burning oil when hot on 89 911 3.2 liter

89red911 · 08-25-2005, 03:44 PM

i bought a car that was sitting for 5 plus years. Yes I know this isnt the best way to start. anyway I got the car running and found that once it got hot it started burning oil. I figured it was time for a rebuild. by the way the car and a little over 17,000 miles on it. So i pulled the motor and sent the heads out tobe checked I was told the valve guildes were wasted. Had everything done to the heads new guildes 3 face valve grind everything. I put new piston rings in installed updated chain tensioners and all new gaskets. I got everything put back together, and started the car. After It got hot im burning oil again.
Any ideas would be great.

By the way I didnt do a $2000 rebuild ( i spent almost $10,000 for all my parts and labor that i put into it)

cjr1 · 04:41 PM

Did you do the work,assembly,rings etc...?Not sure how you spent that much on just a top end job.I'm going thru my 3.2 right now & have about 5k in it.That includes Top & bottom end kit,head redo including all new valves & guides,clutch kit plus a few other odds & ends.

Please tell us your not another MM victim

BTW,an 89 should already have updated(oil fed) tensioners in it from the factory.

Chris

89red911 · 08-25-2005, 05:21 PM

i have done all the work the $10,000 is an estimate including all the labor time i put in I also replace the clutch, flywheel, pressure plate, cap, rotor, wires, plugs, front and rear main seals, all the hard ware, you name it i replaced it i didnt want to take any chances i also replaced an oil line that was leaking ( what a pain in the butt the car has a steel wide body kit on it getting to the cooler temp control valve fittings was a nightmare) anyway she still burns oil just not as bad.

I have been racking my brain trying to think of something i might have missed or didnt do right or didnt torque down right but i cant think of anything.

911TE · 08-26-2005, 04:58 AM

How many miles did you drive since the engine work?
If you just started it and it got hot it might be that just the exhaust is still full of oil that gets hot and is burning slowly.
I had this on a 911 that was sitting for years.
It took an hour driving around fast before it stopped smoking!

(Not an idea if you were driving it already for hours!)

Sebastian

Rot 911 · 08-26-2005, 05:13 AM

How much oil are you using exactly? How full are you filling the oil tank? (Where does the oil level measure on the dipstick). Are you checking the oil level when the engine is up to operating temperature, on level ground and the engine idling?

89red911 · 08-26-2005, 05:54 AM

well i have only run the engine for about 30 mins total. i never thought the oil in the exhaust might be burning off its worth a shot to try running it for a wheile to see if it will go away.

I dont know how much oill it is burning if any at this point. before the rebuild i never ran it long enough to figure out how much it is burning. I think i have only run the car for maybe 2 hours at the most from the time i bought it.

after i got it running for the first time i ran it and i saw it was burning oil i changed out the oil and put in 20/50 and a new filter and ran it again only to find that it still burned oil. at that point i figured rebuild time and pulled the motor.

as far as my oil level is concerned im half way up on the marks on the stick on level ground engine warm at idel so im sure im not over full.

before the engine rebuild when it got up to temp i had a james bond smoke screen no after the rebuild i just have a light clound that at idel is almost not noticable but when reving gets thicker. it is far les now then it ever was though.

jpnovak · 08-26-2005, 08:12 AM

I say get some more break in miles on the new engine. A newly rebuilt engine with only 30 min has just barely had the cams broken in. The rings will not seat for a bit longer and not without high cylinder pressure from driving loads.

89red911 · 08-26-2005, 09:49 AM

i plan to drive it around some today i have to put in a new clutch master before i can go anywhere

thanks for the advice i hope it clears up

Rot 911 · 08-26-2005, 12:00 PM

I think Sebastian got us pointed in the right direction. I confused "using" oil with "burning" oil. If the car sat for 5 years I would be willing to bet that the oil drained from the tank into the sump and made its way past the valve guides into the exhaust, hence all the smoking. I highly recommend you drive the car for a good 2-3 hours and see if the smoking goes away.

89red911 · 08-26-2005, 07:11 PM

well the plan was to drive the car today for a wheile but i was stuck on my rack all day. The damn clutch gave me hell to get all the air out of.

first i found the piston in the mastrer stuck at the end of stroke then i had air in the system. I ended up power bleeding with the brake system it worked like a charm. if you have never done this feel free to contact me and i will explain how. cut my pedal pushing time in half.

i will let you all know how things go next week when i go back into my shop im done with the porsche for the weekend

the wife has put together a nice honey do list.

