97 Cobra Blown Head Gasket Help/Tips

[YUNG VEEZU]

Thank you all for the tips again, today I made some good progress and some discoveries.

Got the crank pulley off with the puller tool:


Valve Covers off:


Timing Cover off:


I noticed that I accidentally broken the metal part of the heater hose that runs into the intake valley. Whoops.


Heads off:


Now! I did hear the popping sound when taking the head bolts off and each and every one of them. I took pictures with the gaskets on.

Here is the passengers side cylinders:

Here is the drivers side:


There is a little bit off coolant because as I was pulling the head off, part of the heater hose got caught on my shirt and I spilled a little everywhere. Now as you can see, the head gaskets are all intact.

What do you guys think? I'm no expert but I assumed they would like like this (picture from Google):

 

[YUNG VEEZU]

Good work man. Its a big project! Youre doing great labeling everything. Keep cataloging it all and their shouldnt be a problem reinstalling.

About the blown gasket. I dont recal reading your plans. A blown head gasket typically means machine work needed on mating surfaces. If your lucky enough to be the head surface, machining will be simple. The block needing the work will be a bummer. Now here is the important part. Paying attention removing each head bolt and how it acts at that first initial turn. Their should be a pop from the shock of the bolt unseating. If no pop, this means the likely blown area, because the head bolt has failed. And what causes a failure is over heating. The bolt loses its tensile from access heat its not designed for and stretches.

Now when removing the head, its important to keep track of how the head gasket laid. If you can remove the head, leaving the gasket intact on the block, then take some real good pictures of the head surface up close as well the gasket on the block.....we gonna get you through this right.

Everything tells a story. Reading gasket and mating surfaces can narrow down the initial problem and hopefully save you from shelling ample amounts of cash out. A blown head gasket between two soft aluminum surfaces is a grindge factor knowing both surfaces will "typically" need machining, BUT!!! Luck may be in your favor! The gaskets be completely attached to the surfaces eliminating machining and the gasket itself has de-laminated allowing coolant to slip between the multi layers of the gasket.

Reading the surfaces and head gasket is your best bet figuring this out. Take good quality pics of all the surfaces. Heads and block. Both sides of head gasket. We all here to help.

Initially I was just going to replace the headgasket, but now I'm going to do the oil pan gasket as well as every other gasket such as the timing cover, header, intake gaskets. I'm going to take both heads to a machine shop this week too. I forgot to take a picture of the surfaces, I will take some more in a bit

 

[96blak54]

Wow! You understand the details! This is good!

The gaskets look pitiful! Was the car ever force feed or nitrous? Take a look at all the pistons. None of the pistons should have any bright areas. There should be carbon or tarnish look uniformly. Clean bright areas means water washing it. The washing affect is greater when engine temps are up. Basically steam cleaning. Both sides appear to be leaking.

Next question is if the engine has ever been apart? Is the flywheel 6 or 8 bolt? Get a good close up of one chamber of the cylinder head. I can confirm if the are in deed cobra or mark8.

I realize this is alot of questions. I also feel good you will accomplish your goals!

 

[YUNG VEEZU]

Wow! You understand the details! This is good!

The gaskets look pitiful! Was the car ever force feed or nitrous? Take a look at all the pistons. None of the pistons should have any bright areas. There should be carbon or tarnish look uniformly. Clean bright areas means water washing it. The washing affect is greater when engine temps are up. Basically steam cleaning. Both sides appear to be leaking.

Next question is if the engine has ever been apart? Is the flywheel 6 or 8 bolt? Get a good close up of one chamber of the cylinder head. I can confirm if the are in deed cobra or mark8.

I realize this is alot of questions. I also feel good you will accomplish your goals!

Thanks!!

So originally when I bought the car in 2012 the previous owner said he had a kennebell and different heads on it for a few months, then reverted it back to stock.

