B18C5-EH2

Well I posted a topic a while back about building an Si-ZC hybird tranny. I finally got around to building the tranny last week.

I did not get any good pics of my ZC tranny rebuild because my parts were ready to go in and I did not have my camera, but I did snap a few shots of the leftover guts from the Si tranny.

Here's what I put together and why:

ZC case and 1-4 gears with synchros + Si 4.25 final drive (counter shaft and ring gear) with Si 5th gear and Si differential.

I took the ZC 1-4 gears because they are close together and the ZC 1-5 gears are actually shorter than any other D series trannies including the 96-00 EX trannies.

I swapped the DX-spec stock ZC 3.88 final drive out in favor of the shorter 4.25 Si unit. This means I get through the gears quicker, and with the ZC gearing the rpm also stay higher with each shift.

I kept the Si 5th gear because it's taller. This means lower rpm cruising in 5th gear. The ZC 5th gear is crazy short when compared to the Si 5th. The Si 5th is a .771 and the ZC is like a .898 or something crazy like that.

This will illustrate just how short the ZC 5th gear is. This is my ZC 5th gear stacked on a shaft with Si 1-4 gears. Pictured are the Si 4th gear *lower on the stack) and the ZC 5th gear (higher on the stack). If one were to run this tranny, shifting into 5th gear would only drop maybe a few hundred rpm!



That should illustrate just how much shorter and closer the ZC gearing is over the Si gearing.

I can take some more good pics of the remaining Si internals amd possibly reassemble the Si tranny with used bearings just for illstration purposes, but I have been known to be lazy.



Here's a shot of Si guts in a box:



Anyways what did I lean from the build?

Well I learned that even with a Honda employee discount, the bearings and seals cost around $180.00.

I also found out that 88-91 spec diff bearings are different from 90-91, so know what year your tranny is if possible.

I kept the Si diff because I wanted to run stock unequal length Si axles because I'm a cheap ***.

The ZC mainshaft takes an 88 spec clutch disc. Maybe an 89 will work to, but the 90-91 doesn't for sure - differen diameter altogether.

I also found out that stacking gears back on the shafts isn't always easy. If some fuckstick messes with your stacks while you aren't looking (ask me how I know this!) then stacking them back up might not be so easy. If everything isn't in alignment then the cases won't go back together.

Gear pulling tools and a press are life savers when it comes to swapping bearings. Doing this at my house would have been impossible. The diff bearings had to be pressed off, and I did not want to hammer them on so I pressed them back on too.

Here's shot of my finished hybrid tranny:



And once it's in my 1990 STD this coming week I'll give you all my driving impressions. The tranny will be mated to this:



Completely rebuilt D16A6 with brand new P29 high-domed pistons, rings, all new O.E bearings, seals, gaskets (using metal D16Z6 head gasket), belts, waterpump, etc.

Late!

1990civicsiguye

looks and sounds good tell me what you noticed in the difference of the two tranny though....

B18C5-EH2

Has anyone else here done a tranny like this yet?

Malgerus

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">Has anyone else here done a tranny like this yet?</TD></TR></TABLE>

Bluelight has. But he doesn't post here much. He did love the combo though!

akb16

this guy here in Austin,TX builds them and sells them

TomO

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">Has anyone else here done a tranny like this yet?</TD></TR></TABLE>

I had the exact same setup mated to my D15B2 (with MPFI) and it kept up with my 98 GSR. I also had a phantom grip installed as well so it hauled pretty well. Enjoy your new setup!

MikeySpec

Best tranny ever!!!!You will get alot of questions along the lines of..."Are you sure thats a SOHC!?"

bartek_b

Awsome build. I'd try to work with a tranny but I'm too much of a *****

sporkcrx

Sweet set up! How did you get the block that clean?

B18C5-EH2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sporkcrx &raquo;</TD></TR><TR><TD CLASS="quote">Sweet set up! How did you get the block that clean?</TD></TR></TABLE>

Hell look at it before:



Then after rigorous cleaning with our wash cabinet:



And some Plasti-Cote Engine Builder's Cast Aluminum paint:



P29 slugs couldn't hurt:



I'm not looking for much whp over any good running D16A6 right now. I guess the header and pistons will help out, but for now I'm just wanting something very reliable, quiet, and with some good gas mileage.

What do you guys think in terms of whp - 100? I think I'd be happy with 100whp considering the engine's rated at 108 crank hp stock. I'll be running a stock 1990 Si exhaust with muffler because I need quiet and it was free. For an intake I'll try to grab up a 1990-1993 Integra intake tube with airbox if it will fit. Again cheap and quiet are my immediate goals.

