92lxsleeper

well another reason since you have b8 block now. you will need 16valve pistons cause the b8 is only a 8 valve motor, and in such only have 2 cutouts in the pistons to clear 2 valves, it needs to clear 4.

pencil thin rods in the d15's

the timing will always be off without an adjustable cam gear

fuel ratio will never be right, unless you use a jdm d15b ecu, but even then it wont be perfect since the compression ratios are different.

i can think of some more. but i gotta go fix my buddies truck

94EG8

D15B7/D15B8 rods are thinner than Z6 or D15B Vtec rods, toothpick isn't far off as a description. IIRC theres no timing issue, only if you run a Y8 head. Some D15B8s have 4 valve reliefs cut in the pistons, some don't. A complete Z6 is a much better platform, but i'm just providing answers for the questions that have been asked. I used to advise people on what to build and what not to build and people just got pissed off so I try to just answer the questions and leave the opinions to someone else.

USDM sI

well im not against them at all but yess, even if i had all the parts i would still get an a6 or z6 just off of xperience. ive never thrown a rod in iether block (spun a few bearings )
and no the 1.5 has different rods... go to the junk yard and pull some oil pans.. its a noticable differce especially in the main bearing retainers
however i had a d15b with z6 rods crank and pistons and i never had a problem sold it in great condition
oh yeah and my brother put a z6 head on a b8 and slammed valves (the 8 valve pistons do not have the necessary valve reliefs

Sr420Det

So the rods r different, that explains alot. Thanks for clearing a few things up. On the flip side, were running a base map anyways and the d15b rods obviously cant take a 75 shot...from a wet kit anyways. Im a stickleir for everything being done right, including cam and ignition timing and I dont have a adj gear so thatl b a problem for me on my buddys build but he only has so much money and were obviously tryin to cheap out on whatever we may get. Im thinking of just runnin a y7 block without spray just to get him riding or just sell the head and try to find a decent z6 like stated above.

Now on my build Id like ur honost opinion (thats based off facts like above). I could throw the d15b crank (assuming that its still good of course id get it checked out) in the b8 along with some vitara/eagles to boost 300+ and keep the factory b8 oil pump. I will have a aftermarket cam and adj cam gear for my build. Is this a good idea?

Whats IIRC??? and y would they put 4 valve pistons in a two valve motor?

94EG8

A complete Z6 would be a better idea, but this is a better idea than simply slapping a Z6/D15B Vtec head on a B8 bottom end.

If I Remember Correctly

To save on production costs. Its often cheaper to just make one thing than it is to make 2 different lines. I know the early B8s used the same PM3 pistons as D15B7s did. But i'm told later models didn't. I've only ever pulled apart 1 D15B8 mainly because they were never sold in Canada, we just happened to get a parts car once that had come from the US at some point. I think that one had 4 valve reliefs, I couldn't swear to it, the only reason the head was even pulled off was to sell it for scrap aluminum, so you can imagine how close I was looking at it. That civic was an early production '92 USDM CX.

Ok, I figured i'd do a little more digging and try to clear up this piston thing once and for all. I just checked some part numbers and honda lists the same part number for D15B7/D15B8 pistons for all years, 13010-P03-010 PISTON SET (STD) So that tells me that all D15B8s came with 4 valve reliefs.

Sr420Det

im well aware of production cost but seems to me that ud still run into valve clearance problems with 4 reliefs instead of two in the middle. Thats crazy though, my b8 came outta my buddys 94..i think. Im going to pull the head right this instant, il b back in ten minutes with the verdict

94EG8

Its been about 3 years since I pulled the one B8 head I had access to, but as I recall the valves are setup exactly like a D15B7 except there on intake and exhaust valve missing, the missing valves are diagonally apart. IE the valves aren't in the middle.

