Ducman82

OK here we go

I have smoke when i accurate (bad depending on time at idle/stoplight) , idle (not bad) and just driving (almost cant see it in mirror)

following pictures were takin by USB cam 3 days after last ran. car was brought up to temp, backed out of garage parked for a few hours. then warmed back up, reved twice to show smoke to to Joel (just did his brakes) then pulled back in and turned off.

most cylinders look like this (this shot i took to see if that spot was a bad cylinder. the rest look great, no marks of any kind that i can see)


here are the trouble makers

number 8



8 intake


and number 3 (was at TDC, so rotated it down to get a look)


back of 3's intake valve (best shot i could get)


im waiting to get the info for the shop that did the head work from my buddy in ABQ's shop (he send them out for me) to see what kind of warranty they have

can valve seals be done in car with a 16v? i know the cam towers are evil to get out and a Biznatch to get back in without lifters falling and gasket getting buggered up. what valve spring tools would i need? never done this job before. let alone in a car.

is it the seals? REALLY bad rings?

thoughts?

Kevin in Atlanta

Shouldn't you do a leakdown test to confirm first?

Ducman82

going to pick up/find a leak down tester tomorrow....

not sure what that would tell me at this point.

Kevin in Atlanta

The difference is between the valves, valve seals or pistons. Knowledge is power. Advance Auto and others rent them for free.

Ducman82

Have to find one not beaten to death.

toofast928

Yes with a tool made up you can replace the valve stem seals in the car. I would pull the engine if it was me. Thats alot of oil on top of that piston.

Few Qs;
Was the valve gudes replaced?
New valves or did you reuse the old valves.
What color is the valve seals, White teflon?

Ducman82

Only 4 valves were reused. All others new. New guides seals, not sure on color ( don't remember) :-(

I'm leaning on pulling it if I can leave the clutch on... :-)

docmirror

Some generalizations. Oil smoke is almost always valve/seat/seal/guide related. Rings will cause more blowby and will be seen in high crankcase pressure, rarely in exhaust smoke. Yes, the valve covers are hateful to get off and on. You can use the rope method(remove plug, stuff rope in cylinder, rotate crank to push rope coil to the inside of the head) to keep the valves seated and get the retainers, keepers and springs off the head.

Once springs are off, back the crank down a few degrees and perform a wobble test on the valves/guides. Push the valve off the seat and see if it has any side-to-side wobble. If so, take the head off. If not, keep shopping. Seals can be replaced in situ, but really check the valves and guides for wear. If you get to the valves, go ahead with the seals and try again I guess.

<edit: what do the plugs look like?>

Dave928S

There's a test you can do that won't give you a leakdown percentage relative to a set orifice size, like a true leakdown test, but will allow you to determine what the issue is.

1. Remove all spark plugs.
2. Lock the motor at TDC compression stroke for your first cylinder, and other cylinders after that, where valves will be both closed. Important to lock it so it can't move, as the pressure test will spin the motor.
3. Make an adapter for a compressor driven tyre pressure gauge, to screw into that spark plug threaded hole. I welded a spigot to a gutted spark plug and clamped the hose from the tyre pressure gauge to it.
4. Pump that cylinder up to 100 psi, and then time how long it takes to drop off to about 10 psi. A normal healthy cylinder should take about 8 to 10 seconds to drop from 100 to 10. Jam the throttle open so you can't pressurise the intake if you have any leaky intake valves.
5. If there is a broken ring, scored bore, leaky valve or leaky head gasket, the pressure will drop in a fraction of that time ... like 2 to 4 seconds.
6. If its a broken ring or bad bore you will get massive blow by out of the oil filler, if it's an intake valve you'll hear it coming out the intake (air filter off), if its an exhaust valve you'll hear it in the exhaust system, and if it's head gasket you'll get pressurisation of the cooling system (take cap off).
7. If all cylinders are OK, then it's leaky valve guides/stem seals.

You could also have a combination of any of these problems, as well as worn guides and leaky stem seals, so that's why it's best to do this test or a true leakdown first, and eliminate other potential issues. Because you're getting oil in the bores you need to eliminate rings as a possibility, before ripping the heads off.

Because 16 valve guides are quite short they tend to wear and then get a lot of slop sideways, and then leak badly. If the seals are leaking you likely find that the guides are at the wear limit and also need replacing. .

If it was me I think I'd be pulling the motor ... much easier than trying to wrestle with it in the car.

LT Texan

How can you get that much oil through the rings?

And do you have any pooled oil on top of the valve once it seats? I'd think the valves would be wet with that much oil.

Ducman82

you can see the valves have a little "moisture" spots on them. the heads were completely rebuilt. new everything. im thinking just to save me a bunch of cussing i will prob pull it.

when i did the short block i did new ring, had them gapped etc. but did not lap the block. no one person had the same answer on doing this.. so i could be getting blow by if they are not seating (takes time).

thanks for the responses guys. i appreciate it.
with the Mega squirt working, im in it for just lost time really at this point. :-P

docmirror

As mentioned, most oil comes through the valves. Very little oil comes up through the rings in an upright or V type engine. During three of the four strokes the cylinder is under positive pressure, and gravity has the regular affect as well. Worn rings can pass some oil but not much, and it's typically burned off. Blue smoke is pretty much exhaust valve, guide, seal.

Leakdown is useful for damage, but not always for oil smoke. If there's intake valve issues, it can show up as plug discoloration.

Ducman82

plugs are mostly black from burning oil, but the electrode is clean. a few a the nice clean/brown.

GregBBRD

I'd be not so quick to pull the engine out.

For rings to pass that much oil, you'd expect to see some really terrible scratches on the bores....which I'm not seeing.

I'd also think with new guides, you could leave the stem seals completely out and not get that much oil in the bores.

Are you sure this oil is not coming in through the intake system?

I'd want to look inside the plenum/low spots and make sure that the oil is not sitting in puddles inside.

Ducman82

took the center section out and fed the USB cam down the runners. the intake is clean as can be. i don't have the breather hooked up to it so no oil can get in.

my crank case exhaust scavenge quit working so the provent is vented to atmosphere (blue smoke started before that happened it think)
my goal next month was to do a vac pump to draw crank gases and help "seal" the rings better. but i figured id take a look with this nifty cam and see what i could see.

i went down each bore , being i could not spin the cam a complete 360 to catch all of the sides, i could not see any coating rubbed off or scratches.