If I end up doing the VTEC head swap in the Spring I think I'll be beating up on the B16A2 1992 Si hatchback that my fiancee' drives. Don't you guys think that a 12:1 VTEC'd D16A6 with FPR and V-AFC tuning could net 140whp?

fastcrxsi90

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">
What do you guys think in terms of whp - 100? I think I'd be happy with 100whp considering the engine's rated at 108 crank hp stock. </TD></TR></TABLE>

dont most d16a6's with i/h/e dyno at about 100-105whp? id say most likely around 120-125 anyways...with stock exhaust/intake/cam. the best part is...now it wont fall on its *** once you hit 3rd gear!

Quik89Si

Glad to see bits and pieces of the project coming together here and there...

The shop in my sig does these trannies all day. They're running one in their All-motor SOHC Drag CRX, if that tells you anything

Alex

davens

So assuming you wanted to build these and make a small profit...how much would you charge now that you know what's invovled?
Considering you need a ZC tranny, a Si tranny, and all the bearings/ seals/ synchros...any machine shop expenses etc etc. People will be surprised what it takes to pull it off.

B18C5-EH2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by davens &raquo;</TD></TR><TR><TD CLASS="quote">So assuming you wanted to build these and make a small profit...how much would you charge now that you know what's invovled?
Considering you need a ZC tranny, a Si tranny, and all the bearings/ seals/ synchros...any machine shop expenses etc etc. People will be surprised what it takes to pull it off.</TD></TR></TABLE>

The problem IMO would be finding enough ZC donor trannies. I don't think that Si trannies would be that hard to find though.

I don't think there will be enough demand for this type of tranny because SOHC guys are budget-minded. I think in order to turn any decent amount of profit you'd have to charge $1,000.00. The biggest factor will be how much will the ZC tranny cost? Hell they still fetch $350.00 from importers.

B18C5-EH2

BTW:

I know the pics aren't working right now. We-Todd-Did-Racing is down though. They'll be back sometime I assume.

rasta420

good job on the rebuild. im thinkin of rebuilding my transmission, its a ZC case with ZC 1-4, Si 5th, and Si final drive. its the ZC diff, and im using ZC axles right now.

you bought all your bearings from a 88 Si transmission? also you said you had to use a 88 clutch disc. im using a 90-91 clutch disc on my tranny right now. were the ZC trannies different from 88-91 as well?

i know for sure i gotta change my input shaft bearing. was it hard to get out? how long did the rebuild take?

thanks, and let us know how it runs~

1.8Tities

Good stuff! I'm anxious to see the pics, damn red x.

madhatter07

ive been thinking about doing kind of the same thing, ive just never opened a tranny case but damn that would be so sweet. i cant wait till you get your engine going.

brent_G

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">

.

What do you guys think in terms of whp - 100? I think I'd be happy with 100whp considering the engine's rated at 108 crank hp stock. ?</TD></TR></TABLE>

quite being modest Tom you KNOW that it would be more then that with that compression. You're an educated man~!

seekerONE

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rasta420 &raquo;</TD></TR><TR><TD CLASS="quote"> also you said you had to use a 88 clutch disc. im using a 90-91 clutch disc on my tranny right now. were the ZC trannies different from 88-91 as well?
</TD></TR></TABLE>
there were different input shafts on different year ZC trans just like the US models.
if you want to use the older 88 style trans with the larger 90+pressure plate and flywheel, you can use the clutch disc from 86-87 Prelude SI.(same diameter as 90+ clutch with same as 88 input shaft)

sporkcrx

Awesome, I've been through your pain too. I should of hot tanked it but I was too cheap I thought about painting it too...but I think I'm going to do that on my next motor. Here's mine before:


and after cleaning (water and soap)


As for the power you should definietly meet that. Here's my old dyno, bone stock a6 with a gutted cat and exhaust: http://www.norcalcrx.org/dyno/sean.jpg 110whp

By the way, what did you use to clean the head gasket surface on the block?

dmotoguy

i have that same cleaning cabinet thingy at work... you think those trannies are hard... i had to help out with a few trannys on freightliners this summer... hard as helll to line everything up.. heavy and 18 gears haha

johnzm

sup tom. looks good. too bad its prolly gonna be faster than mine

davens

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">
I think in order to turn any decent amount of profit you'd have to charge $1,000.00. The biggest factor will be how much will the ZC tranny cost? Hell they still fetch $350.00 from importers.</TD></TR></TABLE>

Ouch...then I guess we're undercharging at $650.

CRX-RX

I have three hybrid trannies right now, and can tell you for sure that there are 88spec and 89-91 ZC trannies also. Sounds like you got an 88 because of the clutch disc. I have one of those and two that are using 90-1.