Switch back to Dino oil?

[jbserra]

Hello all. First time poster.

Last season, I switched my 87 911 over to synthetic. Around that time, I noticed gray smoke out of the left tail pipe. I had never seen smoke out of the pipe, but I also didn't associate the smoke with the new oil. I don't remember which came first.

Anyway, I took it in for a valve adjustment in the off chance that it would fix this issue, plus I was about due. There was no improvement.

Is it safe/worth switching back to Dino to see if it fixes the smoke problem? Any other things that I should be worried about?

Thanks in advance,
-Jeff

[vesnyder]

Have you noticed any leaks? I changed to synthetic several years ago but chnage back after about a year when I noticed leaks all over the place? After swicthing back to dino many (not all) of the leaks disappeared - took about a year. I would recommend switching back. Do a search - that is the concensus around here.

[jbserra]

Thanks for your quick response.

Yes, I think there are a couple extra drops of oil on the ground. I did get the feeling that people in the forums were ok with switching back. I just wanted to see what peoples experiences were. Sounds like you may have had the same issue. Well, it'll have to wait until the next oil change since I already sunk the $$. I have been driving it quite a bit already this season, so it may be sooner then later :-)

[kach22i]

Originally posted by vesnyder
- took about a year.

How many oil changes in that year? Did you dare try any of the stop leak stuff or high milage oils for older cars?

[NoLift911]

Valvoline Racing 20W-50

Using it in my 84 Carrera for 5 years - I have the distinction of having I think the only 911 that has never been opened (engine wise with no leaks and all original parts) 33k miles.

No leaks. None. Oil goes in honey colored and comes out the same everytime - changed every 2k or 6 months.

Great stuff and cheap.

-Jeff

[kach22i]

Originally posted by nolift911
Oil goes in honey colored and comes out the same everytime - changed every 2k or 6 months.

Sounds like you don't ever use fuel conditioners and change the air filter (and oil filter - of course) with every oil change.

I think I'll go from every 3,000 miles to 2,000 miles, it looked a little muddy this spring (but no metal shavings).

[RickM]

I've never heard of Synthetic causing a smoke condition.

[mwbaum]

fwiw my 85 has absolutely no leaks and has never been opened either. (only valve adjustments and basic tune ups) Oil is still new looking after 3K miles......and it uses about a half quart in 2K miles. I use dino oil and have 85K on the car.

[silverc4s]

Smoking (if it is indeed oil smoke AND the fill level is correct)) is usually caused by oil getting past valve guides (on turns) or rings (all the time). Using too thin an oil formulation, or badly worn guides, rings, or all of the above...

[jbserra]

Originally posted by silverc4s
Smoking (if it is indeed oil smoke AND the fill level is correct)) is usually caused by oil getting past valve guides (on turns) or rings (all the time). Using too thin an oil formulation, or badly worn guides, rings, or all of the above...

So, is there a benefit to just letting her smoke? Am I still getting benefits from using the synthetic? Should I just stick with it?

[silverc4s]

No, that's not my point. I would say that if you are using 10W 40 oil for example and the engine smokes, you need to step up to 15W 50 , or even 20w 50 weight. If it STILL smokes, you hyave bad rings or guides...
My 2.4 E would smoke badly on corners (mosquito killer) with 10W 30 synthetic, way too thin for the valve guides. When I went back to Mobil 1 15W 50 the smoking went away completely.

Absolutely no benefit to smoking engine that I am aware of...;-()

[jbserra]

I am using the Mobil 1 15w-50.

Alright, so stop the smoke, and switch back to Dino to see if that fixes the issue. I think that sums it up. I'll give it a shot.

Thanks!

[NoLift911]

Originally posted by kach22i
Sounds like you don't ever use fuel conditioners and change the air filter (and oil filter - of course) with every oil change.

I think I'll go from every 3,000 miles to 2,000 miles, it looked a little muddy this spring (but no metal shavings).

Yup - you got it. No need for fuel conditioners there is enough is the gasolines today...filter changes everytime also air/oil.

Cheap insurance. The car does not puff on start up or use any oil at all either.

Dino oil is the best thing for an older 911. Synthetics are for....well not really sure what they are for unless I am racing for a million dollar purse every weekend turning 9,000 plus RPM's - total waste of money IMO for ANY street vehicle - but we won't go there...

[kach22i]

Originally posted by nolift911
Yup - you got it. No need for fuel conditioners there is enough is the gasolines today...filter changes everytime also air/oil.

Cheap insurance. The car does not puff on start up or use any oil at all either.

