97 Cobra Engine Rebuild - Page 2 - MustangForums.com

4.6L (1996-2004 Modular) Mustang Technical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within.

97 Cobra Engine Rebuild

Reply

 
 
 
Old 01-26-2006, 06:36 PM
  #11  
MikeHawke
Retired MF Moderator
 
Join Date: Apr 2004
Location: I live in Canada, eh
Posts: 7,157
Default RE: 97 Cobra Engine Rebuild

good info asmall. Glad you could join us.

Good luck on the project.
MikeHawke is offline  
Reply With Quote
Old 01-31-2006, 11:59 PM
  #12  
asmall
1st Gear Member
Thread Starter
 
Join Date: Nov 2005
Location:
Posts: 72
Default RE: 97 Cobra Engine Rebuild

For anyone looking to Supercharge thier car, there are some real concerns with detonation, tuning, and intercooler functionality. In my setup, as I mentioned earlier, I chose the Procharger PS1C. It has a very distinctive sound... much like a vacuum cleaner. No one misses it. Anyone who thinks they are installing a centrifugal charger and not going to turn heads (like me... I wanted it to be more of a sleeper) are fooling themselves. You might fool a few, but anyone that knows cars will instantly recognize that whirrr... am I wrong here?

My particular set up works well. At 6500 RPM I am noticing about 9 pounds of boost, apparently the ATI intercooler flows well. Additionally, I bypassed the ATI FMU and went with a custom tune, larger MAF meter (and a blow through style, rather than the stock suck through), and bigger injectors.

If I were going to install a supercharger again, or if anyone else decides to install one, I would give some serious thought to a system that does not have an intercooler, but instead relies on a chemical injection of methonal and water. If I install another system in my car, I will be using this set up over the intercooler for a few reasons.

1) The install of the Supercharger is much easier... no let me repharase that... MUCH MUCH easier!! The plumbing for the air to get to the intercooler, then from the intercooler to the intake takes up a lot of room... additionally, it usually requires you to move a lot of things, like power steering tubes, coolant resevoirs, emissions control equipement, some times the battery.

2) All that duct work and the intercooler blocks airflow. As a result, you are giving up some of the potential of your system... how much? Well, lets look at mine. it is a 10psi system, so lets assume I get 10psi at 6500. The intercooler on my set up blocks about 1psi... I got 260 hp before the s/c... theoretically, with 9psi, I am adding and additional 9/15 of an atmosphere to the cylinders, or about 60% more air. With 60% more air, I should get about 60% more power. My final dyno results were 408 rwhp or an increase of 56%. fairly close, but you have to expect more loss due to cylinder design, exhaust, so on. so 9 psi gave me 56% or in other words, 6.22% (16.22 hp/pound of boost). So if the intercooler was not in the way, I would get 424 rwhp.

3) The intake air charge using the chemical injection system gets as cold or colder than that of the intercooler. As a result, the tune can be more aggressive without the concern with high intake air temps causing detonation.

4) Methonal acts as an Ocane boost, and it has some combustion energy. Since it resists detonation, it allows a more aggressive tune without the risk of doing damage with detonation.

There are some downsides to the system though, and some precautions to take. The biggest draw back is that you have a tank that you need to fill. This risk can be mitigated by using a low level sensor and a warning light. Luckily, the systems I have seen tested don't burn through the tank very quickly. Also, it is a mechanical system that can break. if for some reason the spray does not come on and intake temps shoot up, you need to make sure you know. An intake temp gauge is a must in my opinion. I would also go with a wideband O2 sensor and gauge in the car to monitor the A/F ratio.

So there you have it, that is what I would do in the future.

As for what I have now, the block and heads are going to the machine shop this weekend for a .020 bore, and deck work. The heads are being stripped down and cleaned, then returned to me so that I can port them out.

Cheers!
asmall is offline  
Reply With Quote
Old 02-07-2006, 12:59 AM
  #13  
asmall
1st Gear Member
Thread Starter
 
Join Date: Nov 2005
Location:
Posts: 72
Default RE: 97 Cobra Engine Rebuild

The block just went out to the machine shop to be bored and cleaned up. Here are some things to consider when rebuilding a high performance 4.6L

The aluminum block has cast iron sleeves in it as a wear surface for the rings. From what I have read, these can be bored out to about .030 without significant risk. The aluminum block is interesting in that when the heads are bolted on and fully torques down, it actually changes the shape of the block slightly. For this reason, if you bore this engine out for high performance applications, it is important that the machine shop use the torque plate (basically a head with holes to apply the same load to the block).

