Mazda Rotary 180K miles, some smoke

Pennzoil motor oil
Status
Not open for further replies.
S

Solo2driver

Joined
Jul 6, 2004
Messages
1,385
Location
Houston, TX
Going to pick up an '89 Mazda RX-7 GTU (ligher rotors, 160hp engine, no sunroof or power options!!) this week, engine has 180K miles on it and is probably done with its side seals (not the apex seals). Not sure what oil was in it, but I wil be doing the standard rotary pre-soak in MMO squirted onto the rotor surfaces overnight to free up the seals and provide some lube to the housings.

I usually run Castrol GTX 20w-50 on an old rotary, not know how much oil this one consumes or if it has a terrible fuel dilusion problem or not, and I will not use synthetic until the new rebuilt engine is in. Any other rotor heads have any other opinions?

Thanks, this will become an autocross car once the new engine is in.

-JamesW
www.DaveTurnerMotorsport.com

[ October 19, 2005, 06:58 PM: Message edited by: Solo2driver ]
 
How much is "some" smoke? Mazda rotaries with a few miles often have a puff or two of smoke upon startup; this is considered normal.

I would suggest that the oil seals, not the side seals, might be worn. They were an issue with older ('70s) rotaries. Seldom have I heard of the side seals being an issue. Only when there is excessive wear to the end and intermediate housings would the side seals be a problem.
 
As long as the puff of smoke is white and not blue there is no cause for concern. If the smoke is blue upon start up, the seals are on their way out and a rebuild is inevitable.

I have 123K on an 85 GSL-SE with the 13B engine and have been experiencing some white smoke upon startup for some time, but it is not cause for alarm.

I run Castrol 10w30 most of the time and have never used 20w50 oil as oil consumption is not a concern for me and that is too heavy an oil for the winter, where I live.

I would never use synthetic oil in a rotary engine, other than perhaps for an RX8 and even then I'm not sure if its preferred.
 
My 200K mile GSL-SE (original engine) loved Royal Purple 15w40, and even reduced that slight startup puff and excessive oil consumption.

We are already preparing to replace the engine, I am just looking for an oil for the mean time and maybe even experiment with ARX in an older rotary, as it seems it has not been used in that type of application before.

Haven't picked up the car yet, not sure on how much smoke, but then again we are planning on replacing the engine and I am not a newb when it comes to these rotary engines.

We see very high oil temps here and ambient air of no less than 50 deg for the most part, so 20w-50 is the ticket. I've seen guys run 10w30 and pre-mix, but I don't plan on doing that.

Thanks
 
Bought the car tonight, will tow to my shop in the morning (dead battery, old registration, flat/dryrotted tires). When I finally sat down with the owner he admitted that this was his first Rotary car, and was not used to seeing smoke at all. I asked him to describe with his arms at the rear of the car how much smoke there was during a regular startup, and then after it sits for a while, and it is totally acceptable for an engine of this age -- heck, we used to look for that specifically in the old SpecRX7 series, because it meant that the motor was "loose" enough to make power at 7K+ rpm!

More details to follow, yet another project car that will see National level autocross competition, probably only for ProSolos in the new "Street Touring S - 2" class.

Photos at http://www.garagespirits.com/images/fc3s/ from the previous owner.

-JamesW
'89 Mazda RX-7 GTUs 179K miles
 
Have you started the car up yet? What makes you think that it needs to be rebuilt?

Although, a 13B engine would typically require rebuilding by 200K.
 
FWIW, Royal Purple says it's OK to use synthetic oils in rotary engines:
http://www.royalpurple.com/techa/faqsa.html#re2

quote:
More information and FAQs on lubrication of Rotary Engines:

In a rotary engine, the oil lubricates the eccentric shaft bearings, thrust needle bearings and rotor bearings similar to a crank and rod bearing of a piston engine as well as being injected into the combustion chambers to lubricate the apex seals, corner seals, and side seals helping to create the sealing mechanism doing the equivalent job of the piston rings.

Royal Purple provides outstanding protection for the e-shaft, rotor bearings, thrust bearings and is suitable for the oil injection system as it has proven to run cleaner than other oils and is an excellent choice for rotary apex seals, corner seals, and side seals.

Mazda makes a statement in the Owner’s Manual not to use synthetic oils in a rotary engine, why do you say that it is OK?

Royal Purple has performed seal compatibility testing on the components used in a rotary with excellent results, including older rotary engine seals dating back to the Cosmo. Royal Purple’s Technical Services Manager David Canitz has been an owner and racer of rotary engine cars and has used synthetic motor oils in rotaries since 1985 with excellent results. He has been trying to find an answer to this Mazda statement for the last 18 years.

In the early development of synthetic oils decades ago, there were purportedly some seal compatibility issues. Today’s synthetic oils do not have the compatibility issues of the old oils. There is no substantiated evidence of seal compatibility issues with Royal Purple.

Here are some facts:

- The Mazda Factory racing departments recommend and use ‘synthetic’ oils including the winning 1991 Leman’s 20-G 4 rotor Mazda 787B.

