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When I got my car back from the dyno and first fired it up to take out for a test drive the right exhaust was pumping mucho water (a very nice spray out the end of the side pipe). It hadn't done that when I took it off the transporter a few days earlier. After a few weeks I've more or less gotten over being mad and depressed so decided I to take it apart and see what was wrong. I finally got the head off tonight but I'm not sure what it's telling me.
When it was running number 8 header tube was stone cold so I convinced myself that was where the water was coming from. Looking at it now that apart I see something that "could" be a crack in #8 cylinder wall (shinny somewhat vertical line but not where piston thrust forces are, too far around cylinder, and not quite straight with the piston stroke. It has a slight angle to the stroke and has a short jog in the middle. Is that what a crack should look like? I can't feel anything. Even after the mega leak surfaced it would only pump water when running, just cranking with the plugs out never produced anything so it seems would only draw water under suction/vacuum.
Additional confusion is the #6 piston is absolutely shinny, not a carbon stain in sight. Looks like just out of the box. The other 3 have "burn" coloring as I'd expect. Is it the source of the mega-water, or has it been suffering from a small leak and being steam cleaned for a while. The underside of the head gasket at the bottom of #6 shows some sealer from the head studs, and the bottom two studs on #6 had a ring of sealer around them. Could that be enough for a long term small water leak, and the possible crack in #8 being the fire hose?
The head side doesn't show me anything unusual, all chambers have similar coloration and carbon on the valve heads. #2 actually has the least colored intake valve. All of the chambers have a visible impression from the gasket compression ring around them.
I don't know that the winner of this mystery gets a prize but will certainly be welcome to a ride if/when I get it back together and running right.
Expecting a nice easy to find crack in #8 I've been looking at options for a new short block or a new block with my internals. I'm considering taking the head to a shop to pull the valves and look for possible crack/leak under the valve seats (I don't see anything obvious in the outer port regions I can see from the intake/header sides, can a head be pressure tested?).
Suggestions, clues, or joining in the confusion are all welcome.
When moisture gets in a cylinder it will blow all the carbon off a piston so your number 6 has been running wet. Could number 8 have had a bad plug or plug wire?
Look hard at your head gasket fire rings, the round circle around each cylinder in the head gasket. You can usually see if the combustion has been blowing past the fire ring.
Had this engine been overheated in the past???
The fine verticle scratch is most likely where some dirt went up and down with your piston rings.
This is probably no help but why didn't you pressure test the cooling system it before you took it apart? Now you have to guess and check if it's not obvious. If it were someone I know looking for me to help I would put it back together and pressure test it or make plates to pressure test the pieces apart but you still blew the chance to test the head gasket.
What engine? Is this a new engine rebuild, or just testing a existing powertrain? If new build, who did the machine work on the engine? Did you get the engine built outside or did you buy it completed?
I had a similar issue a while back. Head to block valleys causing combustion gas leaks into the coolant. I found the culprit cylinders with a combination of leak-down tests, reading spark plugs, and using the Napa Blue-Dye Block tester which turns the blue dye green or yellow if gasses are in the coolant.
In my case I never got white smoke out of the exhaust nor any water in the oil. Ultimately It was due to poorly machined heads and block deck mating surfaces. I got the engine as part of a build after machine work was done elsewhere.
I'd suspect a blown head gasket first. That's where mine was ultimately, but both. 5,6,7, & 8 were washed, white spark plug porcelains, and telltales around the spark plug head cooling water ports.
I'm thinking your cylinder "score" is a artifact of the machining process when they pull the cleanup hones out of the cylinder. It leaves a line or lines like this, and if the operator jerks the machine it might put a little kink in it.
Since you have it all apart you can't diagnose real-time on the problem, but you can check many things..... head gaskets, flatness of your block decks and heads, etc. You need a high tolerance flat bar and feeler gauges down to 0.001". Or invest in a surface gauge and dial indicator to make measurements over the deck and head surfaces. Here is what I used to prove the decks were bad on the one I had. I had variations spanning over 0.010" on both decks. Some as high as 0.018" near the china walls.
Zero'd on a flat table between measurements for accuracy.
The motor has been together and running for a few years (long project), showing 60 miles plus 4-5 hours on the chassis dyno plus what ever miles I put on before installing the GPS on the speedo (the trans drive pulse generator never worked). Probably idled in the garage a few hours messing with the EFI. Temp never gets (or got) above 205 (static with the fan on), usual running temp is 195, sensor is in the water plenum just before heading to the radiator.
I'm going to try to get some pictures but not sure what I can get inside the cylinder.
The plug from #8 had water on it when I pulled all the plugs the first time (I tried re-doing intake gaskets once to make sure that want't the problem since the intake had a fairly loose bolt when I first checked them). Plugs in 2/4/6 all looked normal, which is a bit rich. Top of cyl 8 also had some flash rust above the ring travel as sat about a month before pulling the head. Had fogged the cyls so not suprised didn't see any rust on walls.
The suspect line (crack,scratch or whatever) only extends vertically about an inch. Probably try to dye penetrant check it.
I've looked for any signs of leakage on both the gasket and the block and head and didn't see any signs of blow-by, or any combustion "burn" on the compression rings. I miked the removed gasket compression rings and get comparable readings on all cylinders, .0395-.0415 at 12 and 6 o'clock positions, .044-.045 at 3 and 6 but might be getting some error there since the rings contact each other on the between cyl sides.
