[downest]

So, if you read my other post, you know my friend is probably getting an HF, which will be getting an A6 swap. I'm going to get the tranny from him, and I want to put the 5th gear in my Si tranny. Can someone (cough, Heu, cough) tell me how to do this? I haven't taken my tranny apart before.

 

[dohcrxl]

hmmm, thought I heard someone say my name. :wink:

So anyway Tom, you don't like your hair do you? Wanna pull it out with your bare hands do you? Alright, don't say I didn't warn you.

LOL, it's not that bad at all. (easy to say after you've shattered a countershaft bearing figuring it all out) First thing you do is make sure you're completely sober. Next, get a clean table to lay all the parts on. I used an old door. Most important thing to remember is to reference all pieces in exact order and position as they came apart. For instance, lift gear out and off of shaft, do not turn it any which way, set it down on your clean table up side up, lift next shim/sleeve/washer/what have you out and off of shaft, do not turn it any which way, set it down next to the previously removed item, repeat. When putting the assembly back together, install in reverse order while keeping exact positioning (up side up). Do not make the mistake I made; up side of anything must always stay up. You sometimes can't see it with the naked eye but flipping something upside down will change the load distribution and something else will break or bind. In my case I flipped what must've been a tapered washer or something resulting in the shattered bearing.

Now, I can't remember all the steps so use this as a rough guideline. Questions? Stuck? Ask here first. Don't experiment much less force anything. Most pieces in the tranny should come apart without much force. It's all in where the pressure is applied or how the internal parts are held. To be honest with you, As many times as I had my hybrid apart, I'm still not smooth as butter. Some of those parts just take perfect manipulating or finagling to disassemble and especially to reassemble. Get ready to get mad at your inanimate gear stacks.

1) Remove all 12mm case bolts with the input shaft side of the tranny down flat on the ground.

2) Use 3/8 ratchet and short extension alone plus maybe a short pipe for leverage (nothing else) to remove C-clip access plug (do not overtighted that plug when reinstalling or you'll crack the casing, 25 ft lbs is what I torque it to. I think Honda says 30 but I'm not that brave. And be sure to use some kind of sealant on the threads or your tranny will leak)

3) Break the bead of Honda bond that will be between the two halves by lightly and carefully prying with a flat screwdriver on the appropriate tabs. You'll have to look at the casing and visualize where you have to pry to get the halves apart.

4) Once the bead is broken all the way around, with a large snap ring plier, hold the C-clip open while pulling up on the casing. Wiggle upper half off bottom half. An assistant might be helpful here.

5) Remove 10mm's that hold the thingamabobber that holds the reverse idler gear. Set all that junk aside and reference positioning. (important or you wont have reverse when finished)

6) Figure out how the shifting motions work by playing with the selector rod. This is the shaft with the hole in it that you punched the roll pin out of to remove the tranny. Stick a screwdriver in that roll punch hole and turn left/right then move in/out while looking at what the shift forks are doing. This will give you an understanding of how the gear selection is physically done inside the tranny.

7) Once you have that figured out, with your bare hands and not with the selector rod, put the tranny into 2 gears at the same time. This will lock both gear assemblies to allow you to undo the 30mm shaft nut. This is a regular right hand thread nut. jfyi- the 14mm's that hold the ring gear to the differential are left hand threads (but you wont be touching those in this application). Anyway, loosen the shat nut but don't remove it yet. Leave a few threads on so the assembly doesn't just fall apart on you when you lift it out.

8.) Remove the 8mm allen that is on the underside of the bellhousing. This holds a section of the gear selector which wont release the shift forks and thus the gear stacks unless it is undone.

