D16A6 with D16Z6 head

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LOWLIFE

Local Diesel Fanatic
I have read, read, and read some more, all from this head on a D15 and even a write up of one doing this same setup. However the information seems to be conflicting so I have a few basic questions (possibly dumb ones, please forgive me) to clear things up for me and hopefully any others.

First off HERE is a link to the A6 block with Z6 head write up that I found from one the many sites.

In that particular write up it says you need a vtec controller or any type of RPM activated controller to engage the vtec solenoid.

My question here is If I run the proper P28 ECU do I still need the RPM activated switch? My thinking tells me no and that the P28 will do all the controlling needed. Now In that article there is no mention of the ECU change so I am thinking that is why they were using an RPM activated switch. I am full and well aware I will need to convert my OBD0 vehicle to OBD1 to be able to run the P28 ecu to match the 93? 95? (dont remember) Del Sol SI head I have. I had some questions about wiring but just seen another post by a member on this board about THIS harness which will provide the proper jumpers for the OBD0 to OBD1 also the proper jumper for the vtec dizzy from the Z6 head and also has a provision for "integrated vtec subharness (no soldering!)" so that should take care of that. Kinda pricey but A good value as I wont have to do any wiring (that I hate cause I am to picky) and it will all be there.

I should be ok running the stock A6 resistor box and injectors correct? I will be using the Z6 fuel rail and Z6 intake manifold.

So to regroup and make sure I am not over looking anything....

Pull oil jet out of A6 block as Z6 head already has one.
Get a P28 ECU to match Z6 head.
OBD0 to OBD1 jumper harness to run P28 with my OBD0 harness. (get pimp set from rywire and will also take care of vtec wiring and I will also have all that taken care of.
Timing belt from Z6 engine (is this required? my A6 belt has less than 3k miles...) we will see I guess.
All the gaskets obviously.
Also plugs and wires for Z6 also will replace cap and rotor for a fresh start.
head gasket for Z6 or Y8 engine. now with this I am understanding the Z6 is a metal 3 piece gasket such as the b series I am familiar with and the Y8 is a non metal gasket like the A6.

Now one site / link I had come across also stated that there were different thicknesses between the Y8 and Z6 gaskets. However on THIS calculator I found it says they are the same thickness and there is apparently a 2 piece Y8 gasket that goes from 0.037 like the "other" Y8 gasket and the Z6 gasket to 0.025 thickness... I would prefer the thinner gasket of the 3 and also it be a metal one... Can someone help me out here and give some definitive answers on the different head gaskets and thicknesses?

And that should more or less be it right? Please let me know if I missed anything detrimental !

I am doing this as my head gasket on my A6 has begun to leak and and after a 600ish mile trip this last weekend through today it has obviously gotten a little worse from driving on it. It never over heated and I have kept coolant in it but it does not like the A/C running when going up hill. I am an established mechanic and I prefer technician and have worked on vehicles professionally for a while (tho not currently my profession), and also had another hatch that I did a JDB B20 and GSR hydro tranny swap on. I had considered this simply for fun and picked up a complete engine (torn down to short block) and transmission less the harness with alternator and I think a ps pump from the car it came off of for all of $225. And since It failed the block test I did on it last Friday I figured I would bump this on the list.
 
No. If you run a P28, which already supports VTEC and sends a output signal for the VTEC solenoid already, you do not need a switch.

Yes, A6 injectors with the resistor box will work fine, and are compatible with the Z6 rail and manifold.

Yes, you need the Z6 timing belt; the A6 is longer. The Z6 is a tight fit but works fine.

All "new" Z6 and Y8 head gaskets should be multi-layer steel(especially if aftermarket OE-spec). I think the original A6 is still composite.

Actual compressed thickness of both gaskets(MLS) is about .028" conclusive(couple of guys built "jigs" on OneCamOnly to measure). There's really no difference and those varying figures were due to improper measurements or speculation.
 
No. If you run a P28, which already supports VTEC and sends a output signal for the VTEC solenoid already, you do not need a switch.

Perfect! This is what I was also thinking and hoping for as it seemed ignorantly redundant to need both.

Yes, A6 injectors with the resistor box will work fine, and are compatible with the Z6 rail and manifold.

Good deal.

Yes, you need the Z6 timing belt; the A6 is longer. The Z6 is a tight fit but works fine.

