Death by Quaife
 

The word is out - my Quaife 5-speed has died.

I already had the issue of extension housing bolts shearing off and replacing them every session, but now - while looking for a permanent fix for that - we found:"
- seriously overheated bearing
- broken teeth on 1st and 2nd gears
- other gears have serious pitting

So this leaves me at a cross road with mostly dead ends.
- Use 6spd as consumable, $$ and mid-session failures
- Another Quaife, $$$ how long will this last?
- Motorsports gearbox $$$$ is the car worth it?
- V8 conversion $$$$$ expensive in Europe

or

- Find another track car, E46 M3 or something and break that

or

- Detune the 2860 down to .5bar and live a poor life

Suggestions?

Why not swap a Getrag? Pick a model - 260,265,420.
You're in Europe, plenty of people know these transmissions.

Or get a faceplated Tremec from good ol' USA - T56, TKO500, TKO600

The gears from Quaife are replaceable individually. When I got mine from Quaife, the builder (Helios Motorsports), noted that there was pitting and burs on some of the gears. After sending pictures directly to Quaife they were able to overnight individual gears. I would say to call Kevin Hayes at Motivicity (they are the US Quaife wholesaler), tell him what you need and he can get you prices for them.

Who built the transmission for you?
What did you replace when you built it? i.e. Every single part in the gearbox or just the parts that needed to be replaced.
What lubricant were you using? And what was your change interval?

Opps. Didn't realize you weren't in the US. Might still be worth a call to Kevin....he seemed to be able to get Quaife to make my situation right with no issues at all.

I do know that Quaife does still make these gearsets and will still sell them.

I'd be worried about these two to begin with, something is not the way is should be (i.e. why were the bolts shearing?).
If the bearing is overheating for some reason, that reason can be the starting point for all the other problems (except poor quality gears).
Gearbox tolerances are tricky business, more than one have serviced OEM boxes to make them fail very fast.

Buying Motorsport boxes to get away of the teething problems would steer you away from Quaife/Elite and into the arms of Drendt/Sadev etc. €10+k...

Today the 6speed with PAR gears sound attractive, but with the same problem as with your current Quaife box, you have to be QC of the installation yourself. SuperMiata gears for $3+k are not available yet.

Consume 6speeds with a final gear keeping you in 5th a lot of the time (make 6th just long enough for your longest straight)?
My thinking with this is that a shorter gearing will make you spend less seconds in 4th with full torque.
Practice swapping boxes, one hour should be possible.

Visuals.

Turns out 1-2 are worst. 3-5 look fine still.
Suspect is too much low end torque.

Where are all of the gears in relation to the bearing that failed?

Not a failed bearing, but some coloring was visible was said.
The one right next to 1st gear. So the failed gears are close.

See picture.

From those pictures that looks more like FOD rather than "death by low end torque"

The O being a stray tooth.

What type of trans cooling do you have? What are the fluid temps?

+1. Hot bearing = gear misalignment = instadeath

How the hell are we supposed to be able to guard against less than optimal alignment/install on these multi-thousand $ boxes?

Learning by doing (wrong) is one expensive way.

Using a builder who have a track record of making stock boxes survive a rebuild is one tip. Not ignoring the same builders warnings (e.g. about gear quality) is another.

Well not instadeath. Let's not forget I took the box out to have the bolt issue fixed, only then we found some missing teeth parts and pitting. The box was still drivable in all gears.

The bolts however have definitely contributed to the issue and the root cause for the bolts is most likely drive train slack. So, time for some supermiata motor mounts and checking the diff mounts (energy suspension currently).

The extension housing bolts will be 12.9 grade in the next build.

So, current plans:
- Further post mortem to ID anything that needs replacing
- Replacing gears from Quaife (3rd and main/4th)
- 12.9 bolts in extension housing
- Super Miata motor mounts
- Discuss additional gearbox bracing

The idea of a sequential box is out of the window: sequantials needs a GCU for ign cut and blip and additional hardware if you want the box to stay in one piece, making such an investment >10k.

