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Kurt Robertson Enterprises

                     Wankels' to Offenhausers'

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Rotary Review

Posted on November 3, 2013 at 1:56 AM Comments comments (7463)
Look closely at the picture 
 1978 Cosmo
 1974 Cosmo
 1990 RX7 Convertible
 1979 RX7
 2004 RX8
1974 REPU
1974 RX2 Coupe
1976 RX3 Sedan
RX3 Coupe
RX3 wagon
RX4 sedan
RX4 Wagon
RX4 Coupe
Having owned no less than ten of every model except the R-100 (6), FD (0) and the new fangled RX8 (2) I would consider myself an enthusiast and would like to tell you about my driving experience in these models as they appeared stock
 69 -70 R100.
The R-100 had a hard time starting with the origional 10A, but would they wind out.  Most of us retro fit a 12A into them by 1973 because of startup & failures, but with a 10A the car was quick and fairly fast. Handling was nimble but squirley with leaf spring suspension in the rear. The split case 4 speed gear box was short geared like the RX8 and lended a hand to its quick feel. The car had a high center of gravity , but the whole package was ahead of its time. I loved all my R-100s and had two with every engine 10A,12A &13B. The one TRADGEDY that happened to a lot of them was when people would put a 12A or 13B in many times they would cut the shifter hole! These little cars also tended to bend across the seat rail, starting at the shifter hole mid ship after years of launching and by 1980 most good chassis were gone- destroyed. The same rev increase a 12A has over a 13B was the same increment as a 10A so 9000 RPM for a 10A was very realistic. Hmm  . . . maybe thats' why they didn't start or last?
71-74 RX-2.
The RX2 Started ! Yay the 200 cc displacement increase made this car reliable after mid of 1973 when the triple tie rotor housings were cast, we had a great car.
I loved all my RX2s. These cars were quick and fast. Handling was excellent compared to the R100 due to the four link and pan hard rod, this cars' suspension, brakes and platform was later brought back in the 1979-1985 RX7. An RX2 was basically a boxy prototype of the RX7 and if you had a 2/7 sitting next to each other  and you were on a creeper you couldn't tell the difference! The coupe was a pain for getting in & out of the back seat, but the sedan was a way to get your buddies out to go elephant (V8) hunting. The RX-2 was a delightful handling functional whip that would impress and scare even the most staunch rotary skeptics.
1973-1978 RX3
Back to squirley with a leaf spring suspension! Fast, Quick and light I never "clicked" with my RX3s. In fact I think I only bought about twenty and most of them were wagons! I described them back then as tin ee (as in tin can).  The coupes were again hard to access the back seat. The four doors were used for high speed demos and the wagons were just awesome with a ability to fold down and sleep two, host four person road trips and yet still could threaten a 5.0 mustang :).
The last SP I had I sold for $500 in 2003 because everybody had raced it to the point of strutural compromise of the unibody (again tin ee). I also never liked the two piece nose/hood arrangement and felt it was ugly on the Cosmo and 1976-78 RX4 as well. I beat all my coupes and cared for my sedan and wagons. In 1978 I was a passenger in a sedan that rolled at 110MPH in third gear trying to pull thru a corner -we all walked away unscathed! I always thought Mazda went wrong on the RX3 in amenities, HP, weight and suspension
1974 -1978 RX4
My favorite Rotary of all period. First year of the 13B with a five speed transmission type that was used later in the Turbo II and FD. Mazda had produced a car that was the fourth fastest tested in 1974 only beat by 3 exotics from 0-60.  Simple car, simple design simply fast with futuristic interior styling, overhead console, no window "B" pillars and a one piece hood. The coupes were still a pain to get into the back seat , but these cars were solid. Much heavier than the RX2/3 the RX4 had a port configuration the size of a 91-94 FD. These cars were just flat out fast. I drove a stock 1974 RX4 to 145 mph- did I mention stock! how about Automatic! with the AC on! RPM 6800! The RX4 was heavy enough to hold the road above 130, powerful enough to go 130 and you did not feel you were going to die in it like the previous models at 130, in fact it would eat 120 for 4 hours and your mom would just ask " why is everyone going so slow" but in a R100 & RX3 you knew very well anything over 110, but the RX-2 sedan with four people was "OK" at 120 but took a while to get there.The 74s were my favorite as Mazda cut down the port size in 1976 as well as the intake manifold runner sizes in anything past 1975. Why? because they were passing everything on the road . . . . but the gas station! I would argue that the 1974 RX4 wagon was the best driving and most comfortable rotary ever made and have taken more than one of those cross country with a trailer on back to go pick up an RX7. The RX4 Sport Coupe , and RX4 line is by far my pick for the best Rotary ever made. The FC,FD and RX8 are light duty "knock off" versions of this early 13B in terms of basic engine engineering and further undermine reliability and design simplicity with expensive proprietory fuel management as well as pressurized induction. The sedans were ugly as far as styling , but were a delightful way of sharing a wankel experience in comfort.
To Be Continued . . . . . .


