Blown head gasket?

[cookie88]

Originally Posted by SuperDoodie I think you are chasing the wrong thing personally. I actually find that encouraging since I've yet to find anything actually wrong with the motor...other than the head bolts have slightly less than factory spec'd torque. The only problem is...where else should I be looking? I mean the odds of a thermostat suddenly over pressurizing the system the exact time I install a new HPOP seems pretty remote. So what else does that leave?

[Kwikkordead]

Originally Posted by cookie88

I actually find that encouraging since I've yet to find anything actually wrong with the motor...other than the head bolts have slightly less than factory spec'd torque.

The only problem is...where else should I be looking? I mean the odds of a thermostat suddenly over pressurizing the system the exact time I install a new HPOP seems pretty remote. So what else does that leave?

Not much, I'm afraid.

[Kwikkordead]

Here's another thought.
Head studs.
If the head gasket truly is blown because you now are making a LOT more HP than was originally designed, IMO, it makes a lot of sense to pull the engine back out so you can install studs while the heads are off.
And there is the issue mentioned earlier about the rods having a tendancy to break six months down the road.
Is that limited to the PMR's or are forged rods in that group?

[Orezona]

From what I've read (not experienced) any cylinder you think water entered, you need to replace that rod. PMR or Forged.

[cookie88]

Originally Posted by Kwikkordead

Here's another thought.
Head studs.
If the head gasket truly is blown because you now are making a LOT more HP than was originally designed, IMO, it makes a lot of sense to pull the engine back out so you can install studs while the heads are off.
And there is the issue mentioned earlier about the rods having a tendancy to break six months down the road.
Is that limited to the PMR's or are forged rods in that group?

Indeed. I've already priced out a set of studs an Cometic gaskets, and I've arranged to have my truck moved over to a proper work space if necessary. I just don't want to spend all that time and money unless there are no other options.

[bdrummonds]

Hey Scott, just for grins and giggles go out and pull the coolant overflow line, and make sure its not clogged, and forcing the coolant out of the pin hole in the degas bottle.

Do you have a bypass coolant filter? by chance did you pinch a heater hose during the HPOP install?

[tojoski]

Originally Posted by Orezona

From what I've read (not experienced) any cylinder you think water entered, you need to replace that rod. PMR or Forged.

I don't think much, if any actually entered the cylinder.

It all ended up under the hood and down the side of the truck.

Are you re-torquing the heads this morning?

[Texas Charlie]

When I had this or what you might say a similar problem it was a cracked injector sleeve. I am not saying that this is what your problem is but that is what it took to fix mine. Good luck!!

[cookie88]

Originally Posted by bdrummonds

Hey Scott, just for grins and giggles go out and pull the coolant overflow line, and make sure its not clogged, and forcing the coolant out of the pin hole in the degas bottle.

Do you have a bypass coolant filter? by chance did you pinch a heater hose during the HPOP install?

I do...and as far as I can tell I didn't. Here's the kicker for me. When I had the hammer down on the old girl, she puked out more than a gallon of coolant in a matter of 5-6 seconds. I just don't know of anything, besides boost, that can generate that kind of pressure that quickly. The two times I went to WOT it emptied the bottle down the side. The subsequent runs I put much less fire in the hole and only spit a little bit of coolant, but it doesn't build any pressure at all unless it's under boost on the road.

Originally Posted by tojoski

I don't think much, if any actually entered the cylinder.

It all ended up under the hood and down the side of the truck.

Are you re-torquing the heads this morning?

I agree. If this thing were blowing steam out the stacks, or if any of my fluids were cross contaminated I would be worried about it, but they are not.

I am re torquing the heads today, but I expect that it will not make much, if any difference.

According to Jeff I'm experiencing the early stages of a blown head gasket. He says if I continue to drive it that it will eventually degrade into more recognizable symptoms.

[Kwikkordead]

Yeah it really sounds like the heads are lifting.