89red911 · 08-30-2005, 06:11 AM

so i just wanted to give an update I did get the car out yesterday for a short run. I knd of gave the car a shake down. I found some other things i need to fix on it but the smoking did get better. I hoping to get out in it today some and see if it will go away all together. I will let you guys know. I should hae bought a car that wasent sitting for so long lots of stuff to fix.

89red911 · 09-07-2005, 11:44 AM

So i just got the car out and ran it for some time went out for about 40 mins or so the longer it ran the more smoke i got still looking for something wrong. any ideas??

sammyg2 · 09-07-2005, 03:38 PM

Does it smoke all the time, or at idle, or steady cruise, or full acceleration, or decelleration?
that will help us diagnose the internal condition although my gut feeling is it isn't the engine.
Hopefully we wil lbe able to solve this without too much stress.

89red911 · 09-07-2005, 03:48 PM

well here is what happens

at start up i get a small amount of smoke. this goes away untill it get up to operating temp.

once the engine is hot it smokes all the time it seems like more at when im at idel but its hard to tell

when i watch the oil level gauge i find it dosent read anthing untill the motor is warm once it is warn it rises to mid or 3/4 gauge. If i rev the motor it drops depending on how high i get the rpms.

as i said in my other posts it has new piston rings and valve guildes along with all new seals.

I am kind of thinking i may have kicked my self by not spliting the case and replaceing the oil pumps. I do have good oil pressure though i dont know im at kind of a loss.
Rob

Bobboloo · Bobboloo's Garage

There is no reason to open the case and start replacing more parts unless you just like to spend money. Your pump is fine.

Why did you replace the piston rings? Were any broken? 17,000 should be like new.

Have you followed the proper break-in procedure for new rings? There is a proper procedure to get the rings to seal.

More than likely the motor has been over filled with oil.

The changes you see on the gauge are normal. What happens is that when the motor reaches operating temperature the thermostat opens and the cooler enters the loop and the oil level increases on the gauge. This why oil levels are checked at operating temperature. If the car has been overfilled what happens is the thermostat opens and the extra oil gets sucked into the intake through the breather hose. Then some of the oil gets burned and some gets deposited in the muffler.

It takes a long time to burn the oil out of the muffler. The motor has to get to operating temperature and be there a while before the muffler is hot enough to start burning out the oil. It can take 30 min. on some cars to reach this temperature.

I suggest you follopw break-in procedures if you haven't already. Ther worst thing you can do for new rings is let the car idle.

Once you've done that then you need to let the car get to operating temperature and check the oil level.

Once oil level is fine take the car for a long drive and drive the crap out of it. Don't be afraid to rev it. Just don't exceed the redline. 3.2 rod bolts don't like that.

89red911 · 09-08-2005, 08:57 AM

I put new rings in because I was there. I had the heads redone and figured why leave old rings in when I can change them. I'm a firm beliver in save yourself work and effort by changeing parts when you have stuff apart. I have found it prevents headaches down the road.

I admit when I started this project I had to much oil in the tank, but I have sucked it out. To the level I now have.

I am a bit worried about sucking more oil out as the level gauge reads below red when cold and once hot it reads about mid gauge.

My concern is that when I rev the motor the gauge drops into the red. Is this normal? Should I not worry what the level sensor says?

I have good oil pressure at all times never drops below 1.5 bar even when hot.

I guess I am just worried about starving the motor for oil.

Bobboloo · Bobboloo's Garage

The way you check oil levels in a Porsche is by idling the car on level ground at operating temperature and then checking the dipstick with the car running. The gauge is only good for a reference.

You're not gonna starve the motor of oil. Good oil pressure is all you need to know. The pump is fine.

RSupdate · RSupdate's Garage

Well, after reading everything it seems that the obvious problem here is TOO much oil in the engine......

It is normal for the dash gauge to be resting on the bottom of the red zone when the engine is under load, i.e. "in gear" driving. while driving, just be concerned with your oil pressure and temp.
after your engine is up to operating temp (180 deg. f.) next stop light you come to on flat level ground, note the oil level on the dash guage after a moment at a full stop, out of gear, egine at normal idle.

Resting at idle, If it's horizontal (pointing at 9 o'clock) that's perfect.

