BC

Is the smoke only on decel? Could it be sucking in through the heads?

If you replaced the rings but didn't relap the bores it may take a bit longer for them to seat.

Ducman82

5300 ish.
no crank case gases can get to the intake... NONE

crank gases go to a provent filter canister then straight to the exhaust.

here is a picture that shows the filter set up. minus the hose to the exhaust evac valve.

Ducman82

i did not touch the bores.. other then a clean rag.

how long can it take? my thought would be why did it do all the smoke that one time, but not before..

mysteries!

Lizard928

wait a sec.....

do you only have that one tiny line feeding the provent?

You really need to have more than that or your crankcase pressure goes up too high, lifts rings, and BAG smoke screen!

Ducman82

its not really tiny, its a 12 AN line..... if so how would i test that? try a vent to atmosphere?

toofast928

Unscrew the ProVent cap. Filled with oil?

toofast928

Ands what's the WOT ignition timing set to?

IcemanG17

Hmm.....here is my thoughts............new rings sounds like a great idea, BUT if the existing rings are in good condition LEAVE THEM....they are already seated properly to the existing bores.... The really only correct way to change the rings is to lightly hone the bores at the same time....so a clean bore mates with the new rings.....think about it....lots of little tiny matched lands and grooves in the rings-bores....now you put new rings....so its lots and lots of little gaps?

If you had a stock-ish breather I would say classic pressure issues...but thats not possible with your setup..... Have you tried attaching a mityvac to the crankcase....then rev it up.....it might surprise you & in a good way, since this is your best case scenario....

But at 5300rpm for a brief "burst" you shouldn't have any issues at all......that is scary..... I run my racers to redline 4-5 times every 2 minute lap.....for hours per day.....I typically burn 1/2qt per day & get only a few drops in my "breather-vent"....

Lizard928

Brian, please re-read. He has already put in new rings.

Duc,
-12 is only 3/4" this is way way to small!
I would run a minimum of 1" off the filler neck and consider one 1/2" off each cam box.

If he is running the ign map I sent him still it's good and shouldn't be creating any issues. But that said, what is your CR at now? Pulling 3 deg out of the upper end might help if CR is really high.

Speedtoys

IIRC, doesnt Ott only have 1" off the filler cap, and nothing off cam covers?

Mike Frye

Jake,

You were running on the dyno the other day too, right? No smoke issues with that? You had to go to redline that day, or pretty close.

So the car's got a few hours on it, including some dyno runs and then you took it out and on one or more trips up to 5300 it started pouring out black (oil) smoke...

The car runs fine at low RPMs and you can't see any obvious signs of oil? How much oil is showing on the dipstick? Can you tell how much you're down?

Have you done a compression check yet? I'd do that on all cylinders to see what you've got there before proceeding...

Ducman82

Today im going to pick up a compression tester kit and give that a whirl.

i ran a similar vent set up on the stock engine (no vent to intake, stright to the exhaust off the oil fill cap) and NEVER had any smoke or oil issues. the provent was not filled with oil, line to the exhaust was good and clean. and the oil level was good.

Mike, after one dyno pull there was the slightest puff of smoke when he let off, to small to tell the color. and that was it.

Ducman82

think i figured it out. #5 was the worst when i checked last night. had oil even around the plug inside the plug hole.

well today i checked again.. yep UV dye and my tasted buds confirmed it. Coolant.

SO, should i even run compression checks? (i bought a gauge at the local parts store)

looks like out she comes. i will drain the oil and see whats in there.

anything else i should check? if it is not in the oil im guessing my rings are ok?

mark kibort

rings, if sticking, and thats a long shot with the 928, wouldnt do it in two holes. but then again, if its two holes, it wouldnt be breather issues, as all plugs and pistons would be coated with oil. souinds like it could be valve guides.

you are getting a lot of oil into the engine. either getting by the engine rings, that if were not spec, or not put in correctly, that could be the issue. they are directional, if i remember , and you need the right kind. who clipped them and what were they gapped to???
all the engines ive built never had anything more than puffs of smoke, ONLY while racing, because of oil breathers pulling oil from the breathers. (all going back to the post- throttlebody area. scots was the worst at this, but still it was only every so often. our rear view cam on his car shows the story, and it wasnt bad. i have all stock breathers on the holbert car and the new S4 and no smoke issues.

rings dont need to seal. thats the beauty of the 928 engine. the surface is very smooth and hard and doesnt "wear in" its ready to go after minutes of running. if it isnt, the bore has issues, or the rings are bad or installed backward. (or gap is too much) more than likely, it could be a valve guiide, because that will suck valve train oil in under decel

could be, but he has only that one line from the crank case vent.

no, a good engine needs NO break in and honing for stuff to work. true for american iron, but not for Alusil blocks and bores. if the bores are good , the rings will work, they dont need to seat. there is no seating for oiur engines . they just seal from stroke one.

im the same way. i raced all weekend long, brutalized my engine and still only used a half a quart alll weekend, with a 30min race with all redline shifts. no smoke, no oil burn , alll stock breather stuff.

its got to be something else. rings are wrong (and i think they can be installed upside down too) or valve guides then.

mark kibort

thats a lot of water to make a smoke screen. has to be a huge head gasket hole to do that, and usually the water gets pressureized, not sucked in, where the car will blow water out the expansion tank. any hole that could drip water into the heads, would push out the gasses into the water jacket and blow water out the overfllow container.

plus, if you have all that water on a hot piston , let it sit for a few mins and it will evaporate quickly. oil will not.

do you remember the video of scot blowing a water hose? or his slightly blue smoke acceleration at thunderhill pasted the left hander, at the turn 8 kink?