socialistic

iTrader: (2)

About to pick up a '97 LX sedan with a bad block. It's the stock d16y7 and the bottom-end knock is the only thing wrong with it.

I have a '90 DX hatchback sitting in my garage with pretty much an entire Si-swap done, along with the MPFI conversion. I don't drive it because it's a DX so no power windows/locks, and no a/c which is a bitch in SW MO during the summer. Runs and drives great but oil pools on pistons 1 and 2 so it blows smoke on hard throttle or after letting the engine break...replaced valve stem seals, spark plug tube gaskets, rocker assembly gaskets, never could fix that consumption issue so I just started ignoring it and topping the oil off every week or two.

Option #1 is to swap my entire d16a6 over. If I use my entire motor I'll buy top and bottom end gasket sets, piston rings, and probably main bearings just to get them replaced...and hope something in there fixes the oil consumption issue. I assume I'll be reusing my ECU, but can I use the existing y7 harness or will I need to move my MPFI converted harness over, and what changes/modifications need to be made for this to work(mounts, wiring, etc)? Will the A/C and P/S pumps mount to my a6?

Option #2 is to use my a6 block with that y7 head. If I just use my block I'll still end up doing the same amount of work because I'll want to rebuild that y7 head anyway and the block will still get rebuilt. I'll need to know if I need to do anything specific to match that block and head together, like a specific head gasket and/or timing belt. Which ECU do I use? And just like Option #1 I'd need to know if that A/C pump will mount to that a6 block.

Basically I'm just trying to figure out which head would be better on the a6 block, what I need for wiring, and gather up any other information now so I don't get stopped in the middle of the job with any stupid surprises, and make sure I have all the parts necessary before beginning because this requires me to drive an hour south and spend a weekend down there because that's where the '97 is parked and where I'll have shop space/lift usage available to me.

As for the oil consumption issue, I honestly have no idea what will fix that. I already dumped a bunch of money in to it, compression and vacuum tests are great, so I'm just chalking it up to bad valve guides or rings. Unfortunately I won't know if it's fixed or not until after the swap which kinda sucks.

tony_2018

Why not just replace the d-motor in the civic with another, instead of finding a reason to tear into the a6? I'm mean **** if you got money and time than go for it, but you'll probably run into wiring headaches just trying to run the a6 right in an obd2 car. Do they do obd2 inspections where you stay?

socialistic

iTrader: (2)

Engine availability isn't that great in my area and I don't want to drop $400+ on a motor that I don't know the history of. With my ability to buy discounted parts through my buddy's shop it seems more efficient and safer to just clean up/rebuild what I already have. My only risk here is that oil consumption issue that may or may not be fixed with the new rings and gaskets.

I know it's possible to slap a y7 head on an a6 block but I don't remember which head gasket and timing belt I use. This has been done and covered on here before but I haven't had much luck in searching for that info. I think I can re-use the existing harness and ECU in that LX for my a6 block under the existing y7 head, but I'd need confirmation and I'm not sure of the sensor differences between blocks.

We have a basic $12 DOT inspection here that only covers exterior lights, horn, wheels/tires and any play in the hubs/bearings, and making sure you have a complete exhaust system. Basically just making sure you're not driving a death trap down the interstate. They don't even do emission testing here.

tony_2018

I would buy a used engine for cheap, and rebuild. If you already deem the y7 non-repairable I'd just find another and rebuild it. Those long blocks go cheap, might have to drive a good distance but thats the norm anyways.

socialistic

iTrader: (2)

I'd love to find a clean obd1-2 longblock, but availability + budget and time are not on my side currently.

NotARaCist

iTrader: (1)

Why not just rebuild the Y7 that's in the car right now? It's really not that hard...

socialistic

iTrader: (2)

I'm assuming the block is garbage, which may or may not be correct, and comparing it to my a6 block which I know is good(apart from oil consumption on cyls 1 and 2 from an unknown source that I think is valve guides or rings).

Are there any major differences that would keep me from just swapping in my entire a6? Are the a6 and y7 different enough to cause problems with that y7 ecu? The biggest difference I'm seeing is that weird top-loader intake manifold on the y7 compared to my normal style a6 intake manifold.