Here is a better picture of the old gaskets:

Drivers side faced down:


Drivers side faced up:


Passenger side faced down:


Passenger side faced up:
[url=https://postimage.org]

I took a bunch of pictures of the pistons but I forgot to take the towels off of them. But the flywheel.........I honestly have no idea. I will take a lot of more pictures tomorrow to confirm

 

[96blak54]

Yea, those gaskets scream leaks! Particularly bewtween the bores. The deck side appears better, but I wouldnt chance it. If I can judge it by a picture, its bad!

Seeing if the flywheel is 6 or 8 bolt will tell us what block you most likely have. 6bolt is a cast iron crank while 8bolt is cobra specific forged crank. Yours should be cobra specific. A pic of the cylinder chamber will tell us if the heads are indeed cobra.

 

[YUNG VEEZU]

Took the cylinder heads to the machine shop today. The guys over at Rescino Performance here in San Francisco were real cool.

Here are the pictures of the drivers side, from the front of the motor towards the back (don't mind the small debris, they fell in there while I was taking pictures):





passengers side from the rear of the motor towards the front:




I start to clean up the surfaces just a bit, using a non-scratch scotch-brite pad, and some CRC brake cleaner. How does it look? I didn't take a lot of pictures, I was real busy scrubbing and cleaning the timing cover and valve covers as well.

Before:


After:


About 80% of the gasket material came off without a problem, but there was about 3 areas were the gasket "blew" in between the bores, were the material wouldn't come off. I didn't want to use a razor or anything harsh. What would you guys use? Does the surface have to be 100% clean?

Lastly, does anyone recognize or know the part # for the metal part of the heater hose? I accidentally broke it:

 

[96blak54]

The surface must be very clean! Take a razor blade stand up on the sharp edge and start scrubbing it. The aluminum could be discolored a bit from the blown gasket. If its gasket youre scraping, that's a good thing, but if its discolored aluminum. ..not so good. Great example of an engine deck needing machinined. Its possible it may not need to be machined, but youre gonna have to get a straight edge and some shims on it.

Tell us how far you want to take this. What vibe im getting is a simple headgasket swap...right? Im all about cost cutting and building smart. But judging by the blown gaskets, get the block machined too. Leave the bores alone, only a light hone. Grab some good piston rings and rebuild that boy!

 

[96blak54]

If you decide to skip machine work on them surfaces, I would suggest taking that razor blade and scratching up the surface all over. The surfaces need some roughness for the gaskets to adhere to. The scratchy surface will aid for surface roughness.

 

[MustangChris]

If you decide to skip machine work on them surfaces, I would suggest taking that razor blade and scratching up the surface all over. The surfaces need some roughness for the gaskets to adhere to. The scratchy surface will aid for surface roughness.

huh?

 

[96blak54]

We hat you mean "huh" ?

 

[MustangChris]

what surface are you suggesting he "scratch up all over"?

 

[YUNG VEEZU]

The surface must be very clean! Take a razor blade stand up on the sharp edge and start scrubbing it. The aluminum could be discolored a bit from the blown gasket. If its gasket youre scraping, that's a good thing, but if its discolored aluminum. ..not so good. Great example of an engine deck needing machinined. Its possible it may not need to be machined, but youre gonna have to get a straight edge and some shims on it.

Tell us how far you want to take this. What vibe im getting is a simple headgasket swap...right? Im all about cost cutting and building smart. But judging by the blown gaskets, get the block machined too. Leave the bores alone, only a light hone. Grab some good piston rings and rebuild that boy!

sorry for the late reply! Its been raining and I've been working a ton of overtime. But I was going to do just a headgasket swap, but I may put a new oil pan gasket, timing cover, valve cover, head and intake gaskets all around. I will use a razor blade and scrape down the blown areas. My cylinder heads are also finished, I just need to pick it up from the shop.

Also, Late Model Restoration, American Muscle or CJ Pony Parts didn't have the "heater tube" in between the intake valleys (which I broken), so they referred me to Todd at Prestige Mustang and for our SN95 Cobra years, he had a ton of stuff. I'd check them out if you needed anything out of the ordinary.

