Head gaskets again?? Maybe not.

[BOJANGLES]

Well what I thought to be head gaskets may not be this time. Just after I did my hydro boost conversion and still working the bugs out of that and head gaskets last year also. Was driving it last week late night after replacing downpipe and turbo gaskets and seemed to be running fine cruising on all cylinders and nothing seems to be going wrong. Doing some pulls and playing around with it and after some time on my way home I noticed smoke as I was cruising, it gets worse as I accelerate and not so bad when I'm off the throttle. Well I get it to my garage and do some diagnosis... re torque my head bolts and start it up and still doing the same thing, brake boost it and its chugging out smoke from the breathers, more on the drive side. Compression test it and #3 cylinder is @30psi and all others at 160, also the same cylinder that blew the first time Pull the head and don't seem to find a bad head gasket... still put a new one on, meanwhile I was told to check that injector on that cylinder, also checked the valves visually and seemed to be fine along with the piston. Found a burned through wire on the harness from it rubbing on the egr valve so I bought a new harness and a egr block off plate to eliminate that issue. Put together the head and all and do a compression test and I'm still at 30psi.... lifters seem to be moving well enough that the valves are operating correctly, couldn't crank the engine and watch the rockers by myself. So what else should I look for?

 

[michael evans]

crack some where in #3 cylinder.

cam intake/exhaust valve not opening much on #3 cylinder.

burnt/bent valve on #3 cylinder.

With the smoke coming out of the breathers like to describe, it sounds more like a crack some where in #3 cylinder.

 

[ScottHeidinger]

If you're running a flat tappet cam that is the one that is normally wiped out in a cam failure. With the valve cover off on that side of the engine turn it over and see if the valves are opening like the rest.


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[BOJANGLES]

I got a video of the lifters, but can't seem to upload it for some reason, lifters are moving as much as the others it seems like, only thing I could do since I was by myself. It is flat tappet still and I believe some mild cam from what the previous owner had stated. He doesent remember much as he built and played with this car 15 years ago or so. He is a family member of mine. I hope i didn't Burn a piston not ready for a complete stroker and other cool stuff... I'm sick!

 

[Matt McClung]

Sorry to hear your problems. When I had a head gasket go, it was also number three at the top middle of the cylinder. Anyway, at this point, I would get a leakdown tester to find out exactly where the leak is at. Unfortunately, if your blowing smoke out of your breathers, the compression is escaping into the crankcase somewhere. Leakdown test should be able to tell you more.

 

[BOJANGLES]

All valve train appears to me moving equally, got #3 to TDC and shot air into it and it seems like the air is coming from the crankcase, with my hand over the valley I can feel the air coming through. Going to do do a little more investigating tomorrow. I'm leaning towards a broken piston now... as I cranked it with a compression tester it will hold 30psi and won't leak down.


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[Chuck Leeper]

Rattled it, broke the ring lands...
Inj harness goes south, inj either goes static, or it intermittently goes lean, bangs the piston to death.
What did the plug look like?

 

[BOJANGLES]

Looks a little fuel soaked, more than likely I'll need a rebuild now... stroker time


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[BOJANGLES]

Rattled it, broke the ring lands...
Inj harness goes south, inj either goes static, or it intermittently goes lean, bangs the piston to death.
What did the plug look like?

Attached a picture, I blame it on the egr valve which burned my harness.. and myself for not paying very close attention. Time to make it faster.


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[Matt McClung]

Perform a wet compression test. If the problem is in the rings or piston, you will have the compression readings skyrocket up. If the problem is the head gasket the readings will stay low.

 

[earlbrown]

any chance you have aftermarket pistons? Your issue sounds exactly like my 4.1 when I'd crack pistons. Speed Pro's have a long slot under the oil ring and the skirt is held on by two small points close to the wrist pin.

If the piston rocks over, it'll crack and turn the ring grooves into a 'step'. The instant it pinches the ring, all the compression goes into the crank case.

 

[BOJANGLES]

any chance you have aftermarket pistons? Your issue sounds exactly like my 4.1 when I'd crack pistons. Speed Pro's have a long slot under the oil ring and the skirt is held on by two small points close to the wrist pin.

If the piston rocks over, it'll crack and turn the ring grooves into a 'step'. The instant it pinches the ring, all the compression goes into the crank case.

I believe a stock bottom end and head from what he can remember.



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[BOJANGLES]

Just did a wet compression test and the reading stayed the same, might of gave me 32psi instead of the 30psi


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[Matt McClung]

Just did a wet compression test and the reading stayed the same, might of gave me 32psi instead of the 30psi


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That is an indication that the problem is up high. Most likely head gasket failure.

 

[BOJANGLES]

That is an indication that the problem is up high. Most likely head gasket failure.

Head gaskets are brand new, just put a new set on that side specifically RJC kit.


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[Matt McClung]

Head gaskets are brand new, just put a new set on that side specifically RJC kit.


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That is really something. Any cracks in the piston or bad rings should temporarily seal with a wet compression test and bring the compression way up if the issue is down low. A crack in the cylinder would send combustion into the cooling system, not the crankcase. In my experience, a bad valve usually won't make even 30 psi of compression, but it's possible that a valve is leaking. Cracked head would be the same thing as a cracked cylinder, sending pressure to the cooling system. Unless you didn't get quite enough oil in the cylinder to seal the piston/rings? Keep us posted on this one, very interesting. Sorry for your troubles, I know it's frustrating.

 

[BOJANGLES]

Well decided to take the oil pan off and pull the piston for the hell of it... this may be a problem, I figured it was this in the long run...

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[Pronto]

Chuck's the first winner. Earl comes in second. Others were close but not specific.

 

[BOJANGLES]

Chuck's the first winner. Earl comes in second. Others were close but not specific.

Well, I might just put a piston in it for now, all the other cylinders and up to par with no leak down. I'll turn the boost down a touch and got a new injector harness and removed the egr, from which I don't know why it was even on there ... it was eliminated in the intake elbow and plenum already so I'd assume it should be done in the current chip on there. Would like to get he computer checked with this current chip to see if it's doing any good..


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[earlbrown]

That's one horrible looking piston. What brand and type is it?

and do you know the bore size? I'm curious on the piston to wall clearance.