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What reliability mods can be applied to an Mx3 with a KLZE? Most of the archives are filled with performance mods.

What we've considered:
* standard tune-up items (hoses, belts, fluid change, plugs, etc.)
* bigger radiator
* oil cooler
* vented/slotted brakes

Of course all of these are fairly standard items.

We're willing to take a mild performance hit if it means we don't have to worry about fixing something last minute on race day.

Are there any parts on the mx3 that commonly fail?

the internal coil in the distributor is a fairly common one to fail which can be remedied with the hei mod. Mine works fine but I have heard of lots of people who have encoutered this. I am not quite sure why you would need a bigger rad unless you are talking drag racing, the rad in the car is quite efficent at cooling the engine.

What kind of racing will you be doing?
There is a recall on the front suspension springs, but if you're doing serious racing, you'd be changing them out.

I'd say the HEI mod, with an external ignitor would be a good mod since the disty's commonly fail under heat.

I'd also rebuild the engine if it's for racing, and use a better valve train to stop valves dropping under really high revs (7000+).

I race mine a couple times a year and it has been fine for 10 years now. I would suggest changing gears before rev limit and your valves might or might not make it. Some have had issues, but you never know how the car was driven really before the failure. I use a rad with metal end tanks the stock plastic/fiber ones were not meant to last long or hold up to above stock pressure. You can use a 1 bar rad cap to increase heat tollerence, but mine would NOT stop leaking with a 1 bar cap so I went back to a stockish one. It was leaking at the hose fittings so I guess my rad needs deeper bumps on the tubes.
If you drag axles are going to break. The diff is weak if you drag, but is fine on circuits. There is a company that makes a good viscious one in Australia or New Zealand if you want a 1.5 LSD, Quaife makes a indestructible one way if you drag. I would stiffen the motor mounts. Lower gear shifts get tricky if you are puching the motor and cornering, but stiffen the front and rear mount helps.
Check your class before dropping in a ZE. I raced in modified and get my A$# kicked as a result. I hear SCCA changed their classes this year though so maybe it has changed things a bit.

standard tune up items are good
oil cooler is a good idea + a mechanical oil pressure gauge
solid motor mounts - helps with axle wear and tear
HEI mod + external coil - replaces the common fail point stock internal coils
slotted rotors are good but not necessary - the stock rotors do fine but good brake pads are important!(hawk hps+ for the front, ebc greenstuff for the rear is a good combo), I do not recommend drilled rotors

Maybe these are considered performance mods?
SS brake lines and SS clutch line
Bronzoil bushings and third link kit - accuracy in shifting

Newfie_dan wrote:the internal coil in the distributor is a fairly common one to fail which can be remedied with the hei mod. Mine works fine but I have heard of lots of people who have encoutered this. I am not quite sure why you would need a bigger rad unless you are talking drag racing, the rad in the car is quite efficent at cooling the engine.

It's an endurance race (24 hours of lemons).

We have to replace the radiator anyway (it sprang a leak), so we might as well put in as large a radiator as we can fit.

PATDIESEL wrote:I race mine a couple times a year and it has been fine for 10 years now. I would suggest changing gears before rev limit and your valves might or might not make it. Some have had issues, but you never know how the car was driven really before the failure.

That's easier said than done. Revving the engine is so much fun!

OTOH sitting out the race because something blew up isn't fun.

I use a rad with metal end tanks the stock plastic/fiber ones were not meant to last long or hold up to above stock pressure. You can use a 1 bar rad cap to increase heat tollerence, but mine would NOT stop leaking with a 1 bar cap so I went back to a stockish one. It was leaking at the hose fittings so I guess my rad needs deeper bumps on the tubes.

I'm a big fan of metal end tanks. I have a fluidyne in my rx7 and I don't even take it to the track (of course the cost of an overheated wankel is much higher than for most engines).

If you drag axles are going to break.

The previous owner broke many axles drag racing and replaced them every 6 months; in fact, the ones on there now are brand new.

The diff is weak if you drag, but is fine on circuits. There is a company that makes a good viscious one in Australia or New Zealand if you want a 1.5 LSD, Quaife makes a indestructible one way if you drag. I would stiffen the motor mounts.

Would the hockey puck trick I've ready about qualify as stiff?

Why would stiffer mounts make the car more reliable? Wouldn't that mean more vibration (and thus more opportunity for something to come loose)?

Lower gear shifts get tricky if you are puching the motor and cornering, but stiffen the front and rear mount helps.
Check your class before dropping in a ZE. I raced in modified and get my A$# kicked as a result. I hear SCCA changed their classes this year though so maybe it has changed things a bit.

It already has a ZE, so no choice there.

I'm not sure how the classes work for lemons. Our other car we considered entering is a 1975 ranchero with a 460, which would surely put us in one of the lowest classes (actually we'd have to get special permission to race it, since stock it's above the weight limit).