[ernesteugene]

Head gaskets fail due to excessive CP=Cylinder Pressure. Is it possible that the IDM mod + the HPOP mod + a HP chip with an injection timing curve that doesn't take either of these mods into account is causing excessive CP?

The CP~{(KEg)(Ng)}/{CV} where KEg=kinetic ENERGY of each gas molecule, Ng=Number of gas molecules, and CV=Cylinder Volume. The KEg comes from the fuel's chemical ENERGY that's released during combustion so the KEg depends on the mass and atomization of fuel per injection and the Ng depends on the BP. In words this equation says that the CP is proportional to the total ENERGY density in the cylinder.

For a given BP and a given mass and atomization of fuel per injection advancing the injection timing causes the peak value of KEg to occur at a smaller value of CV and this increases the maximum value of CP.

For a given injection timing increasing the BP and or increasing the mass and atomization of fuel per injection increases the peak value of KEg for a given value of CV and this increases the maximum value of CP.

The IDM mod and the HPOP mod alone combine to advance the injection timing and increase the mass and atomization of fuel per injection and when these mods are combined with a HP chip that's independently increasing the mass of fuel per injection and advancing the injection timing the potential exists for excessive CP that leads to compromised head gaskets.

From the graph below which gives an "overview picture" of the RWHP that's required to overcome aerodynamic drag and rolling resistance for a number of different trucks you see that for an air temperature of 70 F it take 310 RWHP for an F350 to do 114 MPH on the flat with no head or tail wind.

That 310 RWHP corresponds to about 375 FWHP and "still pulling strong at 114 MPH" probably corresponds to at least an additional 75 FWHP for a total of 450 FWHP which is 80% higher than the stock rating of 250 FWHP.

So it wouldn't surprise me if a stock head gasket failed under these conditions where my ballpark estimate is that your peak CP is at least 2,850 psi and possibly 3,000 psi or higher if the injection timing is too far advanced and this compares to a CP of about 1,575 psi for a stock engine.

[F250_]

I've been learnign some interesting things regarding bolt torquing the last couple of days, and have been planning on putting together a brief discourse on the subject for group review and discussion... some very facscinating phenomena goes into the whole science of tightening a bolt, and a lot of it remains either "mis-understood" or "completely NOT understood" by most of us.

Point is... if you're getting movement on your bolts at "less than recommended" torque readings, you probably have either bolt stretch or loosening that will give your heads enough room to move a little. Add to that the issue of high rpm under load, and you have created a thermal condition which allows the "already not tight enough" bolt to elongate.... get the picture?

Essentially, the whole issue of setting the proper torque on a bolted connection is to take the bolt to a "tight enough" condition where the bolt remains within its "plastic" region, which means it actually acts like a loaded spring to keep adequate tension on the bolted joint (beads to block in this case) and the joint is not compromised by the effect of bolt elongation due to high temps. I would suggest that you get more heat soak into the engine block and heads when running down the road under load as compared to the throttle-down effort in the driveway, and that could easily be part of why you see it on the road and not in your driveway.

[ernesteugene]

The CE=Coefficient of Expansion in units of 10^-6 in/in/deg F is CE=5.9 for cast iron, CE=7.3 for steel, and CE=8.0 to 9.6 for various grades of stainless steel.

So as the temperature of the head increases from a 70 F ambient to 200 F a 6 in height of cast iron expands by a length Lc={(5.9x10^-6)(6)(130)}=0.005 in and a 6 in steel bolt expands by a length Lb=0.006 in and a stainless steel bolt expands by as much as 0.007 in!

[F250_]

Seems like a potential .001" to .002" gap between the head and the block could result in some real leakage.

[bdrummonds]

Originally Posted by F250_

Seems like a potential .001" to .002" gap between the head and the block could result in some real leakage.

And here I was thinking that maybe his coolant filter was clogged, and overly bypassing the coolant back to the degas bottle.

Thats good stuff Gene and Pete.