Sr420Det

Your exactly right. Heres the pics from a 94 cx, this was the original motor

Sr420Det

So that changes everything, guess well just run this block with a d15b head and I need a z6 belt with d15b headstuds. The timing wont b spot on cause the deck heights are different and I dont have a adj cam gear. That about sum it up?

94EG8

When using a D16Z6/D15B Vtec head on a D15B7/D15B8 block the timing should be right on. Its only when running a Y8 head that you run into funky timing issues. You might want to check out this writeup, its now 7 years old and the pics are gone, but the info is still mostly relevant. https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/faq-d15-sohc-vtec-mini-me-massive-write-up-56k-goodbye-554053/

Sr420Det

Excellent write up, thanks for everything eg. I wonder if the d15b timing belt will fit, from what he said Il be able to figure it out and if we got to, il run a new z6 belt.

94EG8

If you run the D15B vtec tensioner probably, otherwise it will be too tight. There D15B vtec uses a 103 tooth belt (shared with the D15Z1 in the VX) the Z6 belt is 104 teeth. D15B7/D15B8 is 106 teeth. The D15B Vtec tensioner uses a slightly smaller roller than the Z6 tensioner. Biggest issue here is that you just flat out can't get D15B Vtec tensioners in north america, nothing else uses it.

Sr420Det

Right but I have a d15b block with 4 holes in it, so I dont think itl mind if i ****** its timing belt and tensioner. Although i wouldnt of thought to use the tensioner, thanks. And what do u think the b8 rods r good too? Im gonna go check out the dseries calculator to check on the compression. Says i have a 10.22 c/r. What do u thinnk itl b safe to rev too? R the pm3 pistons in the b8 too? Guess i could go clean mine up and c what they say

USDM sI

just get a z6
im on a stock bu rbuilt z6 at the moment in my ef and im on my old a6/z6 tune and when im pushing her... im slammin around 8-8200 rpm
not one prob yet and the engine now has 9k on it since the teardown last decembr

94EG8

Thats true enough, your welcome btw. Any chance you can pull the pistons out of the D15B Vtec block and post some pics and or numbers on them? It was always rumored that they were domed but i've never seen any hard evidence.

I wouldn't rev it abouve 7200 - 7500 RPM if it was me. I would also get it tuned.

Yep, D15B7/D15B8

Sr420Det

The pics i posted on the first page r of the d15b block, although u cant c the piston well but u can still tell its not domed. Il pull em thursday when we complete this swap and post some better close up pics. What kind of hp level u think the b8 rods r good for? Man Im havin a lil problem with this stupid jet, cant get a screw in there good cause it keeps turning, any other advice on that.

USDM sI

yes definatly get it tuned its way worth it

Sr420Det

well its done and it seems to run fine *knock on wood*. Used the d15b head gasket, d15b timing belt (didnt even try the b8), ran d15b8 tensioner, took out the jet, and its a lil hesitant around 3k, but once vtec hits it seems like it does a lil better than the stock d15b. Still on the basemap for a d15b, probably could do the cam timing again, ignition is right on 17, and Il try to get some pics of the d15b rods within the next couple of days. It was a long night tonight haha

USDM sI

congrats!!

Sr420Det

more pics

headgasketdisa

what a write up lads!Congrats with the motor man,hopefully do 1 of these builds shortly!

meadams314

I've been following this, and kinda considering doing something similar to my 92 hatchback.. question though, what do you mean by "does a lil better than stock d15b"? A lil better? The other option i'm considering is an engine swap, but I'm on a budget, so cheaper is better lol

Sr420Det

a lil better is strictly seat of the pants and cant b takin as fact. In Fact im still runnin a complete base map that was for the d15b and its pretty sluggish down low due to a bad (or really no) tune. This swap does net you a lil better compression than the d15b which should bump the hp up a little. If u got the stuff and dont want a fast honda than go for it, if u wanna make more than 150hp than this is not the swap for you, all motor i dont c this thing putting down more than 130whp with a all bolt ons.