9) You can now lift both gearstacks out of the tranny and start the teardown. Be warned: if you have a way to take clear close up pix from varying angles, do so. Once everything is aparts, sometimes it's not so self explanatory how it goes back together. My first time took several hours to put back together but that's because I just started ripping sh** apart and trying to remember how all 100 pieces went. (pretty stupid coming from a guy with such bad memory, he'll set a tool down and will be looking like mad for it 30 seconds later)

10) Additional note: I don't know the name of the deallie (cuz I'm too lazy to look it up) but at the top of the mainshaft there is a collar/sleeve/ring deal. The sleeve and collar only fit together one way. Looking at the teeth(you'll now what I mean) there is slightly longer teeth on the collar that coincides with a shorter teeth on the sleeve. It'll be very fun trying to get those pieces to stay together, at the same time keeping mesh with the countershaft, at the same time trying to line it up with the shift fork, at the same time trying to engage the shifty gear selector rod interlock. Whatever happens, don't throw the gear stacks across the room in a raging fit. (I know I've wanted to many times when I first started experimenting with the internals of a tranny)

You are lucky you don't have to remove much because all you're doing is replacing the 5th gear set. If you were doing a hybrid, you'd have to transfer all the gears/sleeves/collars/washers/rings/syncrhos from the ZC onto the si counter and mainshaft. For your application, simply remove only what is necessary so you can swap out the 5th gear set. In case you don't know, the 5th gear set is made up of 2 different gears; one on the main and one on the countershaft. They are the gears at the very top of the gear stacks.

Have fun. MUAHAHAHA :twisted: *ooops, I mean... be careful and good luck!

-Heu

p.s. it's late but I'll go over what I wrote tomorrow and see if I missed anything

 

[coldtotouch]

I heard from a first hand source this mod doesn't help much with gas mileage and takes away terribly from the power in 5th...

 

[downest]

There's no power in 5th anyway...

 

[coldtotouch]

There's no power in 5th anyway...

Then its really leaving you with negative power, as its taking away from no power!

 

[Tiersin]

just a question, right now, my Si tranny does about 4k rpms at 80 mph. Will it be better with a HF 5th gear? if so, how much better. I have to drive 200 miles to college soon, a lot, and its 75 mph the whole way there. I hate doing 4k the whole time. (driving slower is not an option) :wink:

 

[stick]

It certainly does help with gas mileage, but only if you aren't driving in 5th with the RPMs up at 6000 all the time. Geez!

The whole premise behind this is to keep the RPMs a bit lower when you are cruising on the highway. It will only affect your gas mileage in 5th gear when your RPMs are down at a reasonable level (less than 4500 rpm)

 

[dohcrxl]

Tom, reviewed and corrected/added.

just a question, right now, my Si tranny does about 4k rpms at 80 mph. Will it be better with a HF 5th gear? if so, how much better.

Your exact rpm will be 3487 with the hf 5th

I heard from a first hand source this mod doesn't help much with gas mileage and takes away terribly from the power in 5th...

Look at the above example. There's 400 revolutions per minute where the injectors are not spraying. That's a 10 percent theoretical increase in fuel economy. And that's not the only benefit; there are 400 less times per minute where the pistons/rods are going up and down scraping the rings on the cylinder walls, 400 less times the crankshaft is spinning around in it's cradle, 200 less times the cam is spinning dragging the entire valve train along with it.

I say very worthwhile.

Far as the power issue, when would anyone ever need to punch the gas hard and keep it there in 5th? A quarter mile run in a lightly modified CRX barely even uses 4th gear. You might be in it for a second and a half at most. 5th in this particular application is never needed for maximum acceleration.

 

[Charles]

I have one of the hybrid trannies (ZC 1-4, HF 5, Si FD). When I bought my second Si, the higher RPMs at highway speeds were really annoying. So I would say that a greater benefit than MPG improvement is the lower cruising RPMs.

Of course, as Kwicko pointed out one time, you tend to drive by the sound of your RPMs. So when you get your new hyrid tranny, you will probably just drive faster in 5th than you normally do.

 

[Kwicko]

I heard from a first hand source this mod doesn't help much with gas mileage and takes away terribly from the power in 5th...

Hmmmm... My experience has been a bit different. Gas mileage: At my "normal" highway cruising speed of 80-85mph, with the air conditioning on, with two 250+ - pound guys in the car, AND our luggage, my 85 lb toolbox and a "spare" transmission that we were trading out with a customer along the way, we were getting around 42-46mpg highway.

As for the power loss, I wouldn't say it "takes away terribly" - more like it moves the power band higher on the speedo. How much higher? I can't say; I've always chickened out by the time I'm showing around 115-120mph on the speedo! Something weird does seem to happen with the power if you use the HF 5th gear with an Si final/diff. It feels a bit less powerful than a stock Si 5th, but it feels like it gets "on the cam" at around 95-100mph, and it feels like it keeps pulling harder as the revs climb.