- MazdaComp USA printed manual (now Mazdaspeed) recommends the use of synthetic oils for racing conditions.

- Royal Purple Motor Oils have been used in rotary engines (both race and street) for ten plus years with excellent results.

- Royal Purple Motor Oil is compatible with the bearing material, sealing elastomers, and combustion seals used in a rotary engine.
Click to expand...
 
quote:
Originally posted by bobo:
I would never use synthetic oil in a rotary engine, other than perhaps for an RX8 and even then I'm not sure if its preferred.
Click to expand...
2. that. You have to use oil that will burn clean. A synthetic doesn't do that.
 
Madza Oz sell synthetic oil for the RX8 otc.

I would have thought the synthetic oil actually burns cleaner. Certainly does in two-stroke motors.
 
quote:
Originally posted by bobo:
I would never use synthetic oil in a rotary engine, other than perhaps for an RX8 and even then I'm not sure if its preferred.
Click to expand...
Correct, Mazda specifically warns against synthetic in the RX-7's. Apparantly they make the oil injection system operate funky.

I did use M1 in my 86 RX-7 for 40k miles before I found out this fact and never had a problem, ran great when I sold it at 95k. Still, Mazda says no so probably best to stay w/conventional.
 
Towed the car to my race shop this morning.

Pulled all the spark plugs, looks like they haven't been changed in over 30K miles. Squirted MMO in each hole and turned the eccentric shaft by hand, then squirted more in. Threw in 4oz of MMO in 5 gal of fresh fuel, then poured another 8oz of MMO in the engine to bring the oil level up to full. Fresh NGK plugs.

Engine fired up on the 3rd rotation, nice big plume of smoke from the dual exhausts, quit smoking about 6 minutes later of idling.

Car hasn't wisped a WISP of smoke since, we've driven it around town up to redline and back. Cooling is good, oil pressure is good, power steering is good, brakes are far too phenomenal for the tires that are on it...so is the power!

Then we pulled it in and weighed the car on our corner-balance scales, a stock '89 GTUs in showroom condition/trim weighs 2725lbs.

We then removed all of the fan shrouding and its associated hardware and installed a SPAL electric fan kit, works great and comes on and off at 180 degrees.

I have a race tomorrow in another car, will return next week to change to Castrol GTX 20w-50, drive it a week, and change it again. Then we'll start UOA after fresh oil is in there and all the old stuff is out (capacity is over 7qts but only a 4.7qt pan = BIG oil cooler). Prev owner says its semi-synthetic 10w-40 and has the Iffy Lube reciept to prove it, YIKES, but the rest of the Mazda-dealer-only reciepts show more good stuff and good maintenance.

-JamesW
Lovin the Rotary Again! 180K mile GTUs
 
Still running strong, still haven't changed the oil out after about 100 miles of regular driving, but the fuel smell in the oil went away (probably needed some heat).

Castron GTX 20w-50 going in next, maybe try Idemitsu Rotary oil 20w-50?

-JamesW
 
Engine had an o-ring failure shortly afterwards, upon disassembly the rotor housings, apex seals, and one side housing was bad. Motor was freshened with all new seals, cleaning/lapping, and good used rotor housings. Engine should be broken in on the dyno tomorrow and run with Lubrication Engineering 5w30, may experiment with Idemitsu 10w30 and Royal Purple Racing 21...these viscosities are being recommended by the engine builder based on the tolerances in this particular engine combination. This engine is a semi-race motor and only expected to effectively last 35-40K miles before starting to smoke and require another rebuild, but we're hoping to prolong that with good oil, regular UOA, and a good pre-mix.

First autocross race of the season is this weekend, wish me luck!
 
Solo,
The chasis low weight is perfectly suited for a LS1 V8. The weight pentalty is very little if you move the battery box to the rear.

If you haven't seen these websites, check them out. www.torquecentral.com www.wrongmotor.com v8rx7.com

I have a 91 vert with about 25k miles on it and plan on dumping the rotary engine in 2008. I can't wait to get some real torque under the hood.
 
I think he should try some of this: www.xado.com I have used this stuff in 2 different engines(one of them a turbo engine), with amazing results. First I ordered it too see if it could help my transmission(manual) that I was planning to change. Within 1500 miles it shifted like when the car was new. Then I had it in the engines. The noice from the engines was reduced(some 30-40%) and the engines was a lot stronger, especially at high revs. Since it was cold at the time, I also noticed that I almost lost all the hot air from the heater. Both engines are running as smooth as they have never done before. Could be worth testing. I was sceptical myself, and first tested it in an old car with 205K miles on. Another positive thing is that it seems to reduce consumption as well.
 
jonny-b:

While the rotary does have large bearings and stationary gears, there is little that needs a solid coating of ceramic goo or would benefit from it. A good oil that resists shearing out of grade and can take heat and fuel contamination is what most rotary owners are looking for, while still lubricating the rotor housings (a good pre-mix).
Otherwise your post sounds like spam, but no offense intended.
 
Status
Not open for further replies.

Similar threads

S
  • Locked
New oil recommendation for Rotary engine owners inside
Replies
3
Views
568
Solo2driver
Back
Top Bottom