I don't think that it's much of an obsession (and you don't sound like a jerk) as much swapping in an OEM FMOC to replace the beehive cooler that came with (some of ) the first generation cars is fairly simple, fairly inexpensive and it works. There's not that much reason to go to a different/aftermarket oil cooler for most of the people on this section of the forum.

 

If i still have it it was in good shape when removed no leaks. Came off a car that lost compression and i traded to a guy to use as a parts car. Dono 75 shipped I ll have to look it over first. Pm me if you interested.

 

212F Oil Temp?
Alittlle to Warm to drve it like that day in and day out at least for my Engine.
sgieldon
steve

 

It's well within spec, believe it or not. VW is one of the only cars, the Scirocco anyway, that had a factory oil temp gauge. It's red zone is way up there. I've heard stories from sustainted 100mph+ runs in Europe that make it evident why there is such a gauge.

I've seen 275F once for awhile in a tired TD with a load, on the interstate, in summer, with the AC on running 85mph.
Cooler is nicer, but it don't really hurt anything on a piston motor.
We shoot for 100C(212F) under load.

It does vary from engine design to engine design, but from what I'm seeing so far a rotary does not have particularly hot oil. I'm sure adding a turbo has some effect, much like a piston motor.

 

Due to the way a rotary engine is constructed, the oil cooler performs the same function, in a sense, as the coolant passage ways in the heads on a piston engine. There are 2 things that cool the rotors themselves, the intake charge and the oil. If the rotors aren't sufficiently cooled, well, use your imagination.

 

not to high jack the thread but does the 1st gen fmoc need a temperature gauge i didnt see a place for one on my fmoc that i got for my 85. Shouldnt it all just bolt on?

 

Well, here is the thing. The rotary oil is not that hot because the oil cooler *works* great. We do not want to see high oil temps. At a minimum, the high temperatures can break down the various oil system o-rings. At worst, use your imagination, as trochoid said.

The oil temperature will rise as loads increase, but should stay within the Racing Beat's listed values. If the oil cooler is too small, you will see high oil temps even in low to moderate loads. In addition, if the lines are too small, you will restrict oil flow to the engine.

Anyway, you guys are welcome to try aftermarket oil coolers. It is your engine, after all. We are just giving some warning of the consequences that could occur. As I mentioned before, I see no real reason to experiment with aftermarket oil coolers at this time when good used OEM oil coolers are available at reasonable prices. Maybe in 10 or 20 years it will be a different story, but for now, why chance it?

 

I know, but i dont want to buy a new OEM one when i could buy a new aftermarket one for less. There has to be a OC that flows the correct flow. With a thermostat, even if the oil cooler is larger than a stock rotary, the oil would be released at the correct tempature. Thats how a thermostat works correct? When the oil/liquid reaches the correct tempature the thermostat allows the liquid to flow faster, either mechanically or electronically?

Does anyone have the EXACT measurements of the stock one, ive gotten a few answers but im not sure. Il check back on my old posts to see, if anyone has a volumetric measurment of flow, liters per hour or per minute, that would be great. The tubing has to be 1/2" to match the stock one correct. Even two smaller oil coolers plubed together and a small fan if needed, could be a solution.

Now i know trochoid and a few other members will ensure me that what im doing is stupid, "why not just use the same bloody thing that everyone else uses". Well for one, im a thinker and i usually like to try and be innovative, instead of buying parts, i build them. Second of all, i want to be different, thast kind of obvious tho..

Just as an example, i was the first person to mod the first gen crx bumpers and fenders onto a sedan of the same year. Maybe not that great, but it inspired a few members to really look into it and now they figured out that they can swap on the CRX mugen front clip onto the sedan, where ppl have been looking to change the look of their little drag sedans for along time.

A few members on my old first gen crx forum started to think, hmm you can fit a D16 head on the SOHC EW Engine aslong as you use the D16 pistons, after boring out the block, using an extra tensioner on the belt system, and tapping a few of the head holes. With all that work you create more high-end power than the d16, this way you dont have to swap motor mounts and ECU's and such "which is way more expensive". Bike carbs were used, 4 of them, just to make the engine a little more interesting, but the carbs had to be rejetted, interesting tho.

 

I can see how cooling of oil is more important on a rotary.

