Blown SOHC head gasket *PICS*

[shelbygt]

After deciding that my head gasket was blown (see thread) http://www.explorerforum.com/forums/showthread.php?t=270522

I removed the head to find no visible damage to the gasket. Is it posible that it still failed and I just can't see the place where it failed? The motor never overheated, so I can't imagine that the head was warped and even then, shouldn't I see a burnt area where the cylinder was leaking?

It is obvious that the cylinder was burning coolant as evident by the cleaned piston top....

 

[2000StreetRod]

Coolant in #5 cylinder

As I recall, in your other thread you stated that you found coolant when you removed the spark plug in #5 cylinder but to your knowledge the engine had never overheated. I assume the photos are of the left bank.

Were any of the head bolts loose or broken when you removed them? Is there any area of the gasket that seems compressed less than the rest? It appears from the photo that the metal ring around the cylinder is intact. I can't be sure but the second photo may indicate there was a leak between the gasket and the head from the two coolant passages on the spark plug side. I would also check closely for a crack in the head near the edge of the intake valve farthest from the exhaust valve. There are spray leak detectors that you can purchase that will highlight (by staining) a crack after the head is cleaned.

 

[shelbygt]

Nope, no broken or loose bolts. The gasket itself is made up of what looks like 4 sheets of metal riveted together, that you can pull apart, but I see no evidence that it was compromised anywhere. I will get out there and clean it all up and see if anything else shows up. I would think (from seeing fiber and metal head gaskets blown) that there would be an obvious defect somewhere.
I'd hate to put this back together without finding the source of the breach.

 

[shelbygt]

more pics

Here are 2 shots after I cleaned up the mating surface.

This shot is the only spot where it may be suspect. The discoloration goes just past the outer ring of where the gasket rings were. Does this seem like a feasible failure, although, no damage appears on the gasket itself?

 

[shelbygt]

And another

The suspect cylinder is in the middle

 

[2000StreetRod]

Head flat?

Have you checked to see if the head is flat/warped using a straight edge and feeler gauge?

 

[shelbygt]

I tried laying a straight edge on it with a light behind it and it looks flat, but the metal ruler I have may not be perfect and that is all I have here to check it with.


While cleaning the head, I pulled the fuel injectors out and noticed that the rubber that fits into the head is cracked. Do they sell these at the local parts store? I can't find it on Tasca Ford's site.

I may have to eat it and take the head in to the machine shop and get checked out...more money $$ of course . I may have been better off getting a used motor and hoping for the best, I really expected to find some kind of head gasket damage. I hate to button it all back up, not knowing the cause only to have it leak again and have to pull it all apart and have to buy new bolts and gaskets again. The frustration level is on it's way up!

 

[manaen]

it may be time to magnaflux the head and block to see if there are any cracks.

That spot you pointed out does look suspect but the ring area around the block looks sealed.

Good luck finding those seals for the injectors. when I had my injectors cleaned they could not find me replacement gaskets. unfortunatly it turned out I needed to replace my engine as well (long story) so I ended up getting an entire package from a junk yard. but I know I will need to find a set some day...

 

[shelbygt]

Yeah Rusty... I plan to take the head to the machine guy that did my Shelby motor and see what he thinks. Since the head is aluminum, I would think they would not be able to magna-flux it. Wouldn't the block need to be stripped down to check for cracks?

I read on a site http://www.aa1car.com/library/gasket_failure.htm that on these multi-layer steel gaskets you would check for failure by measuring the thickness around the cylinder wall part of the gasket with a micrometer.

If I can't find the rubber injector insert, I will use gas resistant adhesive to seal up the crack and hope it doesn't leak and burn the truck to the ground.

 

[2000StreetRod]

Zyglo inspection

Zyglo inspection (black/ultraviolet light) is performed instead of magnafluxing on nonferous materials such as aluminum.

Crown used to make a complete set of crack detection sprays: fault-finder cleaner, fault-finder penetrant and fault-finder developer. I don't know if it (or an equivalent) is still available.

I did a search on Crown and found a link. It's not cheap ($81) for a set. You're better off going to your machinist.

Fault Finder Inspection Marking Kit (Crown)

I remember a past post about a member trying to find those injector insulators. He ended up installing the injectors without them. I believe the upper and lower O rings are all that's required to seal the fuel. I think the cup is just for sound and heat insulation. Injectors can be susceptible to heat soaking causing starting problems after short trips.

 

[2000StreetRod]

injector cap?

Linder Technical Services specializes in hard to find fuel injector parts. I don't know if they sell direct retail but you might give them a call at 888-809-3835 or email info@lindertech.com

 

[shelbygt]

Been to the machine shop....

My machine guy confirmed it is a blown head gasket. He said these OHC aluminum heads are notorious for what mine look like. He said he gets them like this from the local car dealerships when they overheat and blow all the time. Apparently the metal gasket will not show any signs of damage unless a catastrophic failure happens which is very unlikely. He explained that the center cylinders are usually the ones to go because the head flexes outwards from the center when overheated. If you look at the pictures I posted prior, you can see that the center coolant passages discolorations are creeping towards the cylinder opening and this is where he says the problem is. What is crazy is that I have had the truck for 3 years and put well over 60k miles on it and it never overheated, but it just now let go. He explained that if the one head went, it is certain the other will blow a gasket also, it's just a matter of how soon, since you can't half overheat the engine. Either the head flexed, or the bolts stretched, from coolant overheating or high combustion chamber temps (detonation).

