S2Ki Team,

I have a bit of a troubleshooting dilemma. I recently finished a rebuild on the S2000. I just got past the break in period and took it out today to play around a little bit during lunch time. Unfortunately, during a quick 1-2 WOT pull, I create some large billows of white smoke. Worried, I had the car towed home.

Once I got it home, I popped the the spark plugs out, everything looks normal. I took the daily driver to the auto parts store to use one of their compression testers. Got a brand new one for use. Compression numbers are:

Cyl1: 120psi
Cyl2: 55psi
Cyl3: 120psi
Cyl4: 122psi

*Confused* Engine was rebuild with oem OS pistons so compression should be much higher. Car runs well but has a slight vibration/miss at idle.

120psi is bad, 55 is absolutely atrocious.The gage mightly be slightly suspect or it may be because I was only able to crank her to about 350rpm with the starter. I don't have any oil consumption (over 500 mi). The white smoke is clearly coolant/water burning.

I put it back together and took it out for a run. The smoke first appears when I snap off the throttle from a boosted state (8~9psi), or it may just be occuring during high rpm high load. Sounds like a bad head gasket seal letting coolant into the combustion chamber. I'll probably order a gasket from Majestic tomorrow. I want to ask two specific questions though:

1. Does coolant pass into the intake manifold from the head, I don't believe it does. I believe the only source is from the cooling lines below. Could this, therefore, be a bad intake gasket seal?
2. Anything obvious I might be missing? lol

 

Yes, coolant runs through the head and into the intake manifold. I used to have a Hondata gasket that started to leak coolant into the cylinders because it stopped seals well. It mimiced a blown HG but was not the case. Make sure your intake gasket is not the Hondata or if its the OEM gasket, its sealing properly. You did replace the intake gasket what you put the intake back on, correct?

 

Yes. I did replace the gasket, it was OEM. I didn't, however, use appropriate torque value because I was a big dummy and forgot to attach the intake manifold to the cylinder head before I bolted it down. (A consequence of rushing to meet timing for an event) I snugged each bolt :/

 

A couple other things I should mention. The smoke remains briefly after high throttle high rpm and then disappears and stays away under normal condition. I reused the original head bolts but torqued them per Honda's manual.

I'm contemplating head studs. Does anyone know if the head can be installed in the car with studs in place or will it interfere with the firewall/cowl?

 

I just installed the head with the head studs on the block already with no issues. If not, you could always set the head down without the studs in, and then drop them down and hand tighten.

I would never notice smoke during high rpm runs, but if I beat on the car and then did not let it idle for a few minutes, i would see a lot of white smoke during the next start up. When I did start it, it would stumble and would not start immediately. I've heard of stock bolts holding up to a decent amount of hp, not sure how much you are putting down though.

 

I'm going to make the assumption that your compression figures and smoke are related.

Now 120 is ok if you're getting 120 on all cylinders. Bad gauge, weak battery whatever. It is the 55 that is the worry.

Lots of white smoke and bad compression on #2 leads me to believe #2 has a leak to the water jacket. So bad headgasket.

But before you go pulling it apart I'd double check those compression figures.

 

120 with stock HG?...

i have the 2mm HG and have 209 on my tester and 220 on a buddies tester.

somethig isnt right bro, especially if you have 55 on another.


when you did the comp test, did you have the throttle all the way down to the floor when you cycled?

 

Good point. Throttle was fully closed when I performed it. I'll recheck to see the efffect. Head gasket is on the way. New head bolts as well.

 

^those numbers that far off is always a good sign of an incorrect comp test.

good luck!

 

Agreed. Engine was cold as well as having the throttle shut. I'm going to look into where my seal is lost be it intake valve, exhaust valve, head gasket, or rings.

However, I have some bad news to report. The steam from the tail pipe is coming from the water in the aftercooler. When the throttle is snapping shut at high rpm the vacuum it's pulling is sucking the water right out of the aftercooler in less than one second. I can only assume there must be a pin hole leak that isn't noticable when the pressure difference between the cooling and air chambers isn't that much. The water levels do not drop under normal driving. Looks like I may be hitting up Air to Air soon enough. Too bad the Novi1000 doesn't quite put out enough boost/flow to effectively deal with the extra pressure drop/volume. =(