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64 Posts
Discussion Starter · #1 ·
Hello everyone,

It is my second time rebuilding my d16z6 engine. Here are the specs:

- ARP cylinder head stud kit.
- Elring OEM head gasket (0.7mm)
- Head porting and polish (professional).
- Valve job (professional).
- Port matching to Intake/exhaust manifold.
- Comp cam 59300 camshaft.
- Repolished camshaft.
- BC racing single valve spring set.
- Skunk2 pro titanium adjustable cam gear.
- Edelbrock intake manifold.
- LMA rebuild (for noise).
- New thermostat
- Distributor rebuild.
- Custom half size radiator.
- Mishimoto radiator hoses.
- New Slim radiator fan.
- Walbro 255 LPH fuel pump.
- Retested fuel injectors.
- Teikin PM7 75.5 pistons.
- TP (japan) piston rings.
- 75.5 bigger bore.
- H22 type R Throttle body (62mm)
- King crankshaft bearings.
- Taiho (japan) rod bearings.
- New OEM intake/exhaust valve stem seals.
- GMB water pump..
- NGK BKR6E spark plugs.
- New spark plug wires.
- 3" intake pipe
- high flow pipercross filter.
- 2.25 exhaust all the way back.
- 4-2-1 Ebay exhaust manifold.
- 2 resonators, bigger muffler.
- Exedy clutch.
- Oil catch can (catches oil from pcv and head).
- New cluch release bearing.
- New belt tensioner..
- all new seals, belts, oils and filter.
- P28 chipped ecu.

Here is the problem I think I might have:

According to zeal autowerks d16z6 compression ratio calculator I am in big trouble. I got d16z6 block and PM7 (P29) pistons which should land me in a safe 12.17 CR.

However, the OEM spec head gasket there is shown to be 0.037 (0.9mm). I tested with regular d16z6 pistons and it shows normal 9.2 CR for d16z6.

This is a problem, because I got a "OEM Elring" headgasket and it is 0.027 (0.7mm), which would land me in 12.53 CR. From what I read the real oem gasket IS 0.027 inches and it should not be a problem. Can anyone confirm what the real d16z6 oem gasket thickness is and if the zeal calculator is straight up wrong?

Also, I got another question, my block has been decked flat, because it was warped after overheating, and my head was milled flat two times. I wonder how much inches or mm that would approximately be? I am hoping it is not more then 0.005 inches total.

I am planing to run 98 european octane (93 US), so having a 12.34-12.5 CR is managable, but if I really fucked up with lets say putting a head gasket that is 0.7mm instead of 0.9mm and the milling and decking is way more, I will be way above 13 CR needing to put race fuel in my civic wagon.

Lastly, is there a reliable way to test out Compression ratio without disassembling the engine?

I really do NOT want my new creation to blow up before even living.

P.s. Here is a picture as a bonus for looking.


5,296 Posts

6,902 Posts
The small bore of D series motors is fairly forgiving with a talented tuner.

There are some dyno's of an 87 octane (US) 13:1 build floating around the archives somewhere, I would imagine testing between octanes to see what worked well.

I think equivalent of our US 93 octane should be pretty tuner friendly as long as the fuel quality is good.

Your situation simply means you will NOT be able to string out the motor to its fullest extent until you run higher octane and maintain its use

Meat Popsicle
91 CRX Si
2,942 Posts
Prob doesn't help ya much now but you CAN measure the cylinder head height using a big ass caliper...or have the machine shop measure it for you.

There is a measurement in the FSM for the cylinder head height.

And lets say you do end up with 13.5:1 CR...

The tune will take care of all that. If it's detonating, pull timing and/or add some fuel.

Like Toaster once told me on the topic of tuning, it's not just going to shit the bed if you've built it right. Unless you do a long 5th gear pull and it's detonating throughout the entire RPM range, you'll be able to detect the detonation and correct it before it causes any damage.

CRX ECODiesel Ram
1,036 Posts
Im running pg6b pistons with at least 0.050" off the head giving me between 12.5 and 13 to 1 compression. I have ac non vtec head and Rocket stage 4 cam. I have run a comp stage 2 and stock cam as well with this compression and am at about 40k miles on it running 93 octane. I have had to adjust timing quite a bit with hondata and keep putting off dyno tuning due to other costs that come up. I don't think you need to be as worried as you should unless a lot has been taken off the block or head.

12 Posts
Hows the build, i'm curious to see how did you manage all that compression on 98 :) i want to rebuild my D16Z6 with P29 Pistons and Y8 Head?? And i'm scared of the compression:/. I'm thinking on add methanol injection to it since E85 isn't avaliable on my shitty country :/
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