Txdragon

So I am working on a boost build and don't want to swap entirely to VTEC. I would have to rebuild my bottom end anyways and have several inexpensive Z6 blocks within my reach. I have taken to the compression calculator and the proposed piston according to the Z6 block/B7 head puts comp. at around 9.1:1. The PM3 piston, however, will put me at a nice 10.5:1 comp.
Honda D-Series Compression Calculator by ZealAutowerks

Any reason that piston could not be used with this block/head combo? The only possibility I can think of is the stroke difference. The B7 is 84.5 and Z6 is 90. I would think that if these would not work, the calculator would tell me(?) Anywho.. Anyone with a bit better engine building knowledge than myself is greatly appreciated for input into this matter!

TomCat39

Are you going to swap the pistons onto the Z6 rods?

B7 rods will not fit the Z6 crank.

Txdragon

yuppers. D16z6 block, crank, rods; b7 pistons. Skunk2 makes a great rod for the z6. Alpha series lite. 306-05-1210
Well within my budget range and supportive of well over my goal. It claims they are compatible with most pistons without additional machining. Their 137mm length combined with the B7 piston puts me in a very nice compression range too. 10.5:1

Txdragon

Anyone? Bad idea? Good idea? It looks damn good on paper. Lol

TomCat39

You will likely have to clay it to check your valve clearances, but other than that, should work if the calculator doesn't show the piston above the deck etc etc.

As far as I know the pin size is the same and the calculator has all the rod and stroke lengths to show you the end result, as well as the piston is the proper size for the block.

Z6 block, Z6 rods, Z6 Crank, B7 pistons.

The pistons are flat top with valve reliefs. The one thing I could see as a challenge is the reliefs are not deep enough for the valves during vtec lift, stage 2 or 3 lift or D16A6 cam lift.

Maybe even the stock B7 lift might be a bit much, hard to say. Clay will tell you once you assemble.

Looking at the calculator, your proposal puts the piston .028" above the block deck.... That will need a seriously thick head gasket. .036+.028=.064" compressed thickness head gasket. That's pretty thick and not sure if you can get one that thick.

On the B7 block the piston comes to .002" from the deck and is why the thicker .036" gasket is used on it for proper quench/squish.

Txdragon

Hmmm.. Good catch. I didn't notice that earlier. PM6 pistons and a Y8 head gasket will put me back to a positive at .02 and the compression stays at a respectable 9.57:1. If I use that setup and shave .02" it'll set me to an even steven 0 piston to deck height and brings compression to 10:1. Interesting indeed!..

Txdragon

Called a local shop that will rebuild the bottom end to what I am shooting for here, or let me know if it won't work; 500 bucks out the door. That sounds like a lot but I'm not sure if it's a good price as I've never taken anything to a builder. I've either done things myself or had a friend hook-up. **shrug**

Txdragon

No other input?

Txdragon

Bumping this as I am nearing my project start time and need some final input on this before really pulling the trigger. Thanks for any and all additional input!

Txdragon

Full Z6 bottom end and B7 head using a y8 multi-layer gasket put me with some nice numbers.. CR is at 8.81, with 6 psi of boost (which is what I am shooting for) puts me at 12.41 CR and an even puts me at 0 PTD height. SOMEBODY has got to have some input here.

JRCivic1

What is the reason you are going backward in cylinder head choice ???

Txdragon

I have no intention on being an *** and am a very straightforward, no B.S. fella... That being said...

Because what I posted is my planned build. It is what I have intended based upon my goals, uses, and intentions. I currently have a 95 DX with a B7. Modded ALMOST to the hilt, minus turbo and cam... I have tuned it myself and have no want or desire to mess with VTEC. The B7 block internals are interchangeable with the B2, and B2 components are much more readily available. However, I do not want my vehicle downtime to be much more extensive than dropping the engine and swapping another in. I have very reliable access to Z6 and A6 blocks within 50 miles that are relatively cheap. Many of the Z6 engines are also stripped to near nothing but a short block anyways when I find them and get to them. Therefore, I can easily build the Z6 block and still drive my car.
I have found some very good info on Z6 block/A6 head builds BUT, it was old and missing some info. Namely, what I am asking about. It leaves one to assume the Z6 internals were used AND it was also using the A6 head. There is a difference between the 2 heads, I don't remember correctly if it was just the casting, or if it was anything more I needed to consider with internal options. Anywho...
Proposed build is

Skunk2 alpha lite rods, clevite bearings, OEM pistons.
ARP head studs, Mahle Y8 multi layer gasket

Precision 5431 turbo (this isn't 100% set in stone, i've read many cases of shaft play VERY early on ~ within 12-15 months of daily/moderate use)
cast iron mani
turbosmart 8psi 38mm wastegate
Intercooler (probably a kit from turbosmart)

Greddy Profec boost control (I have previous experience on these and I love them)

Stock fuel system. I don't plan on going over 250 at this moment. Will upgrade if and when the need arises.

Neptune engine management (currently running in the P06. No need to swap to P28 since I won't be running VTEC)

Goal is for 180-220 HP. I don't see any reason I can't come close to that with this setup.

Back to the question at hand... The specs I just posted came from the zealworks calculator and they look good, I just want to know if anyone may have any input on what I MAY need to double check or watch for. I know the issues to address with the block/head combo itself, I am talking in terms of the PTD height and possible compression concerns.

Txdragon

Ok. So long as I don't, or don't have to mill anything from the block. I'm at .020 PTD clearance. I feel much better with that. I wasn't overly comfortable being right at 0. Think i'm sticking with this..

Z6 block and crank, PM6 (75mm) pistons, Y8 gasket, B7 head.

If any other input, sweet, I'd love to hear it. If not, oh well, the bus is leaving the station..

JRCivic1

I understand your situation and the logic makes sense to me. I wish I had more first hand knowledge to help you... I just don't know much about the interchangeability between the components you are trying to use. The Zealworks calculator puts the basic mechanical clearances in the safe zone, so if you are satisfied with a 9.6:1 compression ratio... I say go with it man !!!

Txdragon

I'm certainly looking forward to it. With the exception of my fuel system, and map sensor, the build I have put together would net some nice numbers. There will be PLENTY room for expansion here. I want to keep it mild as it took me, oh, about a year's time to street tune with Neptune, running naturally aspirated. So I can imagine playing with boost will be even more challenging. Therefore, I am keeping it modest until I am comfy with it. Then, the SOHC non-VTEC will see beast mode.