Bob_The_Normal

NZ, I see your point (that's been repeated like 8 times in this thread... nice patience haha) but I think people ARE missing a good point..

There is NOTHING wrong with the solid thermal pellet.

It CANNOT fail, it's impossible... it doesn't DO anything.

An OEM thermal pellet is only likely to fail if it's very OLD. right?

But if it does, it will damage the engine by restricting oil flow even when the rotors need it.



Is that all right?

So, by having an OEM thermal pellet the pluses are that by LIMITING the oil flow to the rotors when cold, the rotors will warm up faster (is this caused because of less heat taken away by the oil, or is it because of more friction due to less oil?) than the rest of the engine?

With a solid pellet, they will take longer to warm up.


So the argument is what is the effect of having the rotors warming up from the center before the rest of the engine? Or is this needed to get the rotors to warm up at the SAME TIME as the rest of the engine? Seeing as the rotor bearings get oil, and the combustion surfaces get barely any to speak of during normal operation... you could guess the pellet is there to help them heat up at the same time.

But I don't see any strong argument AGAINST using a solid pellet from what you've said NZ.

I have a solid one installed, I'm not worried at all about any damage because rotary rebuilders have been using them for years and nothing has gone wrong. I'll let my engine warm up properly, not putting much load or revs on it at all during warmup. If I revved it up, I might end up warming up the plates and rotor edges before the shaft and rotor centers got up to temp, right?

Anyone else have some guesses?

EDIT: How did my post get put all the way up in the thread?? o_O

--Gary

NZConvertible

I never actually said there was. I simply believe it's better to have an operating thermal pellet.

Not necessarily. The engine would only suffer damage if you continued to use the engine even though you knew oil pressure was low. Even normal driving (i.e. not romping on it) would be unlikely to cause damage in the short term. High-rpm driving would cause much more damage though. The point is, if you notice the oil pressure is low and take appropriate steps, any damage would be minimal and would certainly not kill the engine.

The engine does not warm up faster due to excess friction. That would be a truely stupid design. It warms up faster because the oil squirters than normally cool the inside surfaces of the rotors are disabled until the oil is warm. There is still oil going to the bearings during this time.

I don't think timing is really the issue here, although it's quite possible it has some effect. The idea is simply to keep the heat generated by combustion inside the engine to warm it up quicker. It's the same reason for disabling the radiator until the coolant warmes up.

I've never tried to present a strong argument against using a solid pellet. Go back and read what I've written and you'll see that all I was trying to do is dispel the myths and BS about the thermal bypass. It's pretty obvious that most people don't even understand how or why the thermal bypass works, so how can they argue that it is a bad thing and/or that a solid pellet is better? Most of the arguments presented against the thermal bypass were badly flawed.

If you believe that the thermal bypass in your engine is old enough to be at risk of failing, then you should replace it. But since the longevity of this part is well-proven (and hence there is virtually no risk in using a new one), the only difference between replacing the old one with a new one and replacing the old one with a thermal pellet is the cost.

RotaryEvolution

iTrader: (30)

well i had to make one last reply to your last post...

oil pressure is not only lowered to the rotor faces but to everything in the e-shaft, one main reason when the thermal pellet fails it causes engine damage. true the pellets rarely fail but as Icemark said they do cause damage when they fail and i doubt taking it easy on the engine will save it, maybe a trip or two home won't hurt much but if not caught right away could cause severe damage.

the oil supply from the e-shaft supplies oil to the main rotor bearings, the sides seals and to the oil jets. a thicker oil like 20-50 might be able to lubricate well enough if the pellet failed but someone who doesn't know any better running 5-30 would probably be causing damage quite a bit quicker.

most people consider it a precautionary measure but i see you won't budge on the subject so i'm done.

91mazdarx7

can anyone answer my last post and whats some good motor oil to use on s5 t2's and s5 n/a's

TII '87

this subject is REALLY interesting and extremely well explained!!

maybe we could archive this.... MODS???

Aaron Cake

iTrader: (1)

Read the manual. 10W-30 in the winter, 20W-50 in the summer.

Aaron Cake

iTrader: (1)

Also, I will move a copy to the archives when the topic ends.

Gene

iTrader: (1)

I think what he was getting at is that all engineering is a compromise between the various desired elements of a design (in the case of an engine these would include power, efficiency, reliability, emissions, cost, etc). Putting emissions junk on a motor means that something else gets sacrificed. The 3000RPM startup is an excellent example. Cost, simplicity, and reliability all get hurt by its addition, but emissions are improved.