Still, I don't find the power in 5th gear to be sorely lacking for most situations. Places where I'd normally downshift a stock Si, I still do that; places where I wouldn't... I don't. There's adequate passing power in 5th gear at 75-80mph without downshifting, even with the A/C on.

Revs: It doesn't look like much on paper, but it's a BIG difference. It just might change your driving style. Like Charles mentioned, after years of driving Si's, where 80mph = 4000rpm, my "inner ear" just seems attuned to that frequency. With the HF 5th, I'll look down and find myself surprised to be cruising at close to 90mph!

Out for a drive today in my bone-stock '90 CRX Si, the stock Si 5th gear just felt wrong. Maybe I've been driving the hybrid tranny too long, but the Si transmission just wasn't doing it for me.

All in all, the HF 5th isn't a HUGE difference - but in a world of near-three-dollar-a-gallon gas, even little things can help. And also, the way I see it, if I have the need to still be accelerating that hard by the time I'm into 5th gear, I'm already screwed, because the police radio call has already gotten ahead of me! Right, Mark?

Mike

 

[coldtotouch]

I heard from a first hand source this mod doesn't help much with gas mileage and takes away terribly from the power in 5th...

Hmmmm... My experience has been a bit different. Gas mileage: At my "normal" highway cruising speed of 80-85mph, with the air conditioning on, with two 250+ - pound guys in the car, AND our luggage, my 85 lb toolbox and a "spare" transmission that we were trading out with a customer along the way, we were getting around 42-46mpg highway.

As for the power loss, I wouldn't say it "takes away terribly" - more like it moves the power band higher on the speedo. How much higher? I can't say; I've always chickened out by the time I'm showing around 115-120mph on the speedo! Something weird does seem to happen with the power if you use the HF 5th gear with an Si final/diff. It feels a bit less powerful than a stock Si 5th, but it feels like it gets "on the cam" at around 95-100mph, and it feels like it keeps pulling harder as the revs climb.

Still, I don't find the power in 5th gear to be sorely lacking for most situations. Places where I'd normally downshift a stock Si, I still do that; places where I wouldn't... I don't. There's adequate passing power in 5th gear at 75-80mph without downshifting, even with the A/C on.

Revs: It doesn't look like much on paper, but it's a BIG difference. It just might change your driving style. Like Charles mentioned, after years of driving Si's, where 80mph = 4000rpm, my "inner ear" just seems attuned to that frequency. With the HF 5th, I'll look down and find myself surprised to be cruising at close to 90mph!

Out for a drive today in my bone-stock '90 CRX Si, the stock Si 5th gear just felt wrong. Maybe I've been driving the hybrid tranny too long, but the Si transmission just wasn't doing it for me.

All in all, the HF 5th isn't a HUGE difference - but in a world of near-three-dollar-a-gallon gas, even little things can help. And also, the way I see it, if I have the need to still be accelerating that hard by the time I'm into 5th gear, I'm already screwed, because the police radio call has already gotten ahead of me! Right, Mark?

Mike

I have a friend in NC who had installed it (HF 5th) and personally told me he didn't notice a huge benifit in gas mileage... True there are MANY MANY MANY factors that would contribute (ie. wheel weight... etc.. etc... the list goes on)
this was a mod i wanted to do for a while now, and now, after all this, i may still be going for it.
See the plan was to go with a 3 Stage Vtec D15B, and swap in the hf 5th...
this inturn, would allow me to cruise on the highway at higher speeds, while still being able to take advantage of "lean burn"...

now i'm really considering doing it!!!

ahh man, i change my mind more than a 3 year old... but one things for sure, i love my crx

 

[RamaCrx]

I have not been able to find any of these engines listed online. Are they available? Was thinking of doing the same.

 

[jfrolang]

I have not been able to find any of these engines listed online. Are they available? Was thinking of doing the same.

Link

 

[coldtotouch]

I have not been able to find any of these engines listed online. Are they available? Was thinking of doing the same.