I have 100% faith in a guy who gets flown in on Dakar other rally events to look after and repair gearboxes. Quaife never said these gears would do 300lb/ft.

My 2860 on a 99 block and EBC makes from some early boost, something the box doesn't like. So plan is to detune that slightly too.

What kind of oil should I put in?

My comment was supposed to be general and aimed at the several reports of failed refurbished junkyard boxes used in e.g. Spec Miata.
If there are some tricks to make the 5sp hold together longer (and don't flex too much?) it will take some iterations to improve it.

Whats a GCU? You have an ECU with a spare 0-5v input that can do spark cut based on that input right? Then you only need like $2 worth of parts from the electronics store to make your spark cut setup. Or you could just lift when you shift, that would be easy. Just blip it yourself on downshifts.

There is also downshifting too soon. A GCU can also keep the box from shifting down before it's safe for the engine. Shift by wire essentially

GCU = air shifters?

As for fluid. Redline Heavy Shock proof is the ONLY fluid I would run in a gear box subjected to forces beyond its ratings. I had a STOCK 5 speed last for over 2 seasons of AutoX / Pro Solo launches at significant power levels and very sticky tires using nothing more than that fluid.

The same set up with regular fluids would only last a couple of events, at most, before going boom.

Think long and hard about what "ECU" stands for, then substitute the word "Gearbox" into it.

Don't most people call it a TCU rather than a GCU?

I know that most car manufacturers call it a TCU but perhaps it is different for aftermarket units.

Keith

Amsoil Severe Gear 250 is supposed to be even better than Redline Shockproof. It's also thick as wet concrete, so you can expect it sucks up some more torque. Anecdotal evidence quoted here:

Amsoil Severe Gear SAE 250, Medicine for Weak Transmissions

says that it will keep a 1 weekend transmission alive for an entire season.



There are several other weights now, but I don't know of any reliability data on the lighter weights relative to 250.

AMSOIL Synthetic Gear Lube - Gear Oil

I think I broke at least 3 5 speeds running nothing but redline heavy shock proof.

Broke seven 5 speeds and four 6 speeds and counting. Stacking them up like cord wood.

I broke 7 5 speeds before going to heavy shock proof. After I went to Heavy Shock Proof I only broke 1. Results speak for themselves.

My results were that the shock proof made no difference in time between failures.

Makes sense to me. I tried Shockproof in my diff and I've never seen a fluid break down so quickly and so massively. Nothing Redline makes has decent heat tolerance, in my experience (based on uoa results). I could see it working in an autocross car that doesn't get the gearbox hot, but not doing jack shit in a road race car that essentially overheats the gearbox every session.

When I was much lower Hp ~200 doing mostly track stuff . I also ran all sorts of mixes of tranny oils. The redline mixes of different amounts of shock proof grades, straight shock proof and down to straight mt90 all seemed to produce higher temps than even just cheap volvoline synthetic. actually Royal purple 75W-90 seemed to have the lowest friction. but nothing made a noticeable difference in extending tranny life when I bumped up power levels with over 300 ft-lbs of torque and even though some ran hotter than others I never burnt tranny oil eather. With the 6 speed Amsoil MTG feels the best with the syncros so that is what I have been using.


I did just order some Amsoil severe gear SAE250 to try. Maybe it will do something.

Have you guys tried dumonde tech trans fluid? Its shitty when its cold bite efect once it heats up.

Yep broke a 5 speed with that in it too. lasted two weekends. I broke a clutch fork shift ball at Thunderhill and put it in at AR auto on my way from Thunderhill to Packwood for autocross a few years back. friction characteristics were different in it seemed to get more slippery when hot but its not particularly high viscosity when cold.

Seems like the focus of that oil was how it behaved with syncros not so much about low friction or extreme contact pressure.

Getting
- New motor mounts (70D)
- New gears (main+3rd)
- Some Castrol oil
- 12.9 bolts for the extension housing
- Slight detune low-rpm

Should be good for another season.

Can't help it, Grand Torino reference.

Stupid question: Has anyone experimented with coolers on the gearbox or differential?