Originally posted by MazdaRx7Racer4Life
4k miles breaking in? Im breaking mine in for 600 miles, and ill be using castrol gtx 20w50, since that it what seems to work for everyone here/

Originally posted by f1blueRx7
On rebuilds I use crappy fram filters for the first 2 or 3 ... until it's broken in, then i'll go to a purolator filter. It's more cost effective this way and it really doesn't hurt the engine since you should be gettting your foot into it at this stage.

Originally posted by rotoboy20
are Fram filters no good? im using one right now, is that a bad thing? also if they suck soooooo bad, why use them on a fresh rebuild?

Years ago Fram was a quality filter manufacturer. Now their standard filter (the radioactive-orange cans) is one of the worst out there. These filters are manufactured by Allied Signal, Inc. Please do not buy these filters. By boycotting it, we may be able to cause some change. I have personally had one if these filters fail and actually cause engine damage due to bits of paper and glue floating around in the engine.

Fram Extra Guard PH8A


This filter cartridge has a small outside diameter with a rather low filter element surface area (193 sqin), and features cardboard end caps that are glued in place. The rubber anti-drainback valve seals against the cardboard and easily leaks, causing dirty oil to drain back into the pan. If you have a noisy valve train at startup, this filter is likely the cause. The bypass valves are plastic and are sometimes not molded correctly, which allows them to leak all the time, but they often leak anyway. The backplate has smaller and fewer oil inlet holes, which may restrict flow, and is made of thin material.

The telltale signs for a Fram Extra Guard are: It has 8 small holes for the oil inlet and a thin, cheap-looking backplate, and is currently stamped with a “2Y”. There are 5 very small crimps holding the gasket in place. If you look into the center hole all the way to the top of the filter, you will see a kind of “button” in the end cap of the cartridge (which looks like it's made of metal from there). This is the plastic bypass valve.

Fram Double Guard DG8A


This is a frustrating filter. Please do not buy it. It is one of the most expensive filters you can buy and it is junk. Inside is a basic Fram Extra Guard (PH8A) filter element that has larger diameter

holes at the end and has been pre-oiled. You can see this in the picture above (far left). I assume this is to hold the Teflon particles in the filter element before the unit is installed. Don’t put Teflon in your engine. It does not belong there! DuPont does not recommend using their Teflon product in internal combustion engines.

Although it has the worst filter element possible (193 sqin), it does have a clever spring-loaded nitrile rubber anti-drainback valve and bypass valve combination. Too bad the rest of the filter is worthless. Please don’t buy this filter!

The telltale signs for a Fram Tough Guard filter are: It has a better backplate that is usually shiny, with six larger holes for the inlet and 6 spot welds around the them. The backplate should be

stamped with a “1K”. There are 6 large crimps holding the gasket in place. The anti-drainback valve diaphram behind the inlet holes is black. If you look into the center hole all the way to the top

of the filter, you will not see the “button” in the end cap of the cartridge (which looks like it’s made of metal from there).

When it comes to oil filers you have a lot of choices.
The Mazda Stock Filter
Purolator - L14622
FRAM - PH6607
AC Delco - PF1237
Motorcraft - FL816 (not examined)

A while back we asked ourselves - "What filter is best filter for our Miatas?"
We decided to check out some of the filters the old fashion way - by cutting them open.
Here is what we found.
In the group, the Mazda filer was the smallest - so we figured that is would have the least amount of surface filtering area. Boy were we wrong.
The Mazda filer had almost three times the amount of filtering area as compared to the biggest filter - the FRAM.
The Mazda filter had about twice as much as the Purolator and the AC Delco.
At the time the Mazda and the FRAM were the only two to have check valves (none of the others available now - including the Fram - have check valves of any sort).
So - who needs a check valve anyway? Well what the check valve does it force the filter to work as a filter. It also keeps the filter from back flushing which can happen with any sudden drop in oil pressure. The others, if they get a little clogged, or with a sudden drop in oil pressure, the filter stops filtering and is bypassed. The check valve in the Mazda filter prevents this from happening.
So - if you are out looking for a better filter - it probably hasn't been made yet. Someone would have to work pretty had to make a better filter then the Mazda filter - and they would have to make a hell of a lot of them to even come close to the price Mazda sells theirs for.
So instead of worry about filters - go for a drive.
NEW INFO
(Postscript - around late 1999 Mazda changed their filters. Last time we bought any Mazda oil filter we bought a couple of case and haven't bought any new ones yet.

