CptHMCrunch

So, after trying everything I can think of to get the timing belt to stop running off the cam gears, I finally gave in and bought a leak down tester to check for signs of a warped head. I got some strange results and I am unsure of what to make of them. I want to get some second opinions on what might be happening here.

All four cylinders have ~210 psi after 5 rotations. I cranked cylinder 2 to max and got 240 psi. Didn't crank them all to max because I had to go to work.

However, I got horrible results on the leak down test. I only had time to test cylinder 1 hot and cold, but it was 100% leak down hot and 80% leak down cold. Here is where things get strange in my opinion. I could hear air escaping from cylinder 1. I covered a crank case outlet and I could immediately feel pressure being built up and a change in sound. I then opened the throttle plate, with my hand still covering the crank case breather, and I could hear air escaping from the intake manifold. However, I cannot hear air escaping from the intake when my hand is not covering the crank case breather.

I can definitely hear air escaping into the adjacent cylinder when I remove that cylinders spark plug.

The motor doesn't smoke at all while running, even after letting idle for a while and opening the throttle. There are no signs of oil fouling on the spark plugs. The compression is good. When I drove the car, for a very short period of time, it did not seem to have any power loss. I have not had anyone ride behind me to look for smoke though. No CEL at all.

I have bled the hell out of the cooling system and the motor still bubbles steadily once brought to operating temperature. I drained the coolant today and it definitely had a light layer of oil on it. I drained the oil and did not see any clear signs of coolant in the oil... there was a little bit of froth but it was getting dark and I couldn't see that well. I'm going to look at the oil I drained again tomorrow. When doing the leak down test I have noticed that the coolant level in the radiator seems to go down, but I haven't noticed any bubbling.

I have ruled out valves because of the good compression and the fact that the motor runs good.

By looking at a photo of the block, it seems unlikely that the crank case would be getting pressurized without causing the coolant to bubble unless the head was warped.

Is it likely that I have bad rings even though I have good compression and the motor runs well with no smoke?

The head is coming off regardless because of the bubbling and the timing belt walk. My red top h22 swap .

holmesnmanny

You didn't crank them all to max because you had to go to work ? It takes about 5 seconds to crank until the gauge stops going up. That's all you gotta do. If you had to leave after 4 seconds instead of 5 seconds I really think you need to allocate your time better.

There is no way in hell there is a correlation between your belt walking off the cam gears with a cylinder leak.

CptHMCrunch

I disagree. A warped head could potentially cause timing belt walk and leak down.

If you don't have anything useful to say dont bother responding.

1991_crxsi

iTrader: (1)

Sounds like a head gasket.

No, it is not likely assuming that the engine doesn't smoke under engine breaking.

Okay. Buy my ported H22 Head with new valve-guides, freshly resurfaced, and fresh valve job if you are worried about head warpage. I will give you a core on your old head regardless of warpage. Just PM me an offer and check out my threads for pics. I am paypal verified.

Regarding the timing belt walk... are you sure that the timing belt has proper tension? That is most likely the cause of that particular problem. A typical culprit is failure of the automatic tensioner (very typical), or installer error. The chances of it being from a warped head are close to Zero.

holmesnmanny

My comment is useful, useful to future people that navigate to this thread and actually think that it is possible that a timing belt could walk off the gears due to a warped head.

The problem is that its not what you want to hear and thats your problem.

If you want to pull the head instead of simply doing a compression test to confirm youre wrong thats your choice

CptHMCrunch

So I had time to do some more testing over the weekend. The leak down is blowing into the crank case as well as into other cylinders. I plugged the crank case ventilation for a moment and was able to hear air escaping through the intake manifold while working the throttle plate. Air flow through the intake manifold is nearly non-existent when the crank case is not being plugged. Plugging the crank case ventilation for ~3 seconds built up enough pressure that I could hear air rushing out as I unplugged the ventilation. I get the same results when applying 100 psi and when applying 15 psi. I highly doubt that this leak is being caused by the head gasket based on the wear of the gasket when I removed the head.

I pulled the pistons to inspect the rings and bearings for wear. Rod bearing for piston one has some slight trenching. The pistons and cylinder walls show no signs of scuffing or scoring. The rings show no signs of complete mechanical failure. I will have the ring end gap inspected at the machine shop. The cylinder walls show no signs of cross hatching, which I understand is normal for Honda FRM cylinder walls.

The pistons from the JDM motor do have, what appears to be, signs of ring blow by on the exhaust side. The discoloration and carbon build up present on the JDM piston skirt is not present on the USDM piston skirts that came from a vehicle that threw a rod and had 300k on the chassis. All of the JDM pistons show the same thing. The same thing is visible on the intake side but it is not as prominent. See the attached photo. Could the cylinders be out of round? Is it likely that all cylinders would be out of round and show such consistent wear and leak patterns? I suspect there would be more deviation in wear and leak patterns if all cylinders were out of round.



I have a kaizenspeed manual tensioner. I have tried turning the motor over by hand at all tensions and it still walks. I have tried replacing every component that the timing belt rides on while keeping all others the same to isolate the problem. I have tried using a spare #18 as a guide washer and tried running the OBD-1 pulley using the plate for the sensor as a guide. Nothing has worked.

holmesnmanny

How about a different belt ?

CptHMCrunch

I have stopped by a few machine shops and they have all come to the same conclusion, excessive piston ring blow by. I've taken some time to really study the piston skirts and I would not be surprised if the pistons were out of round. The carbon fouling seems to be following a pattern that would be produced by blow by due to an egg shaped cylinder. You can clearly see in the photographs that the carbon fouling tapers down, from the exhaust side, towards the pin. The taper then continues with the same pattern back up on the other side.

Hopefully I can have the cylinder walls checked for roundness tomorrow. If the cylinders are not too far out of spec I will most likely just deglaze the walls and put new piston rings in. Has anyone ever tried this deglazing method with success?

http://www.ludegeneration.co.uk/hond...ls-t11960.html