About to switch from dino oil to synthetic, any reason why I shouldn't?
 

I've been running Castrol GTX 20/50 for a while, on a rebuilt 83 SC motor that has about 90K miles on it. I just ran through a tank of gas w/ Chem tool B-12 in it and am now about to change the oil. I want to go with Royal Purple 20/50. I am absolutely_not_trying to start another oil thread, I just want to hear, if there are any, legitimate reasons why I should not switch to a synthetic. Also, has anyone heard of doing a "double oil change" after running a can of Chem tool or Techron through their system? As in, drive through a tank of gas w/ Chem tool, change your oil with something cheap--run that only for a little while, like 20-30 miles--then change that oil with the oil you use in a regular oil change? Apparently it works to get rid of any carbon deposits that might be loose in your engine after using a Techron-type product. Total BS?

The only reason, besides cost, that I can think of is the possibility of increased oil leaks. Other than that, no.
As for the double oil change, it's just like in chemistry class when they say to rinse things twice. Yes, you should be removing more contaminants with a double change. Is it necessary? I kind of doubt it unless your engine was really carboned up badly to begin with.
Does it run any better after having used the Chem tool product?

When I purchased my SC it had a very small oil leak. I changed to synthetic and the small leak got much bigger. Changed back to dino and the leak returned to it's former self........

Just get a case of Brad Penn 20W50, change the oil and be done it. Depending on how many miles you drive, you can determine your oil change intervals.

I, too went synthetic before I knew about Pelican and had bigger/more leaks.

ill take the oil leaks with the increased protection of synthetic, Kevin

A dino oil designed for flat tappets is better than a synthetic that is not. Choose wisely.

FYI- Brad Penn is partial synthetic.

OK, what dino oil is designed for flat tappets? Is Royal Purple specifically not?

Flat tappets need Zddp. Do a search, read up on which oils have the most. Unfortunately the reformulation puts most oils and the bottom edge of minimum amounts of Zddp needed. That means you have to change oil more often. Sooo, why spend more for an oil that you change more frequently? Are you doing DE's or Auto-crosses in the desert? Do you park the car outside in 20 below zero weather? You don't need synthetic.
Having said all that, C Navarro does say that some full synthetics are [U]as good as[U] Brad Penn but, why spend the money?

When Syntec first came out, I changed the oil from regular Castrol to Syntec. The only weight available at that time was 5w50. Leaks followed the oil change. I changed back to regular "Dino" and have not had any problems. I do use Valvoline 20W50 VR-1 racing motor oil now due to the increased amount of ZDDP over regular motor oil.

Royal Purple is high in Zddp and is a good product ... Even Penn State . or Brad Pen or whatever it is called is a semi synthetic .. that is what I run ... on my 78 . no complaintes ..i don't thinkthere is any real benefit to synthetic since these engines and bearing clearances were designed arounf dyno oil ... but if you have all that money with nothing to do with .,, go ahead ,,

I had the same question when I first got my Carrera.
The previous owner ran the same dino you are running.
I did the Techron thing, then got some flush from Lubemaster, and ran some Amsoil 20W50 HD Motorcycle oil as recommended by C. Navarro.
Drove for 7k miles and changed the oil and it wasn't very dark, still had a golden look to it.
Refilled with the same...no leaks yet, engine runs cool also...just a tick below the second line on the gauge.

With all of that said, I now don't think that dino is all that bad either as it was mentioned when this motor was built it was with dino oil.

Sit back, relax, and read...

http://forums.pelicanparts.com/porsche-911-technical-forum/367300-ultimate-motor-oil-thread-why-we-hate-cj4-sm-oils.html

It sounded like you were suggesting to change your oil, then add Chem or Techron. The more common approach is to add these additives just prior to your normal oil change cycle. The recommendation to add these gas treatments just prior to an oil change because they can seep into the crankcase and they really aren't designed or intended to be there. Most formal and informal evaluations suggest that Techron and a few others do a good job of removing deposits and operating smoothness of the engine.

+1 on the Brad Penn comments or adding ZDDP. Not all synthetics would be good for your car. Focus on the brand of oil and whether it meets the specific needs of your car, not the general category.

[QUOTE=gregwils;4972209]It sounded like you were suggesting to change your oil, then add Chem or Techron. The more common approach is to add these additives just prior to your normal oil change cycle. The recommendation to add these gas treatments just prior to an oil change because they can seep into the crankcase and they really aren't designed or intended to be there. Most formal and informal evaluations suggest that Techron and a few others do a good job of removing deposits and operating smoothness of the engine.

+1 on the Brad Penn comments or adding ZDDP. Not all synthetics would be good for your car. Focus on the brand of oil and whether it meets the specific needs of your car, not the general category.[/QUOTE
No, no, I specifically mean using the gas treatment, then change your oil with something cheap and just have in your car for 20-30 miles, THEN drain that, and do an oil change with what would be your normal oil (brad penn, etc.) I don't know where in my first post I suggested doing the gas additive AFTER an oil change, but that would be completely counter to what I'm trying to achieve with the double oil change. Basically the first 20 mile oil change is used to wash out any extra carbon, gunk, etc. the gas treatment dislodged but didn't come out with the first draining.

911s with a front oil cooler take 11-13 quarts of oil to be full. When you drain the tank and sump, you'll recover about 9qts. Leaving 2-4qts of old oil in the system that you can't drain! Last time I changed my oil (Brad Penn) I drained out the old oil then added 6-7qts fresh 15-40 I had on hand. I then ran the car 20 or so miles to mix it all up, then drained again before adding the new Brad Penn. Still couldn't get all the old oil out absolutley, but a least I knew it was pretty much all new oil!

tip ... before doing your oil change drive home in a gear lower than you normally would .. i do this all the time nd it spikes the oil temp .. when I change the oil immediately on getting home ..... and i mean within a minute or 2 of stopping the engine .. the stat is open and it pours out. I actuallu got 11.75 quarts out.. a record for me ...

Use any synthetic that you like and add gm eos one pint per oil change. Your zddp will be right on the money. Synthetic oil does not cause oil leaks, leaking gaskets and seals cause oil leaks. I have changed over a half dozen high mile 911s to synthetics and never had one leak attributed to synthetic oil, also you dont have to worry about changing sooner, yo will have all the zddp you need. If you dont want to mix use 20/50 mobil one for 4 stroke motorcycles and you will have the same thing. The "dont use synthetics" message went away with the dinosaurs, except for a few, JL

I've heard a lot about it, but where do I get the GM eos? Can't find it in Austin. Also can't find_enough_of the mobil 1 20/50 for motorcycles, as every store I've gone into only has ONE quart in stock at a time. And there aren't even 12 stores that have the one quart for me to buy enough for a change.

Sounds good, I'm going to try that. Just have to work on the reflexes of getting my hand out of the way in time before being boiled by the 210 degree oil.:D

You can gm eos at a gm dealer if you can find one. about $12 a pint you can order by the case called gm eos assembly lube, J: