tcassaday

Car: 1998 civic hatchback cx 5spd
Engine: Stock d16y7 except for header and 2.5" exhaust.

This winter I'm going to do a bit of engine work to the car before the next race season. I feel this is necessary due to the fact that the car was starting to puff smoke at high rpm gear changes. My plan is to do a mini me swap with a z6 head that I already have. Prior to installing the head, I'm going to mill it .015", replace valves and springs with oe parts, valve job, and diy port cleanup. I will be keeping the stock cam but get an adjustable cam gear. Also I will be replacing pistons and rings. The pistons I will be using are the p29 pistons. I am going to retain the y7 intake manifold to help disguise the swap. Trying to stay in my current class.

With the head milled .015", p29 pistons and y8 head gasket, the compression ratio should come out to 12.4:1 static and 12.2 effective according to zealautoworks calculator. Goal is to use 93 octane if possible.

I will convert to obd1 for tuning purposes with a p28 who and get it tuned by a guy I know of out in Ohio.

At the end of the week I'll be making a trip to the machine shop to talk prices and order
parts.

Any comments, tips or suggestions would be greatly appreciated. I will post pictures as this build progresses.

STRATTON

i built a strong sohc. and have played with mine for the last 2 years or so, upgrading parts and testing etc. 160 or so whp with a L3 trans case with zc gears, 4.7 ats final drive and a mfactory helical 1.5 lsd, in a properly set up crx that i autocross.

Ditch the p29s, the valve reliefs are very shallow, and you will only be able to run a delta 282 cam or less, considering the heavy milling of the head. the delta282 is a good cam, but being unable to go bigger will limit the potential of the build if you do consider going bigger. run an aftermarket piston with your desired compression.

run arp rod bolts, oem rod bolts are the weakness of the sohc's bottom end.

run a z6 intake manifold, it looks so close to the y7 mani as is. the z6 is the best flowing oem manifold for the sohc. i run a z6 manifold that was cut and ported, dyno tested, it makes a big improvement. i also run a 60mm b series tb and the intlet has been knife edged/ported.

port the head, as with any honda motor, alot of power is locked up in the head.

im assuming this is in a obd1 car ? ed or ef, in any case, as long as your oem harness is in good shape, just run rywire obd0 to obd1 jumpers, for ecu and dizzy.

biggest improvement i made to my car was the built trans. complete night and day difference.

these motors do respond well, but you have to be conscious of all the small details, that add up to a better, bigger picture.

good luck.

stratton.

tcassaday

Thankyou for the info. This is an obd2 car it is a 98 hatchback. This car gets a lot of autocross action as well

I had a little change of plans for this build because the z6 head turned out to be junk. The cam journals were shot. So I picked up a y8 head for $20 that checks out good. Other changes to the plan are to run the z6 manifold like you stated, switch to e85, and have the rotating assembly balanced and punch out the cylinders to the first oversize.

Still using the p29 pistons in the calculator with the y8 head and bigger bore put me at roughly 13.1:1 compression.

​​​​​​My goal for this engine is to squeeze out as much low and mid range power as possible.

What cam would you recommend for this?

How extensive of a port job do I need? I was going to go through and do a basic cleanup and minor reshaping, is that enough?

What brand pistons do you recommend for best bang for the buck? How much would fly cutting the p29 pistons be worth it?

STRATTON

you could run a delta 272-2 which is proven and cheap, you could also look into rocket motorsports as they do sohc cams as does webcam. tell them what your goal is and they can recommend the correct specs.

i run a delta 282 in my a6 head, although it made very good power, theres alot being left on the table as far as my setup goes with the cam, i could certainly pick up more power almost everywhere with a bigger cam.

weisco or je pistons are a good choice for a sohc. p29s are cheap and proven and will work great, but at a point they reliefs are not deep enough for bigger cams.

as far as porting the head goes, cleaning up any flash and smoothing everything out never hurt. to get good gains out of these heads they should be gone over with some one who has experience porting them and building them. I use Melvin Ports Engineering , you can find him on facebook and or instagram.

stratton.

tcassaday

Tomorrow I'll be calling my machine shop to get an estimate on my block and crank work as well as getting je pistons. I'll have to start contacting some cam companies and talking to them about cams then.

Aquafina

iTrader: (3)

VTEC solenoid is going to get you punted.

tcassaday

I know the VTEC solenoid would be a dead giveaway. But now that I'm going to be pulling the engine to get lower end work done and running on e85, I decided to say the hell with it and just go to SMF