View Full Version : Is the Mazdatrix ITA-spec engine legal?

08-08-2001, 10:44 PM
I'm engine shopping. Here's how the Mazdatrix website describes their "ITA Special" engine:

"Includes- carbon apex seals, competition apex springs, side cutting of rotors for high RPM use, clearancing of all main and rotor bearings, special housing selection, hardened 3-window rear stationary gear, hardened front gear, rotor to rotor housing clearancing, balancing of rotating assembly, adjustable oil pressure relief valve, large oil pump..."

I know that many people have a far more "creative" interpretation of the ITCS than I do, but I don't see how side cutting the rotors or installing hardened gears is legal. Please help - I'd love to buy one of these if there's a legal rationale for the modifications.


08-08-2001, 11:05 PM
Dave lemon knows his weight in gold about Mazda's, if he says it is I believe him.
mine and countless more scca rx7,s carry the Mazdatrix logo on our front fenders.
his pro7 engines are leading the points in our region, recently one of his pro7 engines finished 2nd in ITA class at laguna seca.
imagine what his ITA motor would have done.

Daryl Brightwell
ITA RX7#90
PRO7 #90
San Francisco region
Cal Club

[This message has been edited by 7'sRracing (edited August 09, 2001).]

lee graser
08-09-2001, 11:35 AM
Side cut rotors and special housing selection----com-on guys---read the rules---this isn't even close to the ITA rules---fast---no question---ITA legal--not a chance--If Dave knows anything about housing selection-(And I expect he does)---his selection of 12A rotor housings may include the Large exhaust port (much more power) version---not even close to ITA legal--- This issue has been settled by MAZDA Comp and SCCA National a long time ago---- this is not to say that there arn't a ton of illegal 12A motors still being built and raced. Racers in the SEDivision had a huge problem with this several years back---but the introduction of a port measuring tool affectionally labled the "Lollipop" has greatly reduced the "popularity" of the large port housings, by assuring a DQ (at a minimum) and driver probation for the more flagrent offenders.

08-14-2001, 06:15 PM
Is the Mazdatrix spec ITA engine $4 grand? Seems pricey for what is supposed to be essentially a stock engine. I've seen other shops sell for less than $1500.

Dave Damouth
08-16-2001, 10:07 AM
Originally posted by sburkett:

"Includes- carbon apex seals, competition apex springs, side cutting of rotors for high RPM use, clearancing of all main and rotor bearings, special housing selection, hardened 3-window rear stationary gear, hardened front gear, rotor to rotor housing clearancing, balancing of rotating assembly, adjustable oil pressure relief valve, large oil pump..."

Ok guys, go easy on Mazdatrix unless you know something is wrong. Balancing, clearancing, ect is ok. Hardening a stock gear is ok. Replacing the bearings is ok. I'm pretty sure that mazdatrix would argue that trimming a thousandth or two off the few little spots on the land that may contact falls under "blueprinting", in that some rotors are wider than others. And I'm pretty sure that the "special housing selection" Involves hand picking the stock housings with the best core shift, as opposed to an illegal housing. I'm sure they will answer any questions you have....

Regarding cost, you pretty much get what you pay for. $1500 will buy you a "street rebuild" from some of the low cost guys. Basically new gaskets and seals, reuse everything else. Tear enough used motors apart and you will find that old 12a's, even the running ones, are used up and worn out. Bare minimum is new rotor housings and side plates machined, eccentric polished, ect. More likely is replace rotors and rotor housings, consider gear and eccentric replacement. In some cases the side housings are trashed. Mazdatrix web site gives you a matrix of parts that get replaced in the different level engines. Look up the price on those parts and you'll see what you're paying for.

B Breon
08-17-2001, 02:51 PM
Carbon Apex Seals aren't exactly OE either. Granted, they are a wear item and don't really give any added performance, but they aren't legal either. I highly doubt that anyone will post a protest and make you tear down the motor because of them though.