NotARaCist

iTrader: (1)

A rod knock doesn't mean the block is garbage. The only way to know for sure is to open the block up and find out.

socialistic

iTrader: (2)

If I can find a newer longblock or find the y7 block to be easily fixable, either of those options would be ideal and maybe even cheaper. However, I'd still like to know how to get that LX on the road with my complete d16a6 or just the a6 block. Having all this information now will really help me out if I end up having to go that route.

It's my understanding that the only way to swap in my a6(complete or block) would be to use an OBD1 conversion harness for the ECU and an OBD1 ECU due to the knock sensor not being usable on the a6 block. I believe I would need to re-use the y7 harness but relocate the fan switch wiring. I would also need to re-use the y7 distributor. What I don't know is which head gasket timing belt I use if I keep the y7 head, if I need to swap any pulleys if I keep the y7 head, and which intake manifold to use for either head.

eghatch9295

iTrader: (1)

the a6 block is a beast, in the d series world. that block will work totally fine in your car. p2e doesn't check for knock. all youll need to do is do the "ckf bypass trick" and you're good to go. y7/y8 headgasket and belt. your obd-2 harness is fine, swap all y7 accessories onto a6, run your current ecu.

socialistic

iTrader: (2)

Awesome, thanks for the info!

Do I re-use the y7 top-loader style intake manifold or my a6 manifold? Or does it not really matter? Ideally I'd like to keep the a6 because it looks "normal," haha.

94EG8

If you really want to swap that A6 in there, reuse complete long block. Find a '96 - '98 D16Y8 automatic Intake manifold and throttle body, reuse the Y7 ECU, perform the CKF trick, done.

The A6 is a better block (steel girdle vs aluminum and 2 oiling holes per crank journal compared to 1 for the Y7. That said unless you're planning to build it for power (look into PM7/P29 pistons if you are) I think you're a whole lot better off just buying an OBD2 JDM SOHC ZC from an importer. Basically replace the timing belt and water pump and then drop it in.

socialistic

iTrader: (2)

What about using eghatch9295's method(my block, y7 everything else including head gasket and timing belt, and assuming he was implying I either keep the y7 intake manifold or use my a6 intake manifold)?

I haven't looked out for '96-98 y8 auto IM availability around here, but I can't imagine that being too hard to obtain. The y8 and z6 heads and ecus definitely aren't as common as they once were so I'll bail on that pipedream for now.

I'm not building a racecar. Right now I just want a reliable daily with A/C and room for my tools and supplies, none of which I get with the hatch. I have reliability with the hatch but it's a DX so no options and no a/c, and it consumes a little oil which isn't exactly a problem but sure as hell annoying have to top it off.

I've been burned on an imported long block(some years ago I was the guy that started that hugh anti-TJ campaign on here and numerous other forums after being sent the wrong longblock and being charged for the right one) and HMotors was always too expensive.

94EG8

You can, but I don't know why you'd want to considering the Y7 manifold will bolt up the A6 head.

You're looking at the same money to build it with PM7/P29 (ZC) pistons as the PM6s that are in it now. It will still be slow, but it's definitely better than stock for the same money.

Tiger Japanese is by far the worst importer out there and it sucks that you got burned, but there are lots of other importers out there. For the most part importers are all the same. The only two that stand out are Tiger Japanese for being just absolutely horrible and H Motors for doing everything right. The rest will normally sell you a good engine at a good price and stand behind it. Personally I'd never rebuild a stock engine, it's so much easier and cheaper to just drop in a low mileage JDM engine and 99% of the time there's no issue.

socialistic

iTrader: (2)

I like the more traditional style intake manifolds like whats on the a6 than the weird looking top-loader intake manifold on the y7. If I can keep my a6 intake manifold and not suffer any downsides that would be ideal. If not, oh well.

Well, technically this would cost more because I'd have to buy those zc pistons and rings compared to just using what I already have in the a6 block. My plan was to replace the rings and bearings in the a6 block because A. rings may be why it's consuming oil on 2 cylinders, and B. it's already pulled and separated so why not just replace those things now.

