I'm a bit shy to post this, because I can't help but feel the answers to my questions lie somewhere archived in these threads. However, hopefully I won't get flamed too bad for asking, because I feel I've done a decent amount of research before posting.

I read Jeff Evans as once saying, "I am firm believer in keeping as many components stock as possible." I would agree with this statement. So seeing as how I already have D16Y7 in my 98 DX, if feasible, I would like to build this motor.

Firstly, I'm not interested in all motoring a D. If I do any build to the Y7, it will have to be turbo. From what I've gathered, the Y7 has several weaknesses. One is an oiling issue with the rod bearings. Could anyone elaborate on this? Is this problem fixable, either with the OEM bearings or aftermarket? Another is pressure on the cylinder walls at high rpms. This is caused by the it's rod to stroke ratio. What does that mean precisely? It is reccomend to get aftermarket rods and pistons for boost applications on the Y7 anyway, could the rod to stroke ratio issue be solved by getting the rods made a different length from stock, and pistons to match them?

And lastly, does the D16Z6 share any of the above problems with the Y7?

If you choose to respond, please keep in mind I am complete novice to building motors. I'm trying, though.

Thanks for your time HCFers.

 

if your wanting to keep the d, most ppl on here would tell you to do a "mini me" swap to the y8, theres a readup on here somewhere..

 

I sincerly appreciate your feedback 97, but at this time the only information I am in need of is of that pertaining to the questions above.

 

Well the 96-00 Y7 and Y8's have had a history with spinning rod bearrings(My Y7 actually did this).

All in all for me to truely answer your question I need a lil bit more info.

How much are you looking to spend
What power/times are you looking to run
How are you with a wrench(not all out engine building but swapping certain external parts)

I am firm on being a d series fan, I allways say when in doubt stick with what you have. But like I said answer those questions for me and I can help you through this.

 

I was hoping you'd chime in md420.

I plan to spend quite a bit, several thousands. This car will be my daily driver, so I will not reduce it's reliability and longevity by skimping on quality parts.

Power wise, I'd like to set the ceiling at about 250, and (here's what I like about turbos) tune it down at my discretion. I would be using a standalone ECU for this, not sure what brand yet.

Right now I have little skill to speak of with a wrench, but by next spring when this build is to take place (after I've completed some courses at my local tech school, fun!), I should be able to do all my own work inside and out. So, there's no real rush. At the moment I am just researching and weighing options, and probably will be for quite some time, until I have a plan in place and can begin collecting parts.

 

Well for that power range I say stay with the D series. Find you a D16Z6 and get a set of tuner toys rods and pistons. Take the head fully apart then haul it to a local machine shop and have it ported and polished on the exhaust side. Have the intake side of the head ported only, you do not want the intake side ported because it needs to have somewhat of a rough surface to atomize fuel correctly.

The D16Z6 does not have the oiling issue's. As far as the turbo setup I would go with a BMC Race super elf D series manifold with a GT28RS turbo being you said you are willing to spend a lil. Also if your looking for a standalone I have to suggest AEM EMS, they are so easy to use. The power that you are looking to get to be honest can be done with the stock Y7 but it will take a couple of things to get there.

1. The Y7 intake manifold sucks the life out of any power adders, your options are a D16Y8 intake manilfold from a 99/00 ex automatic(99/00 ex auto's are a direct bolt on), A Z6 intake manifold from any 92-95 civic ex or si, or any D16Y8 intake manifold from a 96-00 U.S. civic ex. The reason I seperate these like this is that like I said the 99/00 intake manifold is a direct bolt on affair meaning you take your off and put that one in and all the sensors will pug right in. The other 2 manifolds are also a easy swap but for the Z6 you have to convert to obd1 and coonvert the intake air control valve(I.A.V.C.) from a 3 wire which is what your Y7 has to a 2 wire which is what the other ones have. The Y8 manifold you just have to convert the I.A.C.V. to a 2 wire.

2. The Y7 head is better than people give it credit for and the only reason a Y8,Z6 head flows more is because of the cam. While there are not any aftermarket cams for the Y7 you can have a Y7 cam re-grinded for a more agressive profile. Matter of fact alot that stay non vtec with older D15's use Y7 heads because of their ability to make a better tq curve than other single cam honda heads. Valve springs, retainers, valves are all interchangeable meaning when you buy this stuff you can buy it for a Y8/Z6 and it will fit fine.

3. The transmission - If you at all plan on running at a track, any kind of track even just a couple times I suggest a transmission swap to a 96-00 civic ex transmission. The Y7 transmission is geared totally wrong for any kind of performance. The Z6/Y8 transmissions are both geared a good bit shorter. The reason I suggest the Y8 is because it has metal shifter forks while the Z6's are aluminum and prone to bending if pounded on alot.


The fist 2 mods I am going to point you at will help you now and later. I say find and buy a 99/00 ex intake manifold and a 96-00 ex 5 speed transmission before anything. I did this and seen a full second be pulled off my 1/4 miles times and mid range punch was tons better. I would check local junkyards before the web though as most on the web know why people are buying these parts and gouge the prices of them.

 

Would it really be cheaper to swap in a D16Z6 than to correct these oiling issues of the Y7? Or are they not fixable?

Also, is the rod/piston idea I proposed in the first post feasible? Unecessary for that low of power?

As for the tranny, yeah I was planning on a Y8 swap. As for IM, I had planned to go with a skunk 2 aftermarket. Not worth it?

 

There is no way to correct it, the oil passages are smaller than that on other d series. It is kinda like a hit and mis thing though. Some have problems with it and some not so it is inconsistant to say the least. The Skunk2 manifold is a bit overkill for what you want but if that is what you wish to have go for it but I will say that the Z6/Y8 intake manifolds are good designs and there really is not too much to improve on by way of an aftermarket manifold.

The rod/stroke ratio of the D16's is fine, not to far off from what is in the B16's. The D15's actually have a more favorable r/s ratio but it is not anything to worry about. If you are worried about doing anything in the high rpm's dont. Where the D series is better than the B16's is that the tq curve and the way the power is delivered is much more street freindly meaning you dont and will not have to rev the **** out of it to get in your optimum power band.

I advise against any "stroker" kits or anything that alters the main basis of a 1.5, 1.6 or 1.8 honda engine simply because allthough in stock trim they may not make as much power as bigger engines they are balanced correctly, this is why they last so long. Everything works very well together so to speak.

 

Sunrise JDM lists a "ZC SOHC VTEC" in stock from 92-95 Civics. http://www.sunrisejdmmotors.com/honda.php

I had thought ZCs came from earlier models and were DOHC non-vtec. Is that a tpyo then? Could that actually be a Z6? If so, is $899 a good price? Seems decent for everything included. If not, know of any cheaper sites? Sunrise is the cheapest I've found.

 

The ZC came in sohc models and it is identical to a Z6 and yes that is a good price