BHG? can you confirm this?

[eraezer]

Hello,
it started with misfire. I tried changing the coil pack and while I did this I double checked the timing because I wanted to be on the safe side. The things is that I'm an idiot and forgot to change back from fixed timing to table timing (running MS3 ecu) and my laptop battery was running out.

Suddenly on the freeway there was a lot of water blowing over the hood and windscreen so I pulled over, filled up with all the water I had in the car and drove to the closest gas station (not far).
I topped up on coolant and was able to drive to my garage without any problem.
My thought was that because it was only running on 5 cyl., the sixth spark grounded out through the head and heated up the water. I did some work on the coils.
Started the engine several hours later and drove home...just when I pulled up the driveway it overheated ( no water coming out this time).
So I filled the cooling system again, while the engine was running and then went to bed.

The day after the laptop battery was charged so was now able to see that the timing was fixed. Changed that and took it for a test drive.
When I arrived at my goal, it was almost overheating. I was able to remove the rad. cap and filled it with water, but it seamed like the air pockets was unlimited. Drove to a steep road and tried to air out the system again. It didnt want to stop bubbling.
Took a test drive, no problem.
But when I was driving home a bit later it started to overheat. Filled the system again and drove home.

Today I did a compression test. I used a zip tie to keep the throttle open during the whole test. And here are the results:
Cyl.1: just under 10Bar
Cyl.2: ~9,7Bar
Cyl.3: 9,5Bar
Cyl.4: 10Bar
Cyl.5: 11Bar
Cyl.6: ~14,4Bar

Cyl.6 spark plug had some water droplets and when I inserted a dry piece of wood with a clean cut into the cyl. it came out wet.

So I would say that I have blown my headgasket, do you agree?

 

[airhead04]

For the guys that dont know bar to psi or just dont want to look it up. OP you sure number 6 cylinder is 14.4?


Cyl 1: 145
Cyl 2: 140
Cyl 3: 137
Cyl 4: 145
Cyl 5: 159
Cyl 6: 208

 

[radiod]

Correct me if I'm wrong, but doesn't compression typically go down on the cylinder with a leak? 208psi also seems just way out...that's incredibly high in comparison to the others. Did/can you do a leak down test? Do you get white smoke/steam out the back? If you are in fact getting coolant or water in your cylinder to the point of being able to see it on plugs, you should see it out the tailpipe.

 

[IJ.]

Another candidate

 

[eraezer]

I'm sure about cyl. 6. Re-did it to be extra sure. A fluid in the cylinder will cause higher pressure.
No white smoke while driving, but I got a large white puff when I started the engine the last time.
What else would a leakdown test tell me? I have not done that.
Is there another way for getting coolant into the cylinder? I'm loosing coolant.

Can I be 100% sure that it's the headgasket? (ignore the possibility of cracks in head or block)

IJ. This was because there was an idiot behind the steering wheel.

 

[radiod]

Leakdown test is essentially checking to see how fast pressure is escaping the cylinder. You'll pressurize it and then with the tool you can cut off the supply of the pressure and monitor the pressure drop. You'll have to get the engine in such a position that the intake and exhaust valves are both fully closed to accomplish this. It's essentially taking a compression test to the next level.

Wikipedia's version:
http://en.wikipedia.org/wiki/Leak-down_tester

 

[Backlash2032]

Wouldn't a better test (in his case) be a leak-down of the cooling system? Pressure is always going to bleed from the cylinders. It should never bleed from the cooling system, unless something is wrong.

 

[jonahs_supra]

with the pressure on cyl 6 being extremely higher then the other cylinders
cooling system over pressurizing

my vote is on BHG

reason for smoking on 1st start up is your cylinder pressure is 200ish psi when running...when shut off the pressure bleeds off
but your cooling system has 13-17psi(on a healthy motor)
since the 200psi is no longer there the pressurized cooling system will now bleed off into your cooling system

 

[eraezer]

As soon as I'm done with the car I have in my garage, I will tow my supra there and start tearing the engine apart. I hope it's not bad enough to stop me from doing a rebuild (with extras).

 

[eraezer]

The headgasket was broken mostly on cyl. 6 and a little on cyl. 1.
Something strange was that the rear timing cover was not at the same height as the block :S Sure, a regular HG is a little forgiving, but this is just crazy. The difference is just a little below 1mm.

 

[IJ.]

The headgasket was broken mostly on cyl. 6 and a little on cyl. 1.
Something strange was that the rear timing cover was not at the same height as the block :S Sure, a regular HG is a little forgiving, but this is just crazy. The difference is just a little below 1mm.

Sounds like someone swapped in another timing case onto a machined block or they weren't machined together.