#2 piston is toast

[Hangman]

Well I got some real shitty news, I was with my dad doing some high speed runs to about 120 the other day, the problem was I didn't have alot of gas in it when we did the runs, after about the fourth run my dad said the pedal got soft at about 115-120, afterwards we filled it up with gas and took her home. From that point on I started to hear a loud ticking some coming from the passenger side head. Well after some research on the site I found what the culprit could be and took it to ford. #2 piston is in bad shape, it has scratched the side of the cylinder wall but not to bad though, there was some black gunk on top of the piston. The ford tech said the head still looks pretty good, springs look good. What do you guys think I can do in terms of fixing it?? I was planning on replacing the piston with new rings etc. And buttoning it back up and doing a compression test and making sire the valves are good, what do you think? Should the car be good to go after that? Any help would be great guys.

By the way, when the car was ticking, it still had full power and ran great, i only drove the car maybe 20 miles after the ticking sounds occured.

 

[Hangman]

I spoke to ford today, they said that the labor involved in fixing the motor is extensive and that a whole new motor would just be easier on me. I think that is a little over the top, i'm pretty sure my dad and i could fix that thing for alot cheaper. My father and i are not new to motor building, we have installed and put together the livernois 5.0 stroker motor for his 96 cobra and got it up and running just fine, so we have all of the neccesary tools and equipment to work on a motor. I am going to pick up the car today and take it home. We were talking about options for the car, here is a list that we have decided

1.) let ford drop a new motor in, $5,000.00 for motor + plus labor and other extra parts

2.) Replace just the damaged piston with all accesories and put it back together, change the oil, change the plugs and do a compression test on the motor. (cheapest way)

3.) Replace all of the pistons with a new forged set, change plugs and oil and compression test.

4.) Order new 298ci stroker rotating assembly and put her back together, change oil, change plugs and do a compression test.

Look guys, i know there are some great mechanics on this forums, i am asking for opinions on what you guys have seen before and what i should currently do. I need my car up and running, but i dont want to cut corners and just put a band aid on this, i want the car running strong, thanks again, i would appreciate the help.

 

[cbr repsol]

Running the car hard with not that much fuel is a:nonono: It most likely sloshed in the tank and the pump sucked air causing a lean condition. I think if you just put a new piston in the bore #2 cylinder its a bandaid fix, and wont seal correctly. detonation is also hard on engine bearings, that cylinder may need a overbore to get the correct piston to wall clearance and ensure the rings seat so you dont get blow-by. I would inspect all the bearings for wear and also plasti-gauge them to ensure they are within spec. I dont know the extent of the cylinder damage but if it need a bore and assuming the other 7 rods and pistons and bearings are fine. Rather than waste money on parts and boring all the cylinders . Have a sleeve inserted in the damaged cylinder,They bore the cylinder and insert the sleeve. The sleeve retains the stock bore of the block.(buy 1 new stock size piston with rings) You will have to completely take the motor apart but i think its your best option.If the crank has any damage or rods now would be the time to also have the crank machined and rods resized and get oversized engine bearings.There is no strength that is compromised with the use of a sleeve. Ive used them many times and still have engines ive built still running strong.

 

[20SVT03]

if you don't feel comfortable going into the motor then don't attempt it. the 4 valve motor has all kinds of parts inside. besides the short block there is nothing at all similar to a push rod motor except removing and reinstalling it. it sounds like you need to have the short block repaired at a machine shop because the cylinder wall is going to HAVE to be repaired. if you are at the point of it making noise there has been damage. its all really where you want to spend the money. for $5K you will also get a 3 year 100k mile warranty on a long block. if you buy a short block your gonna make up about $800-$1000 in labor and only have a 12/12 warranty plus still buy a short block. if you find a buddy that knows a buddy who just happens to work on cars then you can buy a beefied up long block or fix and beef up yours for $5k and pay him $800 to put it in.

 

[cohhbra]

Well you owning a cobra means you obviously love power, and want more power. So I think a brand beefed up stroker rotating assembly should be in your future. Also, like has already been stated if you just replace the piston something might happen again and that would suck even more. If you and your dad have built one cobra engine and it runs well I'm sure you can do it again.

I feel like for some reason only the hands of god can touch the terminator 4v engine but the other cobra 4v engines are a okay to be worked on. As long as you know what you're working with and what needs to be done then you're fine. But then again I have heard the engine was built by the hands of god and runs on the blood of christ.:burnout:

 

[wjurls]

I'm just going to say what I would do if it was my car. Keeping in mind I do all my own work except for machine shop work. Personally I would punch all holes .020 over and install some CP or Diamond pistons. Replace the bearings on the roatating assembly and depending on mileage send the heads in for a valve job.
What I recommend to you is to buy the longblock from Tousley Ford for $3900 and then you dont have to fool around with all the labor involved with setting the heads and cam timing. You also save on all the extra parts such as head gaskets, head bolts, other related gaskets and machine shop costs. Hell the long block even comes filled with oil and new plugs. I could do a long block swap in a single day if I have everything here.

