windhund116

Cylinder 1 losing air out exhaust?

Billman250

It is extremely rare for an S2000 head gasket to leak. It typically takes a severe overheat to do so. Be 100% sure you are on TDC, firing stroke of the cylinder being tested.

Listen to the exhaust out the tail pipe. Compare the noise you hear to a good cylinder.

How tight were the exhaust valve clearances at time of valve adjustment? I have seen many tight valves, and all cases were burnt ex valves. Never a head gasket.

While doing the leakdown, remove the radiator cap. Watch for bubbles or rising coolant.

slate83

I'm pretty sure I was on TDC of the firing stroke. I had something sitting on top of the piston and it was at it's max height. I also went back and forth to be sure it was TDC compression stroke and not exhaust stroke and on one of the two, the PSI dropped to 0 so I assume that was the exhaust stroke.
It seems that the engine can turn a little while the piston is at it's max height. I did my best to be at the middle of that turn.

Will do. Maybe I need to push more pressure through to detect something out of the exhaust too.

I did not measure that, unfortunately. I know that my 0.279mm gauge would not go in at all but did not try anything smaller.

Will check this too.

During my searching of this forum, I've seen posts about the head bolts needing to be re-torqued. I wonder if that could be a factor. I looked at the front of the head and do see what appears to be some fluid that's leaked out.

Billman250

Head does not need to be re-torqued.

The fluid you see in the front of the head gasket is oil. It is only chaincase seepage, does no harm and is very common. It is not an indication that the head is lose or needs a re-torque, or that the head gasket is bad in any way.

slate83

Thanks again, Billman.

I'll go put some air through #1 and #3 to compare any exhaust sounds I can detect and will also have the radiator cap off to see if anything happens there.

slate83

No surprise, Billman, you were correct. Thank you for all of the advice. There is air coming out of the exhaust -- audible to the naked ear. When I did this earlier today, I was poking the stethoscope around there and I think having that in my ears was causing me not to hear the obvious air out of the exhaust that the stethoscope didn't really pick up.

I tested cylinder #1 at both the top of the compression stroke and the top of the exhaust stroke just to be sure. I listened to the exhaust both times and there was air coming out both times. On the second one, there was a slight bit of pressure holding so I figured that was TDC of compression stroke. I turned the engine 180 again while ensuring the #3 piston was at it's highest point and tested cylinder #3. No air coming out of the exhaust on that one -- I figure if it was on the wrong stroke, there should have been air coming out of the exhaust.

It would appear that I do indeed have one or more burnt valves. I'll be figuring out where to get this serviced now. I'm under the impression that I can still drive the car in the meantime.


P.S. I also left the radiator cap off while putting air into the cylinders and the coolant didn't move.

rpg51

If there are burned valves I'm surprised it wasn't picked up before the head was reinstalled.

slate83

The head was never removed.

shind3

0.279mm = 0.011in

So basically, your measurement tells us nothing other than the valve lash wasn't too large. And you immediately destroyed the evidence by resetting them. Yet you were completely OK repeating the same test over and over again and reporting compression values to 3 significant digits. LOL.

I wish they taught logic in grade school. Seems to be a rare commodity in my experience.

HarryD

Hey shind3, why so negative? There's no need to be that harsh, especially with the bad news of burnt exhaust valves.

OP has been thorough, detailed, and concise, and his posts/replies are better than the majority of posts on this forum.

That said, I'm looking forward to hearing from the experts if a DIY fix is even possible here? Would merely replacing the valves be a valid fix, ala https://www.s2ki.com/forums/s2000-un...-place-569714/ ?