a6 top end build
 

I have a z6 head with valve job and milled of course. I'm going to put this on my z6 build for now. I have a spare a6 head laying around. Would it make sense to build the a6 then slap that on? Will i get the same flow/power from an a6 head with PnP, cam, springs, valve job. As I would from a z6 head with the same?

Re: a6 top end build
 

a6 heads outflow z6 heads. You just won't have the MaD TyTe VeEtAcK!

Re: a6 top end build
 

You need to bump the A6 valves up .5mm in size, the same as Z6, before that flow is realised.

Be careful with a high lift cam in the A6 head, with the Z6 piston flycuts. There's typically *acres* of piston-valve clearance on SOHC, but if you play with cam gear settings or get the timing belt one tooth off you might end up in the danger zone.

Re: a6 top end build
 

great info. Thanks .

Re: a6 top end build
 

if your putting it on the Z6 you will need to have the head or block machined for a oil jet. since it is in the block on the A6 and in the head on a Z6.

Re: a6 top end build
 

It's in the head on a Z6? You sure about that?

I always threw the oil restrictors away, never saw a difference in performance. They were #1 reason for cam failure in the old D15A's, it was common practice to ditch them, and there were no bad side effects.

Re: a6 top end build
 

I thought all VTEC's had them in the head? I always install them, I'm afraid of loosing pressure to the main bearings.

The old D15's (I knew them as EV/EW series, i never had an 87) clogged the port to the dizzy end cam journal didn't they? I know they had a problem snapping cams, but i was told it was a port, not the restrictor. Whoever told me could have been wrong though.

Re: a6 top end build
 

It was an oilling problem, or a broken timing belt, that broke the cam. The EV or EW1 or EW3/D15A had hollow camshafts, very fragile. Removing the restrictor was SOP. I believe there was a TSB about drilling them a little larger, but the old skool dealer techs told me they just ditch them.

And I was asking about the resitrictor, not calling you out... I own two Z6 heads, but I can't say I've looked closely at either of them. I just figured I would have noticed if they had a restrictor in them :l

Re: a6 top end build
 

It's cool. I don't have a Z6 head, only a Y8 head. My only basis was every Mini-Me swap guide i found said all of them had it.

That's neat info on the old engines. I'll keep that in mind, I've always wanted to get another 1st gen for a project car and that could be usefull knowledge. My first cars were both 1G CRX's, and they both rusted out.