924Board.org

[924Kid]

It's oil change time and every 3,000 miles I go thru this. So far, I've just used regular, but I keep hearing all this talk that synthetic is better, tho not for older cars. What do you guys think?

[Diesel]

Regular oil, brand name, in the weight the owner's manual calls for. And a good filter(like NAPA Gold, which is really a Wix) at every change.

[larso]

regular, walmart brand (tech 2000), change every three months.

I have never had a car burn oil BTW, and these are all 80s and 70s cars.

But then on turbo cars you should use synthetic.

[cs]

what is maybe more important than what type of oil you use, is what temperature the oil is running at. ideally oil shouldn't ever get over 200F, but it usually runs up around 280F. very bad. a good oil cooler with it's own fan would do a lot for the life of an engine.

[John Mueller]

I have run Castrol Syntec on all my cars for more than nine years now, and I am now using K&N oil filters.

[TroyDest]

Whatever you do, don't use Pennzoil! It gets gummy and hard to clean out of an engine, especially when it is run hot. On an NA 924 I would use regular Valvoline (whatever weight is appropriate for your locale). For turbos, I recommend Mobil 1 (not 15W-50 though, it's too thick).

[-nick]

synth is superior to dyno oil. in older engines you are more prone to oil leaks as synth oil will open up any weak spots in a gasket. this is usually why it's not recommended.

the viscosity of synth stays much more constant therefore you don't have to warmup as long in the winter or worry about it getting dangerously thin at higher temps. not to mention you can go longer between changes becuase the properties of synth don't break down as fast as dyno oil.

optimal operating temps for oil are about 100-130 Celsius (212 - 265 F). you want the oil to be hot enough so that any water condensation will burn off.

regards,
-nick

[cs]

http://www.permacool.com/Catalog/Cat_page02.html
this is also the range that most of the oil thermostats i've seen operate in.

[-nick]

hmm, i stand corrected- most oil cooler t-stats do open around 190F. some of the assertions on the link are a little extreme though. if i'm reading it right it's saying that my engine which sees oil temps well above 212F (as almost all engines do) shouldn't live past 30,000 miles. and that only engines that keep oil temps 200F will see 100,000. this is a little suspect.

i've always been of the opinion to keep the oil temp above the boiling point of water. this is debatable i'm sure. i'll see what i can find out from some stat write-ups i have on oil from some manufactures. after all, that website is trying to convince that you need lower temps and to buy their product.

i'll see what i can dig up.

regards,
-nick

[cs]

there's definately some theory involved, and i'm sure they're pushing it a little bit to get people to get coolers. i also can't make much scense out of what they mean by engine life. but they do make a strong argument about operating range. maybe it's time for independant testing. i didn't mean to get so off the topic of regular or synthetic. i prefer synthetic because, like nick pointed out, it doesn't break down as easily as regular and that seems to be the reason for the deaths of most turbos.

[cs]

i was going to start a new thread, but this is actually related to the regular/synthetic debate.
http://www.vtr.org/maintain/oil-overview.html
make it to the bottom and they have a good comparison of almost every oil.


[ This Message was edited by: cs on 2001-11-14 12:16 ]

[larso]

No one else here has run wal mart dyno oil in all there cars and had great success?

It's about 75 cents per litre, and after seeing my family buy that stuff for 18 years, and have no cars burning oil, and never seeing an engine rebuild, I seriously think any oil over $1.20/litre is a waste of money!

Lars.

[cs]

knowing wal-mart and their plan to take over the world they probably sell the best oil money can buy for the least money so when they take the lead in motor oil sales they can jack up the price and lower quality. i don't go to wal-mart just for the fact that they've put every small business in my area out of business and now some of the bigger chains are even starting to crumble because of them.

[AppleBit]

Oil is oil... unless you don't do regular changes or you want to get the most life and performance out of your engine.

That's when you have to decide what oil is best for your application.

Castrol oil (synthetic or regular) is by far the best oil. Amsoil is a little better synthetic but the availability of the product is difficult.

I run castrol in all my vehicles. I did run synthetic in the Porsche, and if I were going to do high speed events, it would be synthetic. Otherwise, in the Porsche I run regular because I want to change every 3000 miles anyways.

Synthetic will result in more horsepower. On a near-stock 924, this results in nothing more than maybe if your lucky 0.5 hp.

The thinner the oil the quicker your car revs, but the easier the oil can break up- unless you run synthetic. Synthetic is a lot better in many ways.

The reasons to run synthetic are hands down.

The reasons to stick with regular are if you have an engine that leaks, synthetic will just worsen it. Synthetic costs more and unless you are actually using it to the benefits it provides, you will not need it.

Most 924 applications do not have a need for synthetic. If you are driving a Saturn like I am for a winter car though- you may want to consider changing to synthetic. It's a lot about what you are using your car for...


_________________
Classic British Sports Car Restoration v6 + v8 Engine Conversion Swaps

Porsche 924 Wide Body LS1 Corvette 500 Horsepower Engine

[924Kid]

My car is not a daily driver, I put *maybe* about 2500-3000 m. a year on it. But thanx for all the feedback, I have already changed my oil....I used regular as I've always done. BUT, just to let you know, since changing the oil, my valves are making this horrible tapping sound and I need to adjust them. Maybe it IS time for synthetic?