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Discussion Starter · #1 ·
About a month a go i had an issue with the cobra. Compression was low, so i stripped engine apart and found out i have a broken piston. The outer wall was a little scored, and there was a little bit of scoring and damage to the head. Everything else is ok... but my question is this. My buddy told me that i could take it to a machinist and have it checked out. If everything else looks ok... then i could have him smooth out the scoring on the outer wall, and the head. Also i would have him install a new piston since i think i know someone that might give me one for "FREE". Is this a better route or should I purchae a new shortblock??? How much are shortblocks?? I was told that i could probably have mine fixed for about a $1000.00$. But if i could buy one for cheap... that might be better. Below are some pics of the head and the psiton. Could not really get good pics of the outer wall but the scoring there is very small and it's twowards the top. Thanks!
 

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1965 SPF 427 Cobra, & 2022 BMW M850
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You didn't break a piston. You detonated your engine, blew the top ring land off the piston and then proceeded to melt the aluminum pieces that were flying about the combustion chamber.

You need to get new pistons and rings, bore the engine fitting the pistons to their individual bores, balance the crank, do the valves, get new bearings and a new oil pump and figure out why you detonated your engine in the first place and then fix it before you do it to yourself all over again.

As you can see the repair is both extensive and expensive. You are looking at significantly more than a thousand dollars. The reasons for the detonation can be all over the map but I would check my tune and fuel delivery system(s) for starters especially if you have modified anything like cams, blower, fuel pumps/delivery system etc. I would also also give serious thought to acquiring one of theses devices click here => http://www.jandssafeguard.com/VampirePage/J&S_Vampire.html It is the only product available from anyone today that can detect and correct for detonation on a cylinder by cylinder basis in real time while you drive. Most important it will prevent the damage you now have to pay your hard earned dollars to repair.

Ed

<Begin Edit> p.s. If you do not have 8/9 thread plug holes this is the time to fix that problem before it bites you. The fix is Lock-n-Stitch thread repair. Both Heli-Coil and Timesert have alternative repairs both are good repairs - Lock-n-Stitch is better. Lock-n-Stitch is the recommended repair from Ford. It will cost you about $450 to have someone do it. About $100 for you to do it yourself and $650 or so for the tooling if you choose to buy it. One of the board members has already bought the tooling and has offered to let anyone who needs the repair borrow his tooling instead going through the expense of purchasing their own. Search Thread repair or Lock-n-Stitch and you'll find him. <End Edit>
 

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Discussion Starter · #3 ·
Thanks for the input... and yeah i'm prett sure it was the tune that caused this in the first place.
 

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To add, you can't just bore out a cylinder and replace it with a stock piston. You will need to bore out all the cylinders and get a set of aftermarket pistons.
 

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When I first saw the head, I thought that looks like detonation. Then I saw the piston and the one to the right of it. Both are speckled.

Ouch.
 

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svtoa-nashville
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:( ouch that sucks d0oD me & you are in the same boat. i also tried to go down the " just fix what broke" route its not cheaper & the risk of it happing again
 

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1965 SPF 427 Cobra, & 2022 BMW M850
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Pro-Active Detonation Deterrence

When you have engines like we have you are usually aware of the dangers of detonation but most of us are lulled into a type of secure complacency that persuades us that the only guys that are at risk are the highly modified engines. As it turns out nothing could be further from the truth when you drive a car with a blown gas engine.

If your alternator is in its final death throws (Cobra's never kill alternators - right?) but hasn't yet given up the ghost you will probably be OK as long as you don't get into it. If you do everybody (fuel pumps, ignition, ecu, headlights, stereo, KB BAP, KB BAS) wants electrical power. Guess what happens if the electric fuel pumps get short sheeted?

Ignore the potential electrical problem scenario. Suppose you are out with the guys or just hunting for that last Z06 to make you feel good for the evening. Suddenly you notice its time to find gas. The trap is the pump that says 93 has stale gas or old gas and you don't know ... Maybe you were going to play it safe and throw in two bottles of Torco except you did that two nights ago and after all the Honey Doos you forgot to pick up more Torco.

I think you get the picture. The solution is something made by J&S Electronics. It detects and corrects knock (detonation) on a cylinder by cylinder basis in real time while the engine is under power! Nothing else out there even comes close. Check out the website click here => http://www.jandssafeguard.com/VampirePage/J&S_Vampire.html Read the testimonials at the top left/center of the page.

They say any sufficiently advanced technology is virtually indistinguishable from magic. Watching this thing work you think it is magic. It can save your motor when you find yourself caught in one of those ambushes I listed in paragraph 2 and 3. This one is the Real McCoy! FWIW it's as easy to install as a BAP or BAS.

Ed
 

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svtoa-nashville
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^^^ yea i talked to a friend about that product

& yea the alt is what killed my car
 

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Ford sells cobra longblocks for around $3,700 delivered. MMR can get you a new short block for around $3,000.
 

