205 PSI in all cylinders on rebuilt KA24DE with 9:0:1, why is this happening to me?

[jonnybonds84]

So I went today and did a compression test on my KA24DE, the resulsts were 205 on all 4 cylinders. I rebuilt the engine with Supertech 9:0:1 pistons. Can anyone tell me why this is happening, the compression should be lower cause of the lower compression pistons. I scared this is going to destroy my engine and this is my daily driver. What should I do? Should I retard the timing or something? I use 91 gas. HELP ME JESUS, I IS SCUURRRED!

[NINJASPY]

cylinder compression/leak down test and compression ratio or piston are two different things. having equal pressure amongst all cylinders is good.

[jonnybonds84]

cylinder compression/leak down test and compression ratio or piston are two different things. having equal pressure amongst all cylinders is good.

I've read that but if I did a Cylinder Compression test and got that result wouldn't that mess with my AFR and potentially mess up my engine? The FSM states that it should be 170-180 High and since I'm getting 205ish in all cylinders I think that's bad, would'nt I need to tune it for higher compression?

[WISH ONE]

how long did you crank your engine for when you did the comp test???

[jonnybonds84]

Maybe five cranks or something. Is there a set number of times? I read that 5 seconds should be good. I don't see how that would matter though, is not like it would add compression if you do it longer, the compression peak wouldn't change I would think.

[Lr308]

Your piston ring gap might be tight. When you break in the motor the gap should spread. For NA you should have tighter gaps too.

[jonnybonds84]

The motor should have around 1500-2000 miles in it already. The ring gap are pre done with the supertech rings, I checked them and they were good too. Is it going to mess with my AFR? Should I do anything to my timing?

[jonnybonds84]

Help me Jesus!

[mxexux]

If you ball honed the cylinders which I hope you did since you replaced the rings then I don't see what you are freaking out about. Let the engine break in and retest. Also, did you change cams. Valve timing will also affect cylinder compression.

[greenman100]

Help me Jesus!

I bet your compression gauge is fubared

[negrosx13]

you lower the compression!! sooo you have more air thats gets compressed in the chamber.. soo then?! its bit high,possible from changed cams or etc...dont kill yourself guy!!! its better then having 90psi or lower

[jonnybonds84]

I had the machine shop hone the cylinders but the engine has about 1500 miles on it. I'm just worried because the FSM says it should be at 170-180 psi. Stock cams are in there but so far no one has sad anything bad. I though since the I lowered the compression I would have lower cylinder compression numbers.

[Hashiriya415]

restriction in exhaust, wiped out exhaust cam lobes, just unbolt the exhaust mani and re test, look inside to make sure valves are opening, but hang crank to see.

[jonnybonds84]

I have a Hot shot header, test pipe with a 3 inch exhaust at the end. What do you mean by "hang crank to see."

[S14DB]

Why did you do the Compression Test?

[Om1kron]

is the car running like shit? he's probably doing the test because it's not running right.

[spooled240]

retest with another gauge

[Pacman]

I'm just worried because the FSM says it should be at 170-180 psi.
It's not a factory engine anymore. Those specs shouldn't mattter now. Give it more time to break in.

[mrchomponthis]

was your car at operating temperature?

[importdude]

The motor should have around 1500-2000 miles in it already. The ring gap are pre done with the supertech rings, I checked them and they were good too. Is it going to mess with my AFR? Should I do anything to my timing?


supertech rings are NOT predone

im sure that is not your problem but i hope you spec'd them correct

[Hashiriya415]

I don't know what you are saying about your rings, those have to be set once the block is honed and you place your rings inside and check with a feeler gauge to set them to spec that you want, and also keep them in order. But doubt that will increase the CR so much. I meant is hand crank and look at your exhaust valves while you got your exhaust mani/header off. But prior to this you could just remove the mani/header and run compression, if compression goes to normal you have clog in exhaust, if it don't check to see if valves are opening up through the exhaust ports on the head with a light and hand crank, or crank with starter but wear some goggles in case you have something inside that wants to shoot out at you at 200psi, that's why I say hand crank, to be safe.

[R_G]

WARM UP YOUR ENGINE
When testing compression always open your throttle fully open to each cylinder.

[jonnybonds84]

The Supertech rings that I have were, it said it in the papers for the specs but I still checked them. Are you guys ready for this, I didn't open the throttle when I cranked it, LOLOLOLOL. You guys are AWEsome, I'll do it again.

[greenman100]

The Supertech rings that I have were, it said it in the papers for the specs but I still checked them. Are you guys ready for this, I didn't open the throttle when I cranked it, LOLOLOLOL. You guys are AWEsome, I'll do it again.

closed throttle lowers compression psi.

your compression gauge is fubared

[JVD]

LOL

can't wait until he opens the throttle and gets like 250psi

hahaahha

[GunmetalSR]

LOL

can't wait until he opens the throttle and gets like 250psi

hahaahha
roflmao wow so wait are u suppose to open the throttle? huh i dodnt know that and are u jus suppose to spin the crank or actually start it?
i did it with no spark plugs in any cylinder and jus cranked a few times and my numbers were 125 125 95 105<-this equals shit lulz

[jonnybonds84]

So my numbers will be higher huh, great.

[jspaeth]

Ok, this is so cake.

Pull fuel pump fuse. Start car a couple time to flush fuel pressure.

Pull ALL spark plugs.

Check each cylinder.....While cranking keep throttle ALL THE WAY OPEN.

Let it crank like 5-7 times per cylinder or so.

The gauge reads and holds the maximum pressure obtained.


DONE

[orion::S14]

So my numbers will be higher huh, great.

Dude, are you comprehending any of what people said above?

It's VERY LIKELY that your compression gauge sucks, and is reading really high. If you want a new scale to match your compression gauge, let's just say that the FSM indicates 215psi for a fresh rebuild on a 9.5:1 motor.

There, you're showing 205, and a stock motor should be 215. You're fine.

;)

...

See what they're getting at? Try again, with a new gauge. You cannot shave the head enough to bump the compression enough to blow a 205.

- Brian

[negrosx13]

^^^nice got this info to him before i could..i looked over the fsm..lol

[jonnybonds84]

Sorry, I was being sarcastic, it didn't translate right into text, lol. I'm going to have to buy a compression guage since the one that I used was from the Hobby shop on base and at least 25 people use it a day. I think I will warm up the car a lil' bit more too and see how it goes. I also might buy a oil pressure guage too since the one they had didn't have the right fitting for the motor, anyone in San Diego have any one of those for rent? Let me know.

[mrchomponthis]

When I didn't know how to run a proper compression test i googled searched it and found everything I have heard in this thread. useless....

[gotspins13]

that kind of compression is nothing bad if anything you should be proud of it, just like anyone would be proud to have the hot wife on the block come on man get with the program! haha