03 cobra low compression on just one cylinder

[topless03svt]

im with you hotcobra. Depending on the estimate I may just install a new head. The passengers side doesnt really even need any attention but i figured why have 1 head brand new or at least with all new parts and not do the other. Thanks for everyones help and response. b dike, I would bet my paycheck that your rings are fine. If it was the passengers side you may have more reason to worry but since its the drivers side like EVERYONE else.... i would def say valves are the issue. I couldnt visibly see anything wrong with the valves when I removed the head but a quick look at the cylinder told me I was OK there. Good luck on yours.

 

[333arod333]

So topless how easy was it to remove ur head in-car? Anything in particular, did u just take the brake booster out of way and go at it? I'm thinking I want to try doing this bc I think it's my problem but many are saying to just yank engine and redo the whole thing. I don't hav the money tho... and I'm pretty sure piston rings r ok.

What about cam timing when u put em back in? Was that a bitch? What was that about anyway, piston 1 at tdc when removing and same when installing? Any "special" tools u needed to remove head that service manuals say to buy?

How did u inspect the piston, what did u look for? How did u know they were in perfect shape? Dont u hav to get a look at side of cylindr wall?

Thanks a lot for the help!

 

[b_dike]

Thanks Topless same to you.

 

[topless03svt]

it wasn't too bad with the motor still in the car. Did basically what you said. Removed the brake booster and went to town. I havent gotten the heads back yet so i havent had to re time it yet. Luckily I have a good friend who has had more mustangs than I own underwear. Including two 03 cobras. He is going to help on the re-assembly and is also going to instruct me in timing it. I was newver a good book or instructions learner.....lol So a hands on tutorial works better for me. If he shows me any tips or anything that may help that the instructions arent clear on ill let you know. Im just ready to get it back on the road. I only got to drive it 3 or 4 times before tearing it down. :cryying:

 

[333arod333]

Damn 3 or 4 times that sucks! I guess I will go for it too then and mark timing spots with nail polish or something. How do I inspect the piston Though, just rotate crank until i can see cyl wall and top piston rings?

If rings all ****ed up its going to Ironhand racing. That guy is so legit and has really helped me out through all this. Much love Ironhand!

 

[01cobravortech]

Update.... Got the heads off. Thankfully the piston/cylinder were in perfect shape. No wear or ring play. Close inspection on head revealed valves not seating on the #6 cylinder . Heads are at the machine shop now. Still waitng on a call from them. What was the biggest shocker was the amount of heat showed by this head compared to the passenger side head. Every component associated with the drivers side just showed a ridiculous amount of heat. I know the drivers side head causes more heat due to the way the coolant flows in the head. A cooling mod is def going on after I get the heads back. Other than that. Im gonna throw a 2.8 pulley on it, get it tuned and drive it. Lowering springs and exhaust to come soon. :coolman:

Any pics of both heads??? Would love to see the comparison of the 2 and the indicators that confirmed that the driver side head "showed a ridiculous amount of heat." I was sold on running the head cooling mod simply because Ford redesigned the GT500 cooling system and provided an exit path for the coolant in the driver head, unlike the ones in the Terminators. Always made sense to do it.

 

[topless03svt]

To inspect the piston I just reinstalled the crankshaft bolt by by hand. Then turned the motor over with a ratchet/socket until that piston was all the way down. I felt the cylinder walls by hand. No gouges or scratching. I also made sure there was no ring/piston play by trying to wiggle the piston back and forth with the piston at the bottom and the top. No play what so ever. Now I know there are more precise tests you can perform but that was just a quick test. I didnt want to spend too nuch time fretting over the cylinder until I had the head/valves tested because I was still pretty sure that was my issue. But not feeling any rough gouges or scratches made me feel a lot better. Also, I got in there with a flash light and checked to see if the cross hatch marks were still visible. They were easily visible, so that told me I had very little if any cylinder wall worn down.

 

[topless03svt]

I wish I would have taken some pics before I sent the heads off. Im sure they will be cleaned up when I get them back. But if for some reason they arent cleaned or you can still see the difference I will take some pics and post them.

 

[hotcobra03]

I wish I would have taken some pics before I sent the heads off. Im sure they will be cleaned up when I get them back. But if for some reason they arent cleaned or you can still see the difference I will take some pics and post them.

your piston had no mark from valve?

whos gasket/bolt kit are you using?

i did fords..ouch

 

[topless03svt]

Yeah. I used fords as well. I was going to go with an APR head stud kit but just went with the motorsport head install kit. All gaskets and new tty bolts. I believe it was around 200.00 for everything. I also got cam tty bolts and the crankshaft bolt. As well as the front timing cover O rings, valve cover o ring and plug seals. Had to get the metal blower gasket also. It got bent coming off.

 

[hotcobra03]

Yeah. I used fords as well. I was going to go with an APR head stud kit but just went with the motorsport head install kit. All gaskets and new tty bolts. I believe it was around 200.00 for everything. I also got cam tty bolts and the crankshaft bolt. As well as the front timing cover O rings, valve cover o ring and plug seals. Had to get the metal blower gasket also. It got bent coming off.

that motorsport head changing kit..got any info about that..

the kit in ford racing wasnt for supercharged engine...unless they have 1 now...

i paid 275 for just head gasket,,and 5 bucks per bolt...

