Ok, so heres the deal:

My B18B into '97 Civic hatch has been running like ass, but only intermittently. When it's ok, it will run fine, other than a little stumbling under acceleration and constant throttle at low speeds. When it runs bad, I get stuff like stalling everytime the clutch is in, puffs of white smoke when restarting, very poor power, and stumbling all over the place. Fuel economy is a constant 20 mpg, stock motor with intake, header, and OEM exhaust.

Drained the coolant, and it looks brownish, oil was dirty but 100% water free (I've hydrolocked motors before, so I know the milky look...). When it idles it spits out dirty water (didn't smell sweet or oily, so im assuming its just a normal product of combustion)

So I pulled the head, thinking that I have a blown headgasket, but seeing as how my last 5 motors have run like champs, and I've never blown a headgasket, I'm curious if anyone can point out any other potential problems...

As always, any help is much appreciated.

Top is block, second is headgasket, then chambers 1 & 2, then 3 & 4.

 

Did you complete a leakdown & compression test on the motor ?
The car never overheated or smoked white under load ?

If the compression/leakdown results were fine I would resurface the cylinder head and install an oem headgasket using coperspray.

I would then run 100% distilled water in the coolant system to monitor the color of the coolant.

If the issue still continues I would consider throwing a wideband on the car to see if there are any issues with fuel delivery etc.

 

Did a compression test, not a leakdown. Car NEVER overheated. I also did not ever notice smoke while driving.

Numbers are 1 -> 4, in PSI:
150, 125, 130, 130

All held pressure pretty constantly, as in, no drastic decreases...

Also, when it idled without the radiator cap, it would spit coolant out on a regular basis, which just led me to believe more and more it was a headgasket.

So if I run distilled water, and it gets dirty, even with a resurfaced head and a new headgasket, then I have a crack in the head/block somewhere?

Finally, I have been using both an OEM OBD1 P75 (unsocketed, so I'm assuming stock) ECU, and an OBD1 chipped P75 that you reprogrammed for me, with a program that you said you have used on other B18B's, with good results (O2 sensor function disabled). Both get the same results and MPG.

Thank you for the advice, and I will keep the post updated.

 

Those compression numbers are awkward. Numbers on an ls are usually in the park of 180-200 within 10 psi per cylinder difference etc.

Where did you source the motor from ?

Once you slap the head back on, do a leak down test :-p

 

i know, the standard for an LS is 199, with a factory specified minimum of 140 and a deviation of 28, but i would never want to run a motor with 28 PSI difference...

anyway, i got the motor from a kid on here, who said he worked at a machine shop, told me it was completely rebuilt, and seemed credible (i'd done business with him before). its been idling bad since i got it, and the freakin IM gasket was a gasket-makered used one, so the kid is obvously full of shit.

needless to say, i will never run a motor i didnt build myself again

thanks again for the help.

 

Could an overly restrictive exhaust (OEM D16Y7 system) have anything to do with this?

Also, I've never seen exhaust valves burned that chocolate color, does that have to do with the coolant getting burned?

 

UPDATE: changed the HG, cranked it over, and the SAME FUCKING COMPRESSION NUMBERS.

I'm pissed. Oh well, the Acura dealership is holding rings for me. Theyre getting done once I tear it down AGAIN tomorrow morning.

Special thanks again to John for helpin me out late tonite.

Still wondering if this was exhaust related....

 

Exhaust related in what way ?
A friend of mine had a stock ls motor in an ek which I tuned on a stock d16y7 exhaust. The car gets awsome gas milage & has no performance issues at all.

 

Clogged cat can cause it to idle/run like shit but your problems seem to be motor related (hurt motor), re-ring and see how it goes.

 

no cat. the D16Y7 had a cat/header combo, so anyone who puts in another motor leaves the cat off. i have a 4-2-1 header into the mid-pipe into the muffler section.

i was just wondering if the exceeding restrictiveness could have something to do with it running poorly. im looking for another exhaust currently...