4.6L DOHC

stampede3

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Matt94GT said:
well either way they are wicked motors, whats the diff between the 98 Cobra motor and 03 Cobra, sorry for being a iggnorant but im a 5.0 guy.

Oh god, where to start,

Block, pistons, rods, heads, blower.
The only thing they share is the crank.
 

CY98Cobra

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Read and learn Matt ;)

The 96-98 DOHC motor is an all aluminum engine. The block is made by a company called Teksid. This is an Italian company that also makes blocks for Ferrari. The block has been used in many high powered applications, including John Mihovets (sp?) 6 sec. Cougar. The block and forged crank can withstand serious power stock, the myth saying around 1000 hp. The DOHC also features six bolt mains.

The rods and pistons are powdered metal with cracked rod caps. These are the weak links in the engine. Though they are fine in an N/A application they were never designed for FI.

The heads feature two intake valves and two exhaust valves. Each intake valve has it's own runner/port while the exhaust valves use one common port. The dual intake runners are quite large and not the best for an N/A application. To help boost low end power production there is an Intake Manifold Runner Control (IMRC's, you will hear alot about these when discussing the 96-98 Cobras) inbetween the intake manifold and the heads. The IMRC has a butterfly that blocks one of the ports/intake valves at each cylinder. At 3250 rpms a controller under the intake opens these butterflies to allow full airflow to all 4 intake valves. This is what gives the 4 valve it's top end pull and noticeable increase in power.

The DOHC engines also feature an oil cooler, high volume oil pump and a windage tray. These all help to keep the engine well lubricated since the heads need a ton of oil to lubricate the valvetrain. Though it's only recommended to run 6 quarts alot of people run 6.5 or 7 to help keep the pump submersed while driving aggresively. The pan has plenty of room to run the additional oil without the crank swimming in it. Unlike the 5.0's where it was common to drop a quart in order to gain some power, the 4 valve requires every bit of 6 quarts due to the amount the heads hold.

I think that's about all. If anybody ever wants to learn more about these great engines you can visit any of the forums or pick up a copy of Sean Hylands book on building 4 valves. There is some great info in there.
 

stampede3

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Good lord CY, I gave the short version.
I sure hope you copied and pasted that.
 

stampede3

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I guess we should copy the FAQ stuff and sticky it.
Gonna start tomorrow, got to go to bed, 2:30 am comes quick.
 

CY98Cobra

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stampede3 said:
Good lord CY, I gave the short version.
I sure hope you copied and pasted that.

Nope, no copy and paste. No homework tonight so I had some time :)

I thought about discussing the differences between the terminators since Matt mentioned them but this is the 94-98 site.
 

CManT1914

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CY98Cobra said:
I thought about discussing the differences between the terminators since Matt mentioned them but this is the 94-98 site.

I'd still be interested in hearing that. I'm a 5.0 guy too, and found your info quite informative.
 

Peter

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03/04 4.6 DOHC = one of the best bang for the buck motors ever made

blown or not
 

Peter

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lol same thing

if I play my cards right I might be able to get a new toy in about 6 months but its a pretty big maybe but an SVT maybe ;D
 

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