I'm in the middle of a major rebuild of the engine in my beloved FC, after having it blow up real good on the way home from a track event. Because most of the miles that get put on it are done on track or on the way to and from the track (and remember that Porche's engineers consider a racing mile to be equal to a thousand highway miles, as far as wear and tear is concerned) we are doing all of the major oiling mods, to protect the engine under sustained high RPM use. This includes the oil pellet mod. Anything that could fail and cause a general failure is not something you want on your engine in such a situation. For the street, it's a little harder to say. I think I would still opt to remove it, since I always warm the car up gently, letting it idle for a while and keeping the revs under 3000 until it's at full temparature.

NZConvertible

As Mark stated, those owners continued to use the car normally knowing the oil pressure is low. If you do that, you get what you deserve.

Wrong again, the side seals are lubricated by the OMP (or premix).

Why should I, when not not one person has given any factual technical info to counter anything I've said? You're still posting wrong info, so you certainly won't be changing my mind.

Bob_The_Normal

I think the subject is pretty much dead... it's all down to a matter of personal opinion unless we start breaking out the hardcore testing and diagnosing equipment that probably only Mazda engineers have access to... or something.

--Gary

91mazdarx7

anyone think it would be worth buying the video also there was a thread just acouple weeks ago about who makes the better rebuild video i searched but didnt find it so who makes the best rebuild video and where can i buy it

Bob_The_Normal

Word has it the Rotary Aviation video is better.

I used the Atkins... and it was helpful, but I could think of a ton of ways it could have been MORE helpful... things I thought would be easy to include in the video, but weren't there. So maybe the RA is better... thats what the people in that thread you're talking about were saying.

--Gary

NZConvertible

True, people will always have their own opinion on using the thermal bypass. I'd just like those opinions to be formed using facts, rather than myth, speculation, guesswork and plain ol' BS, quite a bit of which has been posted so far.

RotaryEvolution

iTrader: (30)

by side seals i meant the inner oil seals, sheesh, take a breather man...

RETed

If you take a look at the OIL section of the FSM, it's pretty much self-explanatory.

When the oil thermo pellet is in full extension (HOT), this closes one or two bypass holes in the front of the eccentric shaft.
This causes oil (pressure) to go in from the front stat gear bearing (and rear?) into the eccentric shaft and eventually out to the rotor bearing lobes and eccentric shaft ball-and-spring jet in the center housing area.
With the oil thermo pellet retracted (COLD), oil is bypassing this above sequence.

Now, the question is...what is better?

This whole system was designed by Mazda to shorten the time oil temps come up to normal operating temps.
There is another one that bypasses the oil cooler also.
Emissions was a top priority for the engine, since Mazda knew the rotary engines were "dirty".
This is the reason why U.S.-spec FC's had extra catalytics for emission purposes for stricter U.S. emissions standards.
Pre-cats and accelerated warm-up high idles were to clean up cold-start emissions on the FC turbos.
This is all documented in the Yamaguchi FC "book" and other sources.

So, again, what is better?
Failed oil thermo pellets have been known to drop oil pressure anywhere from 10 to 20psi at maximum over factory spec numbers.
This has been thoroughly documented.
Extended low oil pressures like this will cause accelerated wear on bearings.
This has been documented - any competent rotary engine (rebuilder) shop should know this.

So thus, the questions becomes a matter of getting the oil (and engine) up to temp quicker or premature wear of the bearings.
Slower rise in engine temps affects engine mileage slightly.
Slower rise in engine temps affects emission slightly.

Personally, I'd rather protect my bearings that worry about the slight increase in gas mileage and emissions...


-Ted

NZConvertible

I wish more people would.

The key word here is extended. I'm sure everyone would agree that the stock water temp and oil pressure gauges should be checked regularly when driving. I know I do. This should make a failed bypass obvious pretty quickly. Any extra wear on the bearings in that time should be very small, and certainly not engine-threatening. The general feeling seems to be that the engine is going to grenade the moment the bypass fails, which is a load of crap. If you drive for extended periods with low oil pressure, accelerated wear on the bearings will result as you say. Only a fool would do that.

If I was building a race engine I wouldn't use one, as the possibility of serious damage being done before you notice low oil pressure is much, much greater. For a street car, I would have no hesitation installing a new bypass, confident that I have more chance of winning the lottery than having it fail on me and possibly cause bearing damage.

You state that as if the "premature wear of the bearings" is a forgone conclusion. See above.