But here is a report from (Beau) Beauchamp

Ken and Michele, many thanks for your replies to my questions about oil filters and pressure. Taking your advice, I bought a Miata filter at the local dealer here in Virginia Beach. I too was pleasantly surprised at the price, but, I see that the filters no longer have a check valve at the outlet, rather, they have an anti-drainback, silicon rubber, flapper valve covering the inlet ports. Several brands of after-market filters have this feature also.

Originally posted by JusticeRX7
not supposed to use synthetic in rotorys somthing to do with the cumbustion chamber rotorys are supposed to burn oil problems occur if it doesn't.

Originally posted by Icemark
Please read the thread before posting...

There is not a synthetic oil made that does not burn at or below 500F, which is considerably lower than the combustion temps found in the rotary engine.

Originally posted by rxspeed87
too lazy to look but I think amsoil might be right at or a little above 500



but also doesn't amsoil have a HUGE amount of adatives?

couldthat be part of the reason they don't burn very well?

Originally posted by MazdaRx7Racer4Life
Is redline better?

Originally posted by RETed
Flash point temps is irrelavant.
At the rotor housing surfaces (and other surfaces), it doesn't come close to 500F.
Due to coolant and oil cooling, those surfaces are cooler than the core combustion temperatures and are not high enough to trigger flash points temps for motor oil combustion.

This is why we saw significant deposits from Amsoil 20W50.
I am only going to quote what I've seen and experienced, and I would avoid Amsoil 20W50 because of this.  I would avoid ANY synthetic motor oil with stock oil injection unless you show me proof it's not leaving residue all over the insides of the engine.

Chuck the stock oil injection, go premix, then go synth in the oil case - best of both worlds.


-Ted

Originally posted by Icemark
It is a myth that good quality sythetics don't burn well or leave residue.

The 20W50 Amsoil has a flash point of 482F, and less ash (what is left after the oil is burned) than the famed Castrol GTX oils as well as any other 20W50 other than Redline. As a quick comparison, the ash left from Valvoline Turbo (conventional oil) is .99, while the ash left from Redline and Amsoil, both are less than .5 (with actually Redline showing less than .01 in many cases).

There are less additives and junk in the oil in most good quality synthetics than any conventional oil... which means fewer deposits.

That is why I recommend their use to people that have the extra money. Hands down, without any doubts, and proven over and over and over again, good quality synthetics burn cleaner, with less residue, and increased horsepower. The only thing that does not make them attractive is the cost.

I will say this again, for the people unable to search on this subject or too dumb to read the data sheets:

A good quality synthetic (like Amsoil, Redline, Neo, Royal Purple, Mobil1) is perfectly fine to use in a rotary. It is the poor quality ones (like Valvoine, Castrol Syntec, Havoilne, etc) should be avoided like the plauge as they do have the increased additives and left over ash that makes there use unsuited for a rotary or any high reving engines operation. Valvoline Synthetics and Castrol Syntec oils typically have a ash of 1.5...:o

And that hench is the problem... Mazda could not say, its okay to use Redline synthetic, but not Castrol syntec. Of course, Castrol GTX oils are probably the best conventional oils made, but Mazda couldn't say use one, but not the other... so they said don't use any.

And just for referance, This has been proven in rotary engine operation since the mid 80's. I have old RX-7 Club of America newsletters that say the same thing... so it is not some new testing that has proven this... Its the same thing over and over again.

Originally posted by rxspeed87
I remember seeing somewhere that amsoil is a high addative oil

part of the reason they can claim the 25k mile oil interchanges is due to many oil addatives.

saw it somewhere but don't recall exactly
and was wondering if this might be a reason as to why reted saw the deposits left

Originally posted by Icemark
Then based on what you are saying, wouldn't you also see high deposits from oils like Havoline (which has a flash point of 465F) or even the famed Castol GTX 20W50 with its flash points of 440F??

Each and almost every oil, conventional or synthetic burns at between 390 and 500F. Yet the housing is not seeing that temp??? Okay, then only 40F is hardly enough to make a difference in what is burned or not.

Sorry Ted, there has to be more to the story of why you have seen deposits, than just burn temps. Perhaps too much oil injection for example... was the MOP adjusted correctly, etc?

Originally posted by J-Rat
ROCK ON!!! This topic hasnt come up like 50 or 60 times in the last few months...

Do a search on why synthetic is a no-no. You might reconsider.