Brent Breon
Cendiv ITA #26

Karl Bocchieri
08-18-2001, 08:47 PM
Carbon seals are lighter, therefore they stay in contact with the housing more under high RPM and allow less blow by. This causes you to get more HP at high RPM.
Apex seals are equivelent to piston rings in a regular motor, both of which can use any brand or composition you want. Read the GCR over again.
Carbon apex seals are also much stronger, don't wear as fast, and have less chance of comming dislodged and wrecking the motor when you miss a shift, and wing the motor.
Mazdatrix is one of the best sources for parts and info. Do you really think they would risk there reputation building illegal motors?

B Breon
08-19-2001, 09:47 AM
You are correct - ITCS section D.2.d - Alternate rotor seals and springs permitted. I recant!

08-20-2001, 02:17 PM
You are correct in the fact that the carbon seals to a better job at sealing, but only above 9,000 rpm, for IT, you're better off with the hardened steel seals from mazda.

IT7 #88

08-20-2001, 04:37 PM
I had heard the gains were from 7500 up.

08-21-2001, 12:12 AM
Thanks for all the replies! I am convinced that the "hardened 3-window rear stationary gear, hardened front gear" are not legal, but I think that everything else is okay.

If I did go with their IT special engine, I would ensure that any clearancing is done within factory specs, and would skip the hardened gears.

But after further consideration, I'm probably going to go with one of their stock rebuilds anyway.

Also - I would be seriously impressed if anyone can come up with a rationalization for the hardened and/or 3-window gears.


Karl Bocchieri
08-21-2001, 12:31 AM
The 3 window bearing increases the amount of oil able to reach the shaft and prevent scoring under high RPM. The hardened gears are a safety precaution, again for high RPM use.
You have to remember that in a rotary the encenteric shaft is pushed arround by the rotor only because the front and rear gear cause it to take an elipictial path. All the torque and HP gets feed against those 2 gears. There not very large gears when you think about it.

08-21-2001, 08:39 AM
Originally posted by Karl Bocchieri:
The 3 window bearing increases the amount of oil able to reach the shaft and prevent scoring under high RPM. The hardened gears are a safety precaution, again for high RPM use.

You're right, of course... I didn't phrase my question well - what I want to hear is how someone can justify the gears as legal for IT. I can't see any loophole there.


08-21-2001, 09:15 AM
It's a safety modification.

See... if you and another car directly behind you are going real fast down the straight and your engine suddenly goes south, then the other car will hit you in the rear. This will accelerate your car violently forward (your body will move relatively backwards) and the mandated seat support brace will puncture your seat and poke you in the spine. If you have accidentally mounted your seat support brace so it won't poke a hole in the seat then your entire head/neck will whip forward and you could get a migratory sprain/strain whiplash condition. A spine poke or whiplash is not a good thing and therefore this engine modification is definitely done only in the name of safety.

Dave Damouth
08-21-2001, 12:13 PM
Its a stock gear that someone heated to raise the surface hardness. No coating has been added. No machining has been done. How is it illegal again?

i'd call and bug the guy that you expect to build an engine for you. If they can't convince you they know what they're doing, you need a new engine builder that you're comfortable with. Also, if you're comfortable with their skill and reputation, you should trust their experience to tell you what is and isn't good for your engine.

08-21-2001, 04:57 PM
If a modification is permitted by the rules and the question is whether or not to have it done to improve longevity, that is one thing...

It seems to be an entirely different kettle of fish to define a change as a "safety modification", to rationalize the legality of a modification not specifically allowed by the rules.

Is the hardened gear a case of the first or the second?

I am NO rotary engine expert and maybe I am being pedantic (wouldn't be the first time!) but heat treating is a modification isn't it? What have I missed here?


08-28-2001, 05:12 PM
A few opening statements:

1) Guess how many IT engines we have built in the last 10 years or so ???
Answer: None, zero, zip, nada.
Why?? -- just cost I guess. Since I have never been involved/raced the IT class, and there are many other engine builders out there, nobody ordered one.

2) I never particularly cared for some of the IT rules: way back when headliners were REQUIRED, passenger seats, OEM wiring looms, full dashboards, heaters, etc -- always seemed like a lot of junk to carry around, and kept the cars from looking more like "race cars".

