bigslimdog

Whats up guys...I'm new to the older civics, I've always had an EG but it was in an accident. Now I'm driving my truck around but it's killing me in gas at like $50 a fill up every 4 days or so. My solution was to buy a 1990 DX Hatch with a hydrolocked engine and I have a guy I know who is willing to give me a d16y7 with manual tranny for cheap so I'm gonna drop that in there. He said he got around 40mpg with it.

My question is, what exactly do I need for the swap? Here are the things I know so far (correct me if I'm wrong):

-All of the 1990 stock mounts work except I need to change the driver's side upper motor mount and bracket on the Y7 to the 92-95 D series bracket and mount.

Will the stock axles from the hatch work with the Y7?

What else do I need? Any tips for this swap? Keep in mind I'm trying to get the best gas mileage possible and not really looking for any performance stuff.

Katman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bigslimdog &raquo;</TD></TR><TR><TD CLASS="quote">Whats up guys...I'm new to the older civics, I've always had an EG but it was in an accident. Now I'm driving my truck around but it's killing me in gas at like $50 a fill up every 4 days or so. My solution was to buy a 1990 DX Hatch with a hydrolocked engine and I have a guy I know who is willing to give me a d16y7 with manual tranny for cheap so I'm gonna drop that in there. He said he got around 40mpg with it.

My question is, what exactly do I need for the swap? Here are the things I know so far (correct me if I'm wrong):

-All of the 1990 stock mounts work except I need to change the driver's side upper motor mount and bracket on the Y7 to the 92-95 D series bracket and mount.

Will the stock axles from the hatch work with the Y7?

What else do I need? Any tips for this swap? Keep in mind I'm trying to get the best gas mileage possible and not really looking for any performance stuff.</TD></TR></TABLE>

You're on the right track so far...

You'll need to reuse your DX's tranny, flywheel + clutch components, and axles (you cannot use the Y7 tranny cuz' its a hydro tranny/won't work with an EF chassis).

Reuse your DX's complete intake manifold, distributor, engine wire harness, ecu, & exhaust manifold (everything will bolt up) and you should be set. I think you'll need to use the Y7's spark plug wires if I remember correctly.

good luck...

bigslimdog

Thank you much...I had no idea about many of those things. Thanks again.

Katman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bigslimdog &raquo;</TD></TR><TR><TD CLASS="quote">Thank you much...I had no idea about many of those things. Thanks again.</TD></TR></TABLE>

Your welcome and that's why some of us are here, to help peeps like you

bigslimdog

So wait...I use the DX's ECU? not the Y7 ecu? That sucks that the tranny won't swap over. Is there any way to get a 5 speed tranny? The one in there is 4 speed.

Katman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bigslimdog &raquo;</TD></TR><TR><TD CLASS="quote">So wait...I use the DX's ECU? not the Y7 ecu? That sucks that the tranny won't swap over. Is there any way to get a 5 speed tranny? The one in there is 4 speed.</TD></TR></TABLE>

yes, you have to reuse the DX ecu to retain the DPFi. The Y7 ecu is OBD2 and will not plug n' play into your DX (OBD-0) nor will it run right if you did get it plugged in. Trust me, you wanna stick to OBD-0, converting to OBD2 is not fun if you're not into wiring.

You can get a 5speed tranny from any 88-91 Si if you want, just make sure that if you get an 88-89 or 90-91 Si tranny, you buy the respective clutch disc for the year of the tranny because the teeth count on the clutch spline differs between 88-89 & 90-91 by 1 tooth or so. You can stick with your existing pressure plate & flywheel though....the disc is what matters most tho.

perhaps you can sell or trade the Y7 tranny for an 88-91 Si tranny

bigslimdog

what will the difference be between the 4 and 5 speed transmissions? Just the length of the gears? Anything else?

VTECVillain

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bigslimdog &raquo;</TD></TR><TR><TD CLASS="quote">what will the difference be between the 4 and 5 speed transmissions? Just the length of the gears? Anything else?</TD></TR></TABLE>

Externally the cases are the same and they bolt up the same. You must reuse the stock 4 spd axles if you use a 5 spd Si or DX tranny. The only way to use the Si or DX axles is if you swap the hubs since they are a different size and spline.
In order for the motor to bolt into place, you must reuse the driver's side engine mount and bracket from your stock motor or any 88-91 D series motor. It will not bolt in with the Y7 bracket. You will need to trim the timing cover a little bit around the bracket for it to fit.
Katman has already tackled all the OBD and component issues. Just liek he said reuse all the DPFI stuff to keep it simple and definitely avoid trying to go OBD2. If you want MPFI you will need 88-91 Civic/CRX Si parts.

VTECVillain

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Katman &raquo;</TD></TR><TR><TD CLASS="quote">I think you'll need to use the Y7's spark plug wires if I remember correctly.</TD></TR></TABLE>

Yes, you need to use Y7 plug wires. There is a difference in size between the Y7 and EF D series valve covers. The upper plug hole where the rubber part of the plug wire seals against the cover is smaller on the Y7. If you used the stock plug wires from the EF they would work but won't seal and they will come loose easy, so don't do it. If you have any other Q's let me know, I've swapped quite a few Y7's into EF's.

Katman

....thanks for confirming VTvillian

bigslimdog

thanks for all the help katman and vtecvillain. i'll be sure to PM you guys with any questions i still have

blackeg

so just to re-affirm, if switching to an si cable trans from a dx 4 spd, you can use the dx axles to avoid switching the hubs over? the dx axles fit fine into the si tranny? does this hold true for both 88-89 and 90-91 si trannys?

Katman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackeg &raquo;</TD></TR><TR><TD CLASS="quote">so just to re-affirm, if switching to an si cable trans from a dx 4 spd, you can use the dx axles to avoid switching the hubs over? the dx axles fit fine into the si tranny? does this hold true for both 88-89 and 90-91 si trannys?</TD></TR></TABLE>

yes, you can reuse the DX axles to avoid chaning your hubs to Si hubs; the DX axles will fit the SI tranny fine and holds truth for all 88-91 Si tranny's n' hoes!