And please don't take any of this as argumentative, it's just how I learn, and frankly it's not often on anything four wheels that I really get to delve into anything that's all that different from the last one, you know? It's why I'm attracted to the RX-7 and rotary engine in large part, it's different.

How's the oil pressure and GPH flow on a rotary?

 

4-1/2 X 2-1/2 X 22-1/2 are the dimensions on the stock rotarys according to trochoid.

Stock -----------22.5 x 4.5 x 2.5 = 247 cubic inches (??? tubing)

dual pass, thermostat

First find -------11.5 x 5.5 x 2 = 126.5 cubic inches (1/2 tubing)

thermostat available.

Second find --- 21 x 7 x 1.5 = 222.5 cubic inches (5/8 tubing)

available thermostat and wide variety of fittings, custom made.

The first find would not work individualy but i believe it would work plumbed together, aslong as the thermostat was on the second one or both thermostats worked together.

i dont want to say the second find would work because it does actually have a smaller cooling area than the stock one. But its close, i could get the volumetric flow chart quite easy, if someone could tell me the stock amounts to measure up to this one that would be great.

 

Go back to working on Hondas. I could see if what you were attempting was an innovative idea but it is not. The stock FMOC fits on the car, works on the car and meets the specifications of the car. And there are still tons of them available at a very reasonable price.

I expect the next time you decide to be different that you will atleast come up with something that makes sense and that actually is a benefit or improvement to the 7. There are guys on this forum that have been around these motors for more years than you have been on the planet. 1 being me and the other being Trochoid and I'm sure there are others.
Myself as well as others welcome new and fresh ideas that will benefit all but this is not one of them.
EDUCATED members have tried to school you on this subject but it is being heard on deaf ears.
Last thing said, This is not a HONDA!

 

being knowledgeable is a good thing, but being stubborn is another, the fact that i dont want to stock FMOC bothers you because im young, and i have yet to learn everything about the rotary engine. My old boss once told me something, just because someone has been doing something for 10 years doesnt mean that someone bran new wont see what they are doing and improve on it. I dont care what you say, theres an aftermarket for a reason, to improve on stock items. The stock one might suffice, but if i was to buy an old one and it were to crack as some members have already pointed out, then i would be out a OC and possibly an engine if i were to accidently not notice that my oil pressure pissed out the bottom of the car. Why would i want to replace an old piece of junk beehive with an old FMOC that possibly could break like other ones have.

Yeah i was just refering to honda, im sure im going to be bashed for driving a honda, but what i did wasnt ricey at all.

 

btw, i really dont appreciate you guys trying to make me look like an idiot with my ideas. I once asked if the trany cooler was fine for a stock replacement, the answer was no, and i accepted that. I did not say anything about a AC condensor anywhere and the fact that you are pulling **** out of your asses to make me look bad is just stupid. Call me what you want, but im going to figure this out and do it.

BTW, people replace things all the time that are great stock, but again that doesnt mean they couldnt be better.

 

BLAH BLAH BLAH BLAH!!!!!!!!! I wouldn't bash you for owning a Honda, In my opinion Hondas
have very well engineered motors and are very reliable.

But the piston theories do not apply to the Rotary applications. The only FMOC that have seen that is prone to cracks at the fittings are the GSl-Se ones. I have not ever had a 12A FMOC that had cracks at the fittings. I think alot of has to do with over tightening the fittings when there is a leak believing that it is the fittings when in fact it is the incorrect sealing washer being used. And all of the FMOC that I have ever got out of a wrecking yard that were on a 2nd gen, not one leaked. So I would say that for the most part that they don't leak. And for the hoses, yes after 15-20 years you have one go. What does that tell you about the design, it's pretty darn good. And if you have a hydraulic shop make up an aftermarket cooler hose that uses hose that is rated at 3000 PSI it will never fail. That is an improvement over stock that can be done and what I have done at times. I have only had coolers that leaked with bad sealing washers on them. (using copper instead of aluminum).
And they guys that have been doing this since the beginning. IE: Racing beat/Roatry reliability all concur that the stock FMOC is the best design period. And yes, they have tried many others to determine if there could be a better alternative.