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Discussion Starter · #13 ·
I have a bap. I have a 2.3l whipple nex gen, 60lb injectors, ngk tr7 spark plugs, jlt rai, acufab tb, x pipe, MAFIA... Can't think of anything else. Is it best to just replace the shortblock??? And if so... how much am i lookin at $$$$??
 

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Discussion Starter · #15 ·
Do you have the contact info to MMR. I went to the site, but i did not see contact info. I would like to contact these guys first and at least talk to someone.
 

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i replaced mine because of spark plug blow out on on eof the cylinders tore everything apart and the shortblock looks perfect only the head needed a heli coil but the shop i took it to said it made since that if the motor was apart that now was a good time if i wanted to put in something better so i ordered a mmr950.....i have 9k on the new engine and it runs great an d have a great spare shortblock for another project. i think my s/b with arp 2k everything was like $3200 and have them grind down a boss that sits in the intake valley beforehand fyi.
 

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1965 SPF 427 Cobra, & 2022 BMW M850
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Shortblock Rebuild

I have a bap. I have a 2.3l whipple nex gen, 60lb injectors, ngk tr7 spark plugs, jlt rai, acufab tb, x pipe, MAFIA... Can't think of anything else. Is it best to just replace the shortblock??? And if so... how much am i lookin at $$$$??
408snake,

If you are budgetarily limited (like most of us) and not likely to get a Gov't bailout check for blown engines (gosh thats a good idea) then I would give some consideration to rebuilding yours. In fact I would give serious thought to doing it yourself even if you never did it before - its not hard to do!

The cost to you will be the least, the knowledge you pick up will be priceless and the effort is easier than pulling the motor. If you think you are going to take a swipe at it yourself the first thing I would do (no hissing here guys) go get Sean Hyland's DVD on engine assembly. Regardless of your opinion of Hyland the DVD is GREAT!

After you have watched the DVD you will see just what it takes to assemble the engine and how to do it. You won't be running blind. Neatest part - when you're all done you can say with authority and pride it's all mine!

As someone once said, 'Try it , you'll like it.'

Ed

<Begin Edit> This time give some hard thought to that J&S knock detection/prevention product. It's a lot cheaper than a blown engine.<End Edit>
 

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408snake,

If you are budgetarily limited (like most of us) and not likely to get a Gov't bailout check for blown engines (gosh thats a good idea) then I would give some consideration to rebuilding yours. In fact I would give serious thought to doing it yourself even if you never did it before - its not hard to do!

The cost to you will be the least, the knowledge you pick up will be priceless and the effort is easier than pulling the motor. If you think you are going to take a swipe at it yourself the first thing I would do (no hissing here guys) go get Sean Hyland's DVD on engine assembly. Regardless of your opinion of Hyland the DVD is GREAT!

After you have watched the DVD you will see just what it takes to assemble the engine and how to do it. You won't be running blind. Neatest part - when you're all done you can say with authority and pride it's all mine!

As someone once said, 'Try it , you'll like it.'

Ed

<Begin Edit> This time give some hard thought to that J&S knock detection/prevention product. It's a lot cheaper than a blown engine.<End Edit>
I agree 100%. For people that has never opened a motor, they think it will take a rocket scientist to rebuild it. Once your in the motor you will see how it works. After your done you will come away with so much more knowledge!
I would of rebuilt mine if I stayed with the iron block. Heck, even the motor that is in my Z I rebuilt it in my garage and it has over 10K miles on it already with great compression.
 

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Discussion Starter · #19 ·
Once again... Thanks. I have a buddy of mine who helped me rip apart the motor. Guy really knows his stuff since he had a cobra once upon a time, and built it up himself. He actualy knows a machinist that is reputable out of hayward. He has sugested that we have him take a look at everything and see what other damage was done. Then i could really see how much this is going to cost. i will grab that dvd as soon as i get a chance You mentioned that it would be considerably cheaper. Can you give me a quote, considering what you have seen from my pics? Thanks!!! Wait... Obama's not giving me a bailout check for my blown engine??? DAM him!!! haha.. jk.
408snake,

If you are budgetarily limited (like most of us) and not likely to get a Gov't bailout check for blown engines (gosh thats a good idea) then I would give some consideration to rebuilding yours. In fact I would give serious thought to doing it yourself even if you never did it before - its not hard to do!

The cost to you will be the least, the knowledge you pick up will be priceless and the effort is easier than pulling the motor. If you think you are going to take a swipe at it yourself the first thing I would do (no hissing here guys) go get Sean Hyland's DVD on engine assembly. Regardless of your opinion of Hyland the DVD is GREAT!

After you have watched the DVD you will see just what it takes to assemble the engine and how to do it. You won't be running blind. Neatest part - when you're all done you can say with authority and pride it's all mine!

As someone once said, 'Try it , you'll like it.'

Ed

<Begin Edit> This time give some hard thought to that J&S knock detection/prevention product. It's a lot cheaper than a blown engine.<End Edit>
 

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If you think you are going to take a swipe at it yourself the first thing I would do (no hissing here guys) go get Sean Hyland's DVD on engine assembly. Regardless of your opinion of Hyland the DVD is GREAT!

where can the DVD be purchased?
 
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