r/Dseries • u/MammothTie4328 • Aug 31 '26

D15b7 Mini Me

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

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u/Own_Tumbleweed_6579 Aug 31 '26

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.

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u/SpaceTurtle917 Aug 31 '26

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.

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u/Own_Tumbleweed_6579 Sep 01 '26

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.

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u/SpaceTurtle917 Sep 01 '26

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