 

maybe im just too stupid, or maybe too stubborn to think that stock is the only thing out there, i know a rad shop that would make me one that was the same as stock, but alteast it would be new. Would that be stupid, stock is stupid? if it flows the same as the stock one, and cools the same, and works the same, is that stupid? Just because it doesnt look the same or it isnt the same make doesnt mean it wont perform. Someone said its one the most important things in a rotary, so whats a little extra insurance by making it bigger. whats wrong with being different. "blah blah blah" is right, this topic should be left for people who are interested in trying to change things.

 

We are interested in the improvement of a design when it is needed. AS stated the BEST have looked at the design of the FMOC that the ENGINEERS have built that is WELL ENGINEERED to perform in the most EFFICENT manner. They have all agreed that the stock FMOC is hands down the best design. Being well engineered is one thing, being over engineered is another. Meaning if one can of fuel injector cleaner is good, Wouldn't 2 bottles be better? The answer is NO!

Now if you want the radiator shop to build you a NEW cooler, that's ok. Heck it is your money. But as far as this thread being of any help to anyone at this point it is not. Maybe if you get the cooler built than you can start a new thread that gives the design of the cooler with specs. How much it costed, where it is mounted at and how, what type of hoses were used and how much they cost.
And the biggest thing which would not be known for awhile is how well it functions.

Now if you really want to improve on something. Then improve on the GSL-SE injection/induction sytem and all the quirks that it has.

 

Why o why dont you understand. there are more than enough stock ones around. Racing beat even sells a racing one. There are new ones you can still get from mazda. Still dont know why you think mazda would put something on there cars that doesnt do the job the best.

 

hahah it wouldnt be the first time that a company put something on that wasnt the best.

if someone can get more accurate specs on the flow of these OC's it would be great. No one has came up with any numbers yet.

 

That's because there are no known publicized specs.

 

hmm well aslong as the tubing, and size are the same then it should be fine. Its a dual pass correct? The tubing inside the cooler is 5/8's i presume

 

uh hum, hate to say it but they did put a damn beehive in my car.

As for the rest. I can't say as I blame him for looking elsewhere. I am a huge fan of aftermarket parts. The stock ones are excellent products, but extremely expensive brand new, and I have a loathing hatred of used parts. I personally have removed the beehive and installed a stocker, but put serious though into an aftermarket one. This is just the way I went.

There is nothing wrong with creative thinking. He is just trying to figure out what he thinks would be best for his baby. Give the guy a break.

 

+1

 

In my 3+ decades of many different crafts and trades, I have ALWAYS asked, 'Why is it done this way and is there a better way?'. Most of the guys I've worked with had no idea why the perfomed thier tasks in the manner they did. That's the way they were taught and didn't care about the science of mechincs behind it, I do.

Unless you want to put around town, or shorten the life of your engine, use the stock cooler. I'm not being stubborn. I know what works, why it works amd why it is engineered as it is. Fwiw, some guys that track thier 1st gens run 2 stock fmocs, as do some of the high hp TII street guys and the 3rd gen R1 model came stock with an additional oil cooler.

Be/think creative all you want, that's a good thing You however are the one that is being stubborn and beating a dead horse. If you want to use an aftermarket cooler, do it. Your question has been asked and answered many times by many members.

Install an oil temp gauge when you do it and report your results to the rest of the forum.

No the internal tubing is not 5/8, why would it be? Think about it, creatively.

 

Yes, they tried the beehive in 83-85 12A motors with a taller radiator and a higher CFM fan clutch but found that it did not meet up to the standards of a FMOC. So that's why in 86 they went back to the tried and tested FMOC and stayed with it.
Meaning it is very efficent period.
And he does not know what is best for his "Baby", We do, you know the guys that have been around the rotary scene for 2 decades plus.
That's why they have us old farts and others to educate the Newbies. You see we have already made alot of the mistakes. I can understand where he is coming from. It's thru experience that you learn, but this forum is about helping those that who do not know make the mistakes that have already been made along time ago.
Also he believes that we are set in our ways. We are not if there can be shown a EDUCATED reason why the stock FMOC should be improved upon when it has been proven that it works very efficently.

 

Got any more pics of that?

Assuming the pic is taken from the bottom of the unit. The length looks okay.
Looks a bit shorter in height than the stock FC cooler, but I think the extra thickness on it will help.