Posted on September 27, 2013 at 1:34 PM Comments comments (390)
Mazda kicks it into high gear!
This year I've had quite a few RX8 owners who have been told by Mazda  that their engine is bad. With OEM soft parts weighing in at well over $2100 and better than OEM soft parts weighing in at $1900, not to mention rotor housings at $700 a pop I decided I would do some research a cheaper engine cost.
 My main concern with a Mazda short block has been ongoing since 1980. It seems that the "NEW" engines they sell are just rebuilt and some engines have new housings and some don't . . . . . . hmm, anyway never mind that I have in the past thirty years  installed 7 of them for customers , but I have personally seen chrome flake from a crate engine visible with my $80 Harbor Freight bore camera in 4!
Has anybody actually met Mr. John Q Mazda?
This wasn't my first time calling Mazda on an RX8 engine. In January of 2011 I called a local dealer, lets call them Don Tomkin. They quoted me $2000 for a reman engine with a $500 dollar core with my 20% off as a dealer, that made a total cost of $2100 if my core was good. The core refund I heard was another bone of contention, the customers who have given me those seven remans seldom received full credit, at least thats what my poor customers told me.
Now the rub. 2004/2005 RX8 cars had a 8 year 100,000 mile warrantee. In 2012 I called to inquire about that same $2100 engine I was told that the 04/05 engine is $3000 my cost with a $1000 core if they could find one, nice.
The idea of a $4000 for just the reman engine and with OEM parts accessorizing it scares me, especially when I have two dead remans sitting on the floor with blue mazda tags saying they were built by Mazda in 2010.
What even scares me more is the fact that if I rebuild an RX8 engine that the factories track record has a dismal average life expectancy.  Die Hard rotary nuts I am with you, but you will easily spend $5-6K on a Renesis Wankel. 

The 1971 10A reborn in the 2004-2012 RX8

Posted on August 28, 2013 at 2:36 AM Comments comments (367)
Just when we as rotory enthusiasts had made peace with the 110-130K mile rebuild Mazda produced the RENESIS engine spelled C-R-A-P. 
That sick, anxious and often disappointing feeling trying to start a 1969-73 top start twin distributor 10A or 12 A fit in a neat body like a R100, RX2 or RX3 had all but faded from our memories, until the RX8.
 In defense of the R-100,RX2 and RX3 a 1974 and up engine upgrade was a wonderful fix. . . . until 2004.
Mazda has stopped production in 2012 , for good reason , but not before shooting all us rotor heads squarely in the head.
The idea that the basic engineered design has rotor design problems, hot start problems, side seal carbon buildup, short engine life, apex seals with no room for wear, heat buildup around exhaust ports and oiling starvation in the front rotor, combined with a very limited capacity for  modification make it very hard to defend.
The body is delightful, the ameneties awesome and the engine, well it could learn alot from a 1978 RX4 wagon . . . . . . . . . . retrofit-    Working on it

RX7 values

Posted on July 7, 2013 at 12:55 PM Comments comments (408)
 Unmolested  first gen RX-7s SA & FB values are going the same way the R-100s, RX2,RX3, RX4 , Cosmos and REPUs . A littre bit of  a slower rate due to high production numbers , but never the less they have bottomed around 2009 and are have been increasing in value ever since. There are two main  factors that are driving the first gen value up in North America.
First there are many enthusiasts that customize and modify their car and run the rotary simply to compete with the muriad of 30 year newer and $30K more expensive street cars & bikes. They often will hammer their car repeatedly with no regards for collectability and will drill, screw, cut and mount almost any speed equipment , necessary or not to remain competetive. When done with these chassis these cars are often only good for a parts donor for another chassis.
The second group driving up value are the racers- Chump, LeMons, Drifters, Sport Tuners, SCCA, IMSA and other clubs racers are gutting and cutting in an alarming rate.
My suggestion for the wise- find a complete barn find & sit on it, you won't be sorry