As for boring, here is what you need to consider if trying to determine if you should bore or just hone. If the engine has many miles on it, the cylinder will wear a little. Sometimes a bit more in one spot than another. For this reason, when the cylinders are honed, the cylinders are trued a little, but they are also opened up a little. If the cylinder was a standard bore, and had a standard size piston, then you wear the liner out a bit and hone a bit off and slap a standard piston back in, it makes sense that the piston would now be a bit looser in the cylinder. Rings might not take a good seat, and you may get piston slap (that is the piston kncking around in the loose bore as it moves). To ensure a nice fit, have the cylinder bored to within a few thousands of the final bore size, then hone it to the final spec, depending on the pistons.

Make sure you get the deck checked also. If it is not square for some reason, you maye devolop leaks from your head gasket when you go to put your engine back togehter.

The speed shop I am getting my work done at is going to set up the block for the machine work and do the rough bore, but are going to wait until the pistons come in and hone up each cylinder to match the piston. After that, they are going to weigh the pistons and balance and polish the Cobra Steel crank, which is good for a lot of power.

Cheers
asmall is offline  
Reply With Quote
Old 02-10-2006, 03:07 PM
  #14  
jlauth
2nd Gear Member
 
Join Date: Sep 2005
Location:
Posts: 357
Default RE: 97 Cobra Engine Rebuild

Great posts man keep it up. I like to read stuff that i can learn from.
jlauth is offline  
Reply With Quote
Old 02-21-2006, 12:02 AM
  #15  
asmall
1st Gear Member
Thread Starter
 
Join Date: Nov 2005
Location:
Posts: 72
Default RE: 97 Cobra Engine Rebuild

The heads have been stripped down, and taken to the machine shop where they were desprung and cleaned. Hard to believe there were actually heads under all that carbon and dirt! I'll post some pictures of them next time I get out there.

The work to the heads will consist of some minor porting, polishing, and blueprinting. I am going to start by laying back the edge of the primary intake runner right near the intake valve. With this I plan to ease the air into the valve, rather than force it around that sharp bend (when I get pictures, you will know what I mean). I also plan to smooth up the intake and exhaust runners a bit, 80 grit on the intake, 100 grit on the exhaust. There are a whole bunch of theories about porting and polishing, so I can't possibly cover everything. Basically, the goal is to make the air flow as straight and easy as possible... how this is done is something of an art, from what I am told.

Additionally, I am going to mount the headers (when they arrive) to the heads and look in to see how they line up. Bluing might help, but what I don’t want is to have the exhaust come out of the port and hit an edge. I am going to ensure that doesn't happen. I am going to try to do the same with the intake... somehow. I'll figure that out and pass it on.

I am going to remove all the flashing from the cooling ports, and then take the heads back to the machine shop where they are going to install the new valve guides, perform a 3 angle valve job, and install the new stainless steel valves.

OK, for porting, here are a few good links that I came across:
http://www.sa-motorsports.com/diyport.shtm

http://www.chevyhiperformance.com/techarticles/95518/

http://www.fordmuscle.com/archives/2...ng/index.shtml

http://www.sullivanperformance.com/Y...tech/tech1.htm

http://www.fespecialties.com/HTML/Photo-HeadPort.html

http://www.fordmuscle.com/archives/2...ow/index.shtml

http://www.directmotion.com/images/pic/0632.jpg
http://www.directmotion.com/images/pic/0682.jpg

Some of these sites are more for general head construction, others for pictures of a ported heads. I will use all this information to figure out how I am going to port mine... but you can see the extreme porting from th CNC machine in the last two.






asmall is offline  
Reply With Quote
Old 02-23-2006, 08:54 PM
  #16  
Jglisson
3rd Gear Member
 
Join Date: Apr 2005
Posts: 607
Default RE: 97 Cobra Engine Rebuild

asmall,

I did the same thing to my GT. I am not sure what exactly happened, but I popped my motor regardless. I have a 2001 Police C.V. Interceptor in there now. I am finishing bolting it up as I type. I am debating what to do with my original motor. Piston #7 has a nice clean 2" burn down to the top compression ring. Both head gaskets blew as well. 6 out of the 8 cylinders have no wear at all. I am considering my options.

How much would a bore cost? Any ideas?
Jglisson is offline  
Reply With Quote
Old 02-23-2006, 11:41 PM
  #17  
asmall
1st Gear Member
Thread Starter
 
Join Date: Nov 2005
Location:
Posts: 72
Default RE: 97 Cobra Engine Rebuild

The bore, using the torque plate because of the aluminum block, will cost me $400, which includes a hone to match each piston to the cylinder. The 3 angle valve job, including new bronze valve guides is going to cost me 950.