He is going to clean, pressure test and resurface the mating surface for 50.00 per head. He said it is very unlikely that the block will have any issues, as they rarely fail unless oil starved.

I found the rubber insulators at my local Ford for $5.60 each, so once I get them I will confirm that they are correct. I saw the diagram he ordered from and I am 99% sure they are correct.

Here is what I have now, a short block...YIKES!

 

[2000StreetRod]

right choice

It sounds like you made the right choice when you decided to pull both heads. I doubt that the gasket blew due to detonation if your knock sensor is functional.

I'm glad you found a source for the injector insulators.

 

[ranger7ltr]

Question on the machining work to be done...

Will the camshaft bores need to be line bored after the resurfacing to keep them true? I have always had to have the camshaft supports realigned after head work on an ohc head...

Maybe this is not the case since the head is just being resurfaced...

One more item...Your engine seems to in excellent shape oil sludge wise...What oil are you using in this engine??? This is one of the cleanest higher mileage Ford engines I have ever seen internally...My Explorer engine looked like hell 16k ago when I pulled the oil pan to replace the oil pump and the right valve cover to reposition one of the pushrods that had come out of the rocker arm since the rocker stuck open thanks to sludge in the top end...

I am replacing both heads, the timing chain, and the oil pan gasket on my OHV next month so I am really curious to see if running synthetic oil all of that 16k I have driven it made any difference...

Thanks for the pictures and the updates on your progress Shelbygt...Even though I run an ohv engine right now I am always interested in the issues the other half runs into...

 

[manaen]

There's something very sexy about seeing a short block on an engine stand... OK maybe not sexy but it is darn cool, every guy should have at least one sitting around..

Man I forgot these head are aluminum, geesh that makes all the difference..

hey post a part number for those rubber grommets when you get the packaging...

 

[viking74]

What's the part number for those injector insulators?

Hi There:

Good luck on the engine build! I also need those fuel injector insulators as I have some cracked ones. Could you tell me what the part number is on those that you ordered from Ford? Much appreciated. Thanks!

 

[shelbygt]

Well I decided after talking with the machine guy that the heads needed to be broke down, re sealed and the valves reseated. The leak down test showed all but 3 valves failed miserably. The valves were so filled with carbon, that they were not seating at all. I brought the second head in today and he broke it down in front of me and you can see where the gases were bypassing the seal and burning past the valve, not to mention all the carbon buildup. He also said it was a good thing, that the lifters were filled with murky water/oil from the gasket failure and that the water could rust the lifter's internal parts and could cause a lifter to seize if I ran it uncleaned.
Total cost is 260.00 to do both heads.

Just an FYI: I asked him what he thought of running Seafoam in the intake to burn the carbon off and he explained that the stuff does what it says and cleans the "gunk" off the parts, but where is the "gunk" going once it come off? He said that he has seen it where carbon has come off and entered the valves and cause major blow-by and eventually burns up a valve like a blow torch was taken to it. I have known this guy for well over 20 years and he knows his stuff and he wouldn't steer me wrong, so I thought I would pass this along.

Not sure about what is needs to do to the cams, but he said that I will get the heads back ready to bolt on.

On the oil... the funny thing is that I usually buy whatever brand name oil is on sale at the time...no synthetics here. I just make sure to change every 3-5k miles or whenever the on-board computer says it is time....LOL
Running a stock temp thermostat as well in Florida, maybe that has something to do with it?

I know that pics help immensely for reference, so I hope that maybe these pics might help someone out along the way. If I feel up to it, I may take a step by step of reassembling the timing stuff....

The insulators were 5.48 each F77Z-9G512-AA

 

[2000StreetRod]

Carbon buildup

. . .
Just an FYI: I asked him what he thought of running Seafoam in the intake to burn the carbon off and he explained that the stuff does what it says and cleans the "gunk" off the parts, but where is the "gunk" going once it come off? He said that he has seen it where carbon has come off and entered the valves and cause major blow-by and eventually burns up a valve like a blow torch was taken to it. . . .

I totally agree. My Bosch fuel injection book warns about using fuel injector cleaner that cleans the injectors but promotes carbon buildup on the valves. When Volvo went to fuel injection the only injector cleaner they endorsed was Techron. That's the only brand I use. Many members have mentioned having to replace their spark plugs after burning SeaFoam. I refuse to burn the stuff.

 

[McSlug]

Can you tell me what size bolts you used to mount your engine to the stand.
I bought a second hand engine that I want to rebuild and don't have the tranny bolts to use as a guide.

 

[2000StreetRod]

engine stand bolts

Can you tell me what size bolts you used to mount your engine to the stand.
I bought a second hand engine that I want to rebuild and don't have the tranny bolts to use as a guide.

The engine supports on my engine stand are two inches thick. I purchased four M10-1.50x75 hex cap screws grade 8.8. I wouldn't trust any grade 5 bolts for adequate strength. The bolts were just the right length with a washer inserted at the bolt head.