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Discussion Starter #1 (Edited)
Building my DOHC ZC. tear down begins *12/29/09* pics

hi. i am about to pull my engine an begine a rebuild for it. its a DOHC ZC in a 89 hatch. i am scrapping the car but am pulling anything worth keeping off. this will be an all winter build that i will be doing. and i am keeping it pretty basic. here is the plan,

i am buying a 91 hatch that is in emmaculate condition. it has a a6 in it right now which will be good enough for winter to fuck around in. come summer i will be dropping the zc in. i want this to be a fun car to drive. all motor honda, in general, doesnt do much for me since i have a fully built z6 thats boosted. i just want a bit more pep. this is where i need your opinions

i want to switch pistons. to slightly bump my compression. nothing crazy.

i will be porting the head myself. aswell as the intake manifold.

im going to throw on a b18 throttlebody.

already have full exhaust and intake.

dont want to modify the ignition(isnt necessary anyway) i have brand new plugs, cap, rotor and some 10.2 mm wires(not necessary but cheap and good quality)

i just want to know if there are any secrets with the dohc zcs to gain power. maybe another car has valvesprings stock that would be an upgrade? some cheap options for cams? i want to keep the budget fairly low. i will be replacing the following:

pistons - prefer a stock piston from another motor to up compression... p29s?
hasting rings
acl bearings
top to bottom gasket kit.
all basic parts (thermostat, water pump, timing belt...)

any suggestion or opinions are welcome. if u have a link to a build please link me. i googled zc builds but dont get much. lots of tech info and specs but not builds. thanks in advance
 

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95 civic
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Sounds like your on the right track. The one I built seemed to gain the most off the ls throttle body and ported intake manifold. I cut open the top of the manifold so I could port everything then welded it back. Then good tuning is all you need. I hope this helps.
 

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95 civic
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I just cut the top off the plenum. Not really. It just all depends. I did it so I could open up the runners at the top easily. I basicly put a taper on the runners to get my air velocity up. It had to go to the welder anyway so I could weld an ear on it for the larger tb instead of making an adapter
 

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The Great Weldini
91 civic
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Discussion Starter #6
ok. motor is out. rebuild shall commence. i need some serious help to get the ball rolling.

when i rebuilt my z6 i just ordered a z6 engine gasket kit and a z6 timing kit. is there such things for the dohc zc? i know u need the 88 prelude belt or the b16a2 belt. what tensioner do u use?
does fjdistriutors make a engine build kit?
i will start by porting everything. but how much can u take off the block and head together before clearance becomes an issue?
sorry for all the questions. thanks in advance
 

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93 integra ls b18c
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88 lude belt, for mine i used everything of the a6 (tensioner, water pump)

lot of the bottom end uses a6/z6 parts

thezcr or somewhere on here has a parts list

problem is with the head (head gasket, head studs, etc..) but most of that has been worked out in that parts list

i really don't know how much you can whack off, but has always clay is your freind and take little off at a time.
 

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1988 Honda CRX
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I just did some rough measurements on my D16A8 which should be identical to the DOHC ZC.

It has the pistons 0.040" down the bore, a gasket 0.050" thick and the quench pad 0.074" into the chamber giving a whopping 0.164 quench clearance. It also only had a quench pad on the inlet side. On my head it looks like you could get quite a bit of airflow by simply unshrouding the valves.
 

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1988 Honda CRX
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I think I need to remeasure. It can't have over 1/8th" quench clearance.
 

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Discussion Starter #11
cam gears, add more overlap and done.
can u elaborate on that a bit? i have read alot. but it comes down to the final knowledge of people who have done it. i have read u use the b series gears but u have to re align them becasue they are off 1 tooth.
 

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1988 Honda CRX
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I think Bisi now lists D series DOHC adjustable gears
 

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97 honda coupe
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can u elaborate on that a bit? i have read alot. but it comes down to the final knowledge of people who have done it. i have read u use the b series gears but u have to re align them becasue they are off 1 tooth.
Either way b-series gears or the bisi gears. Put them on line them up and then advance only the exhaust cam by about 2 degrees. should make it harder to start but will definitly help with top end power.
 

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1988 Honda CRX
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As the exhaust is closing and the inlet opening at TDC overlap, advancing the exhaust cam closes it earlier and reduces overlap.

Advancing the inlet or retarding the exhaust gives more overlap.
 

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1987 Acura Integra
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i wouldnt port the intake manifold and a bit bigger TB on it. to my knowledge, B series TB wont work on any of the DOHC ZC's. I was told on here by someone that they ported the intake manifold and slightly bored TB and lost power. Only thing i would do is basic bolt ons and a 30-50 shot of N20 with some bisimoto cams and cam gears.
 

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1988 Honda CRX
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To big a throttle won't lose power. It only hurts drivability at low speed. To big manifold runners and ports can lose bottom end power
 

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As the exhaust is closing and the inlet opening at TDC overlap, advancing the exhaust cam closes it earlier and reduces overlap.

Advancing the inlet or retarding the exhaust gives more overlap.
Your right.. you caught me i would say retard the exhaust and advance the intake and see what happens, sounds like fun to mess around with to me.
 

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1988 Honda CRX
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Sorry about that, but I didn't think I should let it slide.

Certainly moving cams around especially on DOHC can ot only move the power band around, but can increase power but at some cost to fuel efficiency and emissions. As you can also change lobe centres you have about 4 times the scope for change compared to a single cammer.
 

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Discussion Starter #19
dual cams confuse the hell out of me lol. i will begine the tear down over the next few days. part ording will begin shortly. does anyone know of a company that actually sells a rebuild kit for a dohc zc? like all the necessary interchangeable parts rather then ordering piece by piece.
 
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