 

[Hangman]

Running the car hard with not that much fuel is a:nonono: It most likely sloshed in the tank and the pump sucked air causing a lean condition. I think if you just put a new piston in the bore #2 cylinder its a bandaid fix, and wont seal correctly. detonation is also hard on engine bearings, that cylinder may need a overbore to get the correct piston to wall clearance and ensure the rings seat so you dont get blow-by. I would inspect all the bearings for wear and also plasti-gauge them to ensure they are within spec. I dont know the extent of the cylinder damage but if it need a bore and assuming the other 7 rods and pistons and bearings are fine. Rather than waste money on parts and boring all the cylinders . Have a sleeve inserted in the damaged cylinder,They bore the cylinder and insert the sleeve. The sleeve retains the stock bore of the block.(buy 1 new stock size piston with rings) You will have to completely take the motor apart but i think its your best option.If the crank has any damage or rods now would be the time to also have the crank machined and rods resized and get oversized engine bearings.There is no strength that is compromised with the use of a sleeve. Ive used them many times and still have engines ive built still running strong.

That seems like the appropriate route to take, but I feel that if I have to take the whole motor apart I might as well take it to the next step. I'm not sure, I guess I won't really know what MUST be done until we break down the motor ourselves. I will definitely post pictures and updates as we continue.

 

[Hangman]

One of the big pain in the asses for us is we really don't want to tear the whole motor apart, were gonna talk it over tomorrow and make a decision, I'll let you guys know what's up from there and maybe you guys can add some input from there, maybe with ideas on part selection and possibly install help. Thanks for the help so far.

 

[cbr repsol]

keep us posted.

 

[Hangman]

ok just for the update, i replaced the spark plug on my bad cylinder and put a brand new one in and i put some conventional oil in. The car still has the horrible tapping noise but that was expected, i know it wasnt going to fix it but i figured i would start with that. Again, the car still has full power and doesnt make any other noises than the tapping. It is parked and were still talking it over with what we want to do. The livernois 5.0 shortblock is starting to win us over though haha.

 

[20SVT03]

its probably piston slap. try unplugging the coil to that cylinder and if it goes away its piston slap or damaged rod bearings if it stays then its valve train

 

[Hangman]

thanks for the tip, i will try that and post results

 

[hotcobra03]

noise

in your first post you say you took car to ford and they say piston is cooked....than you say you just put in a plug..

question.. how far did ford go when pulling apart motor to see damage,,or did they just guess..


im in your shoes,,do all my own repairs and have had my drivers side head swallow a valve...

when i pulled apart this engine it was my first ever,,done swaps before but never heads...when mine was apart i seen scratches on all of my cylinder walls...

cylinder #6 was the bad valve problem,,it happened twice...piston has two large indentations on top


only parts replaced was the valve..i re installed everything else...

engine had 210k when second valve went now im at 267k...

i dont think 120 is really beating up on these cars

maybe its something small?

 

[Hangman]

When I took the car to ford they have a free general diagnosis, I was busy with work and didn't have the time to dig around and find the problem, all I initially did was jack the car up and listen around with a stethescope to try and isolate the sound, problem with that is no matter what the sound just bounces around like crazy under the car, it was frustrating.

I took it to ford and they said the sound was definitely coming from the passenger side of the motor, they asked permission to pull the valve covers and take a look, I ok'd it and they told me to stop by. The tech showed me my destroyed spark plug and used the borescope to look in on the damaged piston, all the others looked brand new, so now that I know what was wrong I took the car home and here I am.

 

[Hangman]

Update: we have decided on a plan for the car, were going to build another bottom end for my car, in the mean time I am going to drive my car just to work and back, it's my only car and I have to get to work. I'm goin to order a prepped short block and a stroker rotating assembly, once the bottom end is ready to go, gonna pull my motor and send the heads in for some port work and new cams, I know for sure there will be plenty of snags in the process and by no means plan on it being an easy process, but it will be a cool learning experience to build another motor and get my car running right, I've been saving for a while so we will see, plenty of other things to go with it, clutch, tubular k member, longtubes, ported blower and i have a zex kit already halfway installed on the car, gonna smack it with a 100 shot. Anyways, I wanna thank everyone with there help so far and I will certainly be asking questions along the way and posting pictures.