Mooneggs wrote:standard tune up items are good
HEI mod + external coil - replaces the common fail point stock internal coils

Read a bit about this and the link I found suggested taking one off a chevette. Are there any other cars that might have an appropriate HEI system?

I don't think the local junkyard keeps cars around that are old enough to find one of these systems, so my choices will probably be limited to whatever I see sitting around in someone's yard.

slotted rotors are good but not necessary - the stock rotors do fine but good brake pads are important!(hawk hps+ for the front, ebc greenstuff for the rear is a good combo), I do not recommend drilled rotors

Maybe these are considered performance mods?
SS brake lines and SS clutch line
Bronzoil bushings and third link kit - accuracy in shifting

Note familiar with this last one. What is it?

You just replace your shifter linkage bushings with Bronzoil ones. I'm stoked that you're doing that race in an MX-3! I would recommend changing your valvetrain out for KLDE, which is more reliable.

x2 for KLDE valvetrain in the ZE heads.

fowljesse wrote:You just replace your shifter linkage bushings with Bronzoil ones. I'm stoked that you're doing that race in an MX-3! I would recommend changing your valvetrain out for KLDE, which is more reliable.

I'm excited too! I've never done anything like this before, but a few people on the team have. I guess I'm heading up the operation, but it's amazing to see how many people are interested in helping! The mx3 wouldn't be my first choice (I'm a RWD guy), but out of all the FWD hatchbacks it's certainly my favorite!

What's the difference between the KLDE and KLZE valvetrains?

Which ECU would I run for that?

Isn't there a very low budget for this type of race? I wouldn't bother spending money on shifter bushings or even a valvetrain for that matter unless it will be next to free. The valvetrain is just because some people have dropped a valve due to broken retainers in a ZE when revving high. DE retainers are slightly bigger. This is not a common occurrence though. You will not need any other ECU, for the ZE you should be using a stock ECU w/ a probinator chip (might be in there already) otherwise it's ~$40. Might be able to get one from someone on here.

My advice is to spend your money on brakes! Some good pads will go a long way, might even want to splurge on SS braided lines if you can - mx3 pads and lines are a bit mushy but when you upgrade to EBC greenstuff/hawk HPS they work wonders!

PS. Make sure you break in the brakes before track day though, but I'm sure you knew this.

The DE uses solid retainers which means it is less likely to drop a valve. Otherwise, they are more or less the same. The ZE has different intake port shape, but you can grind it close enough to work well. The car might have a DE intake manifold already, so changing to a DE head might not be a big deal. (except all the normal work involved in changing heads) You should use a ZE ECU or a DE ECU chipped to run ZE fuel maps. The heads will not change the ECU you need.
I think you are the third team I've heard of running a MX-3 in Lemons- good luck, I am not sure how it turned out for the other teams.
Stiffeneing the engine mounts make the motor and trans stay still while cornering and under acceleration, so that the shifts are easier. The G series trans is not tolerant of old sloppy mounts. There is a FAQ on here about filling the stock mounts with Urethane.
I do not like the bronzeoil bushings myself. New ones from Mazda are cheaper and will work just as well. If the shifter is sloppy, think about replacing them. A misshift will be an early retirement
There is a FAQ about doing the HEI mod in the V-6 FAQ section. You can buy most all of the parts form any auto parts store off the shelf. I would not do this for one race. It is going to cost a couple hundred dollars that are better spent elsewhere.

The brakes are considered safety equipment, so they don't count toward the $500 budget. I'm not sure whether "brakes" includes "brake lines" or just "pads and rotors", but we definitely plan on making sure our brakes are working at 110%. Brakes and cooling are the two biggest problems I read about with other teams.

The one other team I found on here that did lemons (Formula Un) didn't fare too well:

http://www.mx-3.com/phpBB3/viewtopic.ph ... 30#p431930" onclick="window.open(this.href);return false;

Apparently they had a fast car but it was riddled with problems. We're planning on making our mx3 a daily driver so we can find all the problems up front.

As for the valvetrain/heads, I think we could get a KLDE valvetrain from the junkyard for cheap (that's where we got the water pump pulley, but they didn't charge us for it). It sounds like it would be a lot of work though and there's risk in opening up the engine if we don't have to. I think we'll start on the less drastic mods and go from there.

Also when searching for 24 hours of lemons on mx-3.com I came across this thread:

http://www.mx-3.com/phpBB3/viewtopic.php?f=17&t=58744" onclick="window.open(this.href);return false;

Cheap and easy, but I don't want my hood flying off during the race. We definitely want to increase the amount of air flow and make sure the engine stays cool. We were thinking of making custom hood vents but I think this costs less. Would it work?