Synthetic Oil question??

[English_leather]

Hey, can you switch to synthetic oil in older cars?? we want to know if it will work in the rx-7. Also, can you go back to regular oil if you need to?

[Zero102]

Yep, you can switch to it in anything. Although, some of the Rex guys will tell you you can't. Check out rx7club.com for a LOT of discussions about synthetic's in rex's. The general consensus was it's fine to run in them.
I run synthetic in every car I own. Look up the results of the Olds III-D test, or others similar to it. Those are my reasons.

If you would ever want to (for whatever reason) you can switch back, no problem.
It's not as big of a deal as everybody makes it out to be.

[GTS Jeff]

the main complaint ppl have is that synthetic gets thru small leaks on old motors a lot easier than regular oil. if your engine leaks right now, expect it to get worse with synthetic. if u dont notice any leaks at all, u might see one appear after switching.

with that said, go for it and see how it turns out. if ure leaking, u can always switch back or u can be non-ghetto and actually fix the leak.

[djfob]

I switched at 200k and I see no leaks at all. I used an engine flush before I switched. I think it's really hit or miss depending on condition of engine.

[method]

depending on the additives, synthetic oil can actually renew older seals better than a petroleum based oil can... it's really up in the air.

just switch back if you notice any leaks getting worse.

[dean'er]

I use Red Line oil for all my cars. It works great but the initial invesment seems to be alot but the product is worth it! I have a 96 stang and a 91 civic (for sale)they both go for about 15,000kms on one oil change. I have a 2002 chev under warranty and gm dealership still will warranty my engine if they service it every 9,000kms. The biggest thing i noticed was my winter starts were easier.www.redlineoil.com

[Zero102]

^^^^
Definately, and moreso than it just starting better in the winter, the engine is MUCH better protected than with a conventional.

As was said earlier, if you switch, and for whatever reason don't like it, just switch back.

Although, I really like the extended change interval. I change my synthetic every 10,000km's, with a filter change at 5,000km's.

Amsoil makes an oil they claim can go something crazy like 40,000miles without a change, but that sounds much too high to me =)

If you're not too familliar with synthetic oils, the most popular brands seem to be Mobil 1, Amsoil, and Redline. At this time, Partsource carries all 3 in the most common weights. (Although I have no idea what their pricing is).

[rockym20]

Crappy Tire has them all as well. I just put some Redline 10W30 into my wife's truck last weekend. It was on sale for something like $9.10/bottle. The Amsoil is a few cents cheaper. You can get a 5L of Havoline (or Valvoline, I can't remember) synthetic from Wal-Mart for only $22. It is by far the cheapest sythetic there is. The only thing is that only Amsoil, Redline and Motrlube (look them up on the web, they are based out of Lethbridge) are esther based. In other words, these oils are true synthetics, while all other ones (including Mobil 1) use a conventional base. This is why Amsoil, Redline, and Motrlube can all go for at least a year between oil changes (you do have to change the filter every 3-6 months though), while other synthetics have to be changed on a normal basis. It is also why they are quite a bit more expensive.

In Europe, there are a lot more esther based oils available (ELF, for example, makes it) and is required in some of the new cars there.

[5.9 R/T]

I realize synthetics are better but 15000 between oil changes? I'm not going to be buying any of your vehicles soon.

[HellfireR6]

if u got a boosted ride, the motul 5100 synthesis is awesome! bout $8 perl litre at Walt Healys..... works great for bikes and a few guys recommend it for turbo cars!!

[dave5473]

Ive noticed some older engines will burn a little more oil if you switch to synthetic. Still a good idea to switch imo though. I run Royal Purple in everything i own.

[rip]

It isn't a good idea to run regular oil after you have been running a synthetic. You will burn a pile of oil.

[GTS Jeff]

Originally posted by rip
It isn't a good idea to run regular oil after you have been running a synthetic. You will burn a pile of oil.

how does that make any sense?

[Zero102]

^^^
Just a myth.

[rip]

Well i have seen it time after time in the on engines in the oilfield. The company i worked for swithched to synthetic oil then decided it was too expensive so switched back to regular oil, after that almost every engine burnt a ton of oil. It got to the point of adding up to 1L/ day.

[GTS Jeff]

Originally posted by rip
Well i have seen it time after time in the on engines in the oilfield. The company i worked for swithched to synthetic oil then decided it was too expensive so switched back to regular oil, after that almost every engine burnt a ton of oil. It got to the point of adding up to 1L/ day.

magic?

[Zero102]

It was due to something else.
Unless there is more to the story than has been said, such as they sat un-used with old oil in them for years while they decided to switch back....
Simply switching between the 2 is completely harmless. Although, IMHO, stay with synthetic, it's worth the extra cost for the reduced engine wear.

[Owned 2]

haha, I wouldn't put synthetic in a rotory, rotory engines are almost all seals. synthetic causes some seals to swell up to like 3 times there size. a buddy of mine put some seals in a pail with synthetic, a couple days later they were swollen like big old worms.

[Zero102]

Oh dear.....
Please, just don't post big piles of BS like that.
First of all, it's rotary, not rotory. The apex seals, which seem to be what everybody worries about, are metal I believe. The rest of the seals are just like the seals on any other car. If synthetic oil really caused them to swell up like that, nobody would use it.

Would you mind explaning what is so different about a synthetic oil compared to a conventional, that would cause the seals to swell up?
The biggest difference between synthetics and conventionals, is that in a synthetic, all of the molecules are homogeneous, and there are far less refining by-products in synthetic oil. This ensures greater consistancy, and increased longevity of the oil.
There are no paraffin's in synthetic oils, they are an un-wanted petroleum by-product, which is left in conventional oils, which is what causes them to thicken in the cold.... So far, everything I can think of, tells me that synthetic should have a far less adverse effect on any seals than a conventional.

Yes, of course, rotary engines are almost all seals, no combustion chambers, no rotors, no housings, just seals.....

The biggest argument against putting synthetics in a rotary is the additives that are in a lot of them. People claim that they don't burn as cleanly, although I have seen absolutely no hard evidence to that effect. When we get around to rebuilding the engine in the 81 rex we have, I plan to run synthetic in it.