3) There always seemed to be too many "nit-picking" things being protested. My personal philosophy has always been - If it's not a real performance advantage, and it's not "approved" in the rules, then discuss it with the other guy, and ask him to justify or change it. Things like a fender corner out a 1/4" too far -- just change it before the next race, don't disqualify the guy!

4) I have always been irritated (with many different racing organizations) that limited "longevity increasing" things that did not cost much. -- All racers are tight on $$, and a few $$ extra spent initially that can make something stay together longer really should be ok'd.

I "returned" to road racing (after 11 years out of it) essentially in January of this year with a Pro7 car out here in CalClub. (I think it is a more "cost effective" class than ITA) -- no passenger seats, no wiring looms, etc.+ it's ALL 79-85 RX7's with "same" bars, springs, shocks, wheels, tires, ignitions, manifolds, internal engine parts, etc.
Obviously we did the engine for my car - new seals, rotor housings, etc and spent a lot of time on the dyno to see what a "stock" engine wanted. (we have to use a stock cast iron exhaust manifold). It seems to have worked, as I've won a few races, set a few lap records, and am currently in the points lead.
(We also, in between sessions, swap on a 48IDA Weber and rear slicks and run E/Prodution also. -- won a few of those, and am also in the (regional only) E/P points lead).

We have built a few Pro7 engines, and dynoed a few others. Other than the first double weekend, Mazdatrix engines/or dyno have won all the Pro7 races, and have taken all 3 podium places often.

ALL those Pro7 engines we have been involved with have been completely legal when they left here (I can not vouch for any engines except my own after they leave here).

Now for the direct answers:

Carbon apex seals have been legal for many years. The OEM steel ones tend to "float" above about 8k, and leave "chatter" marks on the rotor housings, which eventually will be a problem. -- When the Pro7 group was talking about carbon seals, I told them NO!! It will just lead to higher revs, more dyno time, more engine failures -- all = higher cost.

I "wrote" that IT engine description way back in about 1990, and really never looked at it again. It was a "OK, if somebody wanted one, what would we want to do". We do NOT side cut the rotors on Pro7 engines, and we will not be cutting them on IT engines-- we decided it is a waste of $$ as they really just won't be at a high enough rpm, for long enough, to warrant the cost. --- nothing to do with "legality" -- I'll let you guys go there.

"Special housing selection" consists FIRST and FOREMOST of NOT using any side housings that even REMOTELY look like they have been TOUCHED with any kind of grinder!! -- When you are looking through a few hundred used housings, you have to be VERY careful that they are untouched! Other than that, there is very little difference in the "core shift" of the RX7 side housings. (The old "3B" RX3 ones had major differences). We just try not to use any really "sharp edged" ones, but it is REALLY rare to find "REALLY" great ones. In fact, the last set we selected for a Pro7 engine, upon closer examination, had been "lightly massaged", so we had to reject them. (I am NOT kidding!!!, they went into a rebuild for a street engine just so we would not keep "picking" them out)

We will NOT build a "racing" engine without NEW rotor housings!! -- we buy straight from MAZDA, RX7 (79-85) rotor housings, do not touch them, and put them in the engine.

Now for the real question -- "hardened" gears. Absolutely no performance advantage. The engine "may" last longer. The later 13B engines (does NOT apply to ITA 12A) came with them, so they are legal in ITS). They cost a little more.
Are they legal?? By the exact rules, probably not. If a customer did not want them, no problem. -- But please remember what I said way back up there -- NOBODY will win a race BECAUSE he made the engine last longer with hardened gears (Yes, I know, he MIGHT win that last one because the engine MIGHT have blown the race before).
Just a question - is the "IT" group THAT worried about something THAT minor????? There are SO MANY ways to CHEAT that give a real performance advantage, and are hard to find, do YOU really care to be the one to tear down somebody, and disqualify him, because he wanted to have it last longer???? Like I said, just a question of mine, reflecting my PERSONAL opinion on some of the rules.

