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Discussion Starter #1
Okay, I have a 94 Civic CX hatch with a shot block, and I have a d16y8 rebuilt block in my shop. I have been trying to do research on what I need to make it work. My goal, is not to have VTEC or make more power, but to have a great MPG car for commuting. I know the CX are really good that way anyway, but I want to make it better while replacing the block with what I have. So far, I have found 24TEN's post on putting a d16a6 head on a d16z6/y7/y8 block but not much else. since that doesn't say anything about d15b8s, I am just trying to get some answers from anyone who might know. My theory is that the larger displacement from the d16y8 and higher compression(9.6:1 vs 9.1:1) will net better MPG with the d15b8 head. I am also shaving the head slightly (0.020) and cutting singe grooves for better combustion.

I think I know for the swap, so far, that I need:
d15b7 timing belt
adjustable cam gear or d16y8 cam gear (crank and cam timing will be off half a tooth because of deck height, but I don't know which way)
oil valve from my b15b8 block(if it has one)
timing cover and crank pully from d16y8

Is there anything else I am missing?
Idk about the water temp sensor, but I have the d16y8 thermostat housing
can the y8 use the stock cx motor mounts?
 

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why would you use a d15b7 T belt? I dunno about you, but I cannot stretch a timing belt with my bare hands to fit over even a loosened tensioner at that point.

you are basically building a d16a6 but half its nuts are chopped off. use a d16a6 timing belt

BUT

I suggest you find a d15z1 cylinder head. it has stupidly tiny intake ports, but makes GREAT low end torque because of it. The rollers in the cylinder head cut down on rotational friction a bit, and once you get a tuning solution, you can easily go beyond 50mpg without any excessive mods.
 

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Another potential is a d16y5 cylinder head. more midrange torque and horsepower, but it also has rollers. Consider it a slightly modified d16y8 head.


again, a tuning solution is how you get the most out of the engine. even a fully stock d16y8 can get over 40mpg and a decent torque increase (midrange torque increase equals gas mileage increase)
 

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Discussion Starter #6
why would you use a d15b7 T belt? I dunno about you, but I cannot stretch a timing belt with my bare hands to fit over even a loosened tensioner at that point.

you are basically building a d16a6 but half its nuts are chopped off. use a d16a6 timing belt

BUT

I suggest you find a d15z1 cylinder head. it has stupidly tiny intake ports, but makes GREAT low end torque because of it. The rollers in the cylinder head cut down on rotational friction a bit, and once you get a tuning solution, you can easily go beyond 50mpg without any excessive mods.
I would love to fully convert it to a vx d15z1, but I don't really have the cash, and I don't care about power. I know d series engines are like legos, it will all fit together, just gotta figure out where all the right parts come from to make it work. It is more a matter of what I had on hand, if I didn't have the d16y8 block, I would have just rebuilt the b8 all the way. But I saw a chance to improve, and im trying to take it. Only reason i said anything about the B7 timing belt is because on the B8 minime swaps, they put a B7 belt on. The VTEC belt is normally too long, and the B8 is too short. I figured the B8 head on Y8 block would use the same belt as a B8 block with a Y8 head. But, I have no idea.
 

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You should probably not do that.

There is no guarantee that it will get better mileage, but there is a guarantee that it will be slow as hell. You can get excellent mileage with a 4 valve head with good tuning and still accelerate faster than a glacier.

If youre looking to do some experimenting there is more interesting stuff that can be done with cam timing. We were discussing it recently in a thread.
 

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why a d15b8 belt? it is the SAME as a d15b7.

the head is even the same beginning stage. honda just finished it off with 8 more valves. you can actually have a talented machinist turn an 8valve head into a 16 valve head.



Here is what you should do

d16a6 timing belt

throw a new water pump and timing belt tensionor on it as well

set valve lash once head is installed onto block. Important it is done only AFTER head is torqued down. heads warp with final torque

go on ebay, buy a new Ignition Control Module for your distributor. its $10-20 shipped. Its hard to screw up an ICM, so being ultra cheap chinese isnt much of an issue, other than it may only last a year or two.

Make sure each and every ground wire under the hood is clean and has good contact.

Then roll with your planned setup. the 8valve head will make a ton more low end torque, but really DIE off over 4k rpms or so. BAD. its suffocating lol
 

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Discussion Starter #10
Great, Thanks for the help. I have finally gathered everything I need, I hope. Putting the block in today(had to wait on a new clutch to get here). Which way should I set the adjustable timing gear? I have been thinking a ton about it, and I just can't figure it out. I am thinking since the block has a higher deck height then the old block, it needs to be advanced the 4.75 degrees. Is that right?
Also, I am starting a new job next week, but until then, I am short of cash. Is there any reason I need a new ICM right now? or can I put it together with the old one to run until I start my new job?
I have had my dx for about a year now, And I don't think I have ever taken it past 4k, so I am cool with that.
 

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Discussion Starter #11
d16a6 timing belt

throw a new water pump and timing belt tensionor on it as well

set valve lash once head is installed onto block. Important it is done only AFTER head is torqued down. heads warp with final torque
I got it all together, new pumps, timing sets, gaskets, etc. the d16a6 belt was too long, but the d15b7 belt went on right ???. I set the adjustable gear to 4.75 advanced, but I don't know if it should be advanced or retarded. I had the head shaved .030, and I am worried about hitting my valves if my timing is off. Now I also realized that my adjustable gear could be from a 96+ and I have no way to tell where it is timed compared to the stocker I pulled off(it came in a pile of d15 parts). I just don't want to have to pull it apart again, lol.

I would love any thoughts.
 

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You can turn the motor over by hand (make sure it has oil in it) and slowly do several rotations to verify it has no contact.

ALso, there is no way to tell if they hit when everything is warmed up. expansion.

you can pull the spark plug out of #1 and set block to top dead center, then pop valvecover off and verify no valves are open. That is your indication the cam is on correctly

There are a few timing guides on here. Some may have had the pictures down from other servers, but a few should still be up.

Also, sometimes a video is your best bet. good ol youtube.

Do you have a tech or service manual?
 

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Cyl #1 at TDC and the cam gear should be at the marks. no need to retard or advance more than 1-1,5 to compansate for the 0.30 mill
 
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