9.5:1 99 motor. My numbers were ~195 on both my 99 engines. That 182psi sounds like a 94 8.8:1 motor.

Yeah, my '00 motor had ~205-210 on all cylinders when I checked it.

The engine wasn't warm when I tested it. I forgot to hold the throttle open. I did disconnect the CAS though, and all the plugs were out when I did the test. I guess I'll warm it up first, and hold the throttle open while testing. I'll get back to you guys in a day or so.

So I re-did it. I took the car to get inspected, went to the store, then came home. I pulled it in the garage and popped the CAS plug, the injector fuse, and the plugs. Then I retested the compression in each cylinder twice, while holding the throttle flat to the floor, and listening for at least 7 compression strokes. Here's what I ended up with.
Cylinder 1: 160psi
Cylinder 2: 140psi
Cylinder 3: 160psi
Cylinder 4: 175psi

Paul, the part where you said "That 182psi sounds like a 94 8.8:1 motor." I got those numbers from my Haynes manual which is for a 90-97 miata, that's probably why it's so low. So I should actually have 195psi? If that's the case, it looks like I need rings. What are my options? Bored it out +1mm and put turbo pistons in it? Hone it and re-ring it? I don't know what to do. I need to buy someones shortblock assembly so I can have something to build on to swap in. It's nice weather now, so I need as little downtime as possible and of course for the cheapest amount of cash from my wallet.

now do it wet with a tsp of oil on each....

depending on the results after the tsp of oil you may need the bottom end or head refurbed.

the way i roll is just to throw a low mileage stock bottom back in. I'm ain't baller like Artie.

The difference between 2 and 4 is 35? Yeah, rebuild time.
Decide whether you are Arite or Paul! lol

For least ammount of downtime, get used low mileage 99/00 motor and swap, then sell of your motor to make some money back, and give your current 99/00 head to me for free for helping you out :eek:

Ok, here it is for the last time. I got home from work this morning, started the car up and left it idle for 10 minutes. Then I pulled the plugs and did the compression test:
Cyl 1: 160
Cyl 2: 140
Cyl 3: 160
Cyl 4: 160

Then I added 3 pumps of 10w30 from my little oil squirter can, and did the test again.
Cyl 1: 175
Cyl 2: 140
Cyl 3: 170
Cyl 4: 180

What is it guys? Am I ripping the head off, changing valve seals, or just pulling the whole damn engine out?

its not your rings.

For real? It's funny...cause all my motor head friends told me the same thing, they all said valve seals or guides. It just doesn't seem right how low my numbers are, when paul gets 195 and that other guy was at like 205, and I'm like 160's. So you think it's in the head? I noticed, if I drive the car nice and stay out of boost as much as possible, it doesn't take near as much oil. When i boost it a lot, it does. As I mentioned before, I tested my PCV and it tests good. I could have f'd up turbo seals due to too small of a drain line diameter. I asked my uncle when I first bought the car, why it takes 1/2 a quart between oil changes. He said that when an engine is manufactured, the tooling wears out just like anything else. Depending on how many times on that particular set of tooling, the tolerances will differ between blocks, thus meaning slight oil consumption pretty much straight from the factory.

If you really want to know for sure where you're compression is going, do a cylinder leakage test. They're a PITA, but it'll tell you what you need to know. You've got a compressor, right?
--Alex

If you have the means to do a leakdown test, you would have more of an idea of what exactly is the problem when you go to pull the motor apart.

Edit: Too slow

the wet test is to better seal the rings. Since #2 didn't increase pressure, the loss of compression is through the head.


CAS disconnected, throttle wide open, crank until no more compression can be made.


what you need now is a leakdown test to confirm it's the valve seals.

That's how I did it (CAS disconnected, throttle wide open, crank until no more compression can be made.)

So someone is going to flame me for asking before searching, but how do I perform a leak down test? I have a tool that I used to use on prior applications... It's an air chuck with a spark plug thread on the end of a pipe nipple, I used it to hold valves open when changing springs. Do I use this for a leak down test?

The leakage tester is a bit different. You have regulator gauge and a "pressure loss" gauge. Setup is the same, cylinder at TDC and fit the rig in the plug hole. Apply pressure and it tells you how much is leaking. But if you have the spring change setup, you could use that. You don't *really* need to know how much is leaking, just where it's going. Once the cylinder is pressurized, you listen for the air leaks in various places. i.e. leakage in the radiator = head gasket. From the TB = leaking intake valves, from the exhaust = leaking exhaust valve, and from the crank case = rings.
--Alex

So last night at work I brought an old spark plug in. I broke the porcelin out of it and welded a 1/4NPT piece of pipe to it. When I came home I threaded the pipe nipple end to a regulator with an air fitting on it. I took all my plugs out. I took my intercooler pipe off my throtte body, my oil dipstick out, my breather line off, and my PCV valve off. I started with cylinder 1. I took a metal rod and put it down the plug hole and then I turned the balancer until the rod was up all the way (piston at TDC.) Then I screwed the shady tree mechanic leakdown tester in there. I ran about 100psi to it? I did all 4 cylinders the same way, (piston at TDC.) There was absolutely no leakage at the oil dipstick, breather, or PCV. If I went to the back of the car, air would blow out the exhaust, and I had my throttle body blocked open, and air came out of that. So those of you who said "it's not your rings" you were right, looks like I'm ripping the head off. I might hold off a while yet, cause if I take it off, with my busy schedule I might not have it back on by the DE Dyno Party.

Valve guides!
Miatas valve seals are stout, I doubt this is your problem, but may as well change them out if you refresh your head. Why not?

I decided what I'm going to do, but like I said, I am probably going to hold off until after the NE Dyno Meet. I'm gonna pull the engine out, bolt it to my stand, and then rip the head off. Get new guides (hopefully the valves are ok), new seals, and get a new clutch (I still have the stock one in there). I'm gonna say, after the dyno meet, it's engine removal time. I gotta have the car back on the road a.s.a.p. So if there's anybody who's interested in a saturday afternoon engine pull in May, maybe this should be planned and we'll make a party out of it...I'll buy the beer.
Does anyone know the average cost of having a shop do seals and guides? (If that's all it needs)

Funny. cause the same time you started this tread I've had the same problems. Paul and I did a leakdown test yesterday. Turns out my head is warped and my head gasket shot. Im going to be taking off my head either today or tomorrow. There's a couple people looking into how much its gonna cost me to get a head redone. Disturbedfan knows a guy who had his 240 head redone for 285. Not sure what work that actually included.

How hard is it to do the valves? Is this something i dont wanna mess with and just have a shop do it right?

Here's a vid that Paul took. About 100Psi going into cylinder 1. Spark plug put back in to cylinder 2 because we felt all the air coming back up it.

Air into cylinder 2 made it come out of 3. Air into cylinder 3 made it come out of 2 and 4. Air into cylinder 4 made it come out of 2 and 3.

I didn't have that problem, my air just came out of my exhaust or my throttle body. Therefore, my compression loss was through the valves.