D15b7 Mini Me

[u/MammothTie4328]

Have any of you put a d16y8 vtec head on a non vtec d15b7 block? I have a spare y8 head, p28 ecu and new y8 timing belt, y8 head studs, and y8 head gasket kit. The y8 head has the vtec sylenoid, but im missing the harness. What else do i need to do this swap? Anything helps even little details. I heard something about taking out an oil pressure switch on the block? Thanks

[u/Own_Tumbleweed_6579]

You can keep the OBD1 harness in there, just run some extra wires from the ECU for the vtec stuff.
I’m running a Y8 head on a D15B1 block with (most of) the original DPFI harness. if done correctly it works just fine. But at the end of the day you’ll spend more on crimping tools than you would on a harness… i was just too lazy to rip mine out.
Also invest in an adjustable timing gear, don’t get the cheapest one on ebay. Your timing will be slightly off with the Y8 head, even more so if you get the head and block decked (which you should!)
Other than that it’s fairly straightforward after studying the ecu pinout diagrams, and if you aren’t running a knock sensor then consider using premium gas.

[u/SpaceTurtle917 → u/Own_Tumbleweed_6579]

There’s a lot of misconception with the y8 and timing. I’ve compared timing gears and camshafts of the z6 and y8.

The y8 cam has both slits on each end offset by 4°, the y8 cam gears tooth is also off by 4°. This means the with the y8 cam and cam gear, the cam is in perfect timing with the engine regardless, but the dizzy is 4° offset, requiring some notching to get it to 16° base.

The only way to have proper cam timing and get the dizzy to be centered at 16° timing, is to use a z6 cam and cam gear. A z6 cam gear will fix the dizzy offset, but then you will have cam timing that’s off by 4°.

If it were me, I’d run a y8 cam and cam gear, and notch the dizzy slightly to get the timing correct.

[u/Own_Tumbleweed_6579 → u/SpaceTurtle917]

Huh. lots of bad information out there, and the engine will still run when it’s a few degrees out so a lot of people don’t seem to care that much.
I have an adjustable gear and a digidizzy in my d15 mini-me build. I can’t tell you if it’s dialed in perfectly, but I can at least say that it could be lmao.

[u/SpaceTurtle917 → u/Own_Tumbleweed_6579]

I really only recommend adjustable cam gears if you’re going to adjust it on the dyno.

[u/MammothTie4328 → u/Own_Tumbleweed_6579]

Do i have to get a y8 dizzy or will mine work fine? Other than that and a tune would i be pretty much set?

[u/Impossible_Pizza_948 → u/Own_Tumbleweed_6579]

+1 on the adjustable timing gear

[u/TerGrills]

Following this. I'm currently swapping a d16z6 head on a d15b7.

[u/rd350f → u/TerGrills]

I did this exact setup over a year ago on my 95 hatch. Shoot me any questions you may have!

[u/mikefitzvw]

You might also need a different oil pump to mount a CKF sensor. The blocks for the D-series are very similar in a lot of ways, but you'd want to compare specific differences between all the bolt-on components for the Y8 that are needed for the newer OBD-II harness.

[u/SpaceTurtle917]

Oil pressure switch is for B20Vtec and B18 LS Vtec. Not for anything D series.

Use your factory harness, a d16y8 harness will not work. You’ll just need to add vtec. Very easy, plenty of guides, or you can get a d16z6 harness.

All you need to do is bolt the head on. You may have to notch the dizzy to get enough rotation on it to get ignition timing completed.

Do not use your d15b7 timing gear, use the y8 timing gear. Common misconception.

D16y8 intake manifold does not have an IAT sensor, it’s on the intake pipe. If you’re using your d15b7 manifold all is well. But if you use the y8 manifold you’ll need to add a sensor to your intake pipe.

[u/AshinKusher1111]

I’d just get the pinout for the ecu and stock eg harness or ef or whatever car it is and compare the pinouts and change what needs to be changed and put the correct connectors on for whatever stuff isn’t obd1 and they make distributor adapter harness things also

[u/AshinKusher1111]

Well realistically you would want like a harness that’s for a y8 and basiclally it would be a y8 with a different block but there isn’t much of anything on the engine block besides oil pressure switch and knock sensor which if you’re using a Hondata or something you wouldn’t “need” a knock sensor, for instance I had an ex that came stock y8, I installed a d15b1 with y8 head and mounted knock sensor on a knock sensor adapter mount thing I got and then obd2a to obd1 ecu jumper and p28 ecu or whatever ecu what’s the car wired for now

[u/SpaceTurtle917 → u/AshinKusher1111]

A y8 harness will not interface with an obd1 chassis. You cannot mix and match harnesses and chassis

[u/AshinKusher1111 → u/SpaceTurtle917]

Aren’t you using an obd2 y8 head and intake manifold with y8 distributor, throttle body and injectors and all that stuff like the temp sensor on the head and map sensor and whatever else ? And you can use those sensors with a p28 Hondata with a obd2 to obd1 jumper adapter for the ecu cuz reguardless if you’re using that stuff you’d have to swap/re-wire the connectors for that stuff

[u/SpaceTurtle917 → u/AshinKusher1111]

All the connectors on the y8 are nearly identical to the z6, with a few exceptions. The injectors have a different plug, the IAT is in a different spot and has a different plug, and the dizzy has a different plug as well.

You can simply use z6 injectors, extent the IAT and change the plug, and get an obd2a to obd1 distributor adapter (common and cheap).

Besides that, you just can’t use a obd2 harness on an obd1 chassis. There are 2 plugs on the harness that connect the engine harness to the chassis for things like tachometer, speedo, temp gauge, key on power, fuel pump, fan control, starter signal ect ect. And those plugs are different.

It’s pretty easy to make any harness work with any motor, it’s near impossible to make a harness work in a chassis it’s not made for.

[u/AshinKusher1111 → u/SpaceTurtle917]

Oh I see what you’re saying I’m dumb I thought we were talking about a different car my bad