Now pull into a parking lot on level ground, engine running, oil temp at 180f. go open up the rear decklid with the drivers door open (to see the oil guage easier fm outside) and check your oil level.

IF your dash oil guage is operating correctly, it should match the dipstick, example if the guage points at 9 'o clock at idle, then the dipstick should read as half full (half way between the top and bottom marks on the dipstick)

911's are a dry sump system, that's why when driving there is not really any oil in the oil tank - it's in the engine when under load - that's why the guage is always in the red.

Remember though....as was said above ALWAYS TRUST THE DIP STICK FIRST. The dash guage is only a convienence.

I think you need to go out and really drive your 911 before doing anything more, providing you check your oil first

Good Luck !!

Walt Fricke · 09-08-2005, 10:48 AM

89

Believe these guys.

It is normal for a 911 to smoke out the tailpipe a bit on startup, either all the time or sporadically depending on the phases of the moons of Jupiter (or maybe where the gaps on the rings happen to have jiggled around to). It is also fairly normal to get some smoking until the rings seat. How quickly they seat depends on a number of things.

I have trouble thinking of what kind of rebuilding error could cause excessive smoking (other than a ring issue). It is not like there is a frammis bolt which, if not tightened to precisely 27.85 inch ounces, will lead to smoking. I suppose if the intake valve seals were left off you could get this smoking, but those were replaced by the shop that did your heads, right? And that shop measured valve stem diameter on your 17,000 mile valves and found those to be within spec, right, before they put them back in the new valve guides they installed?

What did you do by way of roughing up the cylinders so your new rings would seat better? If the answer is nothing, it may take a while for the rings to seat.

I don't see a reference to whether you get more smoke when you decellerate. A bit hard for you to see in the mirrors, of course.

Take the sage advice of others to drive the crap out of it (well, in a moderate way - just drive it and don't baby it and do plenty of accelerating and decellerating) for a couple of thousand miles. Give those rings time to seat and that oil from when you overfilled the tank and may be hanging around in the intake system time to get burned up or otherwise safely sequestered. Plus you will be driving the car, a big plus in and of itself.

While doing so develop a careful routine for measuring the oil on the dipstick (hot oil, level surface, engine has idled for a while) and use that to measure your oil consumption. For example, you could always use the same spot in your driveway or garage (for comparisons equal conditions are more important than being exactly level). If you are in the quart per 600 miles or so range after four or five thousand miles on your top end rebuild and new rings you have reason to be disappointed. But it seems you have no quantitative idea at this point what your consumption is, just that there is more smoke than you want (an understandable consideration - no one wants exhaust smoke).

Now if by smoke you mean that you are laying down a smoke screen worthy of a naval battle or a mosquito fogger for all 30 minutes of your short drives, that may point to some worse problem.

Another thing you might do just to give yourself something more to fuss around with is pull your spark plugs. They may look rather worse than you'd expect for short mileage new plugs, but do they all look the same or do some look different? I'm not sure what one would do with this information, but it might be interesting.

As to oil levels, a mistake many of us have made (usually only once) is to get a dipstick reading in the garage in the morning, see how low it is (egad, it is barely on the bottome of the stick), and add oil. What happens is that oil from the tank migrates through the oil pump and out into the engine sump. When you run the engine for a while all that sump oil ends up back in the tank or in the many feet of plumbing and coolers. For some slightly mysterious reason, when the pump is working hard (above idle) more oil is in the piping and coolers and dripping its way back to the sump inside the engine so the tank level falls. Idling somehow (piston squirter cracking pressure?) gets this oil back into the tank. Oil also expands when it gets hot, though whether it does so enough to affect gross readings like a dipstick was open to debate last time I inquired as to what the coefficient of thermal expansion of motor oil might be. But as to varying tank levels, that's just the way it works and it has nothing to do with leaks or smoke.

Walt Fricke (drives his race prepared, full cage SC to work daily)

89red911 · 09-08-2005, 11:02 AM

Ok so screw the oil level gauge lol

Anyway I will get it hot again and suck some oil out and see what happens.

I hope this will fix the damn thing.

I am dieing to drive it and get out on the road. I still have alot of work to do im converting the head lights to square. Im not sure why but I think it will look cool when im done. Like i said before its got a wide body kit on it which in itself is pretty neat. I like eye candy thats part of why i got this thing. I have to get the convert top replaced yet and it will need a good detail.

Thanks for all the advice i will let you all know how it turns out.