Anyway -- hash it out among yourselves. I will change the wording on the IT engine description to make it fit the rules -- that should lead to a real flood of engine orders???

For what it is worth, I was recently brought an engine for dynoing, that upon closer inspection was not legal (mild porting). I refused to dyno it, and marked it so I could identify it if it showed up in a car. I told the customer that if I was aware that engine was in a car I was racing against, I would "speak" to the tech people to be sure it was pulled. -- just thought I would let you all know.

Dave, Owner @ Mazdatrix

08-28-2001, 05:32 PM
Thought I would post another one, both for the Rotary guys, and those who still have not "seen the light" and still race pistons.

Doing the 7 or 8 Pro7 engines this year, and having spent a LOT of my own time on the dyno, it has confirmed what I believed. With a "stock" 12A (Pro7 or ITA RX7), assembled correctly (correct tolerances), with enough new parts, THERE IS NO POWER DIFFERENCE IN THE ENGINES !! -- ALL of the power gains are in the tuning (read jets and timing) of the engines !!! EVERY engine we have dynoed wanted different jets !!!, and timing can be a little different. I have no real explanation for this, and am still being suprised. The one currently on the dyno (#9?) may be the first one to duplicate a jetting combo (looks to be the same as #3? engine). Power gains with jetting ONLY can be impressive. For instance, I have seen gains of up to 30hp at 8k and 8.5k from the jetting the customer was previously using !!!

And we carry an air density gauge with us at the track, and we DO change jets by what it says, and we DO see a difference in power/lap times.

08-28-2001, 07:23 PM
Thanks for the update, Dave. I am probably not the only one who is glad to see your name back in club racing...

Thanks for explaining where the "hardened" gear comes from. I was thinking that stock parts were being treated rather than parts from different (but stock) engines were being substituted. Both are outside the lines but the first really had me puzzled.

To answer your question, sometimes it seems that the IT "group" can't agree on ANYTHING to be worried about--minor or otherwise. There are as many different priorities as there are licensed drivers.

Your lesson about tuning is a good one and I really enjoyed your story about the marked engine. Well done!

Kirk Knestis
Charlottesville, VA

08-28-2001, 07:51 PM
The 12A "hardened" gears ARE stock parts that have then been heat treated. They (heat treated gears) did not ever come in stock production 12A engines.

Dave Damouth
08-29-2001, 04:01 PM
I hear Andrew is building an ITA car. Maybe you could convince him that his pro7 motor will never work and get him to spring for a new one.
Nice video's on your website. Why do you keep bumping into those other guys?

08-29-2001, 10:41 PM
no, he just bought a SP Lumina formerly a ASC car.
I just think he thought he wasnt going to be able to hold me off in ITA next year.hehe

08-30-2001, 12:01 AM
hey Dave Demouth my PRO7 is the on that took 2nd at Laguna Seca, Ahead of what people think are the fastest ITA cars around, LOL. But yes its true I bought a ASC car I just have to go faster.
And as for DAVE LEMON he just gets lucky once in a while. we will see who is in the points lead after this weekend.

Dave Damouth
08-30-2001, 09:08 AM
Hey Speedy!
After runoffs, we oughta start whining about why the powerlist dried up. Paul said you were buiding an ita car. Musta been the chemicals again....

09-21-2001, 02:05 PM
Hey Andrew,
Did you buy the "Black Beast" from Robert Davis? Welcome to the ASC Gang. I have the #44 ASC Monte Carlo, I think you met my team mate Tim at Buttonwillow a few weeks ago... (you know, friendly 300# guy with mustache). Hope you're planning on Buttonwillow in October with NASA, we'll have to meet in person.
We'll be bringing only the Mazda RX7 SU car with a new injected peripheral port engine that Pablo Mobius built (#46 yellow PENNYWEB car).


09-21-2001, 02:51 PM
Andrew your leaving Pro7?

Dave's going EP?

OK, I'm building a Pro7! Just gotta keep Bob Neal from getting any faster.


09-26-2001, 11:33 AM
hurry up and fix that "NoRaceCarYet"