OneRotor

iTrader: (3)

So i performed my first oil change today in my 7. Bridge Port 12a, Holly 4bbl, etc., etc. I bought it about 10 days ago, and have put about 50 miles on it, and i decided to change the oil so i knew the exact mileage when it had last been changed. i used Mobil 1 15W-50 Extended Performance Full Synthetic, and a Fram HP1 Filter (remote mount oil filter). all went well, easiest oil change EVER!. started it up to check for leaks after filling up with fresh oil, no leaks whatsoever, and i checked my Oil Pressure gauge (mechanical gauge made by Autometer). It was reading ~7psi more pressure at idle. Jumped in the car, slowly took it up through the revs (I do my oil changes when the car is warm so the oil comes out faster), and by 7,000 RPM, i was pushing almost 80 psi of oil pressure! i was so excited. before my oil change, i could barely pull 55psi of oil pressure at redline. new oil is grand.

Stanello

iTrader: (1)

Synthetic huh?

RotorMotorDriver

iTrader: (1)

Oh boy, here we go

~T.J.

https://www.rx7club.com/forum/showthread.php?t=247216
https://www.rx7club.com/forum/search...archid=1000977

Stanello

iTrader: (1)

lol, I was gonna leave it at that

lovintha7

Well, I'm all for synthetics in rotaries. Just not Mobil 1. If you read Royal Purple's website, it was kinda designed for rotaries. The CEO of Royal Purple is a rotorhead. Mobil 1 hasn't impressed me in hi-po engines. We run either Red Line or RP. Just a thought for you on the next oil change.

I noticed on the race car (It's a mustang, but nonetheless) that oil temps dropped 20 degrees with Red Line, after switching from Mobil 1. I also noticed that when Mobil 1 gets hot, it seems to "bake" in the oil pan, much like very hot conventional. I'm not dissing Mobil 1 for street cars, it's great for that, but in a high hp engine, it's not the best idea. That's our findings in an all out race car. I fiqured a BP engine would classify as high performance.

I'm not starting a synthetic war, nor am I starting a "You shouldn't use synthetics in Rotaries". Just posting my findings.

Dan_s_young

iTrader: (1)

haha full synthetic oil and a fram filter, you couldn't have gone more wrong with that oil change lol

rxseven07

IMO genuine mazda is the best filter.. only 6$!!!

timmya2

synthetic is great.. keeps my temp low at high revs

mckinneyml

What weight of oil were you running before? The reason for the boost in oil pressure is because a 15W 50 has a higher Viscosity Index. It has a higher resistance to flow.

"Thicker is Better Myth
The reason that oil viscosities have gotten thinner is because bearing clearances have become smaller. Using thicker oils will interfere with oil flow and the oil pressure will increase. In a worn engine it may be okay to increase the viscosity of the oil because the bearing clearances have become larger. "
Source: Motor Oil Myths and Facts
http://www.nordicgroup.us/oil.htm


Oil Facts v1.2
http://www.repairfaq.org/filipg/AUTO...l#OILFACTS_005

bliffle

Yeah, I'd really be careful about going with 50 weight oil, you could easily gall the clearances, and anyway after a rebuild you usually put some easy breakin miles on with a light oil anyway. High oil pressure isn't necessarily better, either.

I've not rebuilt a rotary, but when I rebuilt boingers for racing we'd open up tolerances a prescribed amount to allow more oil flow thru the crank and rod journals (notice this reduces oil pressure) and even the piston-cylinder clearances, break them in on 30 weight and use 40 weight for sustained racing.

B

OneRotor

iTrader: (3)

well, the engine had 20w-50 Royal Purple when i bought the car, and my OMP isn't hooked up, so i'm premixing, so how well the Synthetic burns doesn't matter to me, because it isn't being burnt. The engine has about 5k on it, it's a bridge ported 12a. I have to use a Fram filter because the car came with a remote mounted oil filter, and the place where i found the filter (it's a HP1, their "racing" filter") only carried Fram filters, and I havn't seen any other brands being sold in my area.