Do you have any other recommendations? I shot HMO an e-mail to inquire about shipping costs for a D15B SOHC VTEC Long block(96-99 3 State VTEC) just to see what total cost will be, but damn $795.00 is a lot for an engine and shipping will probably be around $200, not to mention how much it will cost me to get the correct ECU or chip/tune a p28. I'll be 1200+ deep in to that longblock and at the end of the day it's still going to be a stock d15b vtec.

eghatch9295

iTrader: (1)

you can use the a6 manifold. you'll need your y7 throttle body and injectors. id also be interested in your a6 cam, should you decide to part the head out.

socialistic

iTrader: (2)

Are there any significant differences between the a6 head and y7 head that would result in one being better than the other on that a6 block? I know both will work, but I'm not sure if one is slightly better than the other as far as power goes.

If I swap my entire a6 longblock that would make this swap a lot easier for me, but the problem with this option is that one of the two halves of that longblock has an oil consumption problem and I don't know which one is the culprit. I figured using the y7 head and getting new rings in the a6 block would drastically reduce the risk of still seeing that problem after the swap since I'm convinced it's either bad rings or bad valve guides at this point, and I wouldn't be forced to buy a new set of valve guides granted the ones in the y7 aren't bad. I'm also assuming that the y7 head has lower miles than the a6 head.

socialistic

iTrader: (2)

Apparently if I go with the y7 head on the a6 block with a6 intake manifold and y7 timing belt/head gasket/rail/injectors/throttle body...it will make better power/torque at lower RPMs than the a6 longblock. There are a few threads on it over at d-series, but none of them confirmed what that "dr evil" build went in to. I'm assuming it should work fine for me granted I do the CKF trick.

I guess that also confirms my other questions on if the y7 throttle body/injectors/rails would work on the a6 intake manifold. Still not sure which intake manifold gasket to use, though.

eghatch9295

iTrader: (1)

use the gasket for the manifold. my opinion on the heads is that you use the y7, simply because it is known good.

socialistic

iTrader: (2)

For the y7 throttle body on the a6 intake manifold, which gasket do I use if they are different? Can't find any info online about this one.

eghatch9295

iTrader: (1)

y7.

socialistic

iTrader: (2)

Really appreciate the help guys. Some years ago I was in your shoes answering a bunch of questions about Integras and b18s, haha.

Let me go over this setup to make sure what I have is accurate and that I have the right list of stuff to buy. Plus it doesn't hurt to have this pop up on google for people searching for this build in the future...

d16a6 block(buying a6 rings, main bearings, bottom end gasket kit, and water pump)
d16y7 head(buying y7 top end gasket kit and timing belt)
d16y7 cam and cam gear
d16a6 intake manifold(buying a6 gasket)
d16y7 throttle body(gasket comes with top end kit)
d16y7 injectors and rail(o-rings come with top end kit)

This will interface with the existing OBD2 y7 harness and ECU after the CKF bypass mod(for OBD2a) is performed on the ECU harness, and should result in slightly higher CR and slightly higher torque on the lower end with no CELs granted the CKF trick is done properly and nothing is broken/malfunctioning.

On the right track?

ETA: Would the a6 cam and y7 cam gear be better at all, or would I just be sacrificing bottom end gains for top end gains?

ETA2: And one last question I can think of...anything special that needs to be done for timing or just set that normally?

94EG8

I assumed you were going to replace pistons as well. If not then yes it will cost more.

Sunrise JDM Motors, JDM Source, I think JDM Tokyo performance is good but I haven't bought an engine from them (I think my buddy has though) It's really only ever been Tiger I've heard horror stories about.

Using a Y7 head will give you a slight bump in compression. The A6 had a better cam though.

You'll also need to open up a passage it the throttle body to get it to match a port in the intake manifold or it wont idle right. And reuse the A6 rail, Y7 wont fit.

Yes.

eghatch9295

iTrader: (1)

y7 rails are odd because of the very stupid design of the y7 intake manifold.

socialistic

iTrader: (2)

Is that throttle body modification an easy one? Can't seem to find any info or guides on that.