What do you mean the A6 is no longer? I just bought one less than 2 months ago. maybe the same as the Z6?

All "new" Z6 and Y8 head gaskets should be multi-layer steel(especially if aftermarket OE-spec). I think the original A6 is still composite.

good.

Actual compressed thickness of both gaskets(MLS) is about .028" conclusive(couple of guys built "jigs" on OneCamOnly to measure). There's really no difference and those varying figures were due to improper measurements or speculation.

Ah perfect! That makes me happy.

ok and last dumb question that I thought of earlier while driving...

Can I do the swap and have everything in there but not have the vtec hooked up and run the engine off of my factory OBD0 ECU (yes I am well aware the vtec will not be working)? I can use the jumpers to power the dizzy, then when I purchase an ECU I can put it in and the vtec should be working and I would know it to be good. Or if for some reason I ended up with a bad ECU and needed the car. I dont plan to have to do this just more curious if it would still run proper just less vtec.
 
The A6 belt is physically longer(higher teeth count/belt length): A6 has 107-teeth belts while the Z6/Y8 use 104-teeth count.

Yes, it's possible to run an OBD0 ECU.
 
I take it the center line of the cam to the crank with the Z6 head is a shorter distance than a full A6 or possibly a smaller cam gear? but I wouldn't think the cam gear is smaller.

I appreciate the info and confirming some of my thoughts.
 
Gears are the same size, and I believe the Z6 head is slightly shorter; but the difference also comes from the tensioner and waterpump position.
 
Can I do the swap and have everything in there but not have the vtec hooked up and run the engine off of my factory OBD0 ECU? can i use the jumpers to power the dizzy, then when I purchase an ECU I can put it in and the vtec should be working and I would know it to be good.

sounds like you are wanting to run the obd1 dizzy on the obd0 ecu until you get an obd1 ecu. that you canNOT do. You will have to run an obd0 dizzy until you get the correct ecu. problem is the obd0 distributor doesn't exactly bolt all that well to an a6 head.

quoted from d-series org

"if u really want to run MPFI obd0 get an A6 dizzy and cut that shit up.

see picture i made a few months ago, with included typos. this will fit an obd0 a6 dizzy to an obd1 z6 head. i am not sure of the bolt pattern for a y8. someone else will need to chime in on that. but on the z6 the unmodified arm just flails in the wind... lol"

2mx4d29.jpg
 
Thanks for the post up on this, and with pictures even!

I should have remembered an OBD1 dizzy would not work with an OBD0 ECU.

However I purchased an OBD1 P28 chipped ECU today for $40 so I am covered there. :cool:
 
Short update, Just ordered THIS OBD0 to OBD1 conversion kit and VTEC harness from rywire.com

Still gotta get another $250 worth of parts with head gasket set, plugs, wires, cap, rotor and timing belt for the Z6 and I am also still considering having a basic valve job done and new seals put in. But that will likely add another $200-$250 depending on the condition of the head and current valves.

The head gasket has gotten pretty bad in the last couple of days and I am now adding water once a day at least. If I only drive to work and back (44 miles round trip) it will only require water in the am before I leave but I have been topping it off to be safe. The severity of the gasket and my finances may negate the valve job and end up with me putting it on and praying for the best. I honestly think it will be fine but its one of those while its apart things.

I will say I was planning on building a killer B series but after reading some stuff on onecamonly and a few other sites and seeing some of the power numbers these single cams make I am kinda digging the idea of building one of those for the lighter weight and more so sleeper effect.
I dunno, main goal right now is getting it back into reliable daily condition.
 
Got the Z6 head gasket set ordered today, when I get it tomorrow I guess I will tear the head down and take it to the machine shop for a valve job. Just gotta keep nursing the car along and keeping her full of water, but I don't want to not do the valve job and regret it later, I want to know it is right.
 
Valve job isn't really needed unless you're replacing the valves/seats, etc. The seals are usually replaced by just removing the valve springs as they're on the back of the guides.
 
I had considered this before hand just for $ sake... I decided I would tear it down myself and if anything was wrong I would send it in, if it all checks out I will replace the valve seals and call it good.

I did pick up the head gasket set today as well as the cap, rotor, plugs, and wires. However I forgot to get the timing belt while I was there, but its cool cause I still need oil, filter, and coolant.

