rx7duck

1) If I want to change over from synthetic to dino or the reverse, why do I need to get every molecule out (oil cooler, etc...) as some have suggested in other threads? It seems that a little mixture wouldn't hurt anything.

2) Any thoughts on using oil flush (like the stuff made by Gunk) when changing oil?

3) Does anyone use MMO as a premix (with MOP/OMP still connected)? If so, how much is appropriate? 1:200?

Snrub

iTrader: (1)

Well since no one is answering you, I'll say this much: A guy I know who just finished Materials (mechanical) Engineering learned at school that various additives can react together in a counter productive manner. So it's possible you could damage the new oil a bit. If you go on Castrol's website they refute the claim that you can't switch back and forth from conventional to synthetic.

I run a bit of premix with the OMP still in place. If you're just looking for extra insurance 1:200 seems like a lot to me. I run maybe 1:1000. I do this because I killed my last engine from lack of oil. It's probably not needed. With the normal OMP system I run a 5W50 full synthetic.

I'm no expert, I'm just relaying what I think on these matters.

Agent_D

iTrader: (2)

apparently from various sources, fully synthetic oil leaves residue inside your rotor chambers since it doesnt burn like conventional oils, which is basically like carbon build up. switching on the other hand, i dont believe it would have that horrid an affect, it might contaminate your first or second oil changes but probably flush out after that, and you could probably use the oil flush also. not exactly positive though. and yes you can use MMO as premix, you can use MMO in piston engines, because MMO is a good cleaner of fuel injectors, etc... and you can use the recommended amount on the rear of the MMO bottle as a result, its not like normal premix oil

Snrub

iTrader: (1)

Icemark has posted a number of times debunking the residue claim about sythetics.

Everyone here is convinced sythetics are evil. Go to the FD forum and lots of people use it.

YakATK

The way I see it, synthetics are totally fine to use. As long as you get your oil changed when it needs to be changed and not leaving it longer. Or even do it slightly more often then needed. Its not gonna mess your engine up. I choose to run non synthetic oil in mine.

I have also heard about the 3rd gen guys using Mobil1 Synthetic I think. No problems with it from what I have heard. Not sure if thats the exact oil they use or not. Just what I heard.

Thats what I know though, which is not alot. Just my 2 cents.

NZConvertible

You don't; mineral and synthetic oils are perfectly compatible. I always use and engine flush at oil changes. Some of the stuff that comes out is scary...

HIMNI Racing

I think the oil flush is ok but, my biggest prob. w/it is, how do you get ALL that crap out? I mean, your putting something in the oil that is by no means,oil.

If motor flush removes all the crap in the system then it must be a god oil fighter. I don't know if i'd want that (even a small amount) in the oil that's in the car after the change.

I like to flush the system w/ new/clean oil. (change the oil, run the car for 5 mins, then drain it. Repeat is needed.........I sound like a shampoo bottle

EpitrochoidMan

Engine flush is mostly oil, just a really thin oil with a bunch of detergents and cleaning chemicals in it. You could drive around with just motor flush in the engine for days and it wouldn't hurt anything, I had a customer yesterday who was doing just that (but I wouldn't recommend it b/c it made his engine REALLY hot). In fact, most engine flushes on the market today are beneficial for the seals.

And, OF COURSE synthetics and dino oils are compatible, that's what 'synthetic blend' and many 'high mileage' engine oils are.

Mobil1 is the bomb, but I'd be running redline if I got paid more.


P.S. for best results change the filter then run the engine flush, then change filter again with fresh oil.

Icemark

Man, just do a search, there is nothing wrong with better quality synthetics, as I have posted hundreds of times, it's the cheap oil company brands that you want to stay away from.

Redline, Mobil1, Neo, Royal Purple, amsoil, all have a lower ash (left over deposit after burning) equivellent Flash point (what temp the oil burns up at) and a minor increase in HP (and burn cleaner) than many many conventional oils.

Its the crappy synthetic oils like Havoline or valvoline or even Castrol Syntec that should never be used, because high deposits, high flash point, and other issues.

But again as I have posted many times, Mazda couldn't say, just use the good brands oif synthetics... so they said don't use any.

Now a days, most of us know better than to say the blanket statement of "never use a synthetic". Instead it is never use a crappy synthetic.

rx7duck

Thanks all for your replies. I like the flush with new filter, then new filter again idea.

WolfsRx7

iTrader: (1)

I read on the mobil 1 website that sythentic should not be used on rotary engines. I premix with the omp in place and just use the regular mobil 10-30.

bac22

Why would you want to use a synthetic anyway. Most rotaries burn a quart of oil every 750 to 1000 miles, so with the constant addition of new oil you are maintaining viscosity which is the main purpose of synthetic oil; it is suppose to hold viscosity longer the dino. Mute issue with the rotary engine.