 

[4.6Stangrage]

sorry for the late reply! Its been raining and I've been working a ton of overtime. But I was going to do just a headgasket swap, but I may put a new oil pan gasket, timing cover, valve cover, head and intake gaskets all around. I will use a razor blade and scrape down the blown areas. My cylinder heads are also finished, I just need to pick it up from the shop.

Also, Late Model Restoration, American Muscle or CJ Pony Parts didn't have the "heater tube" in between the intake valleys (which I broken), so they referred me to Todd at Prestige Mustang and for our SN95 Cobra years, he had a ton of stuff. I'd check them out if you needed anything out of the ordinary.

I am enjoying reading this thread! The people on here are incredibly helpful and thats something to appreciate. Not all forums are like this! Anyways, in regard to head/ block prep I personally would use either a sharp straight razor blade with patience. I have heard some people use a fine grit sand paper with care. I think the main goal is to remove all the foreign material off of the block without removing material from block. Looks like you are on a solid path.

 

[96blak54]

what surface are you suggesting he "scratch up all over"?

If he doesnt send the block out for machining.

Suggested prep. Ensure surface is true by take a straight edge and shims to find untrue planer spots. Most times these areas are between bores. Cast iron blocks can be around .001-.002 while aluminum can tolerate up to .005.
Aluminums expansion continuous moving properties is why .005 is acceptable. BUY...if it were my money spending, id be 100% sure the block deck was flat.

Now about taking a razorblade...adding a scratchy surface. Alot of folks like to use scotchbrite in surface preparation. Not a good idea. Cleaning, yes. Scotchbrite reduces or eliminates the desired surface roughness needed for a gasket to adhere to. Smooth is not what you want. The surface needs peaks and valleys in bedded with in like 400 grit sandpapper would do, but we dont want "sand" anywhere near the engine...bad idea. So use a razorblade on its sharp edge and apply scratching to the surface. Not deep scratches, but noticeable imperfections. Not really a scratch your fingernail can drag on either. I qoute "the proper machined surface roughness is idea". But if youre like me pinching pennies, you find away. After cleaning the block surface, youll have reduced the original roughness. This is where the scratching comes in.

Having the proper peaks and valleys, better know as surface roughness, allows the head gasket to securely adhere. A smoother surface and the outer contact of the headgasket wouldnt mate properly.

 

[YUNG VEEZU]

Just an update! I know its been a couple of weeks but I've been busy with work and a pregnant girlfriend.

Picked up the heads from the shop, look at that smooth surface:


I also ordered the heater tube from Prestige Mustang for about $100 plus shipping. I'm going to finish up getting the gasket material off the engine surface, do some last minute cleaning, then begin to put her all together. I plan on getting her running within the next couple of months

 

[YUNG VEEZU]

Finally had time to clean the surface of the top deck, and got some of this:




and did a test fit on the head gaskets:


Now for the reinstallation of the heads, I put high-temp threadlock on the head bolts correct?

 

[96blak54]

No!!
Dont use any thread lock. Use oil. The same oil you use in the engine, dip the tip of the bolt in the oil then proceed. Getting oil on the threads is the idea.

 

[MustangChris]

For those who are curious about putting a lubricant on a bolt (that obviously needs to stay where it lives):

The oil allows the bolt to be torqued to an accurate rating. You wont be fighting the friction between the threads and the bolt when tightening, allowing for a more accurate read. Considering these are TTY bolts, you'll be stretching the bolts anyways.

 

[YUNG VEEZU]

Just to update, I am still alive! I'm still in the process of reassembling everything, but its been raining here and I've been working OT

 

[96blak54]

Be sure when reassembly, to grind off the left half portion of the exhaust cam sprocket key. Then reassemble with cam loaded against the ground portion



Dont pay any attention to me...lol. Glad you reported. Keep going, youre doing good!