Head Gasket Replacement

[03svt_snake]

Hello Everyone,

New to the forum, this is my first post. I have a 1994 Cobra, but picked up a 2003 Cobra a couple weeks ago. I got kind of hosed on it because I bought it off eBay with only 47,000 miles, but it had an undisclosed head gasket leak on the passenger side.

The previous owner replaced the driver side head because of loose valve issues about a year ago, but despite him swearing up and down he did, I don't think the passenger side head was pulled off to check for issues or replace the head gasket on that side.

About a week ago I pulled all the plugs and found water on the number one plug and a couple days ago I took it to a shop and had them do a block test. It came back positive for combustion gases in the coolant and you can smell it in the overflow.

I think the shop that tuned the car for the modifications it currently has made the timing way too advanced even for 93 octane, which is probably what caused the leak.

Anyways, I'm wondering what is the best way to do this job? I'm guessing it is to drop the whole engine, but can it be done with the engine still in the car or pulling it out the top?

I have access to a lift at my parents' house, but possibly not for a couple of months because of another car occupying it. I'd like to get it done sooner if possible.

Also, what shop is better for having someone refresh the heads on these cars? MMR or Modular Head Shop (MHS)? MHS is way more expensive, but some of the reviews for MMR online scare me.

I'm pretty new to the modular scene, but have been working on cars for 12 years.

I couldn't find a how-to on this job, which is why I'm posting it here. Thank you in advance.

 

[geoffmt]

I have had great service with MMR. Their port work on my heads was great.

 

[hotcobra03]

I used oem bolts and gasket..

Sent head to local machine shop..had it pressure checked .valves cut and resurface..

It can be done over fender..worst part is lower caged pulley. .you will need to remove drivers valve cover..

I did both in and out..

I feel out engine out was a lot better..and made lower pulley a lot easier ..

Site has full ford service manual download for instructions..

 

[03svt_snake]

I used oem bolts and gasket..

Sent head to local machine shop..had it pressure checked .valves cut and resurface..

It can be done over fender..worst part is lower caged pulley. .you will need to remove drivers valve cover..

I did both in and out..

I feel out engine out was a lot better..and made lower pulley a lot easier ..

Site has full ford service manual download for instructions..

Car has an aftermarket lower pulley if that makes it easier, but it also has longtubes. How many hours did it take you with the engine in the car? I'm guessing I should still pull both heads and do both gaskets to be safe? Thanks.

 

[badcobra]

It's much easier to pull the motor and do on a stand. Also, just because there was water where the plugs are does not mean a bad head gasket. This happens frequently on these cars when someone pressure sprays the engine....especially when they are trying to clean it up and get it ready to sell.

I know you had a block test done, but what are the other symptoms of a head gasket issue? Is it pushing coolant out the overflow? Is it overheating?

 

[jrgoffin]

Here's a large build thread that will help:

http://www.modularfords.com/threads/236857-Aluminator-Gibtec-Build

If you aren't sure about the passenger side head having been replaced, simply look at the casting number:

http://www.terminator-cobra.com/castings.htm

 

[03svt_snake]

It's much easier to pull the motor and do on a stand. Also, just because there was water where the plugs are does not mean a bad head gasket. This happens frequently on these cars when someone pressure sprays the engine....especially when they are trying to clean it up and get it ready to sell.

I know you had a block test done, but what are the other symptoms of a head gasket issue? Is it pushing coolant out the overflow? Is it overheating?

Water was only on the threads. It overheats pretty badly, randomly stumbles, and shaking over 5k. If combustion gases are in the coolant, what else could it really be? I don't think a cracked intercooler would cause that.

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[badcobra]

Water was only on the threads. It overheats pretty badly, randomly stumbles, and shaking over 5k. If combustion gases are in the coolant, what else could it really be? I don't think a cracked intercooler would cause that.

You could have a cracked cylinder too. Bottom line is you need to pull the motor out and pull the heads off and inspect. If it overheated badly, you'll probably need the heads resurfaced. You'll have to inspect each cylinder for cracks when it's apart.

 

[03svt_snake]

You could have a cracked cylinder too. Bottom line is you need to pull the motor out and pull the heads off and inspect. If it overheated badly, you'll probably need the heads resurfaced. You'll have to inspect each cylinder for cracks when it's apart.

How often do these crack cylinders with the iron block? I know they can crack pistons, but I haven't heard of that. I've had a motor with a cracked piston before though, and it ran much worse than this car. It only got to about 245.

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[badcobra]

I've definitely seen pics of cracked liners here. Most of the time when a head gasket is blown, it pushes coolant out the overflow and doesn't enter into the cylinder. If you have water in your oil, I would definitely do all the due diligence.

 

[Black02GT]

I managed to crack my head between intake and exhaust valves on #2. Water in the cylinder and in the oil... fun times. Hopefully you'll get lucky and it'll just be the gasket and resurface.

 

[Juiced46]

Here is a link below to a very good thread discussing cracked blocks. Head gasket issues are not very common on these cars. Unless someone has been in there and did a shoddy repair (in your case this may be true) However, I have seen more cracked blocks on these cars then headgasket problems and I have worked on many of these cars since they were new.

I would pull the engine and tear it down and inspect.

http://www.modularfords.com/threads/252202-Where-is-the-boundary-for-the-factory-block

 

[03svt_snake]

Here is a link below to a very good thread discussing cracked blocks. Head gasket issues are not very common on these cars. Unless someone has been in there and did a shoddy repair (in your case this may be true) However, I have seen more cracked blocks on these cars then headgasket problems and I have worked on many of these cars since they were new.

I would pull the engine and tear it down and inspect.

http://www.modularfords.com/threads/252202-Where-is-the-boundary-for-the-factory-block

What kind of power levels were most those cars at? From that thread, it seems like most the cars were in the 650-700 rwhp area when they cracked. This car only made 470. I think it was likely abused a lot by one of the previous owners so I'm definitely going to check it, but judging by that thread it doesn't seem like it was making enough hp to crack.

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[Juiced46]

Its more tune related than power related.

 

[03svt_snake]

Its more tune related than power related.

I see, this car did have a stupid amount of timing. I sure hope that isn't the case . I guess I'll find out.

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[Shadow Grey 03]

What's a stupid amount of timing?

 

[03svt_snake]

What's a stupid amount of timing?

Only logged it on HP Tuners up to 5,200, but said 26 degrees total at that rpm on a 93 octane tune.

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[Shadow Grey 03]

Only logged it on HP Tuners up to 5,200, but said 26 degrees total at that rpm on a 93 octane tune.

Sent from my Nexus 6 using the svtperformance.com mobile app

Haha. Ok. Only go with that timing on e85. Damn.

 

[speedoflife]

Only logged it on HP Tuners up to 5,200, but said 26 degrees total at that rpm on a 93 octane tune.

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That's a lot of timing.
Hopefully all is well.