How did you blow your moter? Was it S/Ced? If you got into some serious detonation, I can see it blowing out the head gaskets and doing the damage you described. It doesn't take much to damage the stock engine.
asmall is offline  
Reply With Quote
Old 02-24-2006, 08:39 PM
  #18  
Jglisson
3rd Gear Member
 
Join Date: Apr 2005
Posts: 607
Default RE: 97 Cobra Engine Rebuild

No...I was running 100shot nitrous. It didn't break on me when I was spraying. I think I only sprayed a total of 6 times. Not sure what the problem is? What are you looking at total?

I mean...you have to pay for the bore, head work, piston kit, reassembly, etc. Assuming you pull and install...what will it cost to build the motor?
Jglisson is offline  
Reply With Quote
Old 02-25-2006, 09:59 AM
  #19  
asmall
1st Gear Member
Thread Starter
 
Join Date: Nov 2005
Location:
Posts: 72
Default RE: 97 Cobra Engine Rebuild

The 100 shot may have done it to you. It does not take much to wreck the stock bottom end of the Mustangs with the Hypereuretic pistons. As for me, when the ring lands broke, I didn't notice right away. I never heard a bang, or any other sound. I only noticed that smoke came out of the tailpipe when I started it. Later I noticed the smoke when I revved it. Then lastly, I noticed the smoke on a hard acceleration... then the light came on while she was idling in my garage. But to answer your question:

Yes, most of the work is being done by me. I am not doing the things like machining, etc.

Bore/Hone w/ torque plate: 310 (I misspoke earlier, it is 400 with deckwork)
Complete 3 angle valve job, includinge new bronze valve guides and Manely valves - 1600
Porting (Street P&P, I am doing this myself)- about 500
Crankshaft Micropolish and balance - 220
So my total machine work bill is going to be about 2130 (including 900 worth of valves and guides)

Engine Parts:
Complete rotating assembly minus a new crankshaft (I have the cobra steel one, the cast iron one in the gt would need to be replaced also) - 1500
Upper Gasket Kit - 335
Lower Gasket Kit - 60
ARP Stud Kits - 550
New primary timing chains - 80
New secondary timing chains - 50
Billet oil pump gears - 250
Radiator hose replacements - 60
Primary chain tensioners - 60
Secondary chain tensioners - 280 The tensioners may be alright... they are hydraulic, so I may not replace them)
Upgraded fuel rail - ?
Engine mounts (stock - 60) (race -150)
Billet trigger wheel - 90

And I think that is it for engine components... I am sure I missed something... total - about 3100 for a tough as nails engine (all forged).

Other components for HP - Long tube headers (hooker) 600
H-Midpipe w/ high flow cats - 350
Cat back exhaust - 500
King Cobra or centerforce clutch - 200
wideband O2 with 0-1v output channels (car) and 0-5v output channel (gauge) - 500
3.77 or 4.10 gear set - 200 (+ installation)
4 new wheels (about 800)
New rear tires (285 X 17 or similar) - 500 ish

Total- 3850

Other items

Full functional, NHRA legal 6 point gloss black roll bar w/ removable side bars. - 500 ish
Dual Air Temp gauges (one for intake, one for S/C output prior to I/C) - ?
Rear Suspension Upgrade - about 1000
Black racing stripes - 600
Rear bumper inserts (stainless steel) - 200

Total - 1900 to 2500

The next thing to go is going to be my transmission, or my rear end... I'll deal with that later. But a new TKO trannny costs about 1700... or thereabouts. And the rear end I'll replace with a tru-trac.

Hope this helps. I don't plan to do everything at once. The engine is top priority, dress up stuff is low on the list. To completely rebuild the engine and get the car going again, I am looking at about 6000.

Adam
asmall is offline  
Reply With Quote
Old 02-28-2006, 10:45 PM
  #20  
Rantheman
3rd Gear Member
 
Join Date: Feb 2006
Location:
Posts: 563
Default RE: 97 Cobra Engine Rebuild

hey good luck with the build i just finished my 96 mustang gt with a pi head conversion so hop everything goes well here a couple of pics for you.
Rantheman is offline  
Reply With Quote
Reply
 
 
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Granatelli Sales
The New S550 2015-2020 Mustang
21
04-27-2017 01:33 PM
MustangForums Editor
Mustang News, Concepts, Rumors & Discussion
3
11-10-2015 11:39 AM
mdj89
The New S550 2015-2020 Mustang
2
09-06-2015 11:08 PM
raleigh05GTO
New Member Area
5
09-04-2015 07:09 AM

Forum Jump

Thread Tools
Search this Thread
Advertising
Featured Sponsors
Vendor Directory