Straight Cut Custom Gears for R154

[2JZ_MA70]

Obviously this is not a cheap solution so I'm trying to get idea on how many sets people may be interested in and also just get a general ideas about it.

Considering I will be on my fourth transmission in 3 months. The marlin crawler parts are good but they don't address the real problem that is the trust loading of first and second gear. I have tried different oils the upgraded parts but first gear is still breaking the oil film and getting damaged. The washer did not break last time but the lack of lubrication overheated it and the gear.

I will admit I am very hard on the transmission and some may argue just don't beat on it that little extra is not that important. Well maybe but the fact of the mater is that if it was not important we would not be modifying cars. That little extra is what makes you push your car to the limit. Right now that limit in my car is the drive-train. I know many people have experienced this problem and it is time to addressed where it maters.

Sure you can go to auto conversion or get a six speed V160,V161,T56,T6060 but the cost and fabrication involved is extensive and this may be a cheaper and easier solution.

Here is what I suggest. I know a machine shop that specializes in transmissions and custom gears. They will be able to cut first gear with slightly longer (3.0-2.8):1 gear ratio to help you get out of the hole and improve 60' times. It will also help shifting into second because the gear spread would not be as big. The gears will be straight cut and new counter shaft to match the gears. Third and fourth gear would remain the same so will 5th.

I will post some pictures of the damage I have caused so far.

 

[92TealSupra]

I would consider this. The gearing especially in first is to short and I spin through 2nd and third at times with my '87 I had. These gears would not exactly prevent this, but longer gears would able for a shift to be at a higher speed and I like that.

Would there be any combination that would be able to be done, like two different cuts for 1st? Also are you changing all the gears or certain ones? Also could they get helical cut gears made or no?

Thanks for the thread let me know.

 

[adampecush]

Would there be any combination that would be able to be done, like two different cuts for 1st? Also are you changing all the gears or certain ones? Also could they get helical cut gears made or no?

Thanks for the thread let me know.

It sounds like he's only changing 1 and 2. Helical gears are the source of the thrust load, hence making the move to straight cut.

 

[tissimo]

If you're going to do it, IMO get really close gearing. Pair them with a 3.56 rear diff and you'll be good to go. The stock gearing is pretty wide.

 

[2JZ_MA70]

There are different combinations that could be done with this, it would be easyer and cheaper if we stick with one option because having one offs will get expensive.

 

[crisp]

So, if I understand correctly, this is JUST for the first couple gears...? What all is in the 2~3k price as a "kit"?



(NOTE: My billet/hobbed and treated racing gears in my 23 year old 2-cycle RG500 Gamma motorcycle were at the high end of that price... JUST for the cartridge-style gear set, but that was the entire set of gears. They are AWESOME!)



-crisp

 

[Doward]

Considering the countershaft counters 1st through 4th, are you talking about a custom countershaft with only 1st and 2nd staight cut?

It's an interesting proposition, for sure.

I'm curious, though - when you had the R154 rebuild, did you use Marlin's 1st gear thrust washer, and what was your 1st gear thrust clearance?

 

[2JZ_MA70]

The price is not finalized by all means. It is just to gauge what the price limit people are willing to invest. The price might be more or less. I dont know untill the design is finalised. It will be a kit, likely consisting of first, second driven gears , posibly synchro less hub as an option, and the entire countershaft. It is posible that they might be able to modify the existing countershaft. Most like it would be a whole new shaft. Third gear if the price is not significantly increased. 4th would be hard because it would mean that new imput shaft would have to be made but it is not out of the question.

The trans was rebuild 3 times the first time it was marlin crawler development trust washer and the bearing retainer. That did not last long. The second was same, but with the moly parts. I check all clerancess and make sure they are in spec. I have not opened the last thansmission but by the sound and feel it is broken trust washer. All trust washers had signs of overheating and wear on them and i did not drive long on them. Also the face of first gear where it rides aggains the 1/2 hub is aways worn out and overheated. Granted Im pushing more power through the car now it is definetly trust loading issue.

 

[Doward]

So you're not still running a 2.0 60' with 550tq when the transmission failed? Because seriously, people have come off the line a lot harder without failures.

The reason I ask, is the 1st gear thrust clearance (IIRC from memory) is like 0.1mm-0.5mm. I set mine to 0.08mm (ask Jeff about how tight the transmission was when we first bolted it in, LOL) to avoid shock-loading the thrust washer.

Also make certain to oil everything liberally on installation to prevent dry start.

We'll be taking the transmission apart again in a week or so, so I'll certainly be posting up how the MC thrust washer held up!

I'd love to have disassembled yours to find the fault!

 

[SupraClaou]

If the cost of the straight cut gear kit would be in the range of $ 1500-2000
USD I might be interested.
But I want 1st gear and 2nd gear to be longer...

Stock R154 gearing -----> Wish to have gearing
------------------ -------------------------
First Gear: 3.250:1 -----> 2.800 or 2.900
Second Gear: 1.955:1 -----> 1.600 or 1.700
Third Gear: 1.310:1
Fourth Gear: 1.00:1
Fifth Gear: 0.753:1

What you say about that?

 

[Mr.PFloyd]

i would just put a getrag in for the cost, no offense.

 

[hvyman]

^that would require a a diff with like 3.13 or something gear ratio tho or else your just going to be shifting non stop.

 

[Poodles]

Messing with the ratios is adding variables, Toyota already did all the testing and honestly if you think first and second are too short, change the final drive ratio...

Straight cut gears would stop the loading that causes failures, but you need to keep the scope small (in other words stick to stock ratios as everyone has an opinion on what is better).

Not to mention most MKIII owners are cheap...

 

[gaboonviper85]

Messing with the ratios is adding variables, Toyota already did all the testing and honestly if you think first and second are too short, change the final drive ratio...

Straight cut gears would stop the loading that causes failures, but you need to keep the scope small (in other words stick to stock ratios as everyone has an opinion on what is better).

Not to mention most MKIII owners are cheap...

I don't believe we are cheap...I believe we are broke and want the most hp for our $$$!

 

[Doward]

i would just put a t56 in for the cost, no offense.

ftfy

 

[jugodegolf]

i would just put a getrag in for the cost, no offense.

Just my 2cents. But a better rebuild kit (with specs closer to the getrag) seems like a worthy project. If I were doing the kits I would offer:
kit A. for horsepower 300-500
kit B. for horsepower 500-800
don't think you'll see to many higher hp kits flying of the shelf but would at least spec it out.

Seems also that not enough people use their group power/$$$. We do just so-so on the group buys imo.

I sent email to Aisin to see about rebuild kit.

 

[disturbed1]

http://www.ppgearbox.com.au/

straight cut dog engagement gearsets with billet shifter forks for the r154

retail $8k AUD

 

[jugodegolf]

only 8k.:aigo:
Those are flying off the shelf I imagine.

good find though

 

[IJ.]

$6400 Usd

 

[jugodegolf]

You get what you pay for.