Icemark

Extra HP and reduced wear are why you would use a synthetic.

I agree with that they are not cost effective, but I could see for racing applications where you are changing your oil before and after anyways, that the extra HP and reduced wear would be a considerable benny.

But on the same vein it's not cost effective to swap in a 20B or 13B-REW or even an alternitive engine into a FC, yet people still do it.

Dougster

The Previous owner of my 87 T2 had always used Mobil 1 syn. oil and I must say, the oil looks very clean whenever I check the dipstick. (I haven't done my first oil change in this car yet) I put my new exhaust on maybe 2 weeks ago, and the insides of my SS muffler still look very clean. For what thats worth?

HIMNI Racing

I think I'll just sick w/flushing the engine w clean oil. I'll sleep better at night. It costs me alot more money to fluch the engine w/Amsoil but, it's worth it. I get it @ whole sale prices anyway.

Then, that oil & all my used oil just goes onto all my fence posts (adds life) I have over 8 diff. egines that I use synthetic oil in. The only car I don't use it in is my wifes 1st gen..........that too will change in time

I have so much land I will never run out of posts to put it on. *walks around with a 5 gal. bucket with a spout*

boosted1205

iTrader: (9)

[QUOTE]Originally posted by rx7duck
[B]1) If I want to change over from synthetic to dino or the reverse, why do I need to get every molecule out (oil cooler, etc...) as some have suggested in other threads? It seems that a little mixture wouldn't hurt anything.

That's ridiculous. There is no problem changing to mineral to synthetic. If the above was true it wouldn't be possible unless the engine is torn down completely just to change to synthetic?


2) Any thoughts on using oil flush (like the stuff made by Gunk) when changing oil?

It is a good idea especially it would clean the OMP lines somewhat and oil injectors.



3) Does anyone use MMO as a premix (with MOP/OMP still connected)? If so, how much is appropriate? 1:200? [/B

For pre mix oil, ALWAYS use TC-W3 certified oils.
If you totally disable the OMP, about 8oz for a full tank should be OK. I've use that since day 1.

boosted1205

iTrader: (9)

.

boosted1205

iTrader: (9)

Here's some reading on synthetics.

http://www.bestsyntheticoil.com/amso...nthetics.shtml

boosted1205

iTrader: (9)

****...there was a site that had all spec for popular oils including ash content and viscosity. I lost the damn thing. Anyone know the site?

boosted1205

iTrader: (9)

Interesting reading on oil.

http://www.xs11.com/stories/mcnoil94.htm


Ahhhh...here's the site I was looking for:

http://www.vtr.org/maintain/oil-overview.html

Icemark

http://www.vtr.org/maintain/oil-overview.html

boosted1205

iTrader: (9)

LOL...that was good timing. After I posted it I saw your post

Thanks Mark

Icemark

If you are really concerned with the metal of the engine absording an oil, this is what you want to do:

Wait you say, did Mark really say the metal that your engine is made of absorbs some of the Engine oil in your car into its surface!

Intrigued?

Advice: When you get your car see if you can find out what oil the owner, or his service agent has used, and stick with it, unless it's poor quality then flush it out in the following manner. I explained this to Jeff Tate on the 'phone as his car suffered from sludge deposits, it is a bit involved but worth telling.

1 Warm the car thoroughly, and drain off about 2 quarts of the oil already in the car, replace with a good flushing oil.
2 Go for another good run.
3 Use the car for no more than 300 miles and always decent length runs.
4 After the last run drain all the oil, refill with entirely flushing oil, take her out for another good run, stopping at intervals taking the oil filler cap off and feeling if the sludge becomes less gelatinous and there is a distinctive smell, slightly 'petrolly' in nature.
5 Go home at this point, don't venture more than 20 miles from home, in other words; take a circuitous route until the desired effect is achieved.
6 Drain the oil OVERNIGHT in a warm garage.
7 Do a complete oil change.
8 Do not drive for 30 minutes after filling the car, and before driving check the oil level and top-up to the mark.

Over the next 3 oil changes all the sludge will disappear.

Also NEVER,NEVER,NEVER put Slick 50 (or most other engine treatments) in an Engine with sludging, some people have done this in the past, then tried to blame the product for their own utter stupidity when the Engine died.

What is Sludge?

The oils we use are L.ong C.hain P.olymers, and they all deposit themselves on the surface of the metal, it is designed to be wiped off and replaced with other LCP's as the first ones break down. When a different oil is used it may not be able to remove the old LCP but will leave its own new LCP on top and the pollution just continues as one affects the other causing further build up. This is the basic creation of sludge.

Based on the infor from Iain Wiltshire - Newbury, Berkshire, England. Originally published 21 October 2000