oil smoke. PCV, or valve stem seals?

so, stock,. 132k mile 97 neon dohc acr. and when i say stock, were talking STOCK. only mods are gauges, aluminum radiator, and depo headlights. STOCK.

when i switched the car over to synthetic oil, i developed a snmoking at idle and on deceleration problem within 500 miles. leakdown on a cold engine showed only 22-26% across all 4 cylenders. so im fairly certain its not the rings. also have really good oil pressure, and the cooling system holds to 28PSI overnight. so were looking healthy on the engine. im really thinking its valvestem seals, but on a whim, i checked my intake manifold (i had similar circumstances with a blown belly pan on a magnum 5.2)

sure enough, a bit of oil on the bottom of the plenum, and oil on both sides of the PCV valve. not a ton, but enough that it drippend when i removed it. just a couple of drops. unknown how deep in the plenum.

i read somewhere about an oil restrictor for the DOHC cars, as well as different designed valve covers that should solve this problem. unknown about what covers were different that bolt on. tried a later model pt cruiser valve cover, but one of the bolt holes was in a completely different place, and hose routing would be a nightmare. i also tried to get the factory mopar oil restrictor, but its NLA. doing some google, i came across some guys making their own with brass plumbing fittings and such. one guy suggested a holley metering jet inserted into the end of the PCV valve and drilled out to 1/32.

am i right that an oil restrictor will work? am i right in my deductions on the pcv possibly being the reason for light to medum smoking?

i know this is a lot, but im a fwd noob. give me a v8 and rwd, wether efi or carbd and im good. ohc and 4 valves a cylender are like black magic to me.,...

What happens if you switch back to dino oil?

dont know? hadnt tried that, as ive got less that 700 miles on a 30 dollar oil change.

Have you put a vacuum gauge on it? That should give you where you need to be looking.

Maybe replace the PCV valve? I know they'll get clogged up fairly easily. Turbo guys that keep the PCV system usually try to get a brass PCV from a turbo Supra as it's a bit more stout, but I don't know if that would be necessary for your application.

You could also try disconnecting the PCV from the intake tube, blocking off the port on the tube and putting the PCV to a filter (or leaving it open) and see if it's spitting oil.

Isn't 25% a little high

If smoke only occurs under high vacuum,ie: decelerating. Then valve seals and or guides are suspect.

Could also be oil drawn up from inefective oil rings.

Hmmmmmm, the syn seems to have cleaned up some of what the previous 122k miles left behind???

You also might look into a oil catch can inserted between the breather and the manifold

wae wrote: Maybe replace the PCV valve? I know they'll get clogged up fairly easily. Turbo guys that keep the PCV system usually try to get a brass PCV from a turbo Supra as it's a bit more stout, but I don't know if that would be necessary for your application. You could also try disconnecting the PCV from the intake tube, blocking off the port on the tube and putting the PCV to a filter (or leaving it open) and see if it's spitting oil.

will try that as well. PCV still rattles and stops air flow when blown in by mouth, so assumed good.

iceracer wrote: Isn't 25% a little high If smoke only occurs under high vacuum,ie: decelerating. Then valve seals and or guides are suspect. Could also be oil drawn up from inefective oil rings.

25% is a little higher than id like to see, but this was on a dead cold motor. i find that thise numbers are about 10% higher cold than warmed up to poperating temp, and it gets me burned less. so id expect to see 15-20% leakdown on a warm motor. air escapinginto the crankcase. this seems within range for a factory tolerance ring package in good shape.

In reply to Dusterbd13:

Sounds like the PCV is probably okay, but you might try getting it out of the intake path just to make sure that's not where the oil is coming from...

Oh, and I did a leakdown on my DOHC with 75k and had more like 5-10% across all four on a warm motor, although I'm not sure what is "in spec" for thse...

oldeskewltoy wrote: Hmmmmmm, the syn seems to have cleaned up some of what the previous 122k miles left behind??? You also might look into a oil catch can inserted between the breather and the manifold

thats my thought exactly. and the valvestem seals are my first thought, but cheapest easiest first is PCV modding as i did find iol ion it.

vacuum readings are 18 in at idle.

Dusterbd13 wrote: vacuum readings are 18 in at idle.

But what does the needle do? Flutter? Steady? Gradually drops?

stays pretty steady. flutters a little.

ill retest after work for an extended period to answer this question better.