Automotive → Re: 99 Ford Mustang Cobra

Did you check if air is coming out of the radiator overflow? (leak into coolant.)

You cant check that on that vehicle. It only has a overflow tank with a small hose going from the rad to overflow tank. I would think a cracked head or block wouldnt allow it to hold vacuum? Whats your guys thought on maybe the intake valves not opening or something? It runs but its a dead miss on that cylinder. Plug looks like a tar compound on it.

Might also mention motor is a fresh build. Its my nephews car and he paid a professional mechanic to build it.

If you think a valve is not opening, pull the valve cover and look.

I have seen bad head gaskets hold vacuum. I still don't see why you cant see if there is air coming out the line to the overflow tank. There has to be a cap somewhere to fill. Put a pressure gauge on that (or borrow one made for testing coolant systems.)

The valve cover is going to be pulled next. Its not leaking coolant or running hot. Im not working on it he is. Like i told him the air has to be going somewhere.

Fresh build so get it warrantied lol why even fuck with it the guy screwed up on the build or a part went bad

So have the "professional" diagnose and fix it ?

He is away. Brother just called me. He took off the valve cover and the bolts holding the cam down are all loose and one is missing spewing oil out of it. Im not sure how this can equate to a number two cylinder losing compression but it sure doesnt say much for the mechanic that built it. He said the cam has wear now. Not sure what he means by wear. Im think maybe the missing bolt caused the lifter not to get oil. Now the problem is he ran it like that for a week or two.

Its a 99 cobra with the 03 cobra r motor. He should have stuck with the 99 motor which was perfectly fine. Nephew wanted the 03 cause its a blower motor. He purchased it from a friend and had the mechanic totally take it apart and reassemble it before putting it in the car. The mechanic charged him 500.00 to disassemble and reassemble it. I have a feeling it was the worse 500 bucks he ever spent. He is going to replace and torque the cams and see if it runs. We shall see. The motor alone is worth like 5 grand as a used engine.

Well a pro would give you some sort of warranty...

Also please stop messing with the motor if you do not understand how the cams being lose could give no compression in number 2...

Also you put vac in the cylinder, did you clear it before putting the plug back in?

Why would this guy "take it apart and reassemble" it? What was the point?

He took it apart to check the bearings and such. It was a used motor. Like i said its not your typical 1000.00 yard motor. Its a cobra motor. Factory blower motor in 2003 which is the only motor which was factory installed back than with a blower. He paid 5000.00 as a used motor. It was being prudent to have it checked. He took it all apart and checked it. Installed new bearings, rings and gaskets. Not sure what you mean by did he clear the vac. before he put it in. He pumped a vacuum pump and of course it cleared after he unhooked the vacuum pump. Heres one with 35000 miles on it for 7500 dollars. You dont pay 7500 for a used motor and just put it in. They sell kits for it to push 1100 horsepower out of it. The guy clearly screwed it up. But he is away on vacation for three weeks and to be honest you dont go back to him anyway. Not somebody that didnt torgue the cams down. Thats for sure and now what else did he screw up. Its a mildly blown factory motor. The idea was to install it factory and than do the conversion. Which is basically blower and injector swaps. »www.ebay.com/itm/35k-03- ··· 98&rt=nc

In the case of the cobra the engine makes the car. It why your going to pay 25000 dollars for a 12 year old cobra. If you can find one.

I really don't need to read 10000 times how much the motor was...

All "checking" the motor did was cause you issues... I hope that $500 did not include parts... and even at that $500, aint enough in labor to do that work...

You need to go to a machine shop now that BUILDS motors... and have them do a tear down and rebuild... $$$$$$$$

Head bolts could be torqued wrong, connecting rods... etc...

Hope he put the pistons back in the same cylinder when he took them out and ringed them LOL if that even happened...

Pulled a vacuum, I would never put the plug in with out turning the motor over to make sure if anything was sucked in it was expelled... like coolant... you know, don't want to blow a hole in the motor...

If you really think it is drop in the motor and go, oh god the problems you are gona run into..

I would bet the wiring harness is different, the computer has to be different...

Pretty much NOTHING is going to be interchangeable on those motors...

It was 500 plus parts. Uh the motor is running. The computer, fuel pumps, dash cluster including complete wiring harness. and all associated parts were changed out. I didnt think i needed to mention that since i stated the motor was running. The mechanic claimed he was experienced with the motor and we only used him to do the disassemble and check motor. He was suppose to install piston rings, rod and main bearings and gaskets and make sure all internal parts were good. He gave my brother a assembled motor that was supposedly ready to drop in. My brother took care of all the other issues regarding the swap. The camshaft is interchangable. j Just called the speed shop. 99 4.6 is the same as a 03 cam. Its about the only thing thats the same but its the same. Still dont know that he will swap it out. The bottom end is what was beefed up for the blower. The 2000 and 2001 and some 2002s are not the same cam. But the 99 has the same cam.

I think you misunderstood when i said it held vacuum. Brother installed hoses to the compression tester and used a hand vacuum pump which held at 5 pounds of vacuum when manually pumped up to 30 pounds. A usual way to check for cracks and such when the air to cylinder trick doesnt work.

Its actually a mustang feud between my son and my nephew. A 302 vs 4.6 thing. Son purchased a 348 stroker race block from ford and had a motor builder built that gets 794 hp at the wheels with automatic trans mustang. Now my nephew swears he can have a 4.6 factory engine with mods that can run up against it. Personally i doubt it. Son says he guarantees the 4.6 blows apart before he sees that kind of HP. We shall see.

One of my good friend worked in a machine shop a while ago, and he told me that you not supposed to install new bearings and rings in a *used engine* without additional work such as boring, honing, regrinding, resurfacing, etc. While the engine rebuilt such a way may appear to work well for a while, it will usually experience accelerated wear and the possibility of premature failures.

Well of course he is going to say that. He works for a machine shop. people have been taring good motors down and replacing rings and bearings on good motor for 50 years. In fact engines that are designed to go 500,000 plus have set intervals to do just that from the manufacture. Thats what you do with high dollar engines. Its considered a minor rebuild. Its what you do as preventive maintenance. Its also pretty common on high performance motors. Some race motors get rings and bearings after a couple of runs. Tractor trailors get minor rebuilds after about 300,000 miles or when ever its in a roll over accident. When trucks roll over its expected that the engine ran a couple of minutes with no oil pressure. Rather than wait for the motor to explode you pull it apart, inspect, and usually at least replace mains and rod bearings. If you pull the pistons and everything looks good there is no harm in honing and replacing the rings.

That doesn't necessarily mean it's a good and sound practice in all cases. People sometimes put sawdust into the rear differential ....

One case he particularly stressed were high mileage motors: a ring / bearing / gasket replacement normally restores most of the lost compression and will more or less cure other ailments due to loose bearings, but the wear after such partial rebuilds will be accelerated and there will be a much higher likelyhood of certain failures. (i.e. rings failing) Can you provide a few examples of this? I know and fully understand that race engines can be taken apart very frequently, and partially or fully rebuilt, but I think when that happens all "wear items" are inspected to make sure they are still within specs.