OK, here is a video of the amount of pressure that build in less than 5 minutes of idle. My idle is lower @ 830 RPM than the ECM is programmed for which is 925.

There does not appear to be any oil in my coolant, no steam either.

Here is the video.


http://media.putfile.com/Crankcase-Pressure

 

Gonna do a leak down test later and depending on the results I will pull the heads off.

The pressure is instant from the time I turn the motor on, so whatever it is, ring or head gasket, the engine has issues. I am hoping for a head gasket failure really.

If it is more than a head gasket, I'll make some motor changes.

 

Judging from what I see, I doubt its a head gasket. I am thinking on the lines of broken rings or something with the rings. A leak down test should tell the tale. If it was a head gasket I would think you would be getting combustion gases into the coolant system or coolant into the oil as well.

 

Is this a newly built engine? If not then how many miles or hours are on it. If it is fairly new I may have some ideas for you.

 

I would say that it has a max of 8k miles on it so far.

My fear too is that a ring has gone bad or a cracked piston maybe.

 

I cant see any signs of oil or pressure in the radiator.

 

Update:

oil pan is off,, no coolant in the oil,

did a leak down test and there was no obvious leakage,

looked at the cylinder walls from the bottom of the block with halogen lamp,, no obvious damage

Gonna pull the intake Friday night and heads on Saturday AM

 

OK, I stripped it to the block and found 3 broken rings and at least 4-5 broken rings on the same pistons. I cna post some pics unless you have a weak stomach.

The cylinders wall look great, nothing came loose from the pistons, no metal in the oil or on the magnet. I think I got a bad take of gas and detination toasted the pistons.

I might put some Wiseco forged back into this puppy this time.

 

That's frightening. I haven't tried mine yet with the oilcap off.

Last time I saw a motor steaming that bad was my friends Pontiac. I told him to put it back under the knife. He had broken rings on 3 cylinders, I think his ring gaps were closing.

I know better than to do a leakdown test on mine. It runs, and kicks but at the strip. Otherwise I'd end up tearing it down for 6 months. I'll just blame the blowby and oil leaks on the 'loose' forged pistons.



EDIT... just read your last posts. 3 broken rings, not 2, damn I'm good.

So where are you going from here?

 

I will pull the engine next Saturday, then hone the cylinders and load new pistons and bearings, and if I can find a reasonable price for a set of Forged Wiseco or other pistons, I will buy new forged pistons.

The crank and rod bearings looks great.

I will post some piston damage pics later tonight.

 

???

What kind of pistons are they? Why are you replacing them?

RACE ON!!!

 

Sorry for the out of focus pics, piston # 3, 4 & 6
They are TRW H616P +030

 

I'm already buzzed and out of focus, so your pics make it even tougher
Looks like a see a crack in the ring land. And broken rings

 

Detonation? shouldnt the knock sensor take care of that, or did you remove/desensitize it? would be just interesting

 

Larry, just curious, why would a leakdown test not pick that up? Seems pretty severe.

-Dave

 

Dave,,,It was strange, the leak downs were within 5% ,, and depending on what I read this is still good.

I think that since they were on the top end of the piston less air leaked out because the bottoms were sealing some still and probably the air filling the cylinder "might" have pressurized the cylinder making the parts expand into the ID, just a guess. Also, the cylinder ID shows no signs of damage nor do the rod bearings. I Leak Down tested using 60-psi, maybe this was too much pressure, I don't know

Also, at the point in time that I new that I had a problem, I drove the car for less than a 1/2 mile and shut it off, the jacked it up and started to diagnose the problem.

CFI-EFI = Why are you replacing them? Since 3- of the pistons are bad, I would rather have 8 new ones put back in just in case they may have issues later on, I don't want to do this again

ncChris = Is this a newly built engine? NO
If not then how many miles or hours are on it. The engine probably had @ 8k miles on it.

corvette90 = Detonation? shouldn't the knock sensor take care of that, or did you remove/desensitize it?

Well in thinking back I remember when gas got above $3.00 a gallon, I recall buying a lower grade, 87 or 98 octane, thinking that since I only "put-put" around it was no big deal. Then, I forgot about the lower octane and remember "getting on it" a couple of times and hearing some pinging and then later I remembered I was running a chip that has a fair amount of timing added to it, I will have to see what the chip program says about the knock sensor, I am still new to the chip burning process, but the chip was done by someone else and has worked fine to date.


So I am pretty sure that this is the root cause of the pistons coming apart. The engine has been in the car for 2-years running nicely, has been to the drag strip for a few test runs,,, my CR is 11:1.

So next weekend I will hone the bores, chase/retap all of my holes and clean/prep the block, then re-assemble. All and all, this is only gonna cost me @ $300 or so to fix, so I consider myself lucky to have not messed it up worse than I did.

 

Leak down tests are generally done with 100 psi air pressure. It helps make figuring the leakage percentage really simple. Maybe you had too little pressure to show the problem.



You hadn't mention any of the pistons were bad, when I asked. All you had said was:
Those were hypereutectic pistons. Some require a wider than normal ring gap. It might help you determine the cause of the trouble, if you'll look at the ends of the rings for signs of butting.

RACE ON!!!

 

Good info, I learn something every day

 

I just saw this Larry........crapola. Guess you might've gotten off lucky though if broken rings and broken ring lands could be considered lucky

I'll bet it was that low octane gas...........I think it's too coincidental for a motor to run pretty strong for a couple years and then show signs of detonation damage. It'll be interesting to see how much timing the chip pulls at what knock count levels. Funny, I don't remember you being at 11 static...........I thought you were 10.8 ish or less. Oh well, best of luck on the repairs

 

Hey Tim, it could always be worse

Actually, I have a 10.97:1 CR, not exactly 11.1:1 but close enough.

Anyway, I get to "freshen up" this puppy, not like it needed it but, oh well! I might have the heads ported on the intake side before I put them back on, so it could be better when its back together, we'll see!