Tally for this is climbing pretty quick as follows.
Complete D16Z6
With Transmission ---- $223.00
(Craigslist)

Chipped P28 ECU
(Craigslist) -------- $40.00

OBD0 to OBD1 W/
VTEC Harness -------- $196.00
(RYWire.com)

Felpro
Head Gasket ---- $112.99
Set
Air Freshener -- $2.99
NGK 5584 Spark
Plug Set (4) -- $9.96
BWD D712
Dist Rotor ----- $19.99
BWD C725
Dist Cap ------- $22.99
BWD CH74122
IGN Wire Set --- $49.99
(O'Reilly)
Total With Tax ------- $236.97
238,8xx.x mi
6-21-11

Stainless Cat
Back ------------- $119.00
Exhaust
(Ebay)

Oh yea I also bought a stainless cat back from... ::wispering:: ebay.... It was very cheap and I was curious to how it would sound so I took the gamble. If it sounds like crap I will put the stock back on sell that one and purchase the Buddy Club Spec II like I had originally planned. It claims to have a 2.5" down pipe but I dont know if that is inside or outside diameter (I am guessing out) nor do I know if it will be that same size all the way back or not. (I have spent a lot more on a lot less before so the gamble is worth it to me.):cool:
 
I just did this swap in my 90 lx civic,Very difficult if you do not know what you're doing.The whole z6 timing belt thing is very wrong on a6block/z6head mini me. I used a d15b7 timing belt and a6 tensioner, The closest thing I can get to work,Timing belt tensioners is almost bottomed out do to the shortness of the z6 head, z6 timing belt to short, y8 was too tight a6 to long, d15b7 work the best,Do not use any z6 parts on the a6 block they do not work water pump ect...different year different casting from the factory. If u want power steering you have to modify your power steering bracket..If u use the water pump or tensioner off the z6 have fun with that...Make sure that you stab the timing belt correctiy I was 3 teeth off and cause myself a headache.Also you most run vtech injectors/z6 )They are 240cc and the a6 injectors 195cc because it's a non vetch motor different head design,using a6 injectors will cause detonation at vetch using a6 injector on a vetch motor and your car will probably not run right do to obdo injector verses obd1 injector,obd1 no resistor box peck&hold injector,I'm still in the process of getting this to run right do to the p29 pistons that are in the block,If you are doing this swap Be sure and use all obd1 wiring and or jumper harness and injectors life will be more fun that way.I LOVE VTEC
 
I realize this is an old post. But I'm doing this to my 91 CRX si. Went to the junk yard and grabbed the z6 head, intake manifold, and throttle body complete. When I grabbed the wiring harness off the delsol I didn't take it all the way thru the firewall to the ecu. I unplugged it right before the firewall. Now I realize I need that part, but it is no longer available. What is the name of that part of the harness so I can try and fine the rest? And then on the driverside, the plugs don't match either going into the cabin. (I assume that this is for the tach and the speedo) is there a kit to get those to work? Is there a kit to get the connectors on the passenger side to work?
I hope this isn't confusing.
 
I realize this is an old post. But I'm doing this to my 91 CRX si. Went to the junk yard and grabbed the z6 head, intake manifold, and throttle body complete. When I grabbed the wiring harness off the delsol I didn't take it all the way thru the firewall to the ecu. I unplugged it right before the firewall. Now I realize I need that part, but it is no longer available. What is the name of that part of the harness so I can try and fine the rest? And then on the driverside, the plugs don't match either going into the cabin. (I assume that this is for the tach and the speedo) is there a kit to get those to work? Is there a kit to get the connectors on the passenger side to work?
I hope this isn't confusing.
 
I realize this is an old post. But I'm doing this to my 91 CRX si. Went to the junk yard and grabbed the z6 head, intake manifold, and throttle body complete. When I grabbed the wiring harness off the delsol I didn't take it all the way thru the firewall to the ecu. I unplugged it right before the firewall. Now I realize I need that part, but it is no longer available. What is the name of that part of the harness so I can try and fine the rest? And then on the driverside, the plugs don't match either going into the cabin. (I assume that this is for the tach and the speedo) is there a kit to get those to work? Is there a kit to get the connectors on the passenger side to work?
I hope this isn't confusing.
you need to use the engine wiring harness that was on your D16A6 and make any necessary wiring changes to it - engine wiring harnesses are not interchangeable
 
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