 

[topless03svt]

The head change kit itself was 135.00. Came with both head gaskets, all 20 bolts, and exhaust manifold gaskets. i had to also get the intake gaskets, metal blower mounting gasket, valve cover o rings, plug seals, timing cover o rings, front cam bolts and crankshaft bolt. It was all together just under 200.00 tax and all. I have a long time fiend who works at the local ford dealership. I'm not sure if he gave me a discount or not. I never asked for onr. I just assumed it was at retail. Not sure whether the head install kit was for a supercharged car but he is the same guy who has owned two 03 cobras and is going to help me time the car so i assume he knows which kit to get. Guess i better call him tomorrow and make sure......LOL

 

[333arod333]

To inspect the piston I just reinstalled the crankshaft bolt by by hand. Then turned the motor over with a ratchet/socket until that piston was all the way down. I felt the cylinder walls by hand. No gouges or scratching. I also made sure there was no ring/piston play by trying to wiggle the piston back and forth with the piston at the bottom and the top. No play what so ever. Now I know there are more precise tests you can perform but that was just a quick test. I didnt want to spend too nuch time fretting over the cylinder until I had the head/valves tested because I was still pretty sure that was my issue. But not feeling any rough gouges or scratches made me feel a lot better. Also, I got in there with a flash light and checked to see if the cross hatch marks were still visible. They were easily visible, so that told me I had very little if any cylinder wall worn down.

Ok cool I guess I'll look for the same in cylinder wall. anything else i should b inspecting?

what direction did u turn the crank in to be safe?

Why did u reinstall the crankbolt by hand or y did u even remove it, just because u got a new one?

Did u have to drain coolant or anything to remove heads?

Anyone got recommendations on what gasket sets to use when reinstalling? Which gaskets will i need new anyway? i saw u used a set but also needed other gaskets but im guessing u only need the ones in the set unless others r really damaged.

And DEFINITELY A COOLING MOD while heads r off for sure but thats extra easy to install if the heads are off right? i read something about trans bellhousing but im thinking its just installation in rear of driver head.

Sorry for the newb q's but i really want to get schooled on this head removal and reinstall after machine work. even disassembly of heads to see where problem valves are and inspection of other parts. Thanks guys i really appreciate the help.

 

[topless03svt]

You will have to turn the crankshaft bolt to the right, otherwise it will just thread back out. Dont worry about tightening the bolt. No need. Just run in by hand until you can't turn it anymore. Put ratchet on and the motor will turn over very easily. I had to remove the crankshaft bolt because you have to pull the timing cover off to get the heads off. Therefore you also have to remove the harmonic balancer(which is held on by the crankshaft bolt). The biggest pain I ran into was removing the accessory pulley and bracket that are right in front of the harmonic balancer. It takes a 14mm hex head tool. I finally tracked one down and that thing was super tight. I ended up putting a breaker bar on the socket, Then used a jack to raise up on the breaker bar handle. I didnt think it would ever break loose. Then finally it popped and the bracket/pulley spun right off. Send me a pm if you want. Ill give you my cell #. I dont mind helping you with any questions you may have. My name is Matt.

 

[333arod333]

You will have to turn the crankshaft bolt to the right, otherwise it will just thread back out. Dont worry about tightening the bolt. No need. Just run in by hand until you can't turn it anymore. Put ratchet on and the motor will turn over very easily. I had to remove the crankshaft bolt because you have to pull the timing cover off to get the heads off. Therefore you also have to remove the harmonic balancer(which is held on by the crankshaft bolt). The biggest pain I ran into was removing the accessory pulley and bracket that are right in front of the harmonic balancer. It takes a 14mm hex head tool. I finally tracked one down and that thing was super tight. I ended up putting a breaker bar on the socket, Then used a jack to raise up on the breaker bar handle. I didnt think it would ever break loose. Then finally it popped and the bracket/pulley spun right off. Send me a pm if you want. Ill give you my cell #. I dont mind helping you with any questions you may have. My name is Matt.

Thanks Matt my name is Alex. I sent u a pm.

Anyone know if any gasket set is superior or what cooling mod is the best on the market now?

 

[topless03svt]

i ordered the Gen 2 kit from lethal performance for 120.00. It said it used an o ring seal and retainng plate to secure it in the cylinder head. Says it can also be installed without removing the blower or transmission.

 

[333arod333]

i ordered the Gen 2 kit from lethal performance for 120.00. It said it used an o ring seal and retainng plate to secure it in the cylinder head. Says it can also be installed without removing the blower or transmission.

Sick, Ill try that out.

 

[cobra=trouble]

Did you pull the piston out. The one with the lowest compression? Mine where stuck on #6, Eben though. The bore looked.fine with the piston in still. The revised new Ford heads are 2200.bucks for both I got them I got a good set of 03 cobra heads ready to bolt on. Cheap. Pm me. I just wanted more plug threads. I went with my sig below. Bigger is better. Heads 300.00 bucks complete.for.both.

 

[700hp04Mystic]

i wanted to post this and get some opinions. my car has 101k miles and just done a compression check today so any advice would be good.
cyl. 1 180 cyl. 5 175
cyl . 2 180 cyl. 6 170
cyl. 3 185 cyl. 7 175
cyl 4 185 cyl. 8 180
does everything seem to be fine or is cyl 6 seem to low. thanks for any input....

 

[Quick Strike]

Seems very good for any mileage.