Hey yall new to the honda game, and to the forum. I plan on turboing my 1990 ef hatch with a d16z6. I've been cruising forums trying to find what proper compression would be but I found alot of different answers.. I did the test with engine at normal op temp, and WOT, my wife cranking till the needle stopped moving on the gauge. (While I watched the gauge of course). I got a solid 215 psi across all 4 cyl. Is that good? What was most likely done to increase the psi from what most said 120`s to 180's? Any help would be great. Thanks

 

explain more:
what do you mean WOT and your wife cranking?
WOT and cranking at the same time?
the engine turn over while you were doing this?
you were able to get exactly 215psi on all four cylinder?
is it a rebuilt engine?

 

Wow! Healthy engine!
Sounds like a good foundation for turbo


Can you check the head on the engine and verify if it is actually a Z6 head or maybe it was replaced with a Y8 head?
A Y8 head would give you numbers that you are seeing.


Good info in this thread for some reasons it could read high.
Seeing how you have the same number across the board, I'm going to guess that the engine was recently rebuilt and the head was resurfaced. That would bump your compression up a bit, but I'm not sure if it would be up at 215.
https://honda-tech.com/honda-civic-d...-high-2688287/

Figure a new stock GSR with 10:1 compression is supposed to read something like 270.

184 is nominal on a new 9.2:1 D16Z6 engine.




270 on a 10:1 GSR




199 on a B18B1 - which is 9.2:1 just like the D16Z6.

 

That what I thought as well, maybe a y8 head, but it's a p08-5 head so I belive that's off a 94 d26z6, no info on how recent the motor was rebuilt, or any internals. I bought the car already swapped. WOT means wide open throttle, ie pedal smashed to the floor, and by my wife cranking I mean she was cranking the engine over while in watched the gauge.

 

Yeah, that's a Z6 head.
Probably milled down a bit on a rebuild.

 

oh I didn't mean what the literal meaning of WOT. lol.
what I meant is why was woootie performed while cranking. the method technically does not call for woootie on the pedal. there is no need to attempt to add more fuel and air, you simply activate the starter with the appropriate items disconnected of course.

I have even done it by hand with a wrench, this method is most painful and slow. I would not recommend it.

personally, i have never seen a perfect set of numbers across the board though. so I was curious if that was a mistype.

 

You are supposed to hold the throttle open during the compression test. That is the correct way to do it.

 

doing a wootie will cause the numbers to be higher. that's probably also why the numbers you got, 215, are higher than the book listed above which is 200.

try doing it with out wootie.

shops I have been at also have told me not use the woootie as it is just forcing air in which will increase the pressure.

ultimately its your preference to go either way.

 

I have never heard of doing it with the throttle closed. That makes no sense...

What if you have a vacuum leak, or your TB lets by more air? That would throw off your readings.

Here, right out of the FSM. "wide-open throttle"

 

What is a "wootie"?

 

The only way air could be 'forced' into the cylinder is if it were a boosted application and somehow was boosting when you are simply cranking the key.
Otherwise, the air is going to be sucked in and holding it WOT is going to allow air to be pulled in from an unrestricted source.
WOT is exactly what you want to be doing.

BTW: "using the wootie" sounds really lame like you have a special toy for the bathtub that you bought off an infomercial.
- Now, for a limited time, you can wash your butt clean with a few simple slides of the new WOOTIE! You will just love your WOOTIE! It cleans so well! -
You should probably not call it like that.