Dino oil is the best thing for an older 911. Synthetics are for....well not really sure what they are for unless I am racing for a million dollar purse every weekend turning 9,000 plus RPM's - total waste of money IMO for ANY street vehicle - but we won't go there...

1. Staying away from fuel conditioners...even Textron or what ever it's called.

2. I'm going to change my air filter more than once a year.

3. Synthetics in the 993 (I think), the 996 and Boxster do a dual function. Apparently the hydraulic valve lifters are not lubricated the way they might be on other cars (separately). The lighter weight synthetics are required and recommended.

4. Unless you are racing or tubocharged, and have already rebuilt the engine with all new seals I don't see the point of synthetics in an older car seeing summer only use.

[silverc4s]

Air cooled engines can see much higher oil temperatures, and use the oil to carry heat away from the cylinder heads.
It is not a good idea to economize on oil quality, the high temperature characterisitics of synthetics are much better than any dino oil.
But, it's your engine, YMMV.

[ZOA NOM]

My mech will not put synthetic in my motor, and doesn't recommend it under any circumstances. The issue he described to me is that the manufacturers will put 20w-50 on the can, but the oil may actually be much thinner, which isn't necessarily a problem with newer, tighter engines. It can become a major issue with a motor with miles on it that relies on the spaces being filled with a thicker oil. He has told me that using the synthetic on an older motor will result in a rebuild much sooner than otherwise.

I stick to the dino oil, every 3-5k. 164k so far, never touched.

[silverc4s]

Yeah well, your mechanic probably gets his milk directly from the cow, too.

I used to have a mechanic like that - every time I asked him about something that might improve the car, he would say, "Porsche built it that way, you don't make changes. If you want a faster Porsche, go buy a faster Porsche!" Yes, he was from the Old Country...;-)

[ZOA NOM]

So, you're saying he's wrong? His explanation makes sense to me, and the only proof I need is sitting in my garage.

I suppose you've put your money where your mouth is. Time will tell. Let us know how if your motor makes it to 200k.

You bring up an interesting question, however... What accounts for more of the cooling in these engines, oil or air? I would suggest that keeping the outside of the motor clean (especially on top, behind the fan) would do more for cooling than switching to synthetic oil. The layer of crud that builds up on top of the cylinders creates a very warm "blanket" that the fan can't cool very well.

[ricochet]

Originally posted by nolift911
Dino oil is the best thing for an older 911. Synthetics are for....well not really sure what they are for unless I am racing for a million dollar purse every weekend turning 9,000 plus RPM's - total waste of money IMO for ANY street vehicle - but we won't go there...

You may be right, I am still learning (guess for the next 50 years also). My mechanic also warned against syn oils, but I have been blending (15-20% blend) in my auto's for 17-18 years and have had no ill effects, often on vehicles with 150-200k miles). Not Porsches, till last year. But everything else, cars, trucks, motorcycles, atv'S and everything else I can try. Actually read of doing this in a Sportsman's magazine and decidied to try it. My older semi-high mileage 84 never drips, NEVER. It also only gives any puff after sitting 2-3 weeks or so (which means rarely).

My reason for doing so is for the sometimes cold, dry start situation. I do let many of my motors set a while (not usual for the 911 tho), but happens.

I also have data to look back on for our turbines at work, these turn at 3000-4000 rpms for 24/7 sometimes 6-9 months with zero downtime(many 10000hp+). Data collected for many,many years. We have less detectible wear using synthetics (started with Royal purple syns, now Mobile syn) get the same datafor each. The downside, more is added (leaked by SOME turbines). Next downside, we had management that stretched oil to failure, lost 4 turbines in one year, near catastrophic failures (bearings,shafts). We now analyze the oil, while it lasts MUCH longer than dino oils, it fails quickly towards it's end. Our oil consoles hold many thousands of gallons, our results justify it's much geater cost. Down time costs $thousands per hour, less downtime equal more profits for the greedy bastards mostly.

The metallurgist allowed me the blend is nearly as good, will not last as long. The cold start benefits are nearly equal (does not matter on 24/7 stuff) but appeals to me. Has worked for me for many years, would not try it in a leaker.

Sorry to be longwinded, I will continue using 20-50 dino (Castrol)mixed with 20-50 syn (Castrol) till I find a reason to not use it. Does anyone doubt synthetics are better for cold start?
That's my assumption I mostly base my use on. Also I believe the new Porsches and Vettes come standard with it. Wouldn't their cheap bastard bean counters reject if not worthy?? Thanks guys, I'll listen now.

[M Scahfer]

I will participate also... 75000mi. 3.2 88 that lived on dino until I put in 15-50W Mobil1, smoking/leaks have been on the increase lately so will do valve adjustment and try Valvoline to see what happens.