10/30w or 20/50w
 

I have a 87 T2 just rebuilt with street port, so when im done breaking in the motor which oil weight should i use...for mineral oil should i use 10/30w or 20/50w and if i use synthetic which weight should i use. Also thinking about going premix so i can use synthetic...

search 'oil' and get a shit-load of info. i use 20w50 castrol gtx, but i dont recomend using synthetic, though people say it is fine, the motor was not designed for it, so i stay away from it.

NO SYNTHETICS. Mineral oil only, I use Castrol GTX 20- 50

Ok, a slight sidebar to this question... I've got a higher mileage 87 n/a that's in pretty decent shape. No mods, YET... I've started started using "High Mileage" oils... Is this ok?

You should use 20-50 in the summer and 10-30 in the winter... And some synthetics are ok... When Mazda put the warning out about not using synthetics, the quality of synthetic oil wasn't what it is today... I still don't use it though... lol

Not a problem with high mileage oil...

Castrol GTX 20W50

:)

Wow we've been through this many times...

1030 in the cold 2050 in the summer for mineral

as for synthetic, Mazda recommended against it becuase there are only some types of synthetics that would work with the rotary, only the very high quality ones (mobil1, MMO etc), whereas the lower grade synthetics (castrol) would leave ash deposits when burned.

if the MOP is removed, any oil can be used in the crankcase because it is no longer being burned. Basically any TC3 2 stroke oil will work fine for the premix.

think ive got that right :P

very good detail answer jono20

thanks very informative

"High milage" oils are loaded with additives. Avoid using them.

FWIW, I use Castrol GTX 20W50 in my 170-something thousand mile, stock engine N/A (along with Honda PCX "S2000" filters.)

Castrol 20W50 :bigthumb:

Actually I think the manual says 20W50 for anything over 80 degrees and 10W30 below that. I can't remember what the lower temp range was. Hell (sometimes I think thats where I live it's so hot), we are almost always at 80 or above except for a month or two out of the year!!! I had to flip out on the local Mazda dealer when he put 5W20 in mine. I was like, "Hey, don't you guys have a service manual you are the Mazda dealer? If you don't I can bring you a copy!!!!" "Huh, no your car is too old." "Hello!!!! Not to mention I told your "Service Manager" I wanted 20W50." I got my money back and went and had it changed at the normal place I go. When they drained the oil it was like water it flowed so easy!!!! I guess as the old saying goes "If you want it done right you have to do it yourself" I guess I've just gotten lazy in my old age. :D

Hmm, the climate in Ohio is a bit cooler that in Richmond... I may have to run 10/30 in the winter.

its 5 quarts of oil right?
For some reason i just use 4 and its full on the dip stick

4.5 if I remember correctly...

I used 10W-30 Mobil1 Full Synth at my last oil change, the only difference I saw was my oil pressure rising about 3psi from looked like 27 to 31 at idle and 57 to 61, also used a K&N Oil Filter...

- Tech

mazda did not recomend the use of synthetics yet they ran synthetics in there own race cars

how ironic

as long as you premix and take your omp out i hear synthetic is no problem

You have to account for the filter too... ;)

as I said, high end synthetics work wonderfully. it is the lower end ones that result in probles after combustion

Yep, Mobil1 with no extra additives (high mileage, etc) for me...

Mazda also ran premix, and was not injecting crankcase oil into the intake like the street cars do. As posted above, with no MOP, what you put in the crankcase doesn't matter (as to how burnable it is).

Regarding oil change amounts, the system, totally dry, takes 6 or so quarts. However, when you change the oil, not all of it gets out, mostly due to the oil cooler and lines.

What I've found makes a big difference (5 quarts vs 4 quarts at a change) is having the engine really hot when you change the oil. Not burning yourself can be a bit of a trick, but I always take the car for a good hard spin right before I change the oil. The hot oil flows better, and you get more of it out.

-=Russ=-

i use castrol gtx 20/50 non synthetic.

im thinking of trying to start taking this !!! special oil for rotary !!

http://www.idemitsu-usa.com/page_211.htm

ROTARY LUBRICANTS

These formulations have been specifically engineered to meet the unique requirements of a rotary engine. The technology base for these formulations goes back to the first and only 24 Hour Le Mans race winner using a rotary engine for which IDEMITSU developed the winning oil.

i use mobil 1 20-50

In the sticky at the top of the page, Mazda reccommends 20-50 for temps between 0 - 80, so thats what I use, cause it never gets below 30* F all year, sometimes we will see a hot day here and there

My owners manual calls for 10w-40 year round and I typically use that in the summer and switch to a 5w-40 in the winter.

Contrary to popular belief ring land wear that was associated with older blends of 10w-40 oil is not an issue for our ringless engines. The ash issue isn't much of a problem either with oils with large vicsocity spreads since EPA and API are heading towards low SAP oils to reduce toxicity to catalytic converters.

I did run 20-50 once in the summer and it cost me about 2 mpg in fuel economy. That doesn't sound like much but is a 10% decline.

I am glad this topic was brought up. Its not one that is mentioned much and is important.

It is interesting you say that homebrewer, since it seems on this message board, in the FAQ and many members, tend to stick to the 10w-40 being bad for the rotary, like gospel. It seems to be stated as a fact by a few resources I have found online, and many times saying the FSM's suggestion of 10w-40 is dated, and inaccurate. Admitedly it scared me away from using it, even though I usually follow FSM's pretty strictly.

Since you have been using it, can I ask how long you have used it? I would assume you have been trouble free?

i live in Ca, bayarea, it stays at about 60-80 most of the year, sometimes it gets up tehre but not often, i use 10w-40 GTX, i havent had any problems

what would you guys recommend for tucson az? its more like... 90-110 (110 being max during summer), but.. 5-6 months of the year its basically 90+

20W50 will work for you year-round.

I've used 10W-30 all year long, the engine in my car has been on 10W-30 all year long and it's at 83,000 miles and doesn't smoke a puff...

Thats fine, and I've read that many people are using 10w-30 as an alternative to 10w-40, which seems to have been shunned. My question is, is 10w-40 really not bad at all, is the whole thing a myth?

Okay we don't need another thread on this... there are at least one a month and it is also covered in the FAQ for FC sticky thread found at the top of this section.

Oil questions other than weight (like the formulations and additives used in high spread visositys) to be used in a FC (which again is covered in the FAQ for FC sticky thread) should be brought up on a Oil board such as Bob the Oil guys board and others.

Thread closed. Covered only about a billion times here, and in the FAQ for FC sticky thread.