Bottom end 99 Cobra...

[WarriorStang]

Hey everyone,

New to the forum. I don't personally own a Mustang but my old man does and he's a bit slow when it comes to computers. Here is the situation:

The car was purchased used a long while back with low mileage. The car now sits at 97k with a bottom end issue. It started doing its clunking/knocking so we had a tech. tear it apart and found the crank bearings were spun out. They had checked over the bottom end a bit and put in some new OEM bearings and pieced the beast all back together. We were told to take it easy on the car (don't bring it over 4k rpm) for the first 500 miles and change the oil out. Before the 500 miles were up the same knock issue came back which we are assuming something had spun loose yet again. Now the car sits again with yet another bottom end issue at only 97k miles.

My father is mechanically inclined and has torn apart his fair share of motors, but "it's not as easy as it used to be", he says.

So my questions are;

Are the 99 Cobra stock bottom ends known to be bad?

If you were in the same situation (keeping in mind we don't have alot of money to fix this bad boy) what route would you take? OEM Long Block swap, rebuild bottom end with better parts, do the work ourselves.. etc etc

Also if there is any insight to recommended routes whether it be rebuild kits, deals on solid long blocks with bulkier bottom ends.


Pretty much any insight at this point would help out.

Thanks

 

[slayr281]

I've been down that expensive road, same exact thing. I had rod knock on my 98's Teksid, replaced it with somebody's 99 Cobra shortblock. Barely two weeks later and ONE tank of gas (200 miles later), blew it up on the highway.

Problem for me, was that we used the same oil pump. We assumed it was good, and it was, but apparently it worked just enough to barely get it going, and didn't have the full flow necessary at higher and regular operating rpms.

Granted, our wallets may be different, but I went and got the short block built to the hilt with quality parts, which in hindsight, I really should have done the first time. When you consider the cost of the two motors I blew vs the cost of the new shortblock build, I still would have come out ahead. Definitely... rather, must replace the oil pump, which pisses me off knowing that a what, $299 pump blew a $5000 motor. They're not a great quality, and have numerous threads about their failure leading to engine deaths.

I would not advise building it with OEM parts. The 96-01 Cobras have exceptional blocks and cranks, but rather low quality rods and pistons, which I find especially insulting given what the Cobra is capable of. Ford forged the 2003-2004 Cobra rotating assemblies, which they really should have done in the first place. Mahle and Manley make great strong rotating assemblies which are pretty good bang for the buck.

I'm not sure where you are, but if you're on other boards, see if you can't find a wrecked 2003-2004 Cobra. Most often, the most desirable and popular things being salvaged are the seats, T-56 transmission, and the complete motors for $4-6k, which depending if the blower is spoken for or not.

 

[WarriorStang]

Sucks to hear that. Yeah, this car is being a pain. Hes putting around in this oldschool 850 volvo now and hes just mad at the fact the motor is having the issue again and doesn't want to dump all kinds of money into it again. Basically the cheapest bang for the buck is what hes looking for now, even if its putting in OEM parts and only getting another 90k out of it.

If anyone has any ideas feel free to lend a hand with a link of some sort on a rebuild kit. Or if anyone knows any reliable places to get an engine rebuilt for a reasonable price in the North East (New England) that would be awesome too..

Thanks,
- Steve

 

[Smokeurhonda]

Well first I would ask if the work was done correctly. If you spin bearing it can usually lead to crank scoring. If the crank is not resurfaced, it will spin again. But I really don't have all the information i need to tell you what happened without seeing it myself. Granted, sometime bearings just spin, fact of life. Anyway I would recommend finding a complete longblock out of a wrecked 99-01 car. You could prob find one for $1500-$2000. Then just pull the motor yourselves and drop the new one in. That way you don't have to worry about swaping heads and ****. It isn't that hard to swap the heads but then you have to buy a top end gasket kit. Don't let your dad be intimidated by the mess of stuff under the hood. If you guys have power tools and know your way around a car you should be fine.

 

[WarriorStang]

Well first I would ask if the work was done correctly. If you spin bearing it can usually lead to crank scoring. If the crank is not resurfaced, it will spin again. But I really don't have all the information i need to tell you what happened without seeing it myself. Granted, sometime bearings just spin, fact of life. Anyway I would recommend finding a complete longblock out of a wrecked 99-01 car. You could prob find one for $1500-$2000. Then just pull the motor yourselves and drop the new one in. That way you don't have to worry about swaping heads and ****. It isn't that hard to swap the heads but then you have to buy a top end gasket kit. Don't let your dad be intimidated by the mess of stuff under the hood. If you guys have power tools and know your way around a car you should be fine.

As far as the work that was done. He has a friend who works at a shop do it as a side job for him. He said that he polished the crank down and put new bearings. Which I'm assuming means he didn't get it sent out to have it resurfaced. But just like the above post, it was about 300 miles and the engine started knocking again.

Finding a long block out of a wrecked car would be ideal i suppose. Who knows how bad the motor was beat on, and if the maintenance was done properly, etc. Always creates worries when your buying used.

If i showed you a picture of the old bearing would it help you decide if the crank should have been resurfaced? I'm sure he has them lying around somewhere.