proformance

i recently got a vtec head from a junkyard. it did not come with a valve cover, and i was wondering what physical characteristics i should look for to identify the head. What is the difference between the d16y6, a d16z6, or a d17 head?

anothercivcSi

All of the D16's will have the spark plug wires in the bottom. All the 96-00 D16 valve covers only say "HONDA" on them, he 92-93 D16Z6 valve cover will say "HONDA" and have a honda emblem. the 94-95 D16Z6 valve cover will read "VTEC" and honda.

88crxSi

LOL!!! He said it did NOT come w/ a valve cover. heh..

a d16a6 head will have the spark plugs on the firewall side of the head. the d16z6/y8 (u said y6, i think u mean y are closer to the exhaust ports. what else came w/ the heads?

proformance

hahaha.. i know it is a vtec head, because of the vtec solinoid that i stuck on it (the vtec solinoid only goes on the vtec head) and the fact that there are vtec cam shafts and many more rocker arms than my stock head. i am wondering what the difference between the d16y8 head (thanks for the correction) and the d16z6 head. i know that the y8 has higher compression than the z6. i just want to make sure of which head i have.

88crxSi

hrmm... how to tell.. do you have and dizzy's lying around an a6 or y8 dizzy will fit but a z6 will have different mounting points.

I'm assuming the above because a a6 and y8 bolt onto a d16a6 head and the z6 doesnt. That means the same should be true for a y8 head?

89dxhunchback

A6 with Z6 head = high compression
A6 with Y8 head = a little higher high compression
or... Z6/Y8 block with A6 head = 8.4 to 1 comppression which is the mack daddy for a honda turbo car !!

Or Z6 pistions in a A6 block should do the same 8.4 to 1 compression.

proformance

i found out how to tell the difference. i have an extra d16a6 head laying around, looked at my friends d16z6 and compared it to my d16y8 head. a d16y8 head has check *****, one by the distributer and one in the middle of the intake manifold. also, the d16a6 distributer is able to directly bolt onto a d16y8 head, whereas it wouldnt with a d16z6. the last and final noticable difference would be the water holes where the intake manifold would bolt up. the d16y8 head has round ones only, and the d16a6 and d16z6 head have a square one with one of the corners cut off.

thanks for the help guys! -matt

88crxSi

The dizzy's, like i said.

Elite CRX

Hey 89dxhunchback, why would Z6 pistons on a A6 block have low compression? Different in head design?

89dxhunchback

The cc difference in the A6 vs the Z6 heads AND pistons determan comp. ratio.

Z6 uses small cc heads with dished pistons. 9.2/1
A6 uses flat pistons with larger cc heads. 9/1

A6 head with Z6 equals big cc heads and dished pistons = low compression. I dubbed it an "un-mini-me". 8.4/1, turbo

Z6 head with A6 equals small cc heads and flat pistons = pretty high compression. AKA mini-me. 10.5-ish/1 NOS

the Only real down side is that the Z6 head has 1mm bigger valves than the A6 ( what you thought all the extra power came from "vtec" ? ).
Vtec is good, but the main reason a Z6 makes more power is it has bigger valves and higher compression with a better intake manifold... Vtec/cam helps too...