I went with Mobil 1 because it was the only 50 weight oil that i could find within 30 minutes of my house.

I chose 50 weight because I was going with Mazda's recommended oil weights for warm weather (it's not going to be driven much right now, no interior and i need some body panels), i take it around the block 4-5 times a day to warm it up, and once it's fully warm i run it through the RPM range a few times to give it a workout.

for future reference, what weight oil do you guys use?

OneRotor

iTrader: (3)

oh, and i'll prolly get to 3 months before i put 100 miles on the oil, so i'll change the oil at 3 months, so pretty much i just threw 40 dollars down the drain, but it was fun changing the oil

peejay

I normally see a 10psi jump between 3000 mile oil and new oil.

Part of the issue is the oil gets fuel diluted, part of it is the oil just physically gets worn out (the polymer chains get sheared apart with heat and pressure, so the oil actually does get lower in viscosity)

I don't believe in sludge oil. I use the lightest weight I can find. I don't wing my engine up into the upper ranges (over 8500) where you have to worry about eshadft whip removing all of your bearing clearance, though, so I run stock clearances.

The way I see it, thinner oils mean more oil is flowing through the system when the system reaches regulator blowoff volume. This means more oil cooling the bearings and more oil being sprayed into the rotors.

High pressure and sludge weight oil is merely a crutch for the high bearing clearances required in a high RPM engine to permit E-shaft flex. This is all stuff drag racers went through before high quality forgings became common, back in the days when crappy stock castings were all that were available they would run absurd tolerances (like .005" !) and then have to run 50 or even 70 weight sludge at high pressure to keep oil on the crank before it bled out. Then run restrictors to the top end to keep the oil from filling the valve covers before it could drain back down.

Modern engines, with beefy stiff cranks and decent blocks, often run clearances 10-20% of that, and lower pressure... yes sometimes less than one thousandth of an inch.

The less oil pressure you need to run, and the easier the oil flows, the less power the oil pump sucks up and the more makes it to the flywheel.


Hmm, i seem to have gone off on a tangent. Anyway I run 10W30 synthetic, only because Brad Penn doesn't make a 5W20 racing synthetic. I also do not have an OMP anymore...

OneRotor

iTrader: (3)

well, then when i do my next oil change, i'll order some RP or Redline 10W30 synthetic. Who is Brad Penn and why do you use his oil?

Could you explain why the person above made fun of me for using a Fram filter? It's the HP1 filter, and the bastard is HUGE (i'm talking 4" diameter, 6" tall), are Fram filters really that bad for filtering, or are the normal sized ones just really restrictive? and before you ask, no, the filter is remote mounted on the drivers wheel well, it's a kit from Summit that the guy that owned the car before me put on.

OneRotor

iTrader: (3)

can't run the stock filter, remote mount kit, i'll try and dig up the thread with the pics of it in it, it was installed when i bought the car

OneRotor

iTrader: (3)

SS lines, A/N fittings, oil cooler down by radiator

peejay

I use Brad Penn because it's a quality *racing* oil, and it's fairly inexpensive, and we sell the stuff so I get an even better deal. It has a high amount of ZDDP in it, which isn't so hot for converters, but it's great for engines that see abuse and periods of sitting unused.

Plus it's green. It looks like this health-food drink I used to get that was made out of grasses and spores and god knows what else.

Fram filters have been known to come apart internally and send filter bits through the engine. Not very often btu it does happen.

I use the cheapest filters I can find from the parts store. I've never had an oiling-related engine failure, either.

OneRotor

iTrader: (3)

how expensive is it, and where can i buy it? what is ZDDP and what does it do? oh, and one more question, off topic, what straight through exhaust systems are available for the FB? right now i think i have the RB duals (the guy before me told me that the system is a RB system, but he was an idiot and i'm contemplating replacing it after i get an interior and body panels).