Swapping heads 99 cobra

[Jared Tyler]

Can anyone help me with this question? I have a 99 cobra and one of my spark plugs blew out and now one of the heads is unusable. My question is can I throw any C style head on there? Preferably the one that has 9 threads from the 04 cobra. Or does it have to be the same head that was on there? Thanks

 

[wkornf]

heads from anywhere. I used aviators on mine

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[GodStang]

Can anyone help me with this question? I have a 99 cobra and one of my spark plugs blew out and now one of the heads is unusable. My question is can I throw any C style head on there? Preferably the one that has 9 threads from the 04 cobra. Or does it have to be the same head that was on there? Thanks

Are you doing one head or both? The 99-01 head and the 03-04 Cobra/Mach 1/Aviator heads are not the same and have different flow rates, cooling passages, and oil passages. I mean technically you could bolt one of each type but I would personally want matching heads.

 

[shurur]

If just the threads on the original head is stripped, the head can be fixed with inserts,
Otherwise, as said above, I would want a matched pair of heads.

And do the Head Cooling Mod (HCM) for piece of mind.

 

[Jared Tyler]

I plan on replacing both heads. I just don’t want to put the same shitty 4 thread heads on there. Was just wondering what options I had for the different year heads. I know my car is 52 cc and the 04 is 54 cc so I wasn’t sure if it would work

 

[shurur]

I plan on replacing both heads. I just don’t want to put the same shitty 4 thread heads on there. Was just wondering what options I had for the different year heads. I know my car is 52 cc and the 04 is 54 cc so I wasn’t sure if it would work

The threads can be fixed with inserts and will give you the 6 threads that you want,
It may be cheaper to get new heads...

But if it is just the threads that need fixing, I would look into that first.

 

[01yellercobra]

I ran 4 thread heads on my big bore set up. It had an F1A making 19psi. The only time I had an issue was when I was in a hurry and cross threaded one of the plugs. Naturally that's the one that spit out. I Timeserted that one and never had another issue.

 

[FIREBALL]

The cost to repair the stripped holes with inserts does not even come close to the cost of new heads unless your having a shop do all the work.
Here is the deal with the spark plug threads---yes Ford didnt put enough threads in, but the real problem wasnt enough threads but not enough torque. Ford thought that because they are aluminum heads they better keep the spark plug torque low, but that is really what has caused most of the problem with sprark plugs blowing out. What happens is with the 14 lb. factory torque, the spark plugs start to back out and finally when they get to the last thread they blow out. The solution is to torque the plugs down to 28lb and in the greater majority of time that stops it from happening. The kits with the solid steel inserts (not helicoil) are the only ones to use to fix the threads. They coast around $250 which includes several new inserts. I had to do two of them on my F150 but since Ive torqued my plugs down to 28lb I have not had another blowout and when I replaced my Cobra plugs they all got torqued down to 28lb. Now if you just want better more efficient heads, thats a different story.

Here is the kit I used. Mountain 9200 4.6, 5.4, 6.8 Ford 2V Spark Plug Insert Installer | Hard to Find Automotive Specialty Tools
I did my F150 head while still on the truck, that was quite a challenge.

 

[scottydsntknow]

I dunno I've had multiple modulars over the years and the only time I had issues was when I got a car where some previous owner had overtorqued them. 15ft lbs with anti seize and never a single issue. Currently shift a junkyard 4V at around 7k and its got 4 thread plugs and 0 issues at all. Been a few years now since I did the plugs.

 

[FIREBALL]

Yeah some get lucky with factory torque, but if there are issues with somebody over torquing them its probably because they didnt use a torque wrench and just tighten them up till it felt good which was probably way over 28 lb. The 28lb solution has been used by many on the F150s with no problems. Even 28lb is really not that much. And yes its good to use a dab of anti seize on all plugs. My two original factory torqued plugs on the F150 blew out around 45k miles.

 

[shurur]

I ran 4 thread heads on my big bore set up. It had an F1A making 19psi. The only time I had an issue was when I was in a hurry and cross threaded one of the plugs. Naturally that's the one that spit out. I Timeserted that one and never had another issue.

I put my plugs on the end of a 5/8" ID hose to help keep it lined up for the first few turns.
Then I just pull the hose out. It helps keep the threads from getting cross threaded.

 

[DSG2003Mach1]

1) dont use steel inserts in an aluminum head, they have aluminum inserts, use those

Personally, I'd just have your current threads fixed with lock n stitch or time certs (both have mechanical means to prevent the insert from backing out unlike a helicoil). If the car is higher mileage then might be a good idea to do valve seals etc... This is what we did on my car when building motor, and it's supposed to have been built with 25psi in mind.

 

[01yellercobra]

I put my plugs on the end of a 5/8" ID hose to help keep it lined up for the first few turns.
Then I just pull the hose out. It helps keep the threads from getting cross threaded.

I was in a hurry/being lazy. I didn't remove the intake pipe which caused my extension to be just a little crooked. I had to get back to work so I ran it. Live and learn.

 

[FIREBALL]

1) dont use steel inserts in an aluminum head, they have aluminum inserts, use those

Personally, I'd just have your current threads fixed with lock n stitch or time certs (both have mechanical means to prevent the insert from backing out unlike a helicoil). If the car is higher mileage then might be a good idea to do valve seals etc... This is what we did on my car when building motor, and it's supposed to have been built with 25psi in mind.

Specifically what kit has aluminum inserts, it normally has to be steel to cut into the aluminum, Ive been running my steel inserts from kit I posted earlier, no problems in 50k miles and havent heard anyone that has. Lock and stich?----time certs? never heard of them. The steel inserts are there to stay and you wont have any more problems with blown plugs or striped threads.

 

[DSG2003Mach1]

Specifically what kit has aluminum inserts, it normally has to be steel to cut into the aluminum, Ive been running my steel inserts from kit I posted earlier, no problems in 50k miles and havent heard anyone that has. Lock and stich?----time certs? never heard of them. The steel inserts are there to stay and you wont have any more problems with blown plugs or striped threads.

The kits I’m talking about use a tool to cut the holes for the inserts to screw into. Both brands offer aluminum inserts. Steel inserts in an aluminum head can cause hot spots in the chamber. I know some 2 valve guys had big issues with this.

 

[jrgoffin]

Head info, plus links regarding the spark plug repair: Castings

 

[david ace]

Can anyone help me with this question? I have a 99 cobra and one of my spark plugs blew out and now one of the heads is unusable. My question is can I throw any C style head on there? Preferably the one that has 9 threads from the 04 cobra. Or does it have to be the same head that was on there? Thanks

I know this has nothing to do with the issue you are discussing but since u have a 99 cobra I wanted to let u know that I have one of the black leather apology jackets that was given to the original owners of the 99 cobras by Ford. Didn't know if u had one or not or if u even knew about the jacket. I know a lot of the guys that own these cars now don't know about them. Anyway one was given that year with a patch inside the jacket with the vin number of its matching car stamped on it. I'm looking to sell the one I have. I don't own a cobra and never have. If u are interested let me know and I will send u some pics. Thank you

 

[98 svt]

Not sure how many threads in the B heads, buy I tossed a plug about 10 years ago in my 98. It blew the driver's side hood snorkel clean off the car too.