Adivanman

I concur...There is no indication that there was any detonation (no scarring on the pistons, ect). It definately did get hot based upon the discoloration of the cylinder walls and the gaskets. Heat would seem most likely in this case.

Three Days Only

Thanks to everyone that has checked this out. Im not sure about the overheating. Could the gasket just have fryed due to the heat from combustion and finally gave out causing the flame to travel back and forth, or is this way out of line. Im not a motor guy so bare with me!!!!

Vinny P

TDO,

NO, the head gaskets are designed to take the heat of NORMAL combustion. They would not fail under normal conditions. Something very wrong happened here. As was said, simply replacing the head gaskets, regardless of what type you use, will most likely lead to disaster again. The real cause of the failure has to be found.

dhlaw

An interesting point to consider... when I had my heads redone due to poor leak down results the top end guy noticed something puzzling. The water transfer passages coming from the block on the center cylinders up to the heads was blocked by flashing from the original casting. He said that he had to drill them out(lightly). Ironically the center two cylinders on both of my motors had damaged the valve seats due to heat. He suspects that there was insufficient water flow due to this blockage. He also worked on another set of 502's and found the same thing. The guy was Eickerts top end builder and really knows his stuff..... I wonder if there is a defect on some of the blocks.

Ted G

Sorry for the delay in getting back to you on this. I concur with everyone else about the overheat. The portions of head gasket burned across but not missing material indicate that the heads were warped at the time of failure. Since the are cast iron they may have flattened back out, but I would bet they are still warped. I suspect this engine overheated and the fresh water running around the temp sender gave you a false reading. Do you use crossovers or the stock thermostat housing/pump setup? You have to find out the root cause or the failure will reoccur.

Whipple Charged

It really sounds like you have 1 or 2 possible problems. I'm assuming fuel psi is in stock parameters and ocatne is at least 87.

First is water PSI. 15-17psi is low. Mercury Racing has a bulletin that calls for 25psi. I'm assuming you have a Spectre which runs high X dimensions. If you have the Mercury dual pickups on the drive, the side inlets release pressure. They can also suck air if there exposed to air. Plug them with 1/16" pipe plugs and you'll gain 5-8psi which is important.

Detonation is what caused the head gasket failure, if it burnt a piston, that was temp. The temp could have been from the detonation or from being lean which would've promoted detonation. I would assume that it was lean which then caused detonation which in turn creating tremendous heat and pressure. Pressure lifted the head, heat burnt the piston. From my experiance, the valves usually have a lot of damage if it's water related such as a steam pocket.

Thanks,
Dustin

FlyFast

I too have overheated at wot with a normal indication on the guage. I lost a exhaust valve seat in #3.

This is what happen to my sbc. The stock merc gasket blocks the steam holes between the block and the heads. the fel pro marine gasket has a hole to relieve the steam pressure.

Is the stock merc gasket that failed blocking any steam holes?

Joe

Are you saying a bad fuel pump could have caused this? If you look back toward the top of the link, I commented on having the same problem, but caught it (was lucky enough) before burning the bottom.

Just buttoned mine back up yesterday. New top end and all is fine. My gasket looked identical to 3DO's.

Nordicflame

Well, since these pictures looked so familiar I had to jump in.
I thought we could compare and maybe help diagnose. Mine’s a bit worse but I was running quite a bit of boost also.
I lost substantial water pressure during, or just before, a wide open run and 9 lbs of boost.
The results are what follow.
The pictures show #6 damage results. The Super Alloy exhaust valve was welded in the seat, which in turn broke the push rod, which then broke the intake push rod.
My head gasket shows a lot of bypass from 6 to 4, 4 to 2, 5 to 7 etc….
My gaskets, although they never blew the fire ring had blown the composite material on 2, 6 and 7 right into the lifter valley. This had probably been happening for some time because I would occasionally get a big blow by issue when under heavy boost.

Anyway, I’ve concluded that water (lack of) was my issue.
Number 5 piston was also damaged as was #2 with the rings butted and froze on both of those. More likely a result and not the cause although they were never gapped for a blown application.

Normal cruise water pressure is 13-15 lbs. When we limped back 12 miles on 5 or 6 cylinders at 3300 rpm cruise, I had 5-6 lbs. I never happened to peek at the pressure gauge before nailing the sticks but I’m sure that if I had, I wouldn’t have.
Dave

Nordicflame

Chamber #6