Link

Wrong... that is not the 3 stage Vtec D15B (JDM EK obd2)... that is the regular Vtec D15B (JDM EG obd1).

They aren't hard to find, i've seen quite a few on ebay recently. If you do purchase one, make sure to buy it complete, It will not work without its proper ECU (tranny is not really necessary, but your choice). They go for about 900 bucks (give or take a bit) for a complete swap... The reason i'm debating it is more for the fact that i don't know exactly what i want out of the car yet (whether i want a beast thats fast, or just a nice ride... i'm really thinking the latter)...

Heres a link for one:
3 Stage Vtec D15B

 

[downest]

The auction says it's in Montreal, but I have talked to the seller before when I was considering a motor swap. Their warehouse is in Albany, about 10 minutes from me. I went down to look at a B16 in the summer, most of the motors looked good, no broken sensors, and it looked like they cleaned them up a bit. The guy was really nice and open to pick up too.

 

[coldtotouch]

I know the company he is reffering to then. There is a company called Sunrise that is located in montreal. They also stock these motors, as well as other jdm parts. I have never personally dealt with them, though i have heard good things about them from other people.

I have also called a few places locally and found they also have the swap avaliable for local pickup, so i may endup going that route. 50mpg here we come :shock:

 

[RamaCrx]

I know the company he is reffering to then. There is a company called Sunrise that is located in montreal. They also stock these motors, as well as other jdm parts. I have never personally dealt with them, though i have heard good things about them from other people.

I have also called a few places locally and found they also have the swap avaliable for local pickup, so i may endup going that route. 50mpg here we come :shock:

So if you get the ECU then you just pull the new harness through the firewall and plug and play?
I will start looking for it here and online.
Thanks for the info. I kept getting confused with them listing it as 2 stage vtec when all the articles talk about 3 stage.

 

[coldtotouch]

So if you get the ECU then you just pull the new harness through the firewall and plug and play?
I will start looking for it here and online.
Thanks for the info. I kept getting confused with them listing it as 2 stage vtec when all the articles talk about 3 stage.

When you do get the ecu with the swap (MAKE SURE YOU GET 5 SPEED, unless you want auto :?) It won't be just pulling the new harness through the firewall and plug and play, there is wiring that will need to be done, though i'm not exactly sure of the intricacies just yet, i will go into detail with it when i am doing it in a well thought out post.

I have seen them referred to as "3 Stage Vtec" and "Dual Stage Vtec" also (i guess one means it has 3 stages, the other means it has 2 vtec solinoids engaging).

I also used to think these motors were a bit rare, but they're becomming more common these days. The advantages, Great gas mileage, good power when you want it. Disadvantage, tuning limitations of OBD 2... and theres nothing you can do about it, cause you require the ECU to allow activation of both vtec solinoids, and for "lean burn" to be activated. Also i dunno how vafc's would work so well, again due to "lean burn".

Here are some links i have found useful:

More indepth explaination
The motor
Another one

OBD2 work around, to get the best out of your motor
Workaround

 

[RamaCrx]

When you do get the ecu with the swap (MAKE SURE YOU GET 5 SPEED, unless you want auto :?) It won't be just pulling the new harness through the firewall and plug and play, there is wiring that will need to be done, though i'm not exactly sure of the intricacies just yet, i will go into detail with it when i am doing it in a well thought out post.

Do you think if I do this swap into a 96 hatch there would still be wiring issues? My CRX is strickly for performance and looks, not a daily driver.

Richie

 

[coldtotouch]

Do you think if I do this swap into a 96 hatch there would still be wiring issues? My CRX is strickly for performance and looks, not a daily driver.

Richie

Well if thats the case you want to keep the 3 stage Vtec motor out of the CRX. Its not really wiring issues... its just different. You're going to have to incorporate another wire for the second vtec solinoid, there are also other things necessary that i am just uneducated of, and will go into more detail when i actually do undergo the swap, and do it.

This motor is almost twice the price of the OBD1 d15b (which, when tuned well can achieve a good 35 - 45mpg, and still put out good power). So for what you're looking for, maybe this is a better alternative for your CRX, as you will be able to maintain good mileage, and still make good power (turbo'd ofcourse :wink: )