Not a machinest flat bar but the best edge I have available doesn't show any gaps/high spots on the head or block but block is limited in access with the head studs.
Heads are new AFR. Possible a valve seat would hit water jacket but I'd hope they have better QC since the heads have CNC chambers and ports. Am looking for shop who could pressure check the head.
I've looked for any signs of leakage on both the gasket and the block and head and didn't see any signs of blow-by, or any combustion "burn" on the compression rings. I miked the removed gasket compression rings and get comparable readings on all cylinders, .0395-.0415 at 12 and 6 o'clock positions, .044-.045 at 3 and 6 but might be getting some error there since the rings contact each other on the between cyl sides.
-greg
What head gasket did you use? Thickness? Was that head ever installed, removed and reinstalled?
I think you have a blown head gasket with evidence right around the stud between 6 & 8, along with traces of blowout along the perimeter between the two.
It's hard to see in your pics, but I mag'd them a bit. Maybe that head stud nut between 6 & 8 was torqued a tad low and aided in the blowout.
I can see something that looks like traces on the gaskets, both sides too.
Those are high quality gaskets with the extra sealing features built in. I've used them before for old rebuilds and they are very good.....however pricey and it's painful to keep replacing them.
Those are aluminum heads right? You may want to have them pressure and flatness tested to be on the safe side.
But maybe it's not a head or block issue at all. Maybe you just had a loose head nut and just blew the gasket.
And that scratch on the #8 wall looks just like a machining scratch when they pull the cleanup stones out.....similar to my pic earlier.
If I read your head gasket measurements correct you are showing .020 of compression.
Normal is .003 to .004 if you compare compressed area's of a used gasket to non compressed area's of the same gasket. A new Fel-Pro gasket is normally within .001 at any point. Performance gaskets are hot pressed and measure better than .001.
When you map the gasket to see where your problem was lay the gasket on a sheet of white paper and draw an outline of your gasket and all the Fire rings and head bolt holes.
Then get your mic and start measuring. Measure within 1/4 inch of each head bolt hole and write the numbers down on your paper map of the gasket. Measure the fire rings at about 6 locations in the circle around each cylinder. The map will show what happened to your engine or where the gasket has been crushed.
I suspect when you map it you will see crushed area's, most common will be between the cylinders, in your case 6 and 8.
There are only a few things that will crush a gasket.
1. Overheat, localized overheating will expand the block and head, the gasket gets crushed between them. An air pocket on start up or lean burn in a cylinder can do this.
Normally overheat issues crush the cylinders farthest from the water pump and fresh water supply.
2. Detonation in a cylinder, detonation will cause excess cyl pressure. Normal in a high performance engine like yours is 600 to 900 PSI at wide open throttle. With detonation in the same cylinder you might measure 3,500 PSI to 5,000 PSI. This causes the head bolts to stretch, the head jumps up off the block and slams back down as the piston retracts, this can happen at 5,000 RPM or more so it quickly pounds the gasket in the area that is detonating. One dyno pull with detonation can do this. FYI, Upgrading to MLS gaskets eliminate this failure of the head gasket. MLS can live in detonation and not fail. You still might break a piston or pound out the rod bearings but the gasket will not be the failure point.
If your gasket is crushed you have discovered a fact of the failure. Now you go back and find out why this happened.
I see very high compression pistons, was the fuel up to snuff for this new engine? Low octane can cause detonation as can lean burn or too much total timing.
If you map the gasket and all area's are within spec look for a crack or water leak in the heads or block. The scratch you showed can be caused when the piston rings are installed. Sometimes file fit rings do not get smoothed after the file work and the sharp edge of the ring gap will leave a nice scratch on install just like yours. That small scratch will not cause any issue in the engine but it is not attractive.
Last edited by Westlotorn; 08-15-2014 at 12:52 PM.
I'll take another look. Head gaskets I've had fail in the past were very easy to tell.
Motor runs 10.8:1 on premium (76cc heads). Have never detected any signs of detonation.
Never had any global overheat, runs 190-205, the hot end at idle until fans come one and pust back to 200.
I have dye penetrant so will test the cyl walls just to make myself confortable then possibly put in new gaskets and put back and see what does. Still need to try to find somewho who could pressure check head.
Well I wouldn't have expected it since the heads were new when I put them on (6 or 7 years ago) but the head has a low spot between the two studs/bolts that bridge where the cylinders meet and the exhaust port edge of the head deck. It's probably .001-.002, can see a nice light shine under when put a machinists edge on the head. I'd checked it lengthwise and on diagonal when I took it off but not just across head at each of the cylinder junctions. Going to pull the left head then have both surfaced. Will pressure test when off too just in case.
I see this is a 400 sb. What AFR heads are you running. Also I see you only drilled 1 of the steam holes . I have the same engine combination , roller cam and all. Those type of head gasket can take up to a few thousands out of flatness , steel shims gaskets cannot . It looks like a head gasket to me . Maybe you should re tighten the heads after the engine has been run and cooled down.
What about MLS gasket, would they be a better choice? Still need to pull left head and look at it and then probably send for pressure check since it is all apart.
Heads are AFR220 CNC ported spread exhaust port (to match the intake port size of the Hilborn manifold).
08-13-